CN113124063B

CN113124063B - Dynamic pressure foil radial gas bearing cooling structure and cooling method

Info

Publication number: CN113124063B
Application number: CN202110462727.1A
Authority: CN
Inventors: 杨启超; 刘广彬; 车国铚; 赵远扬; 李连生
Original assignee: Qingdao University of Science and Technology
Current assignee: Qingdao University of Science and Technology
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2023-01-13
Anticipated expiration: 2041-04-28
Also published as: CN113124063A

Abstract

The invention belongs to the technical field of gas bearings, and particularly relates to a cooling structure and a cooling method suitable for a radial dynamic pressure foil gas bearing, wherein the cooling structure comprises a bearing seat and a shell sleeved on the bearing seat; the shell is provided with a cooling fluid inlet, the bearing seat is provided with one or more axial grooves for the cooling fluid to pass through, and the bearing seat is also provided with one or more air supply holes which penetrate through the bearing seat in a way of being vertical to the axis; the cooling structure further comprises a wave foil and a flat foil, and the shell, the bearing block, the wave foil and the flat foil are coaxially arranged from outside to inside in sequence. The structure increases the flow area of the cooling fluid, thereby improving the cooling effect; the cooling method using the cooling structure is applicable not only to a gas cooling medium but also to a liquid cooling medium such as a refrigerant.

Description

Dynamic pressure foil radial gas bearing cooling structure and cooling method

Technical Field

The invention belongs to the technical field of gas bearings, and particularly relates to a cooling structure and a cooling method suitable for a radial dynamic pressure foil gas bearing.

Background

The foil dynamical pressure gas bearing is a self-acting gas bearing which adopts gas as a lubricating medium and can be used in the fields of aircraft environmental control systems (ACM), micro gas turbines, turbo machinery, centrifugal blowers, turbochargers, centrifugal refrigeration compressors and the like. Compared with the traditional oil film bearing, the gas bearing has the advantages of simple structure, high rotating speed, low friction power consumption and the like, and has wide application prospect in high-speed rotating machinery along with the development trend of high speed and miniaturization of a centrifugal refrigeration compressor and the development of new energy sources such as a dye battery and the like.

Foil gas bearings are one of the most common forms of construction for hydrodynamic gas bearings. The radial foil gas bearing generates a dynamic pressure effect by means of a wedge-type gap formed between the bearing and the rotor shaft, thereby generating a bearing force supporting the weight of the rotor. The foil gas bearing has small gas film gap of dozens of microns generally, and the problem of heat management cannot be avoided in the bearing gap along with the increase of the rotating speed of the motor. The inside heat that produces by friction consumption, gas compression of bearing can lead to foil bearing and rotor shaft temperature to rise, if the heat can not in time be derived out, can make gas bearing's working characteristic change on the one hand, even take place thermal runaway and lead to the trouble, the higher temperature of on the other hand still can make foil bearing and rotor shaft take place the thermal expansion, leads to the gas film clearance to reduce and high-speed friction takes place, influences the stability and the reliability of bearing and machine. Cooling and thermal management of bearings is an important aspect of foil gas bearing research.

Existing foil radial gas bearings are typically cooled naturally, i.e. the heat generated by the bearing is transferred to the surrounding environment by the high thermal conductivity of the bearing housing. The mode belongs to a passive mode, can be adopted under the conditions that the rotating speed is not too high and the working condition is not too severe, but has poor heat dissipation effect at high rotating speed. In another mode, external cooling gas is introduced to axially cool the radial gas bearing, namely an air inlet channel is arranged, so that the gas flows from one end of the radial gas bearing to the other end of the radial gas bearing, and the cooling gas channel is a gap between a bump foil and a bearing seat and between the bump foil and a flat foil in the foil gas bearing; in addition, the cooling medium of this cooling system is generally a gas, and when a liquid such as a coolant is used, the effect is not good because the flow area is small.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a cooling structure and a cooling method for a radial gas bearing of dynamic pressure foil, wherein the flow area of cooling fluid is increased by arranging cooling structures such as a transverse groove, a gas supply hole, an annular groove, a cooling channel and the like on the surface of a bearing seat, so that the cooling effect is improved; the cooling method using the cooling structure is applicable not only to a gas cooling medium but also to a liquid cooling medium such as a refrigerant.

The technical scheme of the invention is as follows:

a cooling structure of a radial gas bearing with dynamic pressure foil comprises a bearing seat and a shell sleeved on the bearing seat; the shell is provided with a cooling fluid inlet, the bearing block is provided with one or more axial grooves for the cooling fluid to pass through, and the bearing block is also provided with one or more air supply holes which penetrate through the bearing block perpendicular to the axis; the cooling structure further comprises a bump foil and a flat foil, and the shell and the bearing seat, the bump foil and the flat foil are coaxially arranged from outside to inside in sequence.

Further, when the number of the air supply holes is multiple, an annular groove is formed in the bearing seat; the annular groove is positioned on the outer surface of the bearing seat and is arranged around the circumferential direction of the bearing seat, and the plurality of air supply holes are uniformly distributed in the annular groove; or the plurality of air supply holes are arranged in the axial groove.

Further, the axial groove is arranged on the outer surface of the bearing seat connected with the shell, or on the inner surface of the bearing seat; the axial groove is arranged on the bearing seat along the axial direction or the circumferential direction; the wave foil and the flat foil are full-circle type foils or the wave foil and the flat foil are formed by a plurality of adjacent separated foils, and the number of the wave foils and the number of the flat foils are the same.

Further, when the number of the air supply holes is one, the air supply holes are concentrically arranged with the cooling fluid inlet to ensure the fluid to pass through.

Further, when the cooling structure is used for cooling the three-foil bearing, the wave foil and the plane foil are both formed by three adjacent separated foils, the number of the axial grooves is the same as that of the foil bearing, and the positions of the axial grooves are arranged at the positions of gaps between the adjacent separated foils of the wave foil; the annular groove is vertically intersected with the axial groove, and the plurality of air supply holes are uniformly distributed in the axial groove.

Further, when the axial grooves are located on the inner surface of the bearing seat and are uniformly distributed along the axial direction, the axial grooves and the corrugated foils form axial cooling channels, and the air supply holes are opposite to the axial cooling channels; the corrugated foils are divided into strips along the shaft, gaps are formed among the strip corrugated foils, and the axial cooling channel is communicated with gaps between the flat foils and the corrugated foils through the gaps.

Further, when the axial grooves are located on the inner surface of the bearing seat and are uniformly distributed along the circumferential direction, the axial grooves form circumferential grooves, cooling fluid outlet channels are formed in two ends of the bearing seat, and cooling fluid enters the circumferential grooves from a cooling fluid inlet through the air supply hole and flows and is discharged from the cooling fluid outlet channels at the two ends.

A cooling method for a radial gas bearing cooling structure of a dynamic pressure foil comprises the following steps: cooling fluid enters through a cooling fluid inlet on the housing and then passes through a gas supply hole provided on the bearing block; the cooling fluid passing through the air supply hole enters a gap between the wave foil and the flat foil through a gap position between the separation foils to cool the wave foil and the flat foil;

or the cooling fluid entering the gas supply hole flows out to the two ends of the radial bearing along the axial cooling channel and flows out from the two ends of the radial gas bearing, and the cooling fluid enters the gap between the wave foil and the flat foil through the gap position between the separation foils to cool the wave foil and the flat foil;

or the cooling fluid entering the air supply holes flows along the circumferential direction of the radial bearing along a circumferential cooling channel formed by the circumferential grooves and is discharged from outlets at two ends, and the cooling fluid can enter a gap between the bump foil and the flat foil through a gap between the separation foils, so that the bump foil and the flat foil can be cooled.

The invention has the beneficial effects that:

according to the cooling structure of the radial gas bearing with the dynamic pressure foil, the transverse groove, the gas supply hole and the annular groove are formed in the bearing seat to form a cooling channel and the like, so that the flow area of cooling fluid is increased, and the cooling effect is improved; the cooling method using the cooling structure is applicable not only to a gas cooling medium but also to a liquid cooling medium such as a refrigerant.

Drawings

FIG. 1 is an exploded view of an assembly of a cooling structure for a three-foil bearing provided in example 1;

fig. 2 is a schematic structural view of a bearing seat provided in embodiment 1;

FIG. 3 is a sectional view of an assembly of a three-foil bearing cooling structure according to example 1;

FIG. 4 is a schematic view of the assembly of a bearing seat with a bump foil and a plain foil provided in example 1;

FIG. 5 is a structural diagram of a bump foil provided by the present invention;

FIG. 6 is an exploded view of a radial hydrodynamic gas bearing assembly with axial cooling passages as provided in example 2;

FIG. 7 is a general assembly view of a radial hydrodynamic gas bearing with axial cooling channels as provided in example 2;

FIG. 8 is a cross-sectional view of a radial hydrodynamic gas bearing assembly having axial cooling passages as provided in example 2

FIG. 9 is a partial view provided in example 2;

fig. 10 is a schematic structural view of a bearing seat provided in embodiment 2;

FIG. 11 is a sectional view of a bearing housing according to embodiment 2;

FIG. 12 is an exploded view of a radial hydrodynamic gas bearing assembly having circumferentially surrounding cooling passages as provided in example 3;

FIG. 13 is a cross-sectional view of a radial hydrodynamic gas bearing assembly having circumferentially surrounding cooling passages as provided in example 3;

fig. 14 is a schematic structural view of a bearing housing provided in embodiment 3;

FIG. 15 is a schematic view of the structure of the circumferential cooling channel provided in example 3;

FIG. 16 is a schematic view of a circumferential cooling structure using a three-foil gas bearing according to example 4;

fig. 17 is a schematic structural view of a bearing seat provided in embodiment 4;

in the above figures, 1, a housing; 11. a cooling fluid inlet; 2. a bearing seat; 21. an annular groove; 22. an air supply hole; 23. an axial groove; 24. an axial cooling channel; 25. a circumferential groove; 26. a cooling fluid outlet channel; 3. a bump foil; 31. separating the spaces between the foils; 34. a gap between the bump foil and the flat foil; 4. a flat foil.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

For a further understanding of the invention, reference will now be made to the following description taken in conjunction with the accompanying drawings and examples.

Example 1

Embodiment 1 relates specifically to a three-foil bearing cooling structure. As shown in fig. 1 and fig. 3, the cooling structure comprises a flat foil 4, a corrugated foil 3, a bearing seat 2 and a housing 1 sleeved on the bearing seat 2 from inside to outside in sequence; the housing 1 is provided with a cooling fluid inlet 11. As shown in fig. 2, the bearing housing 2 is provided with an annular groove 21; the annular groove 21 is arranged at the middle section position of the outer surface of the bearing seat 2 connected with the shell 1 and is arranged around the circumferential direction of the bearing seat 2; the bearing seat 2 is also provided with axial grooves 23 with the same number as the foil bearings, and the axial grooves 23 are vertically crossed with the annular groove 21. The bearing seat 2 is further provided with a plurality of air supply holes 22, and the plurality of air supply holes 22 are uniformly distributed in the axial groove 23. As shown in fig. 4, the bump foil 3 and the flat foil 4 in this embodiment are both composed of three separate foils, fig. 5 shows the structure of the bump foil 3, and the position of the gap 31 between the separate foils can be seen in fig. 5. The axial grooves 23 are equal in number to the bump foils 3 and the flat foils 4, and the positions of the axial grooves 23 are set at the positions of the gaps between the adjacent bump foils 3, that is, the positions of the gaps 31 between the adjacent separation foils.

The cooling method of the cooling structure comprises the following steps: cooling fluid with lower temperature from the outside enters the annular groove 21 between the shell 1 and the bearing seat 2 through the cooling fluid inlet 11 arranged on the shell 1, enters the axial groove 23 crossed with the annular groove 21 through the annular groove 21, and then enters the plurality of air supply holes 22 uniformly distributed in the axial groove 23; the cooling fluid passing through the gas supply holes 22 cools the bump foil 3 and the flat foil 4 while the cooling fluid passes through the position of the gap 31 between the split foils and enters the gap 34 between the bump foil and the flat foil.

Example 2

Embodiment 2 relates specifically to a radial dynamic pressure gas bearing cooling structure having an axial cooling passage 24.

As shown in fig. 6 to 8, the cooling structure sequentially comprises a flat foil 4, a corrugated foil 3, a bearing seat 2 and a housing 1 sleeved on the bearing seat 2 from inside to outside; the housing 1 is provided with a cooling fluid inlet 11. As shown in fig. 10, the bearing seat 2 is provided with an annular groove 21, the annular groove 21 is arranged on the middle section of the outer surface of the bearing seat 2, a plurality of air supply holes 22 are uniformly distributed in the annular groove 21, and the air supply holes 22 penetrate through the bearing seat 2 perpendicular to the axis; as shown in fig. 11, the inner surface of the housing 2 is provided with a plurality of axial grooves 23, the plurality of axial grooves 23 are uniformly arranged on the inner surface of the housing 2 at equal intervals, and the number of the air supply holes 22 is the same as that of the axial grooves 23. An axial cooling channel 24 is formed between the axial groove 23 and the corrugated foil 3, and the air supply hole 22 faces the axial cooling channel 24. When opened, the axial cooling channels 24 have a width which is smaller than the width of the foil arch, so that the axial cooling channels 24 are formed between the axial grooves 23, which are opened in the bearing housing 2, and the foils. The bump foil 3 is axially divided into strips, and gaps are formed between the strip-shaped bump foils 3. As shown in fig. 9, inside the bearing, the axial cooling channel 24 formed between the axial groove 23 and the bump foil 3 can communicate with the gap 34 between the bump foil and the flat foil through this gap. While the horizontal portion of the bump foil 3 is in contact with the inner surface of the bearing housing 2 to provide support.

In this embodiment, the bump foil 3 and the flat foil 4 may be full-circle type foils or may be formed by a plurality of separated foils adjacent to each other, and the number of the bump foil 3 and the flat foil 4 is the same, for example, the three-foil structure in embodiment 1; a certain gap exists between the bump foil 3 and the flat foil 4.

The cooling method of the cooling structure comprises the following steps: cooling fluid enters the annular groove 21 of the bearing seat 2 through the cooling fluid inlet 11 on the shell 1 and then enters the air supply holes 22 uniformly distributed in the annular groove 21 through the annular groove 21, and after entering the air supply holes 22, the cooling fluid flows to the two ends of the radial bearing along the axial cooling channel 24 opposite to the air supply holes 22 and flows out from the two ends of the radial gas bearing; at the same time, the cooling fluid may enter the gap 34 between the bump foil and the flat foil through the gap 31 between the separation foils, thereby cooling the bump foil 3 and the flat foil 4.

Example 3

Embodiment 3 specifically relates to a radial dynamic pressure gas bearing cooling structure having a circumferential cooling channel. As shown in fig. 12 to 13, the cooling structure comprises a flat foil 4, a corrugated foil 3, a bearing seat 2 and a housing 1 sleeved on the bearing seat 2 from inside to outside in sequence; the housing 1 is provided with a cooling fluid inlet 11. The housing 2 is provided with a gas supply hole 22, and the gas supply hole 22 is concentric with the cooling fluid inlet 11 to ensure the passage of the fluid. As shown in fig. 14 and 15, the inner surface of the bearing housing 2 is formed with a circumferential groove 25 flowing in the circumferential direction, and the bearing housing 2 is formed with cooling fluid outlet passages 26 at both ends thereof. The fluid entering from the inlet port flows along the circumferential groove 25 and is discharged from the outlets at both ends of the bearing housing 2.

The cooling method of the cooling structure comprises the following steps: the cooling fluid passes through the cooling fluid inlet 11 on the housing 1, enters the air supply hole 22, then enters the circumferential groove 25, flows along the circumferential cooling channel formed by the circumferential groove 25 in the circumferential direction of the radial bearing and is discharged from the cooling fluid outlet channels 26 at both ends, and the cooling fluid can enter the gap 34 between the bump foil and the flat foil through the gap 31 between the separation foils, so that the bump foil 3 and the flat foil 4 can be cooled.

Example 4

Example 4 is an axial cooling structure using a three-foil gas bearing. As shown in fig. 16 to 17, this embodiment is different from the full-circumference foil gas bearing of embodiment 3 mainly in that an annular groove 21 is formed in the bearing seat 2, the annular groove 21 is provided with 3 gas supply holes 22 along the circumferential direction, each gas supply hole 22 provides cooling for one foil covering area, and 3 circumferential grooves 25 are uniformly distributed on the inner surface of the bearing seat 2.

Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various changes, modifications and substitutions can be made without departing from the spirit and scope of the present invention. Any modification, equivalent replacement, or modification made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A cooling structure of a radial gas bearing with dynamic pressure foil is characterized by comprising a bearing seat and a shell sleeved on the bearing seat; the shell is provided with a cooling fluid inlet, the bearing block is also provided with an air supply hole, and the air supply hole penetrates through the bearing block in a manner of being vertical to the axis; the cooling structure further comprises a bump foil and a flat foil, and the shell and the bearing seat, the bump foil and the flat foil are coaxially arranged from outside to inside in sequence;

the inner surface of the bearing seat is provided with a plurality of axial grooves for cooling fluid to pass through, the axial grooves are uniformly distributed on the inner surface of the bearing seat at equal intervals, the axial grooves and the corrugated foils form axial cooling channels, and the air supply holes are opposite to the axial cooling channels; the corrugated foils are divided into strips along the shaft, gaps are formed among the strip corrugated foils, and the axial cooling channel is communicated with gaps between the flat foils and the corrugated foils through the gaps.

2. A cooling structure of a radial gas bearing with dynamic pressure foil is characterized by comprising a bearing seat and a shell sleeved on the bearing seat; the shell is provided with a cooling fluid inlet, the inner surface of the bearing seat is provided with one or more circumferential grooves for cooling fluid to flow along the circumferential direction, the bearing seat is also provided with an air supply hole, and the air supply hole penetrates through the bearing seat in a manner of being perpendicular to the axis; the cooling structure further comprises a wave foil and a flat foil, and the shell is coaxially arranged with the bearing block, the wave foil and the flat foil from outside to inside in sequence;

and cooling fluid can enter a gap between the wave foil and the flat foil through a gap between the separation foils, so that the wave foil and the flat foil can be cooled.

3. The bearing cooling structure according to claim 1 or 2, wherein the number of the air supply holes is plural, and an annular groove is provided on the bearing housing; the annular groove is positioned on the outer surface of the bearing seat and is arranged around the circumferential direction of the bearing seat, and the plurality of air supply holes are uniformly distributed in the annular groove;

or the plurality of air supply holes are distributed in the axial groove.

4. The bearing cooling structure according to claim 3, wherein the bump foil and the flat foil are full-circumference type foils.

5. The bearing cooling structure according to claim 1 or 2, wherein the number of the air supply holes is one, and the air supply holes are provided concentrically with the cooling fluid inlet to ensure the passage of the fluid.

6. A cooling method of a bearing cooling structure according to claim 1, wherein a cooling fluid is introduced through a cooling fluid inlet port provided on the housing and then passes through a gas supply hole provided on the bearing housing; and the cooling fluid entering the gas supply hole flows out to the two ends of the radial bearing along the axial cooling channel and flows out from the two ends of the radial gas bearing, and the cooling fluid enters the gap between the wave foil and the flat foil through the gap between the separation foils to cool the wave foil and the flat foil.

7. A cooling method of a bearing cooling structure according to claim 2, wherein a cooling fluid is introduced through a cooling fluid inlet port provided on the housing and then passes through a gas supply hole provided on the bearing housing; the cooling fluid entering the air supply holes flows along the circumferential direction of the radial bearing along a circumferential cooling channel formed by the circumferential grooves and is discharged from outlets at two ends, and the cooling fluid can enter a gap between the bump foil and the flat foil through a gap between the separation foils, so that the bump foil and the flat foil can be cooled.