Gas thrust bearings, compressors and air conditioning systems

Abstract

The present invention relates to a gas thrust bearing, a compressor and an air conditioning system, wherein the gas thrust bearing comprises: a bearing housing; a smooth foil, one end of which along the circumferential direction is a fixed end connected to the bearing housing; a first wave foil, which is arranged between the smooth foil and the bearing housing; and a second wave foil, which is arranged side by side with the first wave foil along the circumferential direction between the smooth foil and the bearing housing, the first wave foil is located at the fixed end of the smooth foil, the second wave foil is located at the side of the first wave foil away from the fixed end of the smooth foil, and the stiffness of the second wave foil is greater than the stiffness of the first wave foil. By applying the technical solution of the present invention, a second wave foil with a larger stiffness is used in the main bearing area away from the fixed end of the smooth foil, which is conducive to avoiding the problem of failure due to excessive deformation of the wave foil; a first wave foil with a smaller stiffness is used in the non-main bearing area close to the smooth foil, so that the rotor can also smoothly form a dynamic pressure gas film at a low speed.

Description

Technical Field

[0001] The invention relates to the field of mechanical parts, and in particular to a gas thrust bearing, a compressor and an air conditioning system. Background Art

[0002] Bearings are essential basic parts in rotating machinery. Common bearings include rolling bearings, sliding bearings, magnetic bearings, etc. With the development of science and technology, people have higher requirements for oil-free and high-precision bearings, and new air bearing technology has emerged.

[0003] Air bearings are divided into static pressure gas bearings and dynamic pressure gas bearings according to the different mechanisms of lubricating gas film generation. Figure 1 As shown in the figure, the wave foil type dynamic pressure gas thrust bearing is a type of dynamic pressure gas foil bearing, such as Figure 1 As shown, a typical wave foil type dynamic pressure gas thrust bearing includes a bearing housing 1, a wave foil sheet 2 and a top foil sheet 3. The wave foil type dynamic pressure gas thrust bearing provides axial stiffness and damping for the rotor system. Similar to the pads of the lubricating oil thrust bearing, the top foil sheet 3 of the wave foil type dynamic pressure gas thrust bearing is generally designed in a fan shape to act as a pad. In order to ensure uniform force, the top foil sheet 3 is evenly distributed in the circumferential direction.

[0004] The corrugated foil 2 under the top foil 3 has a special corrugated structure, which plays an elastic supporting role. The corrugated foil 2 is the main source of stiffness and damping of the dynamic pressure gas thrust bearing. Figure 1 As shown, one end of the bump foil 2 and the top foil 3 is fixed on the bearing housing 1, and the other end is a free end. Figure 1 As shown, a welding point 4 for connecting the bump foil 2 and the top foil 3 with the bearing housing 1 is provided at one end of the bump foil 2 and the top foil 3 along the circumferential direction. Figure 2 As shown, there is a convergence angle between the front end of the top foil 3 and the bearing housing 1 to form a wedge-shaped gap 6 for gas to enter, and the rear end of the top foil 3 is parallel to the bearing housing 1. When the rotor rotates at high speed, under the action of the convergence angle, a dynamic pressure gas film is formed to support the rotor. The rear end is located downstream of the front end in the rotation direction A.

[0005] From the above description, it can be seen that the key to the working of the foil-type dynamic pressure gas thrust bearing is to form a dynamic pressure gas film. Figures 3 to 5 As shown in the figure, the principle of the formation of the dynamic pressure gas film is: the dynamic pressure gas thrust bearing is stationary, and the rotor 7 drives the thrust plate 5 to rotate at high speed, thereby driving the gas between the thrust plate 5 and the thrust bearing along Figure 3 , 4and 5 move in the direction of arrow A. The gas enters from the higher gap wedge-shaped gap 6, and then as the gap between the top foil 3 and the thrust plate 5 becomes smaller, the gas pressure increases accordingly, forming a dynamic pressure gas film 8 with a certain supporting effect. The distance between the end of the top foil 3 close to the wedge-shaped gap 6 and the bearing housing 1 gradually increases in the direction close to the inside to form the above-mentioned wedge-shaped gap 6, and the end of the bump foil 2 close to the wedge-shaped gap 6 is provided with a height gradient section 9.

[0006] However, for the above-mentioned typical wave foil type dynamic pressure gas thrust bearing, if the wave foil 2 is overloaded and exceeds its elastic limit, the corrugated shape of the wave foil is flattened and cannot be restored to the corrugated shape, the dynamic pressure gas thrust bearing will not be able to effectively form a dynamic pressure gas film due to the deformation of the wave foil. In the actual working process, once the dynamic pressure gas film fails and the rotor continues to rotate at high speed, the thrust bearing and the dynamic pressure gas thrust bearing will collide, causing the rotor and the bearing to be damaged.

[0007] When the rotor 7 rotates at a higher speed, the pressure of the air film between the thrust plate 5 and the top foil 3 that rotates with the rotor becomes greater, and the rigidity requirement of the dynamic pressure gas thrust bearing becomes higher accordingly. At this time, if the rigidity of all the wave foils is increased, it will be difficult for the dynamic pressure gas bearing to form a dynamic pressure air film when the rotor rotates at a low speed, which will cause dry friction between the top foil 3 and the thrust plate 5, reducing the service life of the bearing. Summary of the invention

[0008] The present invention aims to provide a gas thrust bearing, a compressor and an air conditioning system, so as to improve the problem in the related art that the wave foil of the gas thrust bearing is prone to failure when the load is too large.

[0009] According to one aspect of an embodiment of the present invention, there is provided a gas thrust bearing, the gas thrust bearing comprising:

[0010] Bearing housing;

[0011] A smooth foil, one end of which along the circumferential direction is a fixed end connected to the bearing housing;

[0012] A first wave foil is disposed between the smooth foil and the bearing housing; and

[0013] The second wave foil is arranged side by side with the first wave foil between the smooth foil and the bearing housing along the circumferential direction of the gas thrust bearing, the first wave foil is located at the fixed end of the smooth foil, and the second wave foil is located on the side of the first wave foil away from the fixed end of the smooth foil, and the stiffness of the second wave foil is greater than that of the first wave foil.

[0014] In some embodiments,

[0015] The wavelength of the first wave foil is greater than the wavelength of the second wave foil; and / or

[0016] The wave height of the first wave foil is greater than the wave height of the second wave foil; and / or

[0017] The stiffness of the material of the second wave foil is greater than the stiffness of the material of the first wave foil; and / or

[0018] The thickness of the first wave foil is smaller than the thickness of the second wave foil.

[0019] In some embodiments, the wave height of the first wave foil is greater than that of the second wave foil, the bearing housing includes a first bearing surface for bearing the first wave foil and a second bearing surface for bearing the second wave foil, and the height of the second bearing surface is greater than that of the first bearing surface.

[0020] In some embodiments, one end of the first wave foil adjacent to the fixed end of the smooth foil is connected to the bearing housing, and the other end of the first wave foil abuts against the second wave foil.

[0021] In some embodiments, an end of the smooth foil away from the fixed end is a free end, and the second corrugated foil extends from the first corrugated foil to the free end of the smooth foil.

[0022] In some embodiments, a portion of the smooth foil close to the fixed end is an inclined portion inclined relative to the bearing housing, and a distance between the inclined portion and the bearing housing gradually increases in a direction away from the fixed end to form an air inlet for introducing gas, and the first wave foil is at least partially located between the inclined portion and the bearing housing.

[0023] The wave height of the first wave foil gradually increases as it moves away from the fixed end of the smooth foil, so that the end of the first wave foil away from the bearing housing abuts against the inclined portion; or

[0024] The wavelength of the first wave foil gradually increases as it moves away from the fixed end of the smooth foil.

[0025] In some embodiments,

[0026] The first wave foil comprises a plurality of first wave structures arranged side by side in the circumferential direction; and / or

[0027] The second wave foil includes a plurality of second wave structures arranged side by side in the circumferential direction.

[0028] In some embodiments, the gas thrust bearing comprises a hydrodynamic gas thrust bearing.

[0029] According to another aspect of the present invention, a compressor is further provided. In some embodiments, the compressor includes the above-mentioned gas thrust bearing.

[0030] According to another aspect of the present invention, an air conditioning system is provided, the air conditioning system comprising the above-mentioned gas thrust bearing.

[0031] By applying the technical solution of the present invention, a second wave foil with greater rigidity is used in the main load-bearing area away from the fixed end of the smooth foil, which is beneficial to avoiding the problem of failure of the wave foil due to excessive deformation; a first wave foil with less rigidity is used in the non-main load-bearing area close to the smooth foil, so that the rotor can smoothly form a dynamic pressure air film even at a low speed.

[0032] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 A schematic diagram showing the structure of a gas thrust bearing in the related art is shown;

[0035] Figure 2 Shows Figure 1 Schematic diagram of the cross-sectional structure at B in the middle;

[0036] Figure 3 A schematic diagram showing the structure of a gas thrust bearing and a rotor in the related art is shown;

[0037] Figure 4 A schematic cross-sectional structure diagram of a gas thrust bearing and a rotor of the related art is shown;

[0038] Figure 5 A schematic cross-sectional structure diagram of a gas thrust bearing and a rotor of the related art is shown;

[0039] Figure 6 A schematic cross-sectional structure diagram of a gas thrust bearing according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figure 6As shown, the gas thrust bearing of this embodiment comprises a bearing housing 1, a smooth foil 4, a first corrugated foil 3 and a second corrugated foil 2. The gas thrust bearing of this embodiment comprises a dynamic pressure gas thrust bearing.

[0042] One end of the smooth foil 4 along the circumferential direction is a fixed end connected to the bearing housing 1. The other end of the smooth foil 4 along the circumferential direction is a free end. The smooth foil 4 is located outside the first corrugated foil 3 and the second corrugated foil 2, and the smooth foil 4 is also called the top foil.

[0043] The first wave foil 3 is arranged between the smooth foil 4 and the bearing housing 1 and extends along the circumferential direction of the gas thrust bearing, and one end of the first wave foil 3 close to the fixed end of the smooth foil 4 is connected to the bearing housing 1. The second wave foil 2 and the first wave foil 3 are arranged side by side between the smooth foil 4 and the bearing housing 1 along the circumferential direction of the gas thrust bearing, the first wave foil 3 is adjacent to the fixed end of the smooth foil 4, the second wave foil 2 is located on the side of the first wave foil 3 away from the fixed end of the smooth foil 4, and the stiffness of the second wave foil 2 is greater than the stiffness of the first wave foil 3.

[0044] In some embodiments, the first wave foil 3 includes a plurality of first wave structures arranged side by side in the circumferential direction; and the second wave foil 2 includes a plurality of second wave structures arranged side by side in the circumferential direction.

[0045] One end of the first corrugated foil 3 adjacent to the fixed end of the smooth foil 4 is connected to the bearing housing 1, and the other end of the first corrugated foil 3 abuts against the second corrugated foil 2. In some embodiments, one end of the first corrugated foil 3 adjacent to the second corrugated foil 2 is a free end.

[0046] The end of the smooth foil 4 away from the fixed end is a free end, and the second wave foil 2 extends from the first wave foil 3 to the free end of the smooth foil 4. In some embodiments, the end of the second wave foil 2 close to the first wave foil 3 is fixedly connected to the bearing housing 1, and the other end of the second wave foil 2 is a free end. The fixed end of the smooth foil 4 is the air inlet end.

[0047] In some embodiments, the fixed end of the smooth foil 4 is welded to the bearing housing 1. In some embodiments, one end of the first wave foil 3 close to the fixed end of the smooth foil 4 is welded to the bearing housing 1. In some embodiments, one end of the second wave foil 2 close to the first wave foil 3 is welded to the bearing housing 1.

[0048] In this embodiment, the end (e.g., fixed end, free end) refers to an area adjacent to the end point of a component, not just the end point. In other words, "the first wave foil 3 is provided at the fixed end of the smooth foil" is equivalent to "the first wave foil 3 is located between a portion of the fixed end near the smooth foil 4 and the bearing housing 1".

[0049] In actual operation, the load is not evenly distributed on the smooth foil 4, but is mainly concentrated on the area near the free end of the smooth foil 4. Therefore, the stiffness and reliability of the gas thrust bearing mainly depend on the load-bearing capacity of the corrugated foil near the free end.

[0050] When the rotor rotates at a higher speed, the pressure of the air film between the thrust plate 6 and the smooth foil 4 rotating with the rotor becomes greater, and accordingly, the stiffness requirement of the dynamic pressure gas thrust bearing becomes higher. At this time, if the stiffness of all the wave foils is increased, it is difficult for the dynamic pressure gas bearing to form a dynamic pressure air film when the rotor rotates at a low speed, which causes dry friction between the smooth foil 4 and the thrust plate 6, reducing the service life of the bearing. In order to solve this problem, the gas thrust bearing of this embodiment is provided with a first wave foil 3 with a smaller stiffness at a position close to the fixed end of the smooth foil 4, so that the gas thrust bearing can form a dynamic pressure air film at a lower speed.

[0051] In some embodiments, the wavelength of the first wave foil 3 is greater than the wavelength of the second wave foil 2, so that the stiffness of the second wave foil 2 is greater than the stiffness of the first wave foil 3. In other embodiments, the wave height of the first wave foil 3 is greater than the wave height of the second wave foil 2, so that the stiffness of the second wave foil 2 is greater than the stiffness of the first wave foil 3.

[0052] In some other embodiments, the stiffness of the material of the second bump foil 2 is greater than the stiffness of the material of the first bump foil 3 , so that the stiffness of the second bump foil 2 is greater than the stiffness of the first bump foil 3 .

[0053] In some other embodiments, the thickness of the first bump foil 3 is smaller than the thickness of the second bump foil 2 , so that the stiffness of the second bump foil 2 is greater than the stiffness of the first bump foil 3 .

[0054] In this embodiment, the wave height of the first wave foil 3 is greater than the wave height of the second wave foil 2, and the bearing housing 1 includes a first bearing surface for bearing the first wave foil 3 and a second bearing surface for bearing the second wave foil 2, and the height of the second bearing surface is greater than that of the first bearing surface.

[0055] It should be noted that the wave height of the first wave foil 3 is greater than the wave height of the second wave foil 2, which means that the wave height of the main part of the first wave foil 3 is greater than the wave height of the main part of the second wave foil 2, and does not exclude the situation that the first wave foil 3 has an individual wave height smaller than the second wave foil 2 due to the structural limitation of the bearing. For example, the part of the first wave foil 3 close to the air inlet end of the bearing includes a plurality of corrugated structures whose wave height gradually decreases as it approaches the air inlet end, so as to form a wedge-shaped air inlet portion 7.

[0056] The bearing housing 1 comprises a first part and a second part with different thicknesses. The first part is thinner than the second part. The surface of the first part close to the smooth foil forms a first bearing surface, and the surface of the second part close to the smooth foil forms a second bearing surface.

[0057] During operation, the rotor speed gradually increases. When the speed is low, the required stiffness is small, and the first wave foil 3 plays a bearing role first. According to the characteristics of the above-mentioned wave foil type dynamic pressure gas bearing, the first wave foil 3 is designed to have a higher wave height and a larger span of corrugated shape, so that the bearing can form a dynamic pressure gas film at a lower speed.

[0058] As the rotor speed increases, the required stiffness requirements increase. For this working condition, the second wave foil 2 in the main load-bearing area will adopt a low wave height and small span wave design to improve the bearing stiffness. In other embodiments, the second wave foil 2 uses a material with higher stiffness and a thicker wave foil to further improve the bearing stiffness.

[0059] like Figure 6 As shown, a portion of the smooth foil 4 close to the fixed end is an inclined portion inclined relative to the bearing housing 1, and the spacing between the inclined portion and the bearing housing 1 gradually increases in the direction away from the fixed end to form an air inlet 7 for introducing gas, and the first wave foil 3 is at least partially located between the inclined portion and the bearing housing 1, and the wave height of the portion of the first wave foil 3 located between the inclined portion and the bearing housing 1 changes gradually, so that the end of the first wave foil 3 away from the bearing housing 1 (that is, the foil top) abuts against the inclined portion.

[0060] The wave height of the first wave foil 3 gradually increases as it moves away from the fixed end of the smooth foil 4, so that the top of the first wave foil 3 abuts against the inclined part of the smooth foil 4, and the wavelength of the first wave foil 3 gradually becomes longer as it moves away from the fixed end of the smooth foil 4, so that the bearing can form a dynamic pressure air film at a lower rotation speed.

[0061] The technical effects of the gas thrust bearing of this embodiment are as follows:

[0062] 1. A second wave foil 2 with a larger wave height is used in the main load-bearing area away from the fixed end of the smooth foil, which is beneficial to avoid the problem of failure due to excessive deformation of the wave foil; a first wave foil 3 with smaller stiffness is used in the non-main load-bearing area close to the smooth foil, so that the rotor can smoothly form a dynamic pressure air film at a low speed.

[0063] 2. The wave height of the second wave foil 2 in the main load-bearing area is lower than the wave height of the first wave foil 3 in the non-main load-bearing area. In order to enable the second wave foil 2 in the main load-bearing area to provide stiffness in time when the rotor runs at high speed, the bearing housing 1 adopts a stepped design, that is, the thickness of the bearing housing 1 in the main load-bearing area is thicker than that in the non-main load-bearing area, so as to increase the position of the wave foil in the main load-bearing area so that it contacts with the smooth foil 4, thereby providing stiffness support in time when the rotor runs at high speed.

[0064] 3. For the main load-bearing areas, high-rigidity corrugated foils are used to reduce the risk of uneven load on a single corrugated foil, excessive local force, and the flattening of the corrugations leading to failure, thereby improving the reliability of the hydrodynamic gas thrust bearing.

[0065] According to another aspect of the present invention, a compressor is provided, characterized in that it comprises the above-mentioned gas thrust bearing.

[0066] According to another aspect of the present invention, an air conditioning system is provided, characterized in that it comprises the above-mentioned gas thrust bearing.

[0067] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas thrust bearing, characterized in that: include: Bearing housing (1); A smooth foil (4), one end of which along the circumferential direction is a fixed end connected to the bearing housing (1); A first wave foil (3) is arranged between the smooth foil (4) and the bearing housing (1); as well as The second wave foil (2) is arranged side by side with the first wave foil (3) in sequence between the smooth foil (4) and the bearing housing (1) along the circumferential direction of the gas thrust bearing, the first wave foil (3) is located on a side of the second wave foil (2) close to a fixed end of the smooth foil (4), the second wave foil (2) has a stiffness greater than that of the first wave foil (3), The wavelength of the first wave foil (3) is greater than the wavelength of the second wave foil (2); and / or The wave height of the first wave foil (3) is greater than the wave height of the second wave foil (2); and / or The stiffness of the material of the second corrugated foil (2) is greater than the stiffness of the material of the first corrugated foil (3); and / or The thickness of the first wave foil (3) is smaller than the thickness of the second wave foil (2).

2. The gas thrust bearing according to claim 1, characterized in that: The wave height of the first wave foil (3) is greater than the wave height of the second wave foil (2), the bearing housing (1) comprises a first bearing surface for bearing the first wave foil (3) and a second bearing surface for bearing the second wave foil (2), the height of the second bearing surface being greater than that of the first bearing surface.

3. The gas thrust bearing according to claim 1, characterized in that: One end of the first wave foil (3) adjacent to the fixed end of the smooth foil (4) is connected to the bearing housing (1), and the other end of the first wave foil (3) is in abutment with the second wave foil (2).

4. The gas thrust bearing according to claim 1, characterized in that: An end of the smooth foil (4) away from the fixed end is a free end, and the second wave foil (2) extends from the first wave foil (3) to the free end of the smooth foil (4).

5. The gas thrust bearing according to claim 1, characterized in that: A portion of the smooth foil (4) close to the fixed end is an inclined portion inclined relative to the bearing housing (1), the spacing between the inclined portion and the bearing housing (1) gradually increases in a direction away from the fixed end to form an air inlet (7) for introducing gas, and the first wave foil (3) is at least partially located between the inclined portion and the bearing housing (1). The wave height of the first wave foil (3) gradually increases as it moves away from the fixed end of the smooth foil (4), so that the end of the first wave foil (3) away from the bearing housing (1) abuts against the inclined portion; or The wavelength of the first wave foil (3) gradually becomes longer as it moves away from the fixed end of the smooth foil (4).

6. The gas thrust bearing according to claim 1, characterized in that: The first wave foil (3) comprises a plurality of first wave structures arranged side by side along the circumferential direction; and / or The second wave foil (2) comprises a plurality of second wave structures arranged side by side along the circumferential direction.

7. The gas thrust bearing according to claim 1, characterized in that: Includes hydrodynamic gas thrust bearings.

8. A compressor, characterized in that: A gas thrust bearing comprising the gas thrust bearing according to any one of claims 1 to 7.

9. An air conditioning system, characterized in that: A gas thrust bearing comprising the gas thrust bearing according to any one of claims 1 to 7.

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