Bottom foil, thrust gas bearing and rotating machinery

Abstract

The present invention discloses a bottom foil, a thrust gas bearing and a rotating machine, relating to the technical field of bearings. The bottom foil of the present invention is used in a thrust gas bearing. The bottom foil includes a foil body, and the foil body is an annular structure with a hollow interior; the bottom foil further includes a plurality of support structures, which are arranged along the circumferential direction of the foil body, and the support structures are spaced apart in the annular space of the foil body. An air flow space is formed between two adjacent support structures. From the side close to the edge of the foil body to the side close to the center of the annular space, the width of the air flow space first gradually decreases and then gradually increases. At the middle part of the support structure of the bottom foil, the width between two adjacent support structures is the smallest, so that the air pressure here is the largest. By increasing the air pressure, the support stiffness at the middle part of the bottom foil can be improved, thereby improving the stability and accuracy of the thrust gas bearing.

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:

[0007] A first aspect of the present invention provides a base foil.

[0008] 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.

[0009] According to an optional embodiment, from the side close to the edge of the foil body to the side close to the center of the annular space, the width of the support structure gradually decreases, and the width reduction amplitude of the starting section of the support structure is less than that of the ending section of the support structure, or from the side close to the edge of the foil body to the side close to the center of the annular space, the width of the support structure first gradually increases and then gradually decreases.

[0010] According to an optional embodiment, the side of the air flow space close to the edge of the foil body is the inlet side, the side of the air flow 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.

[0011] According to an optional embodiment, the support 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 communicated with the air inlet, the width of the connecting section is less than the width of the side of the supporting section close to the foil body, and the width of the air inlet is greater than the width of the air flow space.

[0012] According to an optional embodiment, both sides of the supporting section are of a first arc structure, and at the end of the supporting section close to the center of the annular space, the first arc structures on both sides of the supporting section intersect.

[0013] According to an optional embodiment, the first arc structure is an arc, the center of the circle where the first arc structure is located is on the foil body, and the centers of the circles where the first arc structures are located are on the same circumference.

[0014] According to an optional embodiment, the connection part between the connecting section and the supporting section is of a second arc structure, and the second arc structure extends to both sides of the supporting section.

[0015] The second aspect of the present invention provides a thrust gas bearing.

[0016] The thrust gas bearing of the present invention includes a top foil, a second-layer foil, a third-layer foil, and a bottom foil stacked in sequence from top to bottom. Among them, the bottom foil is the bottom foil described in any one of the technical solutions of the present invention; the thrust gas bearing further includes a base, and the bottom foil is stacked on the base.

[0017] According to an optional embodiment, the thickness of the third-layer foil at the middle part of the air flow space satisfies: L 1 >L, where L 1The thickness of the third layer of foil at the middle of the air flow space is \(t_0\), and the thickness of the third layer of foil at both ends of the air flow space is \(L\).

[0018] The third aspect of the present invention provides a rotating machine.

[0019] The rotating machine of the present invention includes the thrust gas bearing according to any one of the technical solutions of the present invention.

[0020] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0021] The bottom foil of the present invention can support the structure stacked on the bottom foil through a plurality of support structures located in the annular space of the foil body. Particularly importantly, in the air flow space formed between two adjacent support structures of the present invention, from the side close to the edge of the foil body to the side close to the center of the annular space, the width of the air flow space first gradually decreases and then gradually increases. That is, along the radial direction of the foil body, the width of the air flow space at the middle of the support structure is the smallest. When the air flows through the air flow space, the air pressure at the place where the width of the air flow space is the smallest is the largest. By increasing the air pressure, the support stiffness at the middle of the bottom foil can be improved, thereby improving the stability and accuracy of the thrust gas bearing.

[0022] That is, for the bottom foil of the present invention, through the improvement of the support structure, the width between two adjacent support structures at the middle of the support structure is the smallest, so as to increase the air pressure here, and the stiffness at the middle of the bottom foil is increased by increasing the air pressure, thereby solving the technical problem of the relatively small support stiffness existing in the thrust gas bearing with a laminated structure in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 is the first schematic diagram of the thrust gas bearing in the embodiment of the present application;

[0025] Figure 2 is the exploded view of the thrust gas bearing in the embodiment of the present application;

[0026] Figure 3 is the second schematic diagram of the thrust gas bearing in the embodiment of the present application;

[0027] Figure 4 is Figure 3 the enlarged view of part A in

[0028] Figure 5 is the third schematic diagram of the thrust gas bearing according to the embodiment of the present application;

[0029] Figure 6 is the first cross-sectional view of the thrust gas bearing according to the embodiment of the present application;

[0030] Figure 7 is Figure 6 the enlarged view of part B in

[0031] Figure 8 is the second cross-sectional view of the thrust gas bearing according to the embodiment of the present application;

[0032] Figure 9 is Figure 8 the enlarged view of part C in

[0033] Figure 10 is the structural schematic diagram of the second layer of foil according to the embodiment of the present application;

[0034] Figure 11 is the first schematic diagram of the bottom foil according to the embodiment of the present application;

[0035] Figure 12 is the second schematic diagram of the bottom foil according to the embodiment of the present application;

[0036] Figure 13 is the third schematic diagram of the bottom foil according to the embodiment of the present application;

[0037] Figure 14 is the first schematic diagram of the rotating machinery according to the embodiment of the present application;

[0038] Figure 15 is the second schematic diagram of the rotating machinery according to the embodiment of the present application;

[0039] Figure 16 is Figure 15 the enlarged view of part D in

[0040] In the figure: 100, bottom foil; 110, foil body; 120, support structure; 121, connection 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 layer of foil; 310, support pad; 400, third layer of foil; 410, second gas space; 500, base; 600, rotor; 610, thrust disk; 620, wedge-shaped convergent space. Detailed implementation manners

[0041] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope protected by the present invention.

[0042] The terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of this application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are usually of the same type, and the number of objects is not limited. For example, the first object can be one or multiple. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0043] The support stiffness and damping characteristics are two important parameters in the design of a thrust gas bearing, which have a significant impact on the performance of the bearing and the stability of the rotor system. Specifically, a 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 an increase in the vibration of the rotor system.

[0044] In the related art, a thrust gas bearing with a laminated structure includes a plurality of foil sheets. Among them, a plurality of support sheets are provided on the bottom foil sheet, and the structure stacked on the bottom foil sheet can be supported through the support sheets. Since the support sheets in the related art gradually decrease in width from the side close to the edge of the foil sheet to the side close to the center of the foil sheet, the support ability of the support sheets is greatly weakened near the center side of the foil sheet, resulting in insufficient support stiffness on the center side of the thrust gas bearing and affecting the stability and accuracy of the system.

[0045] From the side close to the edge of the foil to the side close to the center of the foil, although the width of the air flow space formed between two adjacent support pieces gradually decreases, so that from the side close to the edge of the foil to the side close to the center of the foil, the air pressure in the air flow space gradually increases, which can partially compensate for the weakening of the support stiffness caused by the decrease in the width of the support piece. However, due to the combined action of the gas dynamics effect and the deformation of the foil structure, the force on the radial middle part of the thrust disk is the largest. Therefore, it is required that the radial middle part of the thrust gas bearing has better support stiffness. Since the support piece in the related technology is not the widest at the radial middle part, and the width of the air flow space is not the smallest either, that is, the support piece cannot maintain sufficient support stiffness at the radial middle part, resulting in insufficient support stiffness at the radial middle part of the support piece, which affects the stability and accuracy of the system.

[0046] For this reason, the present application provides a bottom foil, which has a plurality of support structures. The air flow space formed between two adjacent support structures has the smallest width at the middle part of the support structure along the radial direction of the foil body. When the air flow passes through the air flow space, the air pressure at the place where the width of the air flow space is the smallest is the largest, so as to improve the support stiffness at the middle part of the bottom foil by increasing the air pressure.

[0047] The following combines the attached Figures 1 to 16 , and through specific embodiments and their application scenarios, the bottom foil, thrust gas bearing and rotating machinery provided by the present application are described in detail.

[0048] The first aspect of this embodiment describes the bottom foil in detail.

[0049] 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-layer foil 300, a third-layer foil 400 and a bottom foil 100 stacked in sequence from top to bottom, as Figures 1 to 4 shown. The thrust gas bearing further includes a base 500, and the bottom foil 100 is stacked on the base 500, as Figures 1 to 4 shown.

[0050] As Figure 5 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 thrust units 210 are separated from each other, as Figure 4 shown. As Figure 6 and Figure 7As shown, the thrust unit 210 may include a connected horizontal section 211 and an inclined section 212. The horizontal section 211 is not inclined relative to the second layer of foil 300, and the inclined section 212 is inclined relative to the second layer of foil 300. Specifically, a support pad 310 is provided on the second layer of foil 300, and the horizontal section 211 is stacked on the support pad 310, so that the horizontal section 211 can be non-inclined relative to the second layer of foil 300. One side of the inclined section 212 is connected to the horizontal section 211, and the other side is stacked on the third layer of foil 400, so that the inclined section 212 can be inclined relative to the second layer of foil 300, as Figure 7 and Figure 10 shown.

[0051] When the thrust gas bearing is applied to the rotor 600, a wedge-shaped converging space 620 may be formed between the thrust unit 210 and the thrust disk 610 of the rotor 600, as Figure 15 and Figure 16 shown. When the rotor 600 rotates at a high speed, it can entrain and draw external gas into the wedge-shaped converging space 620, and generate a gas film in the wedge-shaped converging space 620, so as to support the thrust disk 610 to achieve axial magnetic levitation.

[0052] As Figures 5 to 7 shown, a first intake space 220 is formed near the edge side between the top layer of foil 200 and the third layer of foil 400. A first gas space 230 is also formed between the top layer of foil 200 and the third layer of foil 400. The first intake space 220 and the first gas space 230 communicate with each other. Thus, external gas can enter the first gas space 230 through the first intake space 220. The gas entering the first gas space 230 will make the first gas space 230 have a certain pressure to support the thrust unit 210; and the gas in the first gas space 230 will also impact the thrust unit 210 to apply an upward acting force on the thrust unit 210, so as to support the thrust unit 210.

[0053] In order to enhance the support performance of the thrust gas bearing, a bottom layer of foil 100 is also provided below the third layer of foil 400. Similarly, a second intake space (the second intake space is located below the first intake space 220 and is not marked in the figure) is formed near the edge side between the bottom layer of foil 100 and the third layer of foil 400. A second gas space 410 is also formed between the bottom layer of foil 100 and the third layer of foil 400, as Figure 7 shown. The second intake space communicates with the first intake space 220, and the second intake space also communicates with the second gas space 410 with each other. Thus, external gas can enter the second intake space through the first intake space 220 and then enter the second gas space 410. The gas in the second gas space 410 has a certain pressure to support the third layer of foil 400.

[0054] The gas entering the wedge-shaped convergence space 620, the first gas space 230, and the second gas space 410 can flow out from the side close to the center of the thrust gas bearing.

[0055] The underlying foil 100 in the thrust gas bearing will be described in detail below.

[0056] The underlying foil 100 of this embodiment includes a foil body 110, as Figure 11 shown. The foil body 110 can serve as a support foundation. The foil body 110 is an internally hollow annular structure, as Figure 11 shown. Exemplarily, the foil body 110 and the top foil 200, the second layer foil 300, and the third layer foil 400 are concentric circles.

[0057] In some embodiments, the underlying foil 100 further includes a plurality of support structures 120, as Figure 11 shown. The plurality of support structures 120 are arranged along the circumferential direction of the foil body 110, as Figure 11 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. Figure 11 A schematic diagram showing that the number of the support structures 120 is 10 is shown. Through the support structures 120, the top foil 200, the second layer foil 300, and the third layer foil 400 stacked on the underlying foil 100 can be supported.

[0058] As Figure 11 shown, the support structures 120 are spaced apart and distributed in the annular space of the foil body 110, and the support structures 120 extend from the edge of the foil body 110 towards the center of the annular space. The support structures 120 are spaced apart, so that an air flow space 130 is formed between two adjacent support structures 120, as Figure 11 shown. The air flow space 130 can be used for the air flow to pass through. The air flow passing through the air flow space 130 can also elastically support the top foil 200, the second layer foil 300, and the third layer foil 400 stacked on the underlying foil 100 to achieve air suspension.

[0059] In some embodiments, from the side close to the edge of the foil body 110 to the side close to the center of the annular space, the width of the air flow space 130 first gradually decreases and then gradually increases, as Figure 11 shown. Exemplarily, with the middle part of the support structure 120 as the boundary, from the side close to the edge of the foil body 110 to the middle part side of the support structure 120, the width of the air flow space 130 gradually decreases; from the middle part side of the support structure 120 to the side close to the center of the annular space, the width of the air flow space 130 gradually increases, as Figure 11As shown. That is, along the radial direction of the foil body 110, the width of the air flow space 130 located in the middle of the support structure 120 is the smallest.

[0060] For the bottom foil 100 of this embodiment, when the air flow passes through the air flow space 130, the air pressure at the location where the width of the air flow space 130 is the smallest is the largest. By increasing the air pressure, the support stiffness at the middle part of the bottom foil 100 can be improved, thereby improving the stability and accuracy of the thrust gas bearing. That is, the bottom foil 100 of this embodiment solves the technical problem of the relatively small support stiffness existing in the thrust gas bearing with a laminated structure in the related art, especially solves the problem of relatively small support stiffness in the middle part of the thrust gas bearing.

[0061] In some embodiments, 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 gradually decreases, and the width reduction amplitude of the starting section of the support structure 120 is smaller than the width reduction amplitude of the ending section of the support structure 120, as Figure 11 shown. The starting section of the support structure 120 is a section from the edge side close to the foil body 110 to the middle of the support structure 120, and the ending section of the support structure 120 is a section from the middle of the support structure 120 to the center side close to the annular space, as Figure 11 shown.

[0062] The statement that the width reduction amplitude of the starting section of the support structure 120 in this embodiment is smaller than the width reduction amplitude of the ending section of the support structure 120 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 ending section of the support structure 120; or it can be said that the width reduction degree of the starting section of the support structure 120 is smaller than the width reduction degree of the ending 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 ending section of the support structure 120, the reduction amount of the width of the starting section of the support structure 120 is smaller than the reduction amount of the width of the ending section of the support structure 120.

[0063] In the solution of this embodiment, the width of the support structure 120 gradually decreases, and the width reduction amplitude of the starting section of the support structure 120 is less than that of the ending section of the support structure 120. This can not only achieve that from the side close to the edge of the foil body 110 to the side close to the center of the annular space, the width of the air flow space 130 first gradually decreases and then gradually increases, so as to ensure the support stiffness at the middle part of the bottom foil 100 through the relatively large air pressure in the air flow space 130. Particularly importantly, since the width reduction amplitude of the support structure 120 in the starting section is small, the reduction degree of the support stiffness of the support structure 120 is small, so the support structure 120 can also ensure the support stiffness at the middle part of the bottom foil 100 through its own support effect. On the other hand, the gradually decreasing width of the support structure 120 makes the support structure 120 a streamlined structure, which is beneficial to improving the smoothness of the air flow passing through the air flow space 130, thereby further improving the stability and stiffness of the thrust gas bearing.

[0064] In some embodiments, from the side close to the edge of the foil body 110 to the side close to the center of the annular space, the width of the support structure 120 first gradually increases and then gradually decreases.

[0065] In the solution of this embodiment, the width of the support structure 120 first gradually increases and then gradually decreases, which can not only achieve that from the side close to the edge of the foil body 110 to the side close to the center of the annular space, the width of the air flow space 130 first gradually decreases and then gradually increases to ensure the support stiffness at the middle part of the bottom foil 100. On the other hand, at the middle part of the bottom foil 100, the width of the support structure 120 is the largest, so the support stiffness at the middle part of the bottom foil 100 can be improved through the support effect of the support structure 120 itself.

[0066] That is to say, in the solution of this embodiment, at the middle part of the bottom foil 100, not only can the support stiffness at the middle part of the bottom foil 100 be improved through the air flow, but also the support stiffness at the middle part of the bottom foil 100 can be improved through the support structure 120, so as to ensure that the bottom foil 100 has sufficient support stiffness at the middle part of the bottom foil 100.

[0067] In some embodiments, the side of the air flow space 130 close to the edge of the foil body 110 is the inlet side 131, and the side of the air flow 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, as Figure 11 shown. Exemplarily, the air flow enters through the inlet side 131 and then flows out from the outlet side 132. The equal width of the inlet side 131 and the outlet side 132 can make the air intake volume of the inlet side 131 and the exhaust volume of the outlet side 132 balanced.

[0068] Exemplarily, the opposite sides of two adjacent support structures 120 are symmetric about the diameter of the foil body 110, so that the air flow space 130 can be symmetric about the diameter of the foil body 110. Without limitation, the air flow space 130 is also symmetric about an arc along the circumferential direction of the foil body 110 to ensure that the width of the inlet side 131 of the air flow space 130 is equal to the width of the outlet side 132.

[0069] 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 air flow passes through the air flow space 130, the pressure balance between the intake side and the exhaust side can be maintained, which helps to form a stable air film in the air flow space 130, reduce the uneven deformation of the air film, and further improve the support stiffness of the underlying foil 100 through the stable and uniform air film, so as to improve the stability and accuracy of the thrust gas bearing. On the other hand, when the pressure of the intake side and the exhaust side is kept balanced, it can also avoid the problem that the pressure of the exhaust side is too large in the related art, resulting in too large damping characteristics and affecting the rotation reliability of the rotor 600.

[0070] In some embodiments, the support structure 120 includes a connecting section 121 and a supporting section 122, as Figure 11 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 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-layer foil 300 and the third-layer foil 400 stacked on the foil body 110.

[0071] Exemplarily, the connecting section 121 and the supporting section 122 can be an integral structure; or the connecting section 121 and the supporting section 122 are 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 can be an integral structure; or the connecting section 121 and the foil body 110 are fixedly connected by welding.

[0072] In some embodiments, an air inlet 140 is formed between two adjacent connecting sections 121, and an air flow space 130 is formed between two adjacent supporting sections 122. The air flow space 130 is communicated with the air inlet 140, as Figure 11As shown. Exemplarily, the air flow space 130 mentioned in the above solution of the embodiment of the present application especially refers 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 communicates with the first air inlet space 220 and the second air inlet space. After the external gas 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 air flow space 130, and finally flows out from the outlet side 132 of the air flow space 130.

[0073] In some embodiments, the width of the connecting segment 121 is smaller than the width of the support segment 122 on the side close to the foil body 110, and the width of the air inlet 140 is made larger than the width of the air flow space 130, such as Figure 11 shown. Specifically, the width of the air inlet 140 is made larger than the width of the inlet side 131 of the air flow space 130.

[0074] In the solution of this embodiment, the width of the air inlet 140 is larger than the width of the inlet side 131 of the air flow space 130, which can allow more gas to enter the air inlet 140 and form a larger air film pressure at the air flow space 130, helping 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 prevent vibration or disturbance from occurring after the air flow enters the air inlet 140, thereby improving the stability of the entire system.

[0075] In some embodiments, both sides of the support segment 122 are the first arc structures 122a, such as Figure 11 shown. When the air flow passes through the air flow space 130, compared with the support segment 122 with a straight-line structure, in the solution of this embodiment, both sides of the support segment 122 are the first arc structures 122a, and the first arc structures 122a help to distribute the air flow more evenly, thereby improving the uniformity of the air film pressure distribution; in addition, the first arc structures 122a can guide the air flow, thereby improving the smoothness of the air flow passing through the air flow space 130 and reducing air flow disturbance. It can be seen that both sides of the support segment 122 being the first arc structures 122a can improve the stability and stiffness of the thrust gas bearing at least from two aspects: improving the uniformity of the air film pressure distribution and improving the smoothness of the air flow passing through.

[0076] 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, such as Figure 11 shown. That is, 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 at a point, making the width of the support segment 122 at one end close to the center of the annular space reach the minimum, such as Figure 11 shown.

[0077] In the related art, the outlet end of the support piece has a certain width, which makes it difficult for the air flow to flow to the front of the outlet end of the support piece, and there is a hidden danger of forming an air flow dead zone here. Once the air flow dead zone is formed, the pressure at the dead zone decreases, which not only causes uneven distribution of the air film pressure, but also causes uneven distribution of the air film thickness, affecting the stability and accuracy of the system; forming an air flow dead zone may also cause local eddies in the air flow, and this kind of eddy will exacerbate the instability of the air film, resulting in air film vortex, and further reducing the stiffness and stability of the thrust gas bearing; forming an air flow dead zone also leads to increased friction and energy loss of the air flow, affecting the efficiency of the thrust gas bearing.

[0078] In the solution of this embodiment, the first arc-shaped structures 122a on both sides of the support section 122 intersect at a point, which can make the air flow cover all areas, avoid the formation of an air flow dead zone, improve the smoothness of the air flow passing through the air flow space 130, and at the same time reduce air flow disturbance, thereby improving the performance of the thrust gas bearing. Specifically, the stability, accuracy, stiffness and efficiency of the thrust gas bearing can all be improved.

[0079] In some embodiments, the first arc-shaped structure 122a is an arc. That is, the first arc-shaped structure 122a is a section on a circle. Preferably, the center of the circle where the first arc-shaped structure 122a is located is located on the foil body 110, as Figure 12 shown. Figure 12 The dotted line in shows the circle where the first arc-shaped structure 122a is located, Figure 12 and the center 122c in is the center of the circle where the first arc-shaped structure 122a is located. More preferably, the centers of the circles where the respective first arc-shaped structures 122a are located are located on the same circle. That is, the diameters of the circles where the respective first arc-shaped structures 122a are located are the same. Particularly preferably, the area of the support section 122 is half of the intersecting area of the two circles where the two arcs are located, which is beneficial to maintaining the balance of air intake and air outlet.

[0080] In the solution of this embodiment, the first arc-shaped structure 122a is an arc, and the centers of the circles where the respective first arc-shaped structures 122a are located are located on the same circle. On the basis of ensuring that the width of the air flow space 130 between the first arc-shaped structures 122a gradually decreases first and then gradually increases, and the width of the inlet side 131 of the air flow space 130 is equal to the width of the outlet side 132, the design of the first arc-shaped structure 122a can be simplified.

[0081] In some embodiments, the connection between the connection section 121 and the support section 122 is a second arc-shaped structure 122b, and the second arc-shaped structure 122b extends to both sides of the support section 122, as Figure 13As shown. That is, when the air flow flows from the air inlet 140 to the inlet side 131 of the air flow space 130, the areas through which the air flow passes are all arc-shaped structures, so as to further improve the smoothness of the air flow passing through the air inlet 140 and the air flow space 130. At the same time, it can also reduce air flow disturbance and avoid the formation of air flow dead zones or vortex zones, thereby improving the support stiffness and stability of the bottom foil 100.

[0082] The second aspect of this embodiment will be described in detail for the thrust gas bearing.

[0083] The thrust gas bearing of this embodiment includes a top foil 200, a second layer foil 300, a third layer foil 400, and a bottom foil 100 stacked on top of each other from top to bottom, as Figures 1 to 4 shown. The thrust gas bearing of this embodiment further includes a base 500, and the bottom foil 100 is stacked on the base 500, as Figures 1 to 3 shown. The structures and functions of the top foil 200, the second layer foil 300, the third layer foil 400, and the base 500 can be referred to the foregoing embodiments and will not be elaborated herein.

[0084] 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. Through this bottom foil 100, the stability and accuracy of the thrust gas bearing can be improved.

[0085] In some embodiments, the thickness of the third layer foil 400 located in the middle of the air flow space 130 satisfies: L 1 >L. L 1 is the thickness of the third layer foil 400 located in the middle of the air flow space 130, and L is the thickness of the third layer foil 400 located at both ends of the air flow space 130, as Figure 8 and Figure 9 shown. In the solution of this embodiment, the thickness of the third layer foil 400 located in the middle of the air flow space 130 is made relatively thick, and the axial support stiffness of the thrust gas bearing can be further improved through the third layer foil 400.

[0086] In some embodiments, the support structure 120 is provided with a recess, and the third layer foil 400 corresponding to the upper part of the support structure 120 is provided with a protrusion, and the position of the protrusion corresponds to that of the recess, so that when assembling the thrust gas bearing, pre-positioning can be achieved through the cooperation of the protrusion and the recess, and at the same time, the support performance of the thrust gas bearing can be prevented from being affected.

[0087] The third aspect of this embodiment will be described in detail for the rotating machinery.

[0088] The rotating machinery of this embodiment includes the thrust gas bearing of any one of the technical solutions in the second aspect of this embodiment, as Figure 14As shown. In this way, the rotating machinery has the advantages of stability and reliable precision.

[0089] In some embodiments, the rotating machinery further includes a rotor 600, as Figure 14 and Figure 15 shown. The rotor 600 is sleeved within the thrust gas bearing. The rotor 600 includes a radially protruding thrust disk 610. The number of thrust gas bearings is two. The two thrust gas bearings are spaced along the axial direction of the rotor 600 and arranged in opposite directions. The thrust disk 610 is located between the two thrust gas bearings to utilize the two thrust gas bearings to achieve bidirectional suspension of the thrust disk 610 and maintain the position of the rotor 600 in its axial direction, as Figure 14 and Figure 15 shown.

[0090] It should be noted that in this article, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including that element.

[0091] In addition, it should be pointed out 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 the 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. Additionally, the features described with reference to certain examples may be combined in other examples.

[0092] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within 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), the support structures (120) being arranged along the circumferential direction of the foil body (110), the support structures (120) being distributed at intervals in the annular space of the foil body (110), an airflow space (130) being formed between two adjacent support structures (120), and 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; 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); Two opposite sides of two adjacent support structures (120) are symmetrical about the diameter of the foil body (110), and the airflow space (130) is symmetrical about the diameter of the foil body (110); The support structure (120) comprises a connecting section (121) and a support section (122); both sides of the support section (122) are first arc structures (122a); and at one end of the support section (122) close to the center of the annular space, the first arc structures (122a) on both sides of the support section (122) intersect.

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 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).

4. The bottom foil according to claim 3, 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.

5. The bottom foil according to claim 3, 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).

6. 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 5; The thrust gas bearing further comprises a base (500), and the bottom foil (100) is stacked on the base (500).

7. The thrust gas bearing according to claim 6, characterized in that: The thickness of the third foil (400) located in the middle of the airflow space (130) satisfies: L1>L, wherein: L1 is the thickness of the third foil layer (400) located in the middle of the airflow space (130), and L is the thickness of the third foil layer (400) located at both ends of the airflow space (130).

8. A rotating machine, characterized in that: Includes the thrust gas bearing described in claim 6 or 7.

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