A gas bearing, compressor

Abstract

This invention provides a gas bearing and a compressor, wherein the gas bearing includes: a first foil sheet forming a shaft hole for a rotating shaft to pass through; a housing having a through hole, the first foil sheet being disposed in the through hole; and a top foil assembly located between the inner wall of the through hole and the first foil sheet, the top foil assembly extending circumferentially along the through hole, and having at least a first portion and a second portion connected sequentially along its circumferential direction. When the top foil assembly is subjected to stress, the deformation of the first portion of the top foil assembly is smaller than the deformation of the second portion of the top foil assembly. According to this invention, the defect of poor damping effect in existing gas bearings, leading to poor bearing stability, can be overcome.

Description

Technical Field

[0001] This invention relates to the field of mechanical parts technology, specifically to a gas bearing and a compressor. Background Technology

[0002] During operation, foil gas bearings experience high-speed motion between the rotor surface and the bearing's inner surface. Gas, due to viscosity, is drawn into the wedge-shaped gap, forming a hydrodynamic gas film between the bearing and the shaft. Under this hydrodynamic effect, a relative equilibrium is achieved, thus supporting the shaft structure. Foil gas bearings differ from traditional oil film and ball bearings due to their high load-carrying capacity, good damping characteristics, and low frictional loss. Even so, the lack of high-load-carrying and high-damping foil gas hydrodynamic bearings remains a technical challenge for the development of gas bearings.

[0003] The working principle of the related foil gas bearing is as follows: When the shaft rotates at high speed, a wedge-shaped gap is formed between the shaft and the inner surface of the bearing. Viscous gas enters the wedge-shaped gap and generates a dynamic pressure effect due to compression, causing the gas film to generate a certain pressure. When the pressure of the gas film is sufficient to balance the load on the shaft, the shaft and the bearing completely separate. Traditional gas bearings have a small contact area between the foils, resulting in poor damping effect. Furthermore, due to their limited load range, the bearing's stability is poor when operating under high loads.

[0004] Because existing gas bearings suffer from problems such as small contact area between the foil and the inner surface of the bearing, resulting in poor damping effect and poor bearing stability, this invention researches and designs a gas bearing and a compressor. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of poor damping effect in the gas bearing of the prior art, which leads to poor bearing stability, and thus provide a gas bearing and a compressor.

[0006] To address the above problems, the present invention provides a gas bearing, comprising:

[0007] A first foil sheet, the first foil sheet forming a shaft hole for the shaft to pass through;

[0008] A housing having a through hole, wherein the first foil is disposed in the through hole;

[0009] A top foil assembly is located between the inner wall of the through hole and the first foil sheet. The top foil assembly extends circumferentially along the through hole. Along the circumferential direction of the top foil assembly, the top foil assembly has at least a first part and a second part connected in sequence. When the top foil assembly is subjected to stress, the deformation of the first part of the top foil assembly is smaller than the deformation of the second part of the top foil assembly.

[0010] In some embodiments, the top foil assembly includes a second foil and a third foil, both extending circumferentially along the through hole, and the second foil and the third foil are stacked in a matching manner to each other along the radial direction of the through hole. The inner wall of the housing is provided with a groove. The second foil has a first end and a second end. One end of the third foil and the second end are both connected in the groove. The other end of the third foil and the first end are free ends.

[0011] In some embodiments, the second end and one end of the third foil are both located in the second portion, and the second foil is disposed closer to the housing than the third foil.

[0012] In some embodiments, the second foil includes a plurality of first waveform structures connected in sequence, the plurality of first waveform structures being arranged circumferentially along the through hole, the first waveform structure including a first segment, a second segment and a third segment, the first segment and the third segment being straight, the second segment being arc-shaped, and the two ends of the second segment being connected to the first segment and the third segment respectively.

[0013] In some embodiments, the third foil includes a plurality of second waveform structures connected in sequence, the plurality of second waveform structures being arranged circumferentially along the through hole, the second waveform structure including a fourth segment, a fifth segment and a sixth segment, the fourth segment and the sixth segment being straight, and the two ends of the fifth segment being connected to the fourth segment and the sixth segment respectively.

[0014] In some embodiments, within the first portion, the fifth segment has a trapezoidal structure, the second segment is located within the fifth segment, and the inner wall of the fifth segment is tangent to the second segment.

[0015] In some embodiments, within the first portion, along the radial direction of the through hole, the first segment, the third segment, and the first foil are equidistant, the fourth segment, the sixth segment, and the first foil are equidistant, and the distance between the first segment and the first foil is greater than the distance between the fourth segment and the first foil.

[0016] In some embodiments, within the second portion, the fifth segment is arc-shaped, the second segment is located within the fifth segment, and the radius of the second segment is smaller than the radius of the fifth segment.

[0017] In some implementations, within the second part, the fourth segment is attached to the first segment, and the third segment is attached to the sixth segment.

[0018] The present invention also provides a compressor comprising the gas bearing described in any of the preceding claims.

[0019] The gas bearing, compressor, and motor provided by this invention have the following beneficial effects:

[0020] This invention features a ring-shaped housing structure. The top foil assembly is located between the inner wall of the through-hole and the first foil sheet, extending circumferentially along the through-hole. When the top foil assembly is subjected to stress, the deformation of the first portion of the top foil assembly is smaller than that of the second portion. This increases the contact area with the top foil, and the two layers of foil increase the damping of the radial bearing, improving operational stability and solving the problem of easy bearing wear. Under light loads, the deformation of the first portion of the top foil assembly is smaller than that of the second portion, with the foil sheet deforming to provide primary support. Under higher loads, both portions of the foil assembly deform to provide support. This results in a bearing with high rigidity, a wide load adaptability range, suitability for complex working conditions, and improved bearing operational stability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the gas bearing according to an embodiment of the present invention;

[0022] Figure 2 for Figure 1 Enlarged view of section A;

[0023] Figure 3 for Figure 1 Enlarged view of section B;

[0024] Figure 4 This is a schematic diagram of the structure of the gas bearing according to an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of a gas bearing according to an embodiment of the present invention.

[0026] The reference numerals in the attached figures are as follows:

[0027] 1. Shell; 2. Second foil; 3. Third foil; 4. First foil; 5. Shaft; 6. Groove; 7. First section; 8. Second section; 9. Third section; 10. Fourth section; 11. Fifth section; 12. Sixth section. Detailed Implementation

[0028] See also Figures 1 to 5As shown, according to an embodiment of the present invention, a gas bearing is provided, comprising: a first foil 4, the first foil 4 forming a shaft hole for the shaft 5 to pass through; a housing 1, the housing 1 having a through hole, the first foil 4 being disposed in the through hole; a top foil assembly, the top foil assembly being located between the inner wall of the through hole and the first foil (4), the top foil assembly extending circumferentially along the through hole, and along the circumferential direction of the top foil assembly, the top foil assembly having at least a first portion and a second portion connected in sequence, wherein when the top foil assembly is subjected to stress, the deformation of the first portion of the top foil assembly is less than the deformation of the second portion of the top foil assembly. In this technical solution, the gas bearing provided by the present invention preferably functions as a radial bearing, see [reference]. Figure 1 As shown, the housing 1 is an overall annular structure. The top foil assembly is located between the inner wall of the through hole and the first foil (4). The top foil assembly extends circumferentially along the through hole. When the top foil assembly is subjected to stress, the deformation of the first part of the top foil assembly is smaller than that of the second part. This increases the contact area with the top foil, and through the two layers of foil, the damping of the radial bearing is increased, improving the running stability and solving the problem of easy bearing wear. Under light load, the deformation of the first part of the top foil assembly is smaller than that of the second part of the top foil assembly, and the foil deforms to play a major supporting role. Under higher load, both parts of the foil assembly deform to play a supporting role, making the bearing have higher rigidity, a wide load adaptability range, suitable for complex working conditions, and improving the running stability of the bearing. Preferably, the arch height of the first part of the top foil assembly is smaller than that of the second part of the top foil assembly.

[0029] In one specific embodiment, the top foil assembly includes a second foil (2) and a third foil (3), both extending circumferentially along the through hole. The second foil (2) and the third foil (3) are stacked in a matching manner along the radial direction of the through hole. The second foil (2) and the third foil (3) in the first portion are in contact with each other, while a gap exists between them in the second portion. A groove 6 is provided on the inner wall of the housing. The second foil 2 has a first end and a second end. One end and the second end of the third foil 3 are both connected within the groove 6, and the other end and the first end of the third foil 3 are free ends. In this technical solution, the connection of one end and the second end of the third foil 3 within the groove 6 ensures that the second foil 2 and the third foil 3 do not undergo circumferential displacement. The first end and the second end of the third foil 3 are fixed ends. Fixed ends and free ends refer to a region adjacent to the endpoint of a component, not just the endpoint itself.

[0030] In one specific embodiment, the second end and one end of the third foil 3 are both located in the second part, and the second foil 2 is positioned closer to the housing 1 relative to the third foil 3. In this technical solution, during the high-speed operation of the high-speed motor, at the initial stage of high-speed rotation of the shaft, the eccentric motion of the shaft causes a wedge-shaped region to form in the gap between the rotor and the radial bearing. After the gas enters the wedge-shaped region, a high-pressure lubricating gas film is formed. The second end is located in the first part, and one end of the third foil 3 is located in the second part. This can save materials and reduce costs while improving the bearing's load-bearing capacity, and is beneficial for forming a gas film between the housing 1 and the first foil 4 when the shaft 5 rotates at low speed.

[0031] In one specific embodiment, see Figure 4 As shown, the second foil 2 includes multiple first waveform structures connected in sequence. These first waveform structures are arranged circumferentially along the through-hole. Each first waveform structure includes a first segment 7, a second segment 8, and a third segment 9. The first segment 7 and the third segment 9 are straight, while the second segment 8 is arc-shaped. Both ends of the second segment 8 are connected to the first segment 7 and the third segment 9, respectively. In this technical solution, the first segment 7 and the third segment 9 are straight and fit against the inner wall of the housing 1. The second segment 8 is arc-shaped, and both ends of the second segment 8 are connected to the first segment 7 and the third segment 9, respectively. That is, the first waveform structure is a flat-top-dome-flat-top, with the two flat-top arches having the same arch height on both sides, and the arch height in the middle area being higher than that on both sides. The second segment 8 is the support area, and the first segment 7 and the third segment 9 are the load-bearing areas. The arch height of the second segment 8 in the second part is less than that in the first part.

[0032] In one specific embodiment, see Figure 5 As shown, the third foil 3 includes multiple sequentially connected second waveform structures arranged circumferentially along the through hole. Each second waveform structure includes a fourth segment 10, a fifth segment 11, and a sixth segment 12. The fourth segment 10 and the sixth segment 12 are straight, and both ends of the fifth segment 11 are connected to the fourth segment 10 and the sixth segment 12, respectively. In this technical solution, the number of second waveform structures is the same as the number of first waveform structures, consisting of approximately 25-30 arches. The fourth segment 10 and the sixth segment 12 are attached to the first foil 4, which is an integral annular structure composed of a support and fixing area and a load-bearing area. One end of the support and fixing area is connected to the inner surface of the groove 6, and the end of the first foil 4 should completely cover the arched end of the third foil 3. The inner surface of the first foil 4 is the main load-bearing area. When the rotating shaft 5 rotates at high speed, the high-pressure lubricating gas film between the first foil 4 and the rotating shaft 5 provides load-bearing force for the bearing.

[0033] In one specific embodiment, see Figure 2 As shown, within the first part, the fifth segment 11 has a trapezoidal structure, the second segment 8 is located within the fifth segment 11, and the inner wall of the fifth segment 11 is tangent to the second segment 8. Specifically, within the first part, along the radial direction of the through hole, the first segment 7, the third segment 9, and the first foil are at the same distance; the fourth segment 10, the sixth segment 12, and the first foil 4 are at the same distance; and the distance between the first segment 7 and the first foil 4 is greater than the distance between the fourth segment 10 and the first foil. In this technical solution, the fifth segment 11 has a trapezoidal structure, and the inner wall of the fifth segment 11 is tangent to the second segment 8, increasing the contact area with the first foil 4, improving the bearing damping, and enhancing operational stability. The distance between the first segment 7 and the first foil 4 is greater than the distance between the fourth segment 10 and the first foil, so that there is a gap between the fourth segment 10 and the first segment 7, and between the third segment 9 and the sixth segment 12.

[0034] In one specific embodiment, see Figure 3As shown, within the second part, the fifth segment 11 is arc-shaped, the second segment 8 is located within the fifth segment 11, and the radius of the second segment 8 is smaller than the radius of the fifth segment 11. Specifically, the fourth segment 10 is in contact with the first segment 7, and the third segment 9 is in contact with the sixth segment 12. In this technical solution, within the second part, the fifth segment 11 and the second segment 8 are arc-shaped, and the radius of the second segment 8 is smaller than the radius of the fifth segment 11. The fifth segment 11 and the second segment 8 are the main load-bearing areas. Under light load conditions, the third foil 3 deforms under pressure, providing support; under higher loads, both foil layers deform, increasing the stiffness of the bearing load-bearing area and improving the load-bearing capacity. The double-layer arched foil gives the bearing high stiffness and a wide load-bearing range. When the first foil 4 is under pressure, it slightly sinks in the area where the second foil 2 and the third foil 3 are not in contact, forming several high-pressure air films, increasing the thickness of the high-pressure air films, optimizing the circumferential air film stiffness, and enhancing the running stability of the rotating shaft 5. The first segment 7 and the third segment 9 are attached to the inner surface of the shell 1 to fix the circumferential movement of the arch foil. The middle area is the main load-bearing area, and the arch height of the third foil 3 is greater than that of the second foil 2. Under light load conditions, the third foil 3 deforms; under higher load conditions, both the upper and lower foil layers deform. The bearing has high rigidity and can accept a wide range of load-bearing capacities. On both sides of the bearing, since the third foil 3 is tangent to the first foil 4, and the inner wall of the fifth segment 11 of the two arch foil layers is tangent to the second segment 8, the damping on both sides of the bearing is large, the stability is high, and it is not easy to wear. The two arch foil layers have the same structural parameters: the pitch of the arch foil is between 3-5 mm, the number of arched areas is between 25-30, the bending radius is between 15-20 mm, and the width of the arch foil is between 20-30 mm. The arc-shaped section, i.e., the arc-shaped area of ​​the dome-shaped foil, has a height between 0.5-0.8 mm. The trapezoidal section, i.e., the fourth section 10 at the root of the flat-topped arched foil, the sixth section 12, and the fifth trapezoidal section 11, have a height approximately 0.1-0.15 mm lower than the dome-shaped arched foil. When the rotating shaft 5 rotates, under the action of frictional torque, the second foil 2 and the third foil 3 deform from the free end to the fixed end due to the pressure transmitted by the first foil 4, ultimately resulting in the formation of a wedge-shaped area between the rotor and the top foil.

[0035] The present invention also provides a compressor including the gas bearing described above.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A gas bearing, characterized in that: include: The first foil (4) is formed with a shaft hole for the rotating shaft (5) to pass through; A housing (1) is provided with a through hole, and the first foil (4) is disposed in the through hole; A top foil assembly is located between the inner wall of the through hole and the first foil sheet (4). The top foil assembly extends circumferentially along the through hole. Along the circumferential direction of the top foil assembly, the top foil assembly has at least a first part and a second part connected in sequence. When the top foil assembly is subjected to stress, the deformation of the first part of the top foil assembly is smaller than the deformation of the second part of the top foil assembly; the arch height of the first part of the top foil assembly is smaller than the arch height of the second part of the top foil assembly. The top foil assembly includes a second foil (2) and a third foil (3), both of which extend circumferentially along the through hole. The second foil (2) and the third foil (3) are stacked together in a matching manner along the radial direction of the through hole. The second foil (2) and the third foil (3) of the first portion are attached to each other, and there is a gap between the second foil (2) and the third foil (3) of the second portion.

2. The gas bearing according to claim 1, characterized in that: The inner wall of the housing is provided with a groove (6), the second foil (2) has a first end and a second end, one end of the third foil (3) and the second end are both connected in the groove (6), and the other end of the third foil (3) and the first end are free ends.

3. The gas bearing according to claim 2, characterized in that: The second end and one end of the third foil (3) are both located in the second part, and the second foil (2) is disposed close to the housing (1) relative to the third foil (3).

4. The gas bearing according to claim 2, characterized in that: The second foil (2) includes a plurality of first waveform structures connected in sequence. The plurality of first waveform structures are arranged circumferentially along the through hole. The first waveform structure includes a first segment (7), a second segment (8) and a third segment (9). The first segment (7) and the third segment (9) are straight, and the second segment (8) is arc-shaped. The two ends of the second segment (8) are connected to the first segment (7) and the third segment (9) respectively.

5. The gas bearing according to claim 4, characterized in that: The third foil (3) includes a plurality of second waveform structures connected in sequence. The plurality of second waveform structures are arranged circumferentially along the through hole. The second waveform structure includes a fourth segment (10), a fifth segment (11) and a sixth segment (12). The fourth segment (10) and the sixth segment (12) are straight. The two ends of the fifth segment (11) are connected to the fourth segment (10) and the sixth segment (12) respectively.

6. The gas bearing according to claim 5, characterized in that: Within the first part, the fifth segment (11) has a trapezoidal structure, the second segment (8) is located within the fifth segment (11), and the inner wall of the fifth segment (11) is tangent to the second segment (8).

7. The gas bearing according to claim 5, characterized in that: Within the first part, along the radial direction of the through hole, the first segment (7), the third segment (9) are at the same distance from the first foil, the fourth segment (10), the sixth segment (12) are at the same distance from the first foil (4), and the distance between the first segment (7) and the first foil (4) is greater than the distance between the fourth segment (10) and the first foil.

8. The gas bearing according to claim 5, characterized in that: Within the second part, the fifth segment (11) is arc-shaped, the second segment (8) is located within the fifth segment (11), and the radius of the second segment (8) is smaller than the radius of the fifth segment (11).

9. The gas bearing according to claim 5, characterized in that: Within the second part, the fourth segment (10) is attached to the first segment (7), and the third segment (9) is attached to the sixth segment (12).

10. A compressor, characterized in that: The gas bearing includes any one of claims 1-9.

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