Dynamic and static pressure combined double-layer bump foil gas radial bearing

Abstract

The utility model provides a dynamic and static pressure combined double-layer bump foil gas radial bearing which comprises a bearing sleeve, bump foils and top foils, the bump foils and the top foils are distributed layer by layer along the radial direction of the bearing sleeve and are coaxially sleeved in the bearing sleeve, and the bump foils are provided with double layers and are clamped between the top foils and the bearing sleeve; the air supply hole channels and the throttling small holes are integrally through in the radial direction of the bearing and are coaxial; external bearing supplied air is received by each group of air supply hole channels and the throttling small holes and then flows into a gap between the bearing and the shaft neck through the throttling small holes. According to the utility model, the advantages of a static pressure gas bearing and a dynamic pressure gas bearing are combined, the friction loss in the starting and stopping process can be reduced, the dynamic pressure effect is realized during high-speed rotation, higher stability and lower friction loss can be realized, and the application range is wider.

Description

Technical Field

[0001] The utility model relates to a bearing, more specifically to a dynamic and static pressure combined double-layer corrugated foil gas radial bearing. Background Art

[0002] Gas bearing is an oil-free lubricated bearing. It is widely used in many fields such as turbine machinery, cryogenic technology, aerospace, and micro gas turbines due to its many advantages such as low vibration, no pollution to the environment, high rotation accuracy, long life, friction-free at extremely high speeds, and high stability in both high and low temperature environments.

[0003] According to different working principles, gas bearings are mainly divided into two types: static pressure gas bearings and dynamic pressure gas bearings. Static pressure gas bearings require the support of an external gas supply system, and use an external gas source to form a gas static pressure film to support external loads. However, static pressure bearings have high requirements for the flow and pressure of the gas source in actual work, and need to continuously provide a stable gas source to the rotor system during use, which also leads to high use costs. In addition, under high-speed conditions, static pressure bearings are difficult to maintain the stability of the gas film pressure. Dynamic pressure gas bearings use the gas pressure film in the wedge-shaped space inside the bearing to bear external loads. As the rotor speed increases, the gas gradually enters the wedge-shaped space between the inner surface of the bearing and the outer surface of the rotor, and then forms an air film with a certain load-bearing capacity to support the rotation of the rotor. When the rotor speed reaches the takeoff speed, the air film pressure formed by the wedge-shaped space is balanced with the external load of the rotor, and the rotor and the bearing are completely separated. At this time, the friction between the rotor and the bearing is almost zero. However, when the rotor is in the takeoff or stop state, the speed is low or zero. At this time, the rotor and the bearing cannot be completely separated and are in a dry friction state. There is a large friction loss, which greatly reduces the service life of the bearing and the rotor.

[0004] Foil gas bearings are a type of hydrodynamic gas bearings that support the load by generating a hydrodynamic gas film in the wedge-shaped area between the top foil and the lower elastic wave foil inside the bearing. Traditional single-layer foil gas hydrodynamic radial bearings also have some technical problems common to hydrodynamic gas bearings, and because the rigidity of the single-layer structure is low, it will affect the stability of the rotor system under high load and high speed conditions. Single-layer foil gas bearings may perform poorly in the face of vibration and impact.

[0005] Therefore, it is urgent to design a double-layer corrugated foil gas radial bearing that combines dynamic and static pressure to solve the above problems. Utility Model Content

[0006] In order to solve the above technical problems, the utility model proposes a double-layer corrugated foil gas radial bearing combining dynamic and static pressure, which combines the advantages of static pressure gas bearings and dynamic pressure gas bearings, reduces friction loss during starting and stopping, realizes dynamic pressure effect at high-speed rotation, and can achieve higher stability, lower friction loss, and a wider range of applications.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A double-layer corrugated foil gas radial bearing combining dynamic and static pressure, the structural features of which are:

[0009] It comprises a bearing sleeve and a corrugated foil and a top foil which are distributed layer by layer along the radial direction of the bearing sleeve and are coaxially sleeved in the bearing sleeve, wherein the corrugated foil has two layers and is clamped between the top foil and the bearing sleeve;

[0010] It also includes multiple groups of coaxial air supply channels and throttling holes that penetrate the bearing radially as a whole; the external bearing air is received by each group of air supply channels and throttling holes, and then flows into the gap between the bearing and the journal through the throttling holes; multiple throttling holes that penetrate the bearing radially are formed between the bearing sleeve and the double-layer corrugated foil and the top foil, and corresponding to each throttling hole, the outer wall of the bearing sleeve is formed with the air supply channel that protrudes radially outward.

[0011] The structural features of the utility model also lie in:

[0012] Along the radial direction of the bearing from outside to inside, the double-layer corrugated foil is sequentially a bottom layer corrugated foil and a middle layer corrugated foil, one end of the bottom layer corrugated foil, the middle layer corrugated foil and the top foil on the same side is welded to the inner wall of the bearing sleeve, and the other end is free, and a gap is left between the free end and the welding end along the circumferential direction of the bearing.

[0013] The double-layer corrugated foil has equal number of corrugations and equal span, the corrugated width of the bottom layer corrugated foil is half of the corrugated width of the middle layer corrugated foil, and the corrugated height of the middle layer corrugated foil is equal to the sum of the corrugated height of the bottom layer corrugated foil and the thickness of the middle layer corrugated foil.

[0014] On the bearing, a plurality of groups of air supply channels and throttling holes arranged in rows and spaced apart in parallel to the axial direction constitute a row of air supply channels and throttling hole units, and the plurality of rows of air supply channels and throttling hole units are arranged in spaced apart manner along the circumferential direction.

[0015] The aperture of the air supply channel is larger than the aperture of the throttling hole.

[0016] Compared with the prior art, the beneficial effects of the utility model are embodied in:

[0017] The utility model proposes a double-layer corrugated foil structure, and on this basis configures multiple groups of air supply channels and throttling holes for the bearing, utilizes the static pressure principle to provide a bearing air film for the bearing rotor system, gradually reduces the static pressure air supply as the rotor speed increases, stops supplying air to the bearing when the rotor reaches the take-off speed, and utilizes the dynamic pressure principle to lubricate the bearing rotor system, thereby reducing friction loss during start-stop and realizes the dynamic pressure effect at high-speed rotation, achieving higher stability, lower friction loss and a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the utility model;

[0019] Figure 2 It is a partial structural schematic diagram for illustrating the installation method of the foil;

[0020] Figure 3 It is a schematic diagram of the structure of the bearing sleeve;

[0021] Figure 4 It is a schematic diagram of the structure of the bottom wave foil;

[0022] Figure 5 It is a schematic diagram of the structure of the middle layer corrugated foil;

[0023] Figure 6 is a schematic diagram of the structure of the top foil;

[0024] Figure 7 It is a schematic diagram of the local structure at the throttling hole.

[0025] In the figure, 1 is a bearing sleeve; 2 is a bottom layer corrugated foil; 3 is a middle layer corrugated foil; 4 is a top foil; 5 is an air supply channel; and 6 is a throttling hole. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] Please refer to Figures 1 to 7 The structure of the double-layer corrugated foil gas radial bearing combined with dynamic and static pressure in this embodiment is set as follows:

[0028] It includes a bearing sleeve 1, and a corrugated foil and a top foil 4 which are distributed layer by layer along the radial direction of the bearing sleeve 1 and are coaxially sleeved in the bearing sleeve 1. The corrugated foil has two layers and is clamped between the top foil 4 and the bearing sleeve 1.

[0029] It also includes multiple groups of coaxial air supply channels 5 and throttling holes 6 that penetrate the bearing radially as a whole; the external bearing air is received by each group of air supply channels 5 and throttling holes 6, and then flows into the gap between the bearing and the journal through the throttling holes 6; a plurality of throttling holes 6 that penetrate the bearing radially are formed between the bearing sleeve 1 and the double-layer corrugated foil and the top foil 4, and corresponding to each throttling hole 6, a radially outwardly protruding air supply channel 5 is formed on the outer wall of the bearing sleeve 1.

[0030] In a specific implementation, the corresponding structural setting of the bearing also includes:

[0031] Along the radial direction of the bearing from outside to inside, the double-layer corrugated foil is a bottom layer corrugated foil 2 and a middle layer corrugated foil 3, one end of the bottom layer corrugated foil 2, the middle layer corrugated foil 3 and the top foil 4 on the same side is welded to the inner wall of the bearing sleeve 1, and the other end is free, and a gap is left between the free end and the welding end along the circumferential direction of the bearing.

[0032] The number and span of the corrugated ridges of the double-layer corrugated foil are equal, the corrugated ridge width of the bottom corrugated foil 2 is half of the corrugated ridge width of the middle corrugated foil 3, and the corrugated ridge height of the middle corrugated foil 3 is equal to the sum of the corrugated ridge height of the bottom corrugated foil 2 and the thickness of the middle corrugated foil 3. The specific parameter values ​​are designed according to the actual use environment. The bottom corrugated foil and the middle corrugated foil are formed by stamping the foil through a forming die, and then undergoing heat processing and bending.

[0033] The top foil is a flat foil, which is made by cutting and bending the foil sheet through heat treatment.

[0034] On the bearing, a plurality of groups of air supply channels 5 and throttling holes 6 arranged in rows and spaced apart in parallel to the axial direction constitute a row of air supply channels 5 and throttling holes 6 units, and the plurality of rows of air supply channels 5 and throttling holes 6 units are spaced apart along the circumferential direction; the groups of air supply channels and throttling holes in each row of air supply channels and throttling holes units may be evenly distributed at equal intervals or may be distributed at variable intervals, and the plurality of rows of air supply channels and throttling holes units may be evenly distributed at equal intervals or may be distributed at variable intervals.

[0035] The aperture of the air supply channel 5 is larger than the aperture of the throttling hole 6 .

[0036] This embodiment proposes a double-layer corrugated foil structure, which can make the bearing more advantageous in absorbing shock, vibration or displacement compared with the traditional single corrugated foil structure, and is suitable for applications requiring high flexibility. At the same time, since the two corrugated layers of the double-layer corrugated foil support each other, the stress is dispersed, and the bearing can withstand greater pressure or load, which makes the bearing more reliable in applications requiring high load capacity.

[0037] On the basis of the double-layer corrugated foil structure, this embodiment further configures a plurality of groups of air supply channels and throttling holes for the bearings. During the take-off and stop process of the rotor, air can be first supplied to the throttling holes through the air supply channels, and a bearing air film is provided for the bearing rotor system by utilizing the static pressure principle. As the rotor speed increases, the static pressure air source supply is gradually reduced, and the air supply to the bearing is stopped when the rotor reaches the take-off speed, and the bearing rotor system is lubricated by utilizing the dynamic pressure principle.

[0038] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A double-layer corrugated foil gas radial bearing combining dynamic and static pressure, characterized by: It comprises a bearing sleeve and a corrugated foil and a top foil which are distributed layer by layer along the radial direction of the bearing sleeve and are coaxially sleeved in the bearing sleeve, wherein the corrugated foil has two layers and is clamped between the top foil and the bearing sleeve; It also includes multiple groups of coaxial air supply channels and throttling holes that penetrate the bearing radially as a whole; the external bearing air is received by each group of air supply channels and throttling holes, and then flows into the gap between the bearing and the journal through the throttling holes; multiple throttling holes that penetrate the bearing radially are formed between the bearing sleeve and the double-layer corrugated foil and the top foil, and corresponding to each throttling hole, the outer wall of the bearing sleeve is formed with the air supply channel that protrudes radially outward.

2. The dynamic and static pressure combined double-layer corrugated foil gas radial bearing according to claim 1 is characterized by: Along the radial direction of the bearing from outside to inside, the double-layer corrugated foil is sequentially a bottom layer corrugated foil and a middle layer corrugated foil, one end of the bottom layer corrugated foil, the middle layer corrugated foil and the top foil on the same side is welded to the inner wall of the bearing sleeve, and the other end is free, and a gap is left between the free end and the welding end along the circumferential direction of the bearing.

3. The dynamic and static pressure combined double-layer corrugated foil gas radial bearing according to claim 2 is characterized by: The double-layer corrugated foil has equal number of corrugations and equal span, the corrugated width of the bottom layer corrugated foil is half of the corrugated width of the middle layer corrugated foil, and the corrugated height of the middle layer corrugated foil is equal to the sum of the corrugated height of the bottom layer corrugated foil and the thickness of the middle layer corrugated foil.

4. The dynamic and static pressure combined double-layer corrugated foil gas radial bearing according to claim 1 is characterized by: On the bearing, a plurality of groups of air supply channels and throttling holes arranged in rows and spaced apart in parallel to the axial direction constitute a row of air supply channels and throttling hole units, and the plurality of rows of air supply channels and throttling hole units are arranged in spaced apart manner along the circumferential direction.

5. The dynamic and static pressure combined double-layer corrugated foil gas radial bearing according to claim 1 is characterized by: The aperture of the air supply channel is larger than the aperture of the throttling hole.

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