Bottom foil, thrust gas bearing and rotary machine

Abstract

The invention discloses a bottom foil, a thrust gas bearing and a rotating machine, and relates to the technical field of bearings. The bottom-layer foil is used in the thrust gas bearing and comprises a foil body, and the foil body is of an annular structure with the hollow interior; the bottom-layer foil further comprises a plurality of supporting structures, the supporting structures are arranged in the circumferential direction of the foil body and distributed in the annular space of the foil body at intervals, an airflow space is formed between every two adjacent supporting structures, and the width of each airflow space is gradually reduced from the side close to the edge of the foil body to the side close to the center of the annular space. And gradually increasing. The width between every two adjacent supporting structures in the middle of the supporting structures of the bottom-layer foil is minimum, so that the air pressure in the position is maximum, the supporting rigidity in the middle of the bottom-layer foil can be improved by increasing the air pressure, and the stability and precision of the thrust gas bearing can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of bearings, and in particular to a bottom foil, a thrust gas bearing and a rotating machine. Background Art

[0002] Thrust gas bearings are bearings that use gas as a lubricating medium and use the dynamic pressure effect of gas to provide support. Since the viscosity of gas is lower than that of oil film, thrust gas bearings have low power consumption and a longer life than traditional oil-lubricated bearings. Thrust gas bearings are currently widely used in high-speed and light-load fields.

[0003] The traditional thrust gas bearing includes a top foil, a corrugated foil and a supporting bottom plate. The top foil and the corrugated foil are arranged on the supporting bottom plate. The corrugated foil is used to support the top foil, and a wedge-shaped area is formed between the top foil and the thrust plate. When the thrust plate runs at high speed, the dynamic pressure effect of the gas can be used to generate a high-pressure area, thereby supporting the thrust plate and realizing gas lubrication. In the related art, the top foil is fixed to the supporting bottom plate by welding, which is a complex process and easy to fall off. For this reason, a thrust gas bearing with a laminated structure is proposed in the related art. The thrust gas bearing with a laminated structure includes a plurality of foils stacked in sequence, thereby reducing the difficulty of producing the thrust gas bearing.

[0004] However, the inventors have found that the thrust gas bearing with a laminated structure in the related art has a problem of low support stiffness, resulting in poor stability and accuracy of the system. Therefore, improving the support stiffness of the thrust gas bearing has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The invention discloses a bottom foil, a thrust gas bearing and a rotary machine, so as to solve the technical problem that the thrust gas bearing with a laminated structure in the related art has low supporting stiffness.

[0006] In order to solve the above problems, the present invention adopts the following technical solutions: A first aspect of the present invention provides a base foil.

[0007] The bottom foil of the present invention is used in a thrust gas bearing, and the bottom foil includes a foil body, and the foil body is an annular structure with a hollow interior; the bottom foil also includes a plurality of supporting structures, and the supporting structures are arranged along the circumferential direction of the foil body, and the supporting structures are distributed in the annular space of the foil body at intervals, and an airflow space is formed between two adjacent supporting structures, and the width of the airflow space gradually decreases from the edge side of the foil body to the center side of the annular space, and then gradually increases.

[0008] According to an optional embodiment, the width of the support structure gradually decreases from the edge side of the foil body to the center side of the annular space, and the width reduction amplitude of the starting section of the support structure is smaller than the width reduction amplitude of the last section of the support structure, or the width of the support structure gradually increases and then gradually decreases from the edge side of the foil body to the center side of the annular space.

[0009] According to an optional embodiment, the airflow space close to the edge of the foil body is the inlet side, the airflow space close to the center of the annular space is the outlet side, and the width of the inlet side is equal to the width of the outlet side.

[0010] According to an optional embodiment, the supporting structure includes a connecting section and a supporting section, one end of the connecting section is connected to the foil body, the other end of the connecting section is connected to the supporting section, and an air inlet is formed between two adjacent connecting sections, an air flow space is formed between two adjacent supporting sections, the air flow space is connected to the air inlet, the width of the connecting section is smaller than the width of the supporting section close to the foil body, and the width of the air inlet is larger than the width of the air flow space.

[0011] According to an optional embodiment, both sides of the support segment are first arc-shaped structures, and at one end of the support segment close to the center of the annular space, the first arc-shaped structures on both sides of the support segment intersect.

[0012] According to an optional embodiment, the first arc-shaped structure is an arc, the center of the circle where the first arc-shaped structure is located is located on the foil body, and the center of the circle where the first arc-shaped structure is located is located on the same circumference.

[0013] According to an optional embodiment, the connection between the connecting segment and the supporting segment is a second arc-shaped structure, and the second arc-shaped structure extends to both sides of the supporting segment.

[0014] A second aspect of the present invention provides a thrust gas bearing.

[0015] The thrust gas bearing of the present invention comprises a top layer foil, a second layer foil, a third layer foil and a bottom layer foil stacked in sequence from top to bottom, wherein the bottom layer foil is the bottom layer foil described in any technical solution of the present invention; the thrust gas bearing also comprises a base, and the bottom layer foil is stacked on the base.

[0016] According to an optional embodiment, the thickness of the three-layer foil located in the middle of the airflow space satisfies: L1>L, wherein L1 is the thickness of the three-layer foil located in the middle of the airflow space, and L is the thickness of the three-layer foil located at both ends of the airflow space.

[0017] A third aspect of the present invention provides a rotating machine.

[0018] The rotary machine of the present invention comprises the thrust gas bearing described in any one of the technical solutions of the present invention.

[0019] The technical solution adopted by the present invention can achieve the following beneficial effects: The bottom foil of the present invention can support the structure stacked on the bottom foil through multiple support structures located in the annular space of the foil body. It is particularly important that the width of the airflow space formed between two adjacent support structures of the present invention gradually decreases from the edge side of the foil body to the center side of the annular space, and then gradually increases, that is, along the radial direction of the foil body, the width of the airflow space located in the middle of the support structure is the smallest. When the airflow passes through the airflow space, the air pressure at the place where the width of the airflow space is the smallest is the largest. The support stiffness at the middle of the bottom foil can be increased by increasing the air pressure, thereby improving the stability and precision of the thrust gas bearing.

[0020] That is, the bottom foil of the present invention improves the supporting structure so that the width between two adjacent supporting structures in the middle of the supporting structure is minimized to increase the air pressure there, and the stiffness of the middle of the bottom foil is increased by increasing the air pressure, thereby solving the technical problem of low support stiffness of the thrust gas bearing with a laminated structure in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be 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 work.

[0022] Figure 1 is a first schematic diagram of a thrust gas bearing according to an embodiment of the present application; Figure 2 is an exploded view of a thrust gas bearing according to an embodiment of the present application; Figure 3 is a second schematic diagram of a thrust gas bearing according to an embodiment of the present application; Figure 4 yes Figure 3 A magnified view of part A; Figure 5 is a third schematic diagram of a thrust gas bearing according to an embodiment of the present application; Figure 6 is a first cross-sectional view of a thrust gas bearing according to an embodiment of the present application; Figure 7 yes Figure 6 A magnified view of part B; Figure 8 is a second cross-sectional view of the thrust gas bearing according to an embodiment of the present application; Fig. 9 yes Figure 8 Enlarged view of part C; Fig.10 It is a schematic diagram of the structure of the two-layer foil of the embodiment of the present application; Fig.11 is a first schematic diagram of the bottom foil of an embodiment of the present application; Fig.12 is a second schematic diagram of the bottom foil of an embodiment of the present application; Fig.13 is a third schematic diagram of the bottom foil of an embodiment of the present application; Fig.14 is a first schematic diagram of a rotating machine according to an embodiment of the present application; Fig.15 is a second schematic diagram of a rotating machine according to an embodiment of the present application; Fig.16 yes Fig.15 Enlarged view of part D.

[0023] In the figure: 100, bottom foil; 110, foil body; 120, support structure; 121, connecting section; 122, support section; 122a, first arc structure; 122b, second arc structure; 122c, center of circle; 130, air flow space; 131, inlet side; 132, outlet side; 140, air inlet; 200, top foil; 210, thrust unit; 211, horizontal section; 212, inclined section; 220, first air inlet space; 230, first gas space; 300, second foil; 310, support pad; 400, third foil; 410, second gas space; 500, base; 600, rotor; 610, thrust plate; 620, wedge-shaped convergent space. DETAILED DESCRIPTION

[0024] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0025] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0026] Support stiffness and damping characteristics are two important parameters in the design of thrust gas bearings, which have a significant impact on the performance of the bearing and the stability of the rotor system. Specifically, higher stiffness can reduce the vibration and deflection of the rotor system, thereby improving the stability and accuracy of the system; good damping characteristics can reduce the vibration amplitude of the rotor system and improve the stability of the system. Insufficient damping may lead to poor high-speed stability of the rotor system; excessive damping may lead to increased vibration of the rotor system.

[0027] The thrust gas bearing of the laminated structure in the related art includes a plurality of foils, wherein a plurality of support sheets are provided on the bottom foil, and the structure stacked on the bottom foil can be supported by the support sheets. Since the width of the support sheet in the related art gradually decreases from the edge side of the foil to the center side of the foil, the support capacity of the support sheet near the center side of the foil is greatly weakened, resulting in insufficient support stiffness of the thrust gas bearing near the center side, affecting the stability and accuracy of the system.

[0028] From the edge of the foil to the center of the foil, although the width of the airflow space formed between two adjacent support sheets gradually decreases, the air pressure in the airflow space gradually increases from the edge of the foil to the center of the foil, which can partially compensate for the weakening of the support stiffness caused by the reduction in the width of the support sheet. However, due to the combined effect of the gas dynamics effect and the deformation of the foil structure, the radial middle part of the thrust disk is subjected to the greatest force, so the radial middle part of the thrust gas bearing is required to have good support stiffness. Because the support sheet in the related art is neither the largest in the radial middle part nor the smallest in the airflow space, that is, the radial middle part of the support sheet cannot maintain sufficient support stiffness, resulting in insufficient support stiffness in the radial middle part of the support sheet, affecting the stability and accuracy of the system.

[0029] To this end, the present application provides a bottom foil, which has multiple support structures. The airflow space formed between two adjacent support structures has a width that is smallest at the middle of the support structure along the radial direction of the foil body. When the airflow passes through the airflow space, the air pressure is largest at the point where the width of the airflow space is smallest, thereby increasing the support stiffness at the middle of the bottom foil by increasing the air pressure.

[0030] The following is combined with Figures 1 to 16 , the bottom foil, thrust gas bearing and rotating machinery provided by the present application are described in detail through specific embodiments and their application scenarios.

[0031] The first aspect of this embodiment describes the bottom foil in detail.

[0032] The bottom foil of this embodiment is used in a thrust gas bearing. The thrust gas bearing of this embodiment includes a top foil 200, a second foil 300, a third foil 400 and a bottom foil 100 stacked in sequence from top to bottom. Figure 1~Figure 4 The thrust gas bearing further comprises a base 500, on which the bottom foil 100 is stacked. Figure 1~Figure 4 shown.

[0033] like Figure 5 As shown, a plurality of thrust units 210 are provided on the top foil 200. The plurality of thrust units 210 are arranged at intervals, and any two adjacent plurality of thrust units 210 are arranged separately, such as Figure 4 As shown. Figure 6 and Figure 7 As shown, the thrust unit 210 may include a horizontal section 211 and an inclined section 212 connected to each other, the horizontal section 211 is not inclined relative to the second-layer foil 300, and the inclined section 212 is inclined relative to the second-layer foil 300. Specifically, a support pad 310 is provided on the second-layer foil 300, and the horizontal section 211 is stacked on the support pad 310, so that the horizontal section 211 is not inclined relative to the second-layer foil 300, and one side of the inclined section 212 is connected to the horizontal section 211, and the other side is stacked on the third-layer foil 400, so that the inclined section 212 is inclined relative to the second-layer foil 300, as shown in FIG. Figure 7 and Fig.10 shown.

[0034] When the thrust gas bearing is applied to the rotor 600, a wedge-shaped convergence space 620 may be formed between the thrust unit 210 and the thrust disk 610 of the rotor 600, such as Fig.15 and Fig.16 When the rotor 600 rotates at a high speed, it can draw in external gas into the wedge-shaped convergence space 620 and generate an air film in the wedge-shaped convergence space 620, thereby supporting the thrust disk 610 to achieve axial air suspension.

[0035] like Figure 5~Figure 7 As shown, a first air inlet space 220 is formed near the edge between the top foil 200 and the third foil 400, and a first gas space 230 is also formed between the top foil 200 and the third foil 400, and the first air inlet space 220 and the first gas space 230 are connected to each other. Thus, external gas can enter the first gas space 230 through the first air inlet space 220, and the gas entering the first gas space 230 will make the first gas space 230 have a certain pressure, so as to support the thrust unit 210; and the gas in the first gas space 230 will also impact the thrust unit 210, so as to exert an upward force on the thrust unit 210, so as to support the thrust unit 210.

[0036] In order to enhance the support performance of the thrust gas bearing, a bottom foil 100 is further provided below the three-layer foil 400. Similarly, a second air intake space is formed between the bottom foil 100 and the three-layer foil 400 near the edge (the second air intake space is located below the first air intake space 220, and the second air intake space is not marked in the figure), and a second gas space 410 is further formed between the bottom foil 100 and the three-layer foil 400. Figure 7 The second air inlet space is connected to the first air inlet space 220, and the second air inlet space is also connected to the second gas space 410. Thus, external gas can enter the second air inlet space through the first air inlet space 220, and then enter the second gas space 410. The gas in the second gas space 410 has a certain pressure, so that the three-layer foil 400 can be supported.

[0037] The gas entering the wedge-shaped convergent space 620 , the first gas space 230 , and the second gas space 410 may flow out from the side close to the center of the thrust gas bearing.

[0038] The bottom foil 100 in the thrust gas bearing is described in detail below.

[0039] The bottom foil 100 of this embodiment includes a foil body 110, such as Fig.11 As shown. The foil body 110 can be used as a supporting base. The foil body 110 is a hollow annular structure. Fig.11 As shown, the foil body 110 is illustratively a concentric circle with the top foil 200 , the second foil 300 and the third foil 400 .

[0040] In some embodiments, the bottom foil 100 further includes a plurality of support structures 120, such as Fig.11 A plurality of support structures 120 are arranged along the circumferential direction of the foil body 110, as shown in FIG. Fig.11 As shown. Exemplarily, the plurality of support structures 120 are evenly distributed along the circumferential direction of the foil body 110. Exemplarily, the number of the support structures 120 is 6 to 16. Fig.11 The schematic diagram shows that there are ten supporting structures 120. The supporting structures 120 can support the top foil 200, the second foil 300 and the third foil 400 stacked on the bottom foil 100.

[0041] like Fig.11 As shown, the support structures 120 are spaced apart in the annular space of the foil body 110, and the support structures 120 extend from the edge of the foil body 110 to the center of the annular space. The support structures 120 are spaced apart so that an airflow space 130 is formed between two adjacent support structures 120. Fig.11 The airflow space 130 can be used for airflow to pass through. The airflow passing through the airflow space 130 can also play an elastic supporting role for the top foil 200, the second foil 300 and the third foil 400 stacked on the bottom foil 100, thereby achieving air suspension.

[0042] In some embodiments, the width of the airflow space 130 gradually decreases and then gradually increases from the edge side of the foil body 110 to the center side of the annular space. Fig.11 As shown. For example, with the middle of the support structure 120 as the boundary, the width of the airflow space 130 gradually decreases from the edge side of the foil body 110 to the middle side of the support structure 120; the width of the airflow space 130 gradually increases from the middle side of the support structure 120 to the center side of the annular space, as shown. Fig.11 That is, along the radial direction of the foil body 110 , the width of the airflow space 130 located in the middle of the support structure 120 is the smallest.

[0043] In the bottom foil 100 of this embodiment, when the airflow passes through the airflow space 130, the air pressure at the place where the width of the airflow space 130 is the smallest is the largest. The increase in air pressure can increase the support stiffness at the middle of the bottom foil 100, thereby improving the stability and precision of the thrust gas bearing. That is, the bottom foil 100 of this embodiment solves the technical problem of the low support stiffness of the thrust gas bearing of the laminated structure in the related art, especially solves the problem of low support stiffness in the middle of the thrust gas bearing.

[0044] In some embodiments, the width of the support structure 120 gradually decreases from the edge side of the foil body 110 to the center side of the annular space, and the width reduction amplitude of the initial section of the support structure 120 is smaller than the width reduction amplitude of the final section of the support structure 120, such as Fig.11 The starting section of the support structure 120 is a section of the support structure 120 from the edge side of the foil body 110 to the middle of the support structure 120, and the ending section of the support structure 120 is a section of the support structure 120 from the middle side to the center side of the annular space, as shown in FIG. Fig.11 shown.

[0045] In this embodiment, the width reduction amplitude of the starting section of the support structure 120 is smaller than the width reduction amplitude of the last section of the support structure 120. It can also be said that the width reduction trend of the starting section of the support structure 120 is smaller than the width reduction trend of the last section of the support structure 120; or the width reduction degree of the starting section of the support structure 120 is smaller than the width reduction degree of the last section of the support structure 120. That is, in the radial direction of the bottom foil 100, when the length of the starting section of the support structure 120 is the same as the length of the last section of the support structure 120, the width reduction amount of the starting section of the support structure 120 is smaller than the width reduction amount of the last section of the support structure 120.

[0046] In the solution of this embodiment, the width of the support structure 120 is gradually reduced, and the width reduction range of the starting section of the support structure 120 is smaller than the width reduction range of the last section of the support structure 120, which can not only realize that the width of the airflow space 130 gradually decreases and then gradually increases from the edge side of the foil body 110 to the center side of the annular space, so as to ensure the support stiffness of the middle part of the bottom foil 100 through the larger air pressure of the airflow space 130; more importantly, the width reduction range of the support structure 120 in the starting section is small, so that the support stiffness of the support structure 120 is reduced to a small extent, so that the support stiffness of the support structure 120 can also ensure the support stiffness of the middle part of the bottom foil 100 through its own support function. On the other hand, the width of the support structure 120 is gradually reduced, so that the support structure 120 is a streamlined structure, which is conducive to improving the smoothness of the airflow passing through the airflow space 130, thereby further improving the stability and stiffness of the thrust gas bearing.

[0047] In some embodiments, the width of the support structure 120 gradually increases and then gradually decreases from the edge side of the foil body 110 to the center side of the annular space.

[0048] In the scheme of this embodiment, the width of the support structure 120 first gradually increases and then gradually decreases, which not only realizes that the width of the airflow space 130 first gradually decreases and then gradually increases from the edge side close to the foil body 110 to the center side close to the annular space, so as to ensure the support stiffness in the middle part of the bottom foil 100; on the other hand, in the middle part of the bottom foil 100, the width of the support structure 120 is the largest, so that the support stiffness in the middle part of the bottom foil 100 can be improved by the supporting effect of the support structure 120 itself.

[0049] That is, in the solution of this embodiment, at the middle of the bottom foil 100, the support stiffness at the middle of the bottom foil 100 can be improved not only by the airflow, but also by the support structure 120. This ensures that at the middle of the bottom foil 100, the bottom foil 100 has sufficient support stiffness.

[0050] In some embodiments, the side of the airflow space 130 close to the edge of the foil body 110 is the inlet side 131, and the side of the airflow space 130 close to the center of the annular space is the outlet side 132, and the width of the inlet side 131 is equal to the width of the outlet side 132. Fig.11 As shown. Exemplarily, the airflow enters through the inlet side 131 and then flows out from the outlet side 132. The width of the inlet side 131 is equal to the width of the outlet side 132, so that the intake volume of the inlet side 131 and the exhaust volume of the outlet side 132 can be balanced.

[0051] Exemplarily, the two opposite sides of two adjacent support structures 120 are symmetrical about the diameter of the foil body 110, so that the airflow space 130 can be symmetrical about the diameter of the foil body 110; without limitation, the airflow space 130 is also symmetrical about a circular arc along the circumferential direction of the foil body 110 to ensure that the width of the inlet side 131 of the airflow space 130 is equal to the width of the outlet side 132.

[0052] In the solution of this embodiment, the width of the inlet side 131 is equal to the width of the outlet side 132. When the airflow passes through the airflow space 130, the pressure balance between the inlet side and the exhaust side can be maintained, which helps to form a stable air film in the airflow space 130 and reduce the uneven deformation of the air film, so that the support stiffness of the bottom foil 100 can be further improved through a stable and uniform air film to improve the stability and accuracy of the thrust gas bearing. On the other hand, the pressure balance between the inlet side and the exhaust side can also avoid the problem in the related art that the pressure on the exhaust side is too large, resulting in excessive damping characteristics and affecting the rotation reliability of the rotor 600.

[0053] In some embodiments, the support structure 120 includes a connecting section 121 and a supporting section 122. Fig.11 As shown. One end of the connecting section 121 is connected to the foil body 110, and the other end of the connecting section 121 is connected to the supporting section 122. Specifically, the connecting section 121 is mainly used to fix the supporting section 122 on the foil body 110, and to make the supporting section 122 located in the annular space of the foil body 110. The supporting section 122 is mainly used to support the top foil 200, the second foil 300 and the third foil 400 stacked on the foil body 110.

[0054] Exemplarily, the connecting section 121 and the supporting section 122 may be an integral structure; or the connecting section 121 and the supporting section 122 may be a split structure, and the two are connected by a connecting piece or a clamping piece. Exemplarily, the connecting section 121 and the foil body 110 may be an integral structure; or the connecting section 121 and the foil body 110 may be fixedly connected by welding.

[0055] In some embodiments, an air inlet 140 is formed between two adjacent connecting segments 121, and an air flow space 130 is formed between two adjacent supporting segments 122. The air flow space 130 is connected to the air inlet 140. Fig.11 As shown. Exemplarily, the airflow space 130 mentioned in the above scheme of the embodiment of the present application refers in particular to the space formed between two adjacent support segments 122. The air inlet 140 is close to the edge of the foil body 110, and the air inlet 140 is connected to the first air inlet space 220 and the second air inlet space. After the external air enters, it first enters the air inlet 140 through the first air inlet space 220 and the second air inlet space, and then flows through the air inlet 140 to the inlet side 131 of the airflow space 130, and finally flows out from the outlet side 132 of the airflow space 130.

[0056] In some embodiments, the width of the connecting section 121 is smaller than the width of the supporting section 122 close to the foil body 110, and the width of the air inlet 140 is larger than the width of the air flow space 130. Fig.11 Specifically, the width of the air inlet 140 is made greater than the width of the inlet side 131 of the airflow space 130 .

[0057] In the scheme of this embodiment, the width of the air inlet 140 is greater than the width of the inlet side 131 of the air flow space 130, which allows more gas to enter the air inlet 140 and form a larger air film pressure in the air flow space 130, which helps to increase the support stiffness of the bottom foil 100 to improve the stability and accuracy of the thrust gas bearing; on the other hand, the larger width at the air inlet 140 can also avoid vibration or disturbance of the air flow after entering the air inlet 140, thereby improving the stability of the entire system.

[0058] In some embodiments, both sides of the support section 122 are first arc-shaped structures 122a, such as Fig.11 As shown. When the airflow passes through the airflow space 130, compared with the support section 122 of the linear structure, in the solution of this embodiment, the two sides of the support section 122 are the first arc structure 122a, and the first arc structure 122a helps to distribute the airflow more evenly, thereby improving the uniformity of the air film pressure distribution; in addition, the first arc structure 122a can guide the airflow, thereby improving the smoothness of the airflow passing through the airflow space 130 and reducing airflow disturbance. It can be seen that the two sides of the support section 122 are the first arc structure 122a, which can at least improve the stability and rigidity of the thrust gas bearing from two aspects: improving the uniformity of the air film pressure distribution and improving the smoothness of the airflow passing.

[0059] In some embodiments, at one end of the support segment 122 close to the center of the annular space, the first arc structures 122a on both sides of the support segment 122 intersect. Fig.11That is, the end of the support segment 122 close to the center of the annular space and the first arc structures 122a on both sides of the support segment 122 intersect at one point, so that the width of the end of the support segment 122 close to the center of the annular space is minimized, as shown in FIG. Fig.11 shown.

[0060] The support sheet in the related art has a certain width at the outlet end of the support sheet, which makes it difficult for the airflow to flow to the front of the outlet end of the support sheet, and there is a hidden danger of forming an airflow dead zone. Once the airflow dead zone is formed, the pressure in the dead zone is reduced, which not only leads to uneven distribution of the air film pressure, but also leads to uneven distribution of the air film thickness, affecting the stability and accuracy of the system; the formation of the airflow dead zone may also cause local vortices of the airflow, which will aggravate the instability of the air film, causing the air film to swirl, and further reduce the stiffness and stability of the thrust gas bearing; the formation of the airflow dead zone also leads to increased friction and energy loss of the airflow, affecting the efficiency of the thrust gas bearing.

[0061] In the solution of this embodiment, the first arc-shaped structures 122a on both sides of the support section 122 intersect at one point, so that the airflow can cover all areas, avoid the formation of airflow dead zones, improve the smoothness of the airflow passing through the airflow space 130, and reduce airflow disturbances, thereby improving the performance of the thrust gas bearing. Specifically, the stability, precision, rigidity and efficiency of the thrust gas bearing can be improved.

[0062] In some embodiments, the first arc-shaped structure 122a is an arc. That is, the first arc-shaped structure 122a is a segment of a circle. Preferably, the center of the circle where the first arc-shaped structure 122a is located is located on the foil body 110, such as Fig.12 shown. Fig.12 The dotted line in FIG. 1 shows the circle where the first arc structure 122a is located. Fig.12 The center 122c in the figure is the center of the circle where the first arc-shaped structure 122a is located. More preferably, the centers of the circles where the first arc-shaped structures 122a are located are located on the same circle. That is, the diameters of the circles where the first arc-shaped structures 122a are located are the same. It is particularly preferred that the area of ​​the support segment 122 is half of the intersection area of ​​the two circles where the two arcs are located, which is conducive to maintaining the balance of air intake and air outlet.

[0063] In the solution of this embodiment, the first arc structure 122a is an arc, and the center of the circle where each first arc structure 122a is located is located on the same circle. The design of the first arc structure 122a can be simplified while ensuring that the width of the airflow space 130 between the first arc structures 122a gradually decreases first and then gradually increases, and the width of the inlet side 131 of the airflow space 130 is equal to the width of the outlet side 132.

[0064] In some embodiments, the connection portion between the connecting segment 121 and the supporting segment 122 is a second arc-shaped structure 122b, and the second arc-shaped structure 122b extends to both sides of the supporting segment 122, such as Fig.13 That is, when the airflow flows from the air inlet 140 to the inlet side 131 of the airflow space 130, the area through which the airflow passes is an arc-shaped structure, which can further improve the smoothness of the airflow passing through the air inlet 140 and the airflow space 130, and also reduce the airflow disturbance, avoid the formation of airflow dead zone or eddy zone, so as to improve the support stiffness and stability of the bottom foil 100.

[0065] The second aspect of this embodiment describes the thrust gas bearing in detail.

[0066] The thrust gas bearing of this embodiment includes a top foil 200, a second foil 300, a third foil 400 and a bottom foil 100 stacked in sequence from top to bottom. Figure 1~Figure 4 The thrust gas bearing of this embodiment further comprises a base 500, and the bottom foil 100 is stacked on the base 500. Figure 1~Figure 3 The structures and functions of the top foil 200, the second foil 300, the third foil 400 and the base 500 can be found in the above embodiments, and will not be described in detail here.

[0067] The bottom foil 100 of the thrust gas bearing of this embodiment is the bottom foil 100 of any one of the technical solutions in the first aspect of this embodiment. The bottom foil 100 can improve the stability and precision of the thrust gas bearing.

[0068] In some embodiments, the thickness of the three-layer foil 400 located in the middle of the airflow space 130 satisfies: L1>L. L1 is the thickness of the three-layer foil 400 located in the middle of the airflow space 130, and L is the thickness of the three-layer foil 400 located at both ends of the airflow space 130. Figure 8 and Fig. 9 In the solution of this embodiment, the thickness of the three-layer foil 400 located in the middle of the airflow space 130 is made thicker, and the three-layer foil 400 can further improve the axial support stiffness of the thrust gas bearing.

[0069] In some embodiments, a recessed portion is provided on the support structure 120, and a protruding portion is provided on the three-layer foil 400 corresponding to the support structure 120. The position of the protruding portion corresponds to the recessed portion, so that when assembling the thrust gas bearing, pre-positioning can be achieved through the cooperation between the protruding portion and the recessed portion, and at the same time, the support performance of the thrust gas bearing can be prevented from being affected.

[0070] The third aspect of this embodiment describes the rotating machine in detail.

[0071] The rotating machinery of this embodiment includes the thrust gas bearing of any technical solution of the second aspect of this embodiment, such as Fig.14 As shown. This gives the rotating machinery the advantages of stability and reliable precision.

[0072] In some embodiments, the rotary machine further includes a rotor 600, such as Fig.14 and Fig.15 The rotor 600 is sleeved in the thrust gas bearing, and the rotor 600 includes a radially protruding thrust disc 610. The number of thrust gas bearings includes two. The two thrust gas bearings are spaced and arranged in opposite directions along the axial direction of the rotor 600. The thrust disc 610 is located between the two thrust gas bearings, so that the two thrust gas bearings are used to realize the bidirectional suspension of the thrust disc 610 and maintain the position of the rotor 600 in its axial direction, as shown in FIG. Fig.14 and Fig.15 shown.

[0073] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0074] In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in a reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0075] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A bottom foil for use in a thrust gas bearing, characterized in that: The bottom foil comprises a foil body (110), and the foil body (110) is an annular structure with a hollow interior; The bottom foil further comprises a plurality of support structures (120), wherein the support structures (120) are arranged along the circumferential direction of the foil body (110), and the support structures (120) are distributed at intervals in the annular space of the foil body (110), and an airflow space (130) is formed between two adjacent support structures (120), and the width of the airflow space (130) first gradually decreases and then gradually increases from the edge side of the foil body (110) to the center side of the annular space.

2. The bottom foil according to claim 1, characterized in that The width of the support structure (120) gradually decreases from the edge side of the foil body (110) to the center side of the annular space, and the width reduction amplitude of the starting section of the support structure (120) is smaller than the width reduction amplitude of the last section of the support structure (120); or, From the edge side close to the foil body (110) to the center side close to the annular space, the width of the support structure (120) first gradually increases and then gradually decreases.

3. The bottom foil according to claim 1 or 2, characterized in that The side of the airflow space (130) close to the edge of the foil body (110) is an inlet side (131), and the side of the airflow space (130) close to the center of the annular space is an outlet side (132), and the width of the inlet side (131) is equal to the width of the outlet side (132).

4. The bottom foil according to claim 3, characterized in that The support structure (120) comprises a connecting section (121) and a supporting section (122), one end of the connecting section (121) is connected to the foil body (110), and the other end of the connecting section (121) is connected to the supporting section (122). An air inlet (140) is formed between two adjacent connecting sections (121), and an airflow space (130) is formed between two adjacent supporting sections (122); the airflow space (130) is in communication with the air inlet (140); the width of the connecting section (121) is smaller than the width of the supporting section (122) on a side close to the foil body (110), and the width of the air inlet (140) is larger than the width of the airflow space (130).

5. The bottom foil according to claim 4, characterized in that Both sides of the support segment (122) are first arc-shaped structures (122a), and at one end of the support segment (122) close to the center of the annular space, the first arc-shaped structures (122a) on both sides of the support segment (122) intersect.

6. The bottom foil according to claim 5, characterized in that The first arc-shaped structure (122a) is an arc, the center of the circle where the first arc-shaped structure (122a) is located is located on the foil body (110), and the center of the circle where the first arc-shaped structure (122a) is located is located on the same circumference.

7. The bottom foil according to claim 4, characterized in that The connection point between the connecting section (121) and the supporting section (122) is a second arc-shaped structure (122b), and the second arc-shaped structure (122b) extends to both sides of the supporting section (122).

8. A thrust gas bearing, characterized in that: The invention comprises a top foil (200), a second foil (300), a third foil (400) and a bottom foil (100) which are stacked in sequence from top to bottom, wherein the bottom foil (100) is the bottom foil according to any one of claims 1 to 7; The thrust gas bearing further comprises a base (500), and the bottom foil (100) is stacked on the base (500).

9. The thrust gas bearing according to claim 8, characterized in that: The thickness of the three-layer foil (400) located in the middle of the airflow space (130) satisfies: L1>L, wherein: L1 is the thickness of the three-layer foil (400) located in the middle of the airflow space (130), and L is the thickness of the three-layer foil (400) located at both ends of the airflow space (130).

10. A rotating machine, characterized in that: Includes the thrust gas bearing described in claim 8 or 9.

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