Radial foil air bearing and air suspension equipment

Abstract

The invention relates to a radial foil air bearing and air suspension equipment, and belongs to the technical field of air bearings. The radial foil air bearing comprises a bearing seat, a bottom foil, a bump foil, a top foil and a shaft sleeve which are sequentially arranged from outside to inside; a plurality of bump foils are sequentially arranged on the inner side of the bottom foil along the circumference, one end of each bump foil is fixed on the bottom foil, the other end of each bump foil is a free end, and each bump foil comprises a plurality of multistage elastic units which are connected with one another; two top foils are sequentially arranged on the inner side of each bump foil in the circumferential direction, one end of each top foil is a fixed end, and the other end of each top foil is a free end; the shaft sleeve is used for limiting the bottom foil and the bump foil and the top foil arranged on the bottom foil between the bearing seat and the shaft sleeve. The heat dissipation problem of the radial air bearing is solved by arranging the two top foils on the bump foil; and meanwhile, the bump foil is provided with the three bulges of which the heights are sequentially reduced, so that the bearing capacity of the radial foil air bearing can be improved through the synergistic effect of the bump foil and the top foil.

Description

Technical Field

[0001] The present invention relates to a radial foil air bearing and an air suspension device, belonging to the technical field of air bearings. Background Art

[0002] Foil air bearings have the advantages of low friction, high rotational speed, oil-free and pollution-free, etc., and are currently widely used in high-speed rotating machinery fields such as air circulators, blowers, and air compressors.

[0003] Foil air bearings are widely used in high-speed rotating machinery due to characteristics such as oil-free lubrication and low friction loss. There are two major technical bottlenecks in traditional radial foil bearings: First, thermal management defects: Under high-speed conditions, the shear heat accumulation of the air film is significant, and the single-top foil structure has a single heat dissipation path, resulting in heat stress concentration and causing the top foil to creep and fail. At high rotational speeds, the local temperature rise of the top foil can reach more than 120°C. Second, the load-carrying performance is limited: The stiffness curve of the single-wave foil structure shows a linear characteristic, and it is impossible to achieve the gradient load-carrying of the air film pressure. When dynamically loaded, the air film pressure distribution is uneven, and the bearing capacity fluctuates greatly, severely restricting its application in equipment with variable working conditions.

[0004] Therefore, there is an urgent need for a new type of radial foil air bearing to solve the problems of bearing heat dissipation and bearing capacity. Summary of the Invention

[0005] In view of the deficiencies of the prior art, an object of the present invention is to provide a radial foil air bearing, which has a multi-stage elastic unit and a multi-piece double-top foil heat dissipation channel design. By setting two top foils on each wave foil, the heat dissipation effect of the radial air bearing is enhanced, and by setting a multi-stage elastic unit in the wave foil, the gradient load-carrying of the air film pressure is realized.

[0006] An object of the present invention is to provide an air suspension device.

[0007] The technical solution of the present invention is as follows: On the one hand, the present invention provides a radial foil air bearing, which includes a bearing housing, a bottom foil, wave foils, top foils, and a shaft sleeve arranged in sequence from outside to inside, and the shaft sleeve is sleeved outside the rotating shaft; The bottom foil is an unclosed cylindrical structure, and several wave foils are sequentially arranged along the circumference on the inner side of the bottom foil. One end of each wave foil is fixed on the bottom foil, and the other end of the wave foil is a free end. The wave foil includes several multi-stage elastic units arranged along the circumferential direction for gradiently carrying different bearing capacities between the rotating shaft and the shaft sleeve; Two top foils are sequentially arranged along the circumference on the inner side of each wave foil. One end of each top foil is a fixed end, and the other end of the top foil is a free end; The shaft sleeve is used to confine the bottom foil and the wave foils and top foils arranged on the bottom foil between the bearing housing and the shaft sleeve.

[0008] In the air bearing structure provided by the present invention, two top foils are arranged on each wave foil. On the one hand, the independent top foils form a split heat dissipation channel, and the design of the top foil with the cooperation gap forming a convective heat transfer area is beneficial to dissipate heat from the radial air bearing, avoiding the excessive temperature of the bearing caused by the accumulation of gas film shear heat; the design of the two top foils enables the top foils to expand and contract independently, which can reduce the risk of deformation of the top foil caused by thermal stress and improve the reliability of the bearing. On the other hand, the top foil and the multi-stage elastic unit act synergistically to further increase the stiffness of the initial low-frequency vibration, provide bearing capacity for the gas film, and ensure the stability of the gas film, so that the air bearing can work normally.

[0009] Preferably according to the present invention, the multi-stage elastic unit includes a first-level arc, a second-level arc and a third-level arc distributed radially.

[0010] Preferably according to the present invention, the height of the first-level arc is greater than the height of the second-level arc, and the height of the second-level arc is greater than the height of the third-level arc.

[0011] Preferably according to the present invention, the chord length of the first-level arc is greater than the chord length of the second-level arc, and the chord length of the second-level arc is greater than the chord length of the third-level arc.

[0012] Preferably according to the present invention, the first-level arc, the second-level arc and the third-level arc protrude towards the center of the radial foil air bearing.

[0013] Preferably according to the present invention, the top foil is a flat foil.

[0014] Preferably according to the present invention, for the two top foils arranged on the same wave foil, the fixed ends of the two top foils are both fixed at the top of the first-level arc.

[0015] Preferably according to the present invention, for the two top foils arranged on the same wave foil, there is a certain distance between the two top foils.

[0016] Preferably according to the present invention, a plurality of wave foils are arranged along the axial direction on the bottom foil.

[0017] On the other hand, the present invention provides an air suspension device, which is characterized in that it includes the above-mentioned radial foil air bearing; the air suspension device includes an air suspension blower, an air suspension vacuum pump or an air suspension compressor.

[0018] The beneficial effects of the present invention are as follows: A radial foil air bearing and an air suspension device provided by the present invention reasonably arrange two top foils on each wave foil. The design of the top foil not only ensures the smoothness of the heat dissipation channel but also enables a stable load-bearing structure to be formed on the top foil for the air film, achieving a good balance between heat dissipation and load-bearing performance and improving the comprehensive performance of the radial foil air bearing. At the same time, three arcs with gradually decreasing radii on the wave foil can form a multi-stage support structure, which can withstand air film extrusion of different degrees and improve the load-bearing capacity of the radial foil air bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a schematic structural diagram of the radial foil air bearing provided by the present invention.

[0020] Figure 2 FIG. is a three-dimensional structural diagram of the bottom foil, wave foil and top foil provided by the present invention.

[0021] Figure 3 FIG. is a cross-sectional structural diagram of the bottom foil, wave foil and top foil provided by the present invention.

[0022] Figure 4 FIG. is a partial structural diagram of the bottom foil, wave foil and top foil provided by the present invention.

[0023] Figure 5 FIG. is a structural diagram of the wave foil provided by the present invention.

[0024] In the figure, 1, bearing housing; 2, bottom foil; 3, wave foil; 4, top foil; 5, bushing; 6, first arc; 7, second arc; 8, third arc; 9, multi-stage elastic unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following will disclose several embodiments of the present application by means of illustrations, and clearly and completely describe the technical solutions of the present invention, which constitutes a part of the present application. The accompanying drawings of the specification are used to provide a further understanding of the present invention. The illustrative embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] It should be noted that unless otherwise defined, the up, down, left, right and other directions involved in this article are based on the up, down, left, right and other directions shown in the embodiments of the present application Figure 1 If the specific posture changes, the directional indication will also change accordingly. The "first", "second" and similar terms used in the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. In addition, in various embodiments of the present disclosure, the same or similar reference numerals represent the same or similar components.

[0027] In the present invention, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral one, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In addition, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0029] Embodiment 1 The present invention provides a radial foil air bearing, as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 shown, including a bearing housing 1, a bottom foil 2, a wave foil 3, a top foil 4, and a sleeve 5 arranged in sequence from outside to inside; the bottom foil 2 is sleeved between the bearing housing 1 and the sleeve 5, the bottom foil 2 is an unclosed cylindrical structure, and a plurality of wave foils 3 are arranged in sequence along the circumference on the inner side of the bottom foil 2. One end of each wave foil 3 is fixed on the bottom foil 2, and the other end of the wave foil 3 is a free end. The wave foil 3 includes a plurality of multi-stage elastic units 9 arranged along the circumferential direction, which are used to gradiently bear different bearing capacities between the rotating shaft and the sleeve 5; two top foils 4 are arranged in sequence along the circumference on the inner side of each wave foil 3. One end of the first top foil 4 is a fixed end, and the other end is a free end; the second top foil 4 also has one end as a fixed end and the other end as a free end; and the fixed end of the second top foil 4 is close to the free end of the first top foil. The sleeve 5 is used to limit the bottom foil 2 and the wave foils 3 and top foils 4 arranged on the bottom foil 2 between the bearing housing 1 and the sleeve 5.

[0030] During the rotation of the rotating shaft, a pressure air film is formed between the rotating shaft and the sleeve 5, and the pressure air film presses the sleeve 5 to make the sleeve 5 approach the top foil 4 and adhere to the surface of the wave foil 3.

[0031] Arranging two top foils 4 on each wave foil 3 can increase the contact points between the sleeve 5 and the top foils 4, avoid local stress concentration, and is also beneficial to improving the bearing capacity of the bearing. The top foils 4 cooperate with the multi-stage elastic units 9 to further increase the stiffness of the initial low-frequency vibration, provide bearing capacity for the air film, and ensure the stability of the air film.

[0032] The air bearing structure provided by the present invention is provided with two independent top foils 4 on each wave foil 3. The design of the top foil 4 increases the heat dissipation area inside the bearing. During the high-speed operation of the radial air bearing, heat will be generated due to the viscous shear of the air film, gas compression and expansion, etc. The independent top foil 4 forms a split heat dissipation channel, which cooperates with the gap to form a convective heat transfer area, and conducts this heat out faster, avoiding problems such as the decline of material performance and the deterioration of air film stability caused by too high temperature of the air bearing, and ensuring that the air bearing works in a suitable temperature environment. When the temperature inside the bearing changes, the independent top foil 4 forms a split heat dissipation channel, reducing the concentration of thermal stress, thereby greatly reducing the possibility of deformation of the top foil 4 caused by thermal stress. This helps to maintain the shape accuracy of the top foil 4, ensures its supporting and bearing performance for the air film, and improves the reliability of the bearing operation.

[0033] Embodiment 2 This embodiment provides a radial foil air bearing, and the difference from Embodiment 1 is that: As Figure 4 and Figure 5 shown, the multi-stage elastic unit 9 includes a first-stage arc 6, a second-stage arc 7 and a third-stage arc 8 distributed radially. The first-stage arc 6 provides an initial stiffness to resist low-frequency vibration, and the second-stage arc 7 and the third-stage arc 8 are sequentially involved in deformation to absorb high-frequency impacts, so that the bearing capacity is improved and the stiffness adjustment range is expanded.

[0034] Embodiment 3 This embodiment provides a radial foil air bearing, and the difference from Embodiment 2 is that: As Figure 4 and Figure 5 shown, the height of the first-stage arc 6 is greater than the height of the second-stage arc 7, and the height of the second-stage arc 7 is greater than the height of the third-stage arc 8. It is beneficial to form a gradient support structure for the air film.

[0035] Embodiment 4 This embodiment provides a radial foil air bearing, and the difference from Embodiment 2 is that: As Figure 4 and Figure 5 shown, the chord length of the first-stage arc 6 is greater than the chord length of the second-stage arc 7, and the chord length of the second-stage arc 7 is greater than the chord length of the third-stage arc 8. It is beneficial to form a gradient support structure for the air film.

[0036] Embodiment 5 This embodiment provides a radial foil air bearing, and the difference from Embodiment 2 is that: As Figure 1 shown, the first-stage arc 6, the second-stage arc 7 and the third-stage arc 8 protrude towards the center of the radial foil air bearing. Thus, effective supporting force is provided.

[0037] Example 6 This example provides a radial foil air bearing, which is different from that in Example 1 in that: As Figure 2 shown, the top foil 4 is a flat foil. Designing it as a flat foil facilitates installation and manufacturing, and also facilitates the uniform transfer of the air film pressure to the multi-stage elastic unit 9 of the corrugated foil 3.

[0038] Example 7 This example provides a radial foil air bearing, which is different from that in Example 2 in that: As Figure 3 and Figure 4 shown, for the two top foils 4 provided on the same corrugated foil 3, the fixed ends of the two top foils 4 are both fixed at the top of the first-stage arc 6.

[0039] Such a design enables the two top foils 4 to effectively cooperate with the multi-stage elastic unit 9 of the corrugated foil 3 for expansion and contraction.

[0040] Example 8 This example provides a radial foil air bearing, which is different from that in Example 2 in that: As Figure 2 and Figure 3 shown, for the two top foils 4 provided on the same corrugated foil 3, there is a certain distance between the two top foils 4. Specifically, there is a certain gap between the free end of one top foil 4 and the fixed end of the other top foil 4, which facilitates heat dissipation. While the top foil 4 meets the heat dissipation requirements of the radial air bearing, it also takes into account the load-bearing requirements of the air film.

[0041] Example 9 This example provides a radial foil air bearing, which is different from that in Example 1 in that: As Figure 2 shown, a number of corrugated foils 3 are arranged along the axial direction on the bottom foil 2.

[0042] Example 10 This example provides an air suspension device, including the radial foil air bearing provided in any one of Examples 1-9; the air suspension device includes an air suspension blower, an air suspension vacuum pump or an air suspension compressor.

[0043] The foregoing description has shown and described the preferred embodiments of the present application. However, as mentioned above, it should be understood that the present application is not limited to the forms disclosed herein, and should not be regarded as excluding other embodiments. Instead, it can be used in various other combinations, modifications, and environments, and can be changed within the scope contemplated herein through the above teachings or the techniques or knowledge in the relevant field. Any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A radial foil air bearing, characterized in that: It includes a bearing seat, a bottom foil, a corrugated foil, a top foil and a shaft sleeve which are arranged in sequence from outside to inside, and the shaft sleeve is sleeved on the outside of the rotating shaft; The bottom foil is an unclosed cylindrical structure, and a plurality of corrugated foils are arranged in sequence along the circumference of the inner side of the bottom foil, one end of each corrugated foil is fixed on the bottom foil, and the other end of the corrugated foil is a free end, and the corrugated foil includes a plurality of multi-stage elastic units arranged along the circumferential direction, which are used to gradiently bear different bearing forces between the rotating shaft and the sleeve; Two top foils are arranged in sequence along the circumferential direction on the inner side of each corrugated foil, one end of each top foil is a fixed end, and the other end of the top foil is a free end; The shaft sleeve is used to confine the bottom foil and the bump foil and the top foil arranged on the bottom foil between the bearing seat and the shaft sleeve.

2. A radial foil air bearing according to claim 1, characterized in that: The multi-stage elastic unit includes a primary circular arc, a secondary circular arc and a tertiary circular arc distributed in the radial direction.

3. A radial foil air bearing according to claim 2, characterized in that: The height of the primary arc is greater than the height of the secondary arc, and the height of the secondary arc is greater than the height of the tertiary arc.

4. A radial foil air bearing according to claim 2, characterized in that: The chord length of the primary arc is greater than that of the secondary arc, and the chord length of the secondary arc is greater than that of the tertiary arc.

5. A radial foil air bearing according to claim 2, characterized in that: The primary arc, the secondary arc, and the tertiary arc are raised toward the center of the radial foil air bearing.

6. A radial foil air bearing according to claim 1, characterized in that: The top foil is a flat foil.

7. A radial foil air bearing according to claim 2, characterized in that: For the two top foils arranged on the same corrugated foil, the fixed ends of the two top foils are both fixed on the top of the primary arc.

8. A radial foil air bearing according to claim 2, characterized in that: For two top foils arranged on the same bump foil, there is a certain distance between the two top foils.

9. A radial foil air bearing according to claim 1, characterized in that: The bottom foil is provided with a plurality of corrugated foils along the axial direction.

10. An air suspension device, characterized in that: It comprises the radial foil air bearing according to any one of claims 1 to 9; the air suspension equipment comprises an air suspension blower, an air suspension vacuum pump or an air suspension compressor.

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