A bearing foil assembly, a bearing assembly and an air compressor

Abstract

The application provides a bearing foil assembly, a bearing assembly and an air compressor, the bearing foil assembly is composed of one layer of flat foil and one layer of wave foil, the wave foil is located at the outer periphery of the flat foil, the inner periphery of the flat foil is a flat structure with a center O, the upper half curve segment of the inner periphery of the flat foil is smoothly connected with the opposite lower half curve segment through a first virtual curve segment, the upper half curve segment is smoothly connected with the opposite lower half curve segment through a second virtual curve segment; the distance between the intersection point of the X axis and the first virtual curve segment and the intersection point of the X axis and the second virtual curve segment is x, the distance between the intersection point of the Y axis and the upper half curve segment and the intersection point of the Y axis and the lower half curve segment is y, and x>y. According to the application, the wedge-shaped ratio can be effectively improved, the air suspension buoyancy can be increased, the single layer of wave foil and the single layer of flat foil are adopted, the smooth and continuous wave valley can be formed to cut the flat and continuous curve, and the rotor can be uniformly and continuously supported after the flat foil is attached, so that the supporting performance is improved.

Description

Technical Field

[0001] This invention relates to the field of bearing technology, and more specifically to a bearing foil assembly, a bearing assembly, and an air compressor. Background Technology

[0002] High-speed permanent magnet synchronous motors have advantages such as small size, high power density, and high efficiency, and are widely used in the centrifuge field. Small-power high-speed centrifuges generally use air-bearing bearings for rotor support, with motor speeds exceeding 100,000 rpm. The gas supporting the motor rotor is the same as the gas pumped out of the centrifuge, thus eliminating any pollution. Dynamic pressure air-bearing bearings form a dynamic pressure gas film through wedge-shaped gaps. Current air-bearing bearings are generally made by stamping and assembling special metal foil sheets, primarily with a circular structure.

[0003] This structure has a major drawback: the ratio of the front and rear cross-sectional areas (or the larger and smaller cross-sectional areas) of the wedge-shaped gap is limited, and the magnitude of this ratio determines the air suspension pressure. If the gap between the motor shaft diameter and the inner foil diameter of the bearing is large, although the wedge ratio can be increased, the coaxiality of the shaft and bearing is poor, resulting in greater shaft vibration and poor operational stability. If the gap between the motor shaft diameter and the inner foil diameter of the bearing is small, the air suspension pressure is limited, and the rotor weight must be light, which restricts the motor structure and performance.

[0004] Because existing air suspension bearings have technical problems such as low wedge ratio, resulting in low air suspension pressure and poor support effect, as well as poor transition smoothness between two or more layers of corrugated foil, making it impossible to support the rotor evenly and continuously, this invention studies and designs a bearing foil assembly, a bearing assembly, and an air compressor. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the existing air suspension bearings, such as poor support effect and the inability to uniformly and continuously support the rotor when using two or more layers of corrugated foil, thereby providing a bearing foil assembly, a bearing assembly and an air compressor.

[0006] To address the above problems, the present invention provides a bearing foil assembly:

[0007] It consists of one layer of flat foil and one layer of corrugated foil. The corrugated foil is located on the outer periphery of the flat foil. In the projection plane of the vertical plane, the inner periphery of the flat foil has a flat structure with a center O. The horizontal straight line passing through point O is the X-axis, and the vertical straight line passing through point O is the Y-axis. The inner periphery of the flat foil includes an upper half-curved segment above the X-axis and a lower half-curved segment below the X-axis. The first lower end of the upper half-curved segment and the first upper end of the opposite lower half-curved segment are spaced apart and are smoothly connected by a first dashed curve segment. The second lower end of the upper half-curved segment and the second upper end of the opposite lower half-curved segment are spaced apart and are smoothly connected by a second dashed curve segment. Both the first dashed curve segment and the second dashed curve segment are virtual non-solid line segments.

[0008] The distance between the intersection point of the X-axis with the first dashed curve segment and the intersection point of the X-axis with the second dashed curve segment is the length x of the inner circumference of the flat foil along the X direction. The distance between the intersection point of the Y-axis with the upper half curve segment and the intersection point of the Y-axis with the lower half curve segment is the length y of the inner circumference of the flat foil along the Y direction, and x > y.

[0009] In some implementations...

[0010] The corrugated foil includes multiple radially outward protruding peaks, spaced apart from each other, and forming troughs between adjacent peaks. The inner peripheries of the multiple troughs are all fitted to the outer periphery of the flat foil. A continuous annular curve is circumscribed around the multiple peaks, with the center of the annular curve also being point O. The distance between the two intersections of the annular curve and the X-axis is the length x' of the outer periphery of the corrugated foil along the X-direction, and the distance between the two intersections of the annular curve and the Y-axis is the length y' of the outer periphery of the corrugated foil along the Y-direction, with x' ≥ y'.

[0011] In some implementations...

[0012] The upper half-curved segment of the flat foil is a partial curve segment of an ellipse, parabola, or involute, and the lower half-curved segment of the flat foil is also a partial curve segment of an ellipse, parabola, or involute. When both the upper and lower half-curved segments are ellipse, the upper half-curved segment, the first dashed curve segment, the lower half-curved segment, and the second dashed curve segment connect to form a complete elliptical circle, and the radially inward convex surfaces of the plurality of troughs are all tangent to the complete elliptical circle. When both the upper and lower half-curved segments are parabolas, the radially inward convex surfaces of the plurality of troughs are all tangent to the parabola. When both the upper and lower half-curved segments are involutes, the radially inward convex surfaces of the plurality of troughs are all tangent to the involute.

[0013] The wave peaks closer to the Y-axis in the wave foil have higher heights, while those farther from the Y-axis have lower heights. The radially convex surfaces of multiple wave peaks are located on the same first circumcircle, i.e., the annular curve is a circle, such that x' = y', and the center of the first circumcircle is located at point O.

[0014] In some implementations...

[0015] The wave foil includes an upper half-wave foil located above the X-axis and a lower half-wave foil located below the X-axis. The radially outward convex surfaces of all the peaks of the upper half-wave foil are connected to the first circumscribed circle, and the radially inward convex surfaces of all the troughs of the upper half-wave foil are tangent to the outer peripheral surface of the upper half-curved segment of the flat foil. The radially outward convex surfaces of all the peaks of the lower half-wave foil are connected to the first circumscribed circle, and the radially inward convex surfaces of all the troughs of the lower half-wave foil are tangent to the outer peripheral surface of the lower half-curved segment of the flat foil.

[0016] In some implementations...

[0017] The upper half-curved segment and the lower half-curved segment of the flat foil are symmetrically arranged with respect to the X-axis, the upper half-curved segment of the flat foil is symmetrically arranged with respect to the Y-axis, and the lower half-curved segment of the flat foil is symmetrically arranged with respect to the Y-axis.

[0018] The upper half-wave foil and the lower half-wave foil are symmetrical with respect to the X-axis, the upper half-wave foil is symmetrical with respect to the Y-axis, and the lower half-wave foil is symmetrical with respect to the Y-axis.

[0019] In some implementations...

[0020] The upper half of the curved segment of the flat foil is a circular arc segment, and the lower half of the curved segment of the flat foil is a circular arc segment.

[0021] First, a circular flat foil is created within the projection plane of a vertical plane. The circular flat foil has point O as its center, the X-axis as its horizontal axis of symmetry, and the Y-axis as its vertical axis of symmetry. Then, arc segments of a certain length are cut off at two points where the circular flat foil intersects with the X-axis to form the upper half-curve segment and the lower half-curve segment. Finally, the upper half-curve segment and the lower half-curve segment are connected together.

[0022] In some implementations...

[0023] After the excision, the first lower end of the upper half curve segment is connected to the first upper end of the opposite lower half curve segment through the first dashed curve segment, and the second lower end of the upper half curve segment is connected to the second upper end of the opposite lower half curve segment through the second dashed curve segment. The lengths of the arc segments of the two excised portions are equal, and the lengths of the first dashed curve segment and the second dashed curve segment are equal and symmetrically arranged with respect to point O.

[0024] In some implementations...

[0025] The corrugated foil includes multiple radially outward protruding peaks, spaced apart from each other, with troughs formed between adjacent peaks. The inner peripheries of the multiple troughs are fitted to the outer periphery of the flat foil. The corrugated foil is also cut off at a position radially opposite to the cut-off portion of the flat foil, and the two cut-off portions of the corrugated foil are spliced ​​together. A continuous annular curve is circumscribed around the multiple peaks, with the center of the annular curve also being point O. The distance between the two intersections of the annular curve and the X-axis is the length x' of the outer periphery of the corrugated foil along the X-direction, and the distance between the two intersections of the annular curve and the Y-axis is the length y' of the outer periphery of the corrugated foil along the Y-direction, with x' ≥ y'.

[0026] In some implementations...

[0027] Before and after the excision, the radially convex surfaces of the multiple troughs are tangent to the outer peripheral surface of the flat foil; the peak heights of the multiple foils are all equal.

[0028] Before the removal, the radially convex surfaces of the multiple peaks are located on the same second circumcircle, and the center of the second circumcircle is located at point O, such that after removal, x' > y'.

[0029] In some implementations...

[0030] It also includes a rotor shaft, which is located on the inner circumference of the flat foil and in the projection plane in the vertical plane. The minimum distance between the rotor shaft and the ellipse, parabola or involute of the inner circumference of the flat foil on the X-axis is the side gap, and the minimum distance between the rotor shaft and the ellipse, parabola or involute of the inner circumference of the flat foil on the Y-axis is the top gap. The side gap is greater than the top gap, and the ratio between the side gap and the top gap is the wedge ratio.

[0031] In some implementations...

[0032] It also includes a rotor shaft, which is located on the inner periphery of the flat foil and in the projection plane in the vertical plane. The minimum distance between the rotor shaft and the first or second dashed curve segment of the inner periphery of the flat foil on the X-axis is the side gap, and the minimum distance between the rotor shaft and the inner periphery of the flat foil on the Y-axis is the top gap. The side gap is greater than the top gap, and the ratio between the side gap and the top gap is the wedge ratio.

[0033] The present invention also provides a bearing assembly, which includes the aforementioned bearing foil assembly and a bearing housing having a shaft hole, wherein the bearing foil assembly is disposed in the shaft hole to support a rotor shaft.

[0034] In some implementations...

[0035] In the projection plane of the vertical plane, the inner circumference of the bearing seat has a first receiving groove at the axial side where it connects with the X-axis, and the inner circumference of the bearing seat has a second receiving groove at the axial side where it connects with the X-axis. The first lower end of the upper half of the flat foil and the first upper end of the opposite lower half of the flat foil are connected by a first connecting part. The first connecting part is a protruding structure protruding toward the first receiving groove. The first connecting part is inserted into the first receiving groove to form a fixed end. The second lower end of the upper half of the flat foil and the second upper end of the opposite lower half of the flat foil are connected by a second connecting part. The second connecting part is a protruding structure protruding toward the second receiving groove. The second connecting part is inserted into the second receiving groove to form a free end.

[0036] In some implementations...

[0037] The third lower end of the upper half of the corrugated foil is connected to the third upper end of the opposite lower half of the corrugated foil via a third connecting part. The third connecting part is a protruding structure that protrudes toward the first receiving groove. The third connecting part is inserted into the first receiving groove to form a fixed end of the corrugated foil. The fourth lower end of the upper half of the corrugated foil is connected to the fourth upper end of the opposite lower half of the corrugated foil via a fourth connecting part. The fourth connecting part is a protruding structure that protrudes toward the second receiving groove. The fourth connecting part is inserted into the second receiving groove to form a free end of the corrugated foil.

[0038] In some implementations...

[0039] When the flat foil includes a free end, a fixed end, a corrugated foil, and a fixed end, the rotor shaft rotates in a direction such that the lower half of the flat foil rotates from the free end to the fixed end.

[0040] The rotor shaft rotates in such a direction that the lower half of the corrugated foil rotates from the free end of the corrugated foil to the fixed end of the corrugated foil.

[0041] The present invention also provides an air compressor, which includes the aforementioned bearing assembly and a rotor shaft, wherein the bearing assembly supports the rotor shaft.

[0042] The bearing foil assembly, bearing assembly, and air compressor provided by this invention have the following beneficial effects:

[0043] 1. This invention, by setting the inner circumference of the bearing foil assembly, particularly the flat foil, to a flat structure, i.e., the length x of the inner circumference of the flat foil along the X direction is greater than the length y of the inner circumference of the flat foil along the Y direction, enables the inner circle of the air suspension bearing to be a flat ellipse or quasi-ellipse, with the horizontal length being greater than the vertical length. This effectively makes the side clearance greater than the top clearance, further increasing the front cross-sectional area, thereby increasing the ratio of the front and rear cross-sectional areas, improving the wedge ratio, and effectively increasing the buoyancy of the air suspension, thus enabling the suspension of heavier rotors. Compared to the prior art's scheme of at least two layers of corrugated foil and / or at least two layers of flat foil, this invention uses a single layer of corrugated foil plus a single layer of flat foil. Through parameter adjustment, a very smooth and continuous flat continuous curve (such as an elliptical curve or a quasi-elliptical curve, including parabolas, involutes, etc.) with tangent inside the trough can be formed. After being bonded to the flat foil, it can support the rotor more evenly and continuously, improve the support performance, and reduce the resistance of the rotating airflow inside the bearing.

[0044] 2. This invention optimizes the inner diameter of the air suspension bearing in an ultra-high-speed motor by employing an elliptical or near-elliptical flat foil structure with a large lateral dimension and a small longitudinal dimension. This elliptical or near-elliptical air suspension bearing has a larger wedge ratio than a circular air suspension bearing, resulting in higher air pressure and increased buoyancy, allowing it to withstand heavier rotors. With the rotor weight remaining constant, increasing the front-to-rear cross-sectional area ratio increases the air suspension pressure at the same rotational speed. Conversely, by reducing the rotational speed, the same air suspension pressure as a circular inner diameter can be achieved, effectively increasing the motor's adjustable speed range. Since the rotor's center of gravity is downward, it generally deviates from the center of the air suspension bearing. The greater the bearing buoyancy of this invention, the smaller the deviation between the rotor centerline and the bearing centerline. This further reduces rotor whirl and vibration, minimizes collisions caused by whirl, and reduces motor noise generated by vibration.

[0045] 3. The elliptical air suspension bearing of Scheme 1 of this invention is achieved through a structure with a smooth, stepless gradual change in corrugation amplitude and a variable or constant corrugation width. Specifically, the corrugation amplitude is large in the middle (close to the y-axis) and low on both sides (away from the y-axis). Through simulation calculations, the height and width of the corrugations are accurately adjusted to form the envelope of the corrugated foil's inner diameter (or the inscribed curve of the inner diameter), i.e., the inner foil, which becomes a standard ellipse, parabola, or involute, i.e., a continuous curve. The outer diameter envelope of the corrugated foil is a standard circle, resulting in a gas bearing with only one layer of corrugated foil. This achieves a novel structure with a circular outer diameter and an elliptical, parabolic, or involute inner diameter. Thus, an elliptical, parabolic, or involute inner ring shape can be achieved using a circular bearing housing. Compared to existing technologies that use two layers of corrugated foil with different lengths, this invention eliminates one layer of corrugated foil, enabling a continuous curve, and is simpler and lower in cost. Therefore, this invention, by increasing dynamic pressure with a single layer of corrugated foil, has structural and cost advantages compared to existing technologies using double or multiple layers of corrugated foil.

[0046] 4. The approximate elliptical air suspension bearing of Scheme Two of the present invention involves designing the bearing housing into an approximate elliptical shape and making foil sheets with equal corrugation height into the same shape as the bearing housing, with their outer diameter matching the inner diameter of the bearing housing. The flat foil sheets are made to have the same size and shape as the inner diameter of the corrugated foil sheets, thus forming the approximate elliptical air suspension bearing of Scheme Two. Both Schemes One and Two of the present invention involve two pieces joined together, with one side fixed to the bearing housing to form a fixed end, and the other side free to form a free end. The major axis of the inner circumference of the ellipse is the fixed position of the foil sheets. When the motor rotates clockwise, the left side is the fixed end and the right side is the free end; when the motor rotates counterclockwise, the right side is the fixed end and the left side is the free end. That is, the motor rotor should rotate from the free end to the fixed end. This arrangement makes the motor starting process smoother and more stable. Attached Figure Description

[0047] Figure 1a This is a structural diagram of a bearing foil assembly in the prior art;

[0048] Figure 1b It is a diagram of the fit structure between the bearing assembly (including the bearing foil assembly and the bearing housing) and the rotor shaft in the prior art;

[0049] Figure 2a This is a structural diagram of the bearing foil assembly according to Scheme 1 of the present invention;

[0050] Figure 2b yes Figure 2a Draw the structural diagram of the first circumcircle of the wave crest of the foil;

[0051] Figure 2c yes Figure 2a Top view;

[0052] Figure 3a This is a structural diagram of the upper half of the flat foil in the bearing foil assembly of Scheme 1 of the present invention;

[0053] Figure 3b yes Figure 3a Top view;

[0054] Figure 4a A structural diagram of the upper half of the corrugated foil in the bearing foil assembly of Scheme 1 of the present invention;

[0055] Figure 4b yes Figure 4a Top view;

[0056] Figure 5 This is a structural diagram of the fit between the bearing assembly (including the bearing foil assembly and the bearing housing) and the rotor shaft according to Scheme 1 of the present invention.

[0057] Figure 6a This is a structural diagram of the bearing foil assembly of Scheme 2 of the present invention (after cutting off part of the arc segment);

[0058] Figure 6b yes Figure 6a The structural diagram before the cut-off arc segment (including the second circumcircle drawn from the crest of the foil);

[0059] Figure 6c yes Figure 6a Top view;

[0060] Figure 7a This is a structural diagram of the upper half of the flat foil in the bearing foil assembly of Scheme 2 of the present invention;

[0061] Figure 7b yes Figure 7a Top view;

[0062] Figure 8a A structural diagram of the upper half of the corrugated foil in the bearing foil assembly of Scheme 2 of the present invention;

[0063] Figure 8b yes Figure 8a Top view;

[0064] Figure 9 This is a structural diagram of the fit between the bearing assembly (including the bearing foil assembly and the bearing housing) and the rotor shaft in Scheme 2 of the present invention.

[0065] The reference numerals in the attached figures are as follows:

[0066] 1. Flat foil; 2. Corrugated foil; 3. Upper half-curved segment; 4. Lower half-curved segment; 5. First lower end; 6. First upper end; 7. First dashed curve segment; 8. Second lower end; 9. Second upper end; 10. Second dashed curve segment; 11. Crest; 12. Trough; 13. Upper half-corrugated foil; 14. Lower half-corrugated foil; 15. First circumscribed circle; 16. Second circumscribed circle; 17. Rotor shaft; 18. Side clearance; 19. Top clearance; 20. Bearing housing; 21. First receiving groove; 22. Second receiving groove; 23. First connecting part; 24. Second connecting part; 25. Third connecting part; 26. Fourth connecting part; 27. First cut-out portion; 28. Second cut-out portion. Detailed Implementation

[0067] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0069] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0070] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0071] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0072] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0073] like Figure 2a-9 As shown, the present invention provides a bearing foil assembly:

[0074] It consists of one layer of flat foil 1 and one layer of corrugated foil 2. The corrugated foil 2 is located on the outer periphery of the flat foil 1. In the projection plane of the vertical plane, the inner periphery of the flat foil 1 has a flat structure with a center O. The horizontal straight line passing through point O is the X-axis, and the vertical straight line passing through point O is the Y-axis. The inner periphery of the flat foil 1 includes an upper half-curved segment 3 located above the X-axis and a lower half-curved segment 4 located below the X-axis. The first lower end 5 of the upper half-curved segment 3 is spaced apart from the first upper end 6 of the opposite lower half-curved segment 4. The two are smoothly connected by a first dashed curve segment 7. The second lower end 8 of the upper half-curved segment 3 is spaced apart from the second upper end 9 of the opposite lower half-curved segment 4. The two are smoothly connected by a second dashed curve segment 10. The first dashed curve segment 7 and the second dashed curve segment 10 are both virtual non-solid line segments.

[0075] The distance between the intersection point of the X-axis and the first dashed curve segment 7 and the intersection point of the X-axis and the second dashed curve segment 10 is the length x of the inner circumference of the flat foil 1 along the X direction. The distance between the intersection point of the Y-axis and the upper half curve segment 3 and the intersection point of the Y-axis and the lower half curve segment 4 is the length y of the inner circumference of the flat foil 1 along the Y direction, and x > y.

[0076] This invention, by configuring the bearing foil assembly, particularly the inner circumference of the flat foil, into a flat structure (here, flat structure refers to the spacing x along the X-axis being greater than the spacing y along the Y-axis), i.e., the length x of the inner circumference of the flat foil along the X-axis being greater than the length y of the inner circumference along the Y-axis, enables the inner circle of the air suspension bearing to be a flattened ellipse or quasi-ellipse shape, with the horizontal length greater than the vertical length. This effectively makes the side clearance greater than the top clearance, further increasing the front cross-sectional area, thereby increasing the ratio of the front and rear cross-sectional areas, improving the wedge ratio, and effectively increasing the air suspension pressure. Therefore, it can suspend heavier loads. The rotor of this invention is a single-layer corrugated foil plus a single-layer flat foil. Compared with the existing technology which uses at least two layers of corrugated foil and / or at least two layers of flat foil (the existing technology uses circular flat foil, but the wedge ratio is small and the buoyancy is limited; in order to increase the side clearance, the existing technology uses double-layer corrugated foil of different lengths to increase the wedge ratio), the present invention uses a single-layer corrugated foil plus a single-layer flat foil. It can form a very smooth and continuous trough-tangled flat continuous curve (such as an elliptical curve or a quasi-elliptical curve, quasi-elliptical curves include parabolas, involutes, etc.) by adjusting the parameters. After being attached to the flat foil, it can support the rotor more evenly and continuously, improve the support performance, and reduce the resistance of the rotating airflow inside the bearing.

[0077] This invention optimizes the structure of the air suspension bearing inner diameter in ultra-high-speed motors by employing an elliptical or near-elliptical flat foil structure with a large lateral dimension and a small longitudinal dimension. This elliptical or near-elliptical air suspension bearing has a larger wedge ratio than a circular air suspension bearing, resulting in higher air pressure and increased buoyancy, allowing it to withstand heavier rotors. With the rotor weight remaining constant, increasing the front-to-rear cross-sectional area ratio increases the air suspension pressure at the same rotational speed. Conversely, by reducing the rotational speed, the same air suspension pressure as a circular inner diameter can be achieved, effectively increasing the motor's adjustable speed range. Since the rotor's center of gravity is downward, it generally deviates from the center of the air suspension bearing. The greater the bearing buoyancy of this invention, the smaller the deviation between the rotor centerline and the bearing centerline. This further reduces rotor whirl and vibration, minimizes collisions caused by whirl, and reduces motor noise generated by vibration.

[0078] This invention optimizes the design of air suspension bearings for ultra-high-speed motors, primarily by increasing the wedge ratio (or wedge angle) to improve the bearing's pressure-bearing capacity and allow for the levitation of a larger rotor. Through two different structural optimization schemes, this invention enables the inner diameter of the air suspension bearing to be elliptical or approximately elliptical, with the horizontal axis being the major axis and the vertical axis (direction of gravity) being the minor axis. This increases the inlet cross-sectional area of ​​the dynamic pressure air suspension bearing, thereby improving the wedge ratio and the bearing's pressure-bearing capacity.

[0079] In some implementations...

[0080] The upper half-curved segment 3 and the lower half-curved segment 4 of the flat foil 1 are symmetrically arranged with respect to the X-axis, the upper half-curved segment 3 of the flat foil 1 is symmetrically arranged with respect to the Y-axis, and the lower half-curved segment 4 of the flat foil 1 is symmetrically arranged with respect to the Y-axis.

[0081] This is a preferred structural form of the flat foil of the present invention. By making the upper and lower half-curved segments of the flat foil symmetrical with respect to the X-axis, the upper half-curved segment symmetrical with respect to the Y-axis, and the lower half-curved segment symmetrical with respect to the Y-axis, the gas on the inner circumference of the flat foil can support the internal rotor shaft in a uniform manner, thereby improving the support force and support effect.

[0082] like Figure 2a-5 In some implementation methods,

[0083] The corrugated foil 2 includes multiple radially outward protruding peaks 11, with adjacent peaks 11 spaced apart and valleys 12 formed between adjacent peaks 11. The inner periphery of each valley 12 is fitted to the outer periphery of the flat foil 1 (i.e., the inner periphery of the corrugated foil is also a flat structure with a horizontal length greater than the vertical length x > y). A continuous annular curve is connected to the multiple peaks 11, with the center of the annular curve being point O. The distance between the two intersections of the annular curve and the X-axis is the length x' of the outer periphery of the corrugated foil 2 along the X-axis, and the distance between the two intersections of the annular curve and the Y-axis is the length y' of the outer periphery of the corrugated foil 2 along the Y-axis, with x' ≥ y'.

[0084] The outer periphery of the corrugated foil of the present invention is an annular curve. The annular curve may or may not be a circle. Scheme 1 of the present invention is preferably a circle, which needs to match the shape of the bearing seat hole. However, all of them can form a flat structure with an elliptical or approximately elliptical inner periphery of the flat foil, thereby improving the wedge ratio and improving the load-bearing performance.

[0085] In some implementations...

[0086] The upper half-curve segment 3 of the flat foil 1 is a partial curve segment of an ellipse, parabola, or involute, and the lower half-curve segment 4 of the flat foil 1 is a partial curve segment of an ellipse, parabola, or involute. When both the upper half-curve segment 3 and the lower half-curve segment 4 are ellipse, the upper half-curve segment 3, the first dashed curve segment 7, the lower half-curve segment 4, and the second dashed curve segment 10 are connected to form a complete elliptical circle, and the radially inward convex surfaces of the plurality of troughs 12 are tangent to the complete elliptical circle. When both the upper half-curve segment 3 and the lower half-curve segment 4 are parabolas, the radially inward convex surfaces of the plurality of troughs 12 are tangent to the parabola. When both the upper half-curve segment 3 and the lower half-curve segment 4 are involutes, the radially inward convex surfaces of the plurality of troughs 12 are tangent to the involute.

[0087] The wave peaks closer to the Y-axis in the wave foil 2 have higher heights, while the wave peaks farther from the Y-axis have lower heights. The radially convex surfaces of multiple wave peaks 11 are located on the same first circumcircle 15, that is, the annular curve is a circle, such that x' = y', and the center of the first circumcircle 15 is located at point O.

[0088] This is the specific structural form of Scheme 1 of the present invention. The elliptical, parabolic, or involute air suspension bearing of Scheme 1 is achieved through a structure in which the corrugation amplitude changes smoothly and steplessly, and the corrugation width is variable or constant. That is, the corrugation amplitude is large in the middle (close to the y-axis) and low on both sides (far from the y-axis). Through simulation calculation, the height and width of the corrugation are accurately adjusted to form the envelope of the corrugation foil's inner diameter (or the intangent curve of the inner diameter), i.e., the inner foil, which becomes a standard ellipse, parabola, or involute, i.e., a continuous curve. The outer diameter envelope is a standard circle, allowing the gas bearing to have only one layer of corrugated foil. This achieves a novel structure with a circular outer diameter and an elliptical, parabolic, or involute inner diameter. Thus, an elliptical, parabolic, or involute inner ring shape can be achieved using a circular bearing housing. Compared to existing technologies that use two layers of corrugated foil of different lengths, this invention eliminates one layer, enabling continuous curves, and is simpler and less costly. Therefore, this invention, by increasing dynamic pressure with a single layer of corrugated foil, has structural and cost advantages over existing technologies using double or multiple layers of corrugated foil.

[0089] In some implementations...

[0090] The wave foil 2 includes an upper half-wave foil 13 located above the X-axis and a lower half-wave foil 14 located below the X-axis. The radially outward convex surfaces of all the wave crests 11 of the upper half-wave foil 13 are connected to the first circumscribed circle 15, and the radially inward convex surfaces of all the wave troughs of the upper half-wave foil 13 are tangent to the outer peripheral surface of the ellipse, parabola, or involute of the upper half-curved segment 3 of the flat foil 1. The radially outward convex surfaces of all the wave crests 11 of the lower half-wave foil 14 are connected to the first circumscribed circle 15, and the radially inward convex surfaces of all the wave troughs 12 of the lower half-wave foil 14 are tangent to the outer peripheral surface of the ellipse, parabola, or involute of the lower half-curved segment 4 of the flat foil 1.

[0091] This is the specific structural form of the corrugated foil of the present invention, namely, a corrugated foil structure comprising upper and lower halves, wherein the upper and lower halves of the corrugated foil are symmetrical with respect to the X-axis, and the radially convex surface of the trough of the upper half of the corrugated foil is in contact with the flat foil on its inner periphery, which can form a uniform support effect on the inner periphery of the flat foil and improve the support performance; and the crests of the upper and lower halves of the corrugated foil form a circular outer peripheral surface, which is in contact with the first circumscribed circle, so that the structure surrounded by the crests is circular, which can be adapted to the circular shaft hole of the bearing seat and improve its versatility.

[0092] In some implementations...

[0093] The upper half-wave foil 13 and the lower half-wave foil 14 are symmetrical with respect to the X-axis. The upper half-wave foil 13 is symmetrical with respect to the Y-axis, and the lower half-wave foil 14 is symmetrical with respect to the Y-axis.

[0094] This is a further preferred structural form of the corrugated foil of the present invention, namely, the upper and lower corrugated foils are symmetrical with respect to the X-axis, the upper corrugated foil is symmetrical with respect to the Y-axis, and the lower corrugated foil is symmetrical with respect to the Y-axis. This enables the inner circumference of the corrugated foil to provide uniform support to the flat foil, and further makes the gas in the inner circumference of the flat foil provide uniform support to the internal rotor shaft, thereby improving the support force and support effect.

[0095] Solution 1 of the present invention involves designing corrugations of varying amplitudes on a corrugated foil, employing a structure with lower amplitudes at both ends and a higher amplitude in the middle. Through molding and bending, the crest contours of the corrugated foil's outer diameter are made to lie on the same circumcircle. See details... Figure 2b The dotted line circle, that is, the outer circle of the outer diameter of the corrugated foil after forming, should coincide with the inner diameter of the bearing seat. In this way, the inner tangent curve of the trough automatically forms an ellipse, parabola, or involute, rather than a circular arc (belonging to elliptical arc, parabolic arc, or involute arc), which coincides with the outer diameter curve of the flat foil. This forms the elliptical, parabolic, or involute air suspension bearing of Scheme 1. Both the flat foil and the corrugated foil can be made by die punching and cold pressing.

[0096] like Figure 6a-9 In some implementation methods,

[0097] The upper half-curved segment 3 of the flat foil 1 is a circular partial arc segment, and the lower half-curved segment 4 of the flat foil 1 is a circular partial arc segment.

[0098] First, a circular flat foil is created within the projection plane of a vertical plane. The circular flat foil has point O as its center, the X-axis as its horizontal axis of symmetry, and the Y-axis as its vertical axis of symmetry. Then, arc segments of a certain length are cut off at two points where the circular flat foil intersects with the X-axis to form the upper half-curve segment 3 and the lower half-curve segment 4. Finally, the upper half-curve segment 3 and the lower half-curve segment 4 are connected together.

[0099] This is the preferred structural form of Scheme 2 of the present invention. The approximately elliptical air suspension bearing of Scheme 2 is obtained by first designing the inner circumferential curve of a circular flat foil, then cutting off the positions where the two sides meet the X-axis, and then splicing the upper and lower arc segments. This allows the bearing seat to be designed into an approximately elliptical shape, and the foil with the same corrugation height is made into the same shape as the bearing seat, with the outer diameter matching the inner diameter of the bearing seat (the inner hole of the bearing seat is also approximately elliptical). The flat foil is made to have the same size and shape as the inner diameter of the corrugated foil. In this way, the approximately elliptical air suspension bearing of Scheme 2 is formed. It has only one layer of corrugated foil, which can achieve a continuous curve, and is simpler and lower in cost. Compared with the existing double or multi-layer corrugated foil, increasing the dynamic pressure by using a single layer of corrugated foil has structural and cost advantages.

[0100] In some implementations...

[0101] After the excision, the first lower end 5 of the upper half curve segment 3 and the first upper end 6 of the opposite lower half curve segment 4 are connected by the first dashed curve segment 7, and the second lower end 8 of the upper half curve segment 3 and the second upper end 9 of the opposite lower half curve segment 4 are connected by the second dashed curve segment 10. The lengths of the arc segments of the two excised portions are equal (including the first excised portion 27 on the left and the second excised portion 28 on the right). The lengths of the first dashed curve segment 7 and the second dashed curve segment 10 are equal and symmetrically arranged with respect to point O.

[0102] This is a preferred structural form of the flat foil of the present invention. By making the upper and lower half-curved segments of the flat foil symmetrical with respect to the X-axis, the upper half-curved segment symmetrical with respect to the Y-axis, and the lower half-curved segment symmetrical with respect to the Y-axis, the gas on the inner circumference of the flat foil can support the internal rotor shaft in a uniform manner, thereby improving the support force and support effect.

[0103] In some implementations...

[0104] The corrugated foil 2 includes multiple radially outward protruding peaks 11, with adjacent peaks 11 spaced apart and valleys 12 formed between adjacent peaks 11. The inner peripheries of the multiple valleys 12 are all fitted to the outer periphery of the flat foil 1. The corrugated foil 2 is also cut off at a position radially opposite to the cut-off portion of the flat foil 1, and the two cut-off portions of the corrugated foil are spliced ​​together. A continuous annular curve is circumscribed around the multiple peaks 11, with the center of the annular curve also being point O. The distance between the two intersections of the annular curve and the X-axis is the length x' of the outer periphery of the corrugated foil 2 along the X direction, and the distance between the two intersections of the annular curve and the Y-axis is the length y' of the outer periphery of the corrugated foil 2 along the Y direction, with x' ≥ y'.

[0105] The outer periphery of the corrugated foil of the present invention is an annular curve. The annular curve may or may not be a circle. In the second embodiment of the present invention, it is preferably not a circle, but a flat structure formed by cutting off the middle part of the structure and splicing it together. This structure matches the (flat) shape of the bearing seat hole and can form a flat structure with an elliptical or approximately elliptical inner periphery of the flat foil, thereby improving the wedge ratio and improving the load-bearing performance.

[0106] In some implementations...

[0107] Before and after the excision, the radially inward convex surfaces of the multiple troughs 12 are tangent to the outer peripheral surface of the flat foil 1; the heights of the wave peaks 11 in the multiple wave foils 2 are all equal.

[0108] Before the removal, the radially convex surfaces of the multiple wave peaks 11 are located on the same second circumcircle 16, and the center of the second circumcircle 16 is located at point O, such that after the removal, x' > y'.

[0109] This is a preferred structural form of the second embodiment of the present invention. By ensuring that the peak heights are all equal, the inner periphery of the troughs is tangent to the flat foil both before and after removal, which can provide uniform support for the flat foil. Before removal, the radially convex surfaces of multiple peaks are located on the same second circumcircle, which facilitates the integrated processing and fabrication of the wave foil and the flat foil.

[0110] In the second embodiment of the present invention, the bearing housing is designed as an approximately elliptical structure. This approximately elliptical structure is preferably composed of two arcs smaller than semicircles. The corrugated foil has equal wave amplitudes, and after forming, the circumcircle of the wave crest and the incircle of the wave trough are both standard circles. See details... Figure 6b A dotted line is used to indicate that the circumcircle of the wave crest is a complete circle. Figure 6a This indicates that after being joined, it becomes two segments of circular arcs joined together, with the inner diameter forming an approximately elliptical shape. For the bearing housing inner diameter in Scheme 2, the bearing housing inner circle can be machined first, then a portion can be cut off within a certain range along both sides of the horizontal diameter, and then the upper and lower circular arcs can be joined together and fastened with bolts (not shown in the figure). The corrugated foil and the inner diameter flat foil of this invention are also completed by molding.

[0111] In some implementations...

[0112] The rotor shaft 17 is located on the inner circumference of the flat foil 1 and in the projection plane in the vertical plane. The minimum distance between the rotor shaft 17 and the ellipse, parabola or involute of the inner circumference of the flat foil 1 on the X-axis is the side gap 18. The minimum distance between the rotor shaft 17 and the ellipse, parabola or involute of the inner circumference of the flat foil 1 on the Y-axis is the top gap 19. The side gap 18 is greater than the top gap 19, and the ratio between the side gap 18 and the top gap 19 is the wedge ratio.

[0113] This is a preferred structural form of Scheme 1 of the present invention. The present invention increases the wedge ratio and increases the air suspension pressure by making the minimum gap (side gap) between the elliptical circle, parabola or involute of the inner circumference of the flat foil and the rotor shaft on the X-axis, and the top gap in the Y-axis direction such that the side gap is greater than the top gap (achieved by the aforementioned flat structure or elliptical or approximately elliptical structure). Therefore, a heavier rotor can be suspended.

[0114] In some implementations...

[0115] The rotor shaft 17 is located on the inner circumference of the flat foil 1 and in the projection plane in the vertical plane, the minimum distance between the rotor shaft 17 and the first dashed curve segment 7 or the second dashed curve segment 10 of the inner circumference of the flat foil 1 on the X-axis is the side gap 18, and the minimum distance between the rotor shaft 17 and the inner circumference of the flat foil 1 on the Y-axis is the top gap 19. The side gap 18 is greater than the top gap 19, and the ratio between the side gap 18 and the top gap 19 is the wedge ratio.

[0116] This is a preferred structural form of the second embodiment of the present invention. The present invention increases the wedge ratio and increases the air suspension pressure by making the relationship between the minimum gap (side gap) between the first or second dashed curve segment of the inner circumference of the flat foil and the rotor shaft on the X-axis and the top gap in the Y-axis direction greater than the top gap (achieved by the aforementioned flat structure or elliptical or approximately elliptical structure). Therefore, a heavier rotor can be suspended.

[0117] The present invention also provides a bearing assembly, which includes the aforementioned bearing foil assembly and a bearing housing 20 having a shaft hole, wherein the bearing foil assembly is disposed in the shaft hole to support the rotor shaft 17.

[0118] In some implementations...

[0119] In the projection plane of the vertical plane, the inner circumference of the bearing seat 20 is provided with a first receiving groove 21 at the axial side of the X-axis, and the inner circumference of the bearing seat 20 is provided with a second receiving groove 22 at the axial side of the X-axis. The first lower end of the upper half of the flat foil 1 is connected to the first upper end of the lower half of the flat foil 1 opposite to it by a first connecting part 23. The first connecting part 23 is a protruding structure protruding toward the first receiving groove 21. The first connecting part 23 is inserted into the first receiving groove 21 to form a fixed end. The second lower end of the upper half of the flat foil 1 is connected to the second upper end of the lower half of the flat foil 1 opposite to it by a second connecting part 24. The second connecting part 24 is a protruding structure protruding toward the second receiving groove 22. The second connecting part 24 is inserted into the second receiving groove 22 to form a free end.

[0120] This is a preferred structural form of the bearing housing of the present invention. The first receiving groove can accommodate the insertion of the first connecting part of the flat foil to form a fixed end, and the second receiving groove can accommodate the insertion of the second connecting part of the flat foil to form a free end. Thus, the flat foil is relatively fixed and can move to a certain extent to support the rotor shaft on its inner circumference.

[0121] In some implementations...

[0122] The third lower end of the upper half of the corrugated foil 2 is connected to the third upper end of the lower half of the corrugated foil 2 opposite to it by a third connecting part 25. The third connecting part 25 is a protruding structure protruding toward the first receiving groove 21. The third connecting part 25 is inserted into the first receiving groove 21 to form a fixed end of the corrugated foil. The fourth lower end of the upper half of the corrugated foil 2 is connected to the fourth upper end of the lower half of the corrugated foil 2 opposite to it by a fourth connecting part 26. The fourth connecting part 26 is a protruding structure protruding toward the second receiving groove 22. The fourth connecting part 26 is inserted into the second receiving groove 22 to form a free end of the corrugated foil.

[0123] This is a preferred structural form of the bearing housing of the present invention. The first receiving groove can accommodate the insertion of the third connecting part of the corrugated foil to form a fixed end, and the second receiving groove can accommodate the insertion of the fourth connecting part of the corrugated foil to form a free end. Thus, the flat foil is relatively fixed and can move to a certain extent to support the rotor shaft on its inner circumference.

[0124] The present invention also provides an air compressor, which includes the aforementioned bearing assembly and a rotor shaft 17, wherein the bearing assembly supports the rotor shaft 17.

[0125] In some implementations...

[0126] When the flat foil includes a free end, a fixed end, a free end, and a fixed end, the rotor shaft 17 rotates in a direction such that the lower half of the flat foil 1 rotates from the free end to the fixed end.

[0127] The rotor shaft 17 rotates in such a direction that the lower half of the corrugated foil 2 rotates from the free end of the corrugated foil to the fixed end of the corrugated foil.

[0128] Both schemes 1 and 2 of this invention involve two pieces joined together, with one side fixed to the bearing housing to form a fixed end, and the other side left open to form a free end. The major axis of the inner circumference of the ellipse, parabola, or involute is the fixed position of the foil. When the motor rotates clockwise, the left side is the fixed end and the right side is the free end; when the motor rotates counterclockwise, the right side is the fixed end and the left side is the free end. That is, the motor rotor should rotate from the free end to the fixed end. This arrangement can reduce the impact force and whirl during the starting process, making the motor starting process smoother and more stable.

[0129] The first embodiment of the invention uses two curved segments to form an elliptical, parabolic, or involute inner diameter. The core of its claim is a corrugated foil sheet that is high in the middle and low at both ends, and its bent characteristics. The second embodiment uses two circular arcs to form an elliptical, parabolic, or involute inner diameter. The claim is that the circular arcs of the bearing housing form an elliptical structure corresponding to the same shape as the foil bearing assembly.

[0130] The first solution of this invention is a single-layer corrugated foil. By adjusting the corrugation height, which must be higher in the middle and lower at both ends, the ellipticity, parabola, or involute of the inner diameter ellipse and the cross-sectional area of ​​the bearing inlet can be adjusted. The unequal-height corrugated foil of this invention can form a very smooth and continuous trough-tangent elliptical curve, parabola, or involute, etc., through parameter adjustment. After being attached to the inner foil, it can support the rotor more evenly and continuously and reduce the resistance of the rotating airflow inside the bearing.

[0131] The second embodiment of the invention is that the inner diameter of the bearing is composed of two arc segments. A notch is opened at the intersection of the two arc segments to fix the foil bearing. At the same time, the intersection point of the arc segments is eliminated to achieve an approximately elliptical effect. This can improve the smoothness of the airflow in the inner diameter rotation and reduce the airflow resistance.

[0132] Solution 1 of the present invention is simple and practical. The inner diameter of the bearing housing is circular, while the inner diameter of the foil bearing is elliptical, parabolic, or involute, etc. Corrugated foils of different heights are formed by molding. Simultaneously, the circumscribed circle of its outer diameter can also be formed by molding. The technological challenge of Solution 2 of the present invention lies in the inner diameter of the bearing housing, which requires one more process than a full circle. The processing method for the foil bearing assembly is basically the same as that of Solution 1.

[0133] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A bearing foil assembly, characterized in that: Composed of a flat foil (1) and a wave foil (2), the wave foil (2) is located on the outer periphery of the flat foil (1). In the projection plane of the vertical plane, the inner periphery of the flat foil (1) is a flat structure with a center O. The horizontal straight line passing through point O is the X-axis, and the vertical straight line passing through point O is the Y-axis. The inner periphery of the flat foil (1) includes an upper half-curve segment (3) above the X-axis and a lower half-curve segment (4) below the X-axis. The first lower end (5) of the upper half-curve segment (3) is spaced apart from the first upper end (6) of the lower half-curve segment (4) opposite to it. The two are smoothly connected by a first dashed curve segment (7). The second lower end (8) of the upper half-curve segment (3) is spaced apart from the second upper end (9) of the lower half-curve segment (4) opposite to it. The two are smoothly connected by a second dashed curve segment (10). The first dashed curve segment (7) and the second dashed curve segment (10) are both virtual non-solid line segments. The distance between the intersection point of the X-axis and the first dashed curve segment (7) and the intersection point of the X-axis and the second dashed curve segment (10) is the length x of the inner circumference of the flat foil (1) along the X direction, and the distance between the intersection point of the Y-axis and the upper half curve segment (3) and the intersection point of the Y-axis and the lower half curve segment (4) is the length y of the inner circumference of the flat foil (1) along the Y direction, and x > y; The corrugated foil (2) includes multiple corrugations (11) protruding radially outward, with adjacent corrugations (11) spaced apart and a trough (12) formed between adjacent corrugations (11). The inner periphery of the multiple troughs (12) is attached to the outer periphery of the flat foil (1). The upper half-curve segment (3) of the flat foil (1) is a partial curve segment of an elliptic curve, a parabola, or an involute. The lower half-curve segment (4) of the flat foil (1) is a partial curve segment of an elliptic curve, a parabola, or an involute. When both the upper half-curve segment (3) and the lower half-curve segment (4) are elliptic curves, the upper half-curve segment (3), the first dashed curve segment (7), the lower half-curve segment (4), and the second dashed curve segment (10) are connected to form an elliptical circle. The radially inward convex surfaces of the multiple troughs (12) are all tangent to the elliptical circle. When both the upper half-curve segment (3) and the lower half-curve segment (4) are parabolas, the radially inward convex surfaces of the multiple troughs (12) are all tangent to the parabola. When both the upper half-curve segment (3) and the lower half-curve segment (4) are involutes, the radially inward convex surfaces of the multiple troughs (12) are all tangent to the involute.

2. The bearing foil assembly according to claim 1, characterized in that: Multiple wave peaks (11) are circumscribed by a continuous loop curve, the center of which is also point O. The distance between the two intersections of the loop curve and the X-axis is the length x' of the outer periphery of the wave foil (2) along the X direction, and the distance between the two intersections of the loop curve and the Y-axis is the length y' of the outer periphery of the wave foil (2) along the Y direction, and x'≥y'.

3. The bearing foil assembly according to claim 2, characterized in that: The wave peaks closer to the Y-axis in the wave foil (2) have higher heights, while the wave peaks farther from the Y-axis have lower heights. The radially convex surfaces of multiple wave peaks (11) are located on the same first circumscribed circle (15), that is, the annular curve is a circle, such that x' = y', and the center of the first circumscribed circle (15) is located at point O.

4. The bearing foil assembly according to claim 3, characterized in that: The wave foil (2) includes an upper half wave foil (13) located above the X-axis and a lower half wave foil (14) located below the X-axis. The radially outward convex surfaces of all the wave crests (11) of the upper half wave foil (13) are connected to the first circumscribed circle (15). The radially inward convex surfaces of all the wave troughs of the upper half wave foil (13) are tangent to the outer peripheral surface of the upper half curve segment (3) of the flat foil (1). The radially outward convex surfaces of all the wave crests (11) of the lower half wave foil (14) are connected to the first circumscribed circle (15). The radially inward convex surfaces of all the wave troughs (12) of the lower half wave foil (14) are tangent to the outer peripheral surface of the lower half curve segment (4) of the flat foil (1).

5. The bearing foil assembly according to claim 4, characterized in that: The upper half-curved segment (3) and the lower half-curved segment (4) of the flat foil (1) are symmetrically arranged with respect to the X-axis, the upper half-curved segment (3) of the flat foil (1) is symmetrically arranged with respect to the Y-axis, and the lower half-curved segment (4) of the flat foil (1) is symmetrically arranged with respect to the Y-axis. The upper half-wave foil (13) and the lower half-wave foil (14) are symmetrically arranged with respect to the X-axis, the upper half-wave foil (13) is symmetrically arranged with respect to the Y-axis, and the lower half-wave foil (14) is symmetrically arranged with respect to the Y-axis.

6. The bearing foil assembly according to claim 3, characterized in that: The rotor shaft (17) is located on the inner circumference of the flat foil (1) and in the projection plane in the vertical plane, the minimum distance between the rotor shaft (17) and the inner circumference of the flat foil (1) on the X-axis is the side gap (18), and the minimum distance between the rotor shaft (17) and the inner circumference of the flat foil (1) on the Y-axis is the top gap (19). The side gap (18) is greater than the top gap (19), and the ratio between the side gap (18) and the top gap (19) is the wedge ratio.

7. A bearing foil assembly, characterized in that: Composed of a flat foil (1) and a wave foil (2), the wave foil (2) is located on the outer periphery of the flat foil (1). In the projection plane of the vertical plane, the inner periphery of the flat foil (1) is a flat structure with a center O. The horizontal straight line passing through point O is the X-axis, and the vertical straight line passing through point O is the Y-axis. The inner periphery of the flat foil (1) includes an upper half-curve segment (3) above the X-axis and a lower half-curve segment (4) below the X-axis. The first lower end (5) of the upper half-curve segment (3) is spaced apart from the first upper end (6) of the lower half-curve segment (4) opposite to it. The two are smoothly connected by a first dashed curve segment (7). The second lower end (8) of the upper half-curve segment (3) is spaced apart from the second upper end (9) of the lower half-curve segment (4) opposite to it. The two are smoothly connected by a second dashed curve segment (10). The first dashed curve segment (7) and the second dashed curve segment (10) are both virtual non-solid line segments. The distance between the intersection point of the X-axis and the first dashed curve segment (7) and the intersection point of the X-axis and the second dashed curve segment (10) is the length x of the inner circumference of the flat foil (1) along the X direction, and the distance between the intersection point of the Y-axis and the upper half curve segment (3) and the intersection point of the Y-axis and the lower half curve segment (4) is the length y of the inner circumference of the flat foil (1) along the Y direction, and x > y; The upper half-curved segment (3) of the flat foil (1) is a circular arc segment, and the lower half-curved segment (4) of the flat foil (1) is a circular arc segment. First, a circular flat foil is made in the projection plane of the vertical plane. The circular flat foil is centered at point O, with the X-axis as the horizontal axis of symmetry and the Y-axis as the vertical axis of symmetry. Then, a portion of the arc segment is cut off at two points where the circular flat foil intersects with the X-axis to form the upper half-curve segment (3) and the lower half-curve segment (4). The upper half-curve segment (3) and the lower half-curve segment (4) are then connected together. After the excision, the first lower end (5) of the upper half curve segment (3) and the first upper end (6) of the opposite lower half curve segment (4) are connected by the first dashed curve segment (7), and the second lower end (8) of the upper half curve segment (3) and the second upper end (9) of the opposite lower half curve segment (4) are connected by the second dashed curve segment (10). The lengths of the arc segments of the two excised portions are equal, and the lengths of the first dashed curve segment (7) and the second dashed curve segment (10) are equal and symmetrically arranged with respect to point O. The corrugated foil (2) includes multiple radially outward protruding peaks (11), with adjacent peaks (11) spaced apart and valleys (12) formed between adjacent peaks (11). The inner periphery of the multiple valleys (12) is attached to the outer periphery of the flat foil (1). The corrugated foil (2) is also cut off at a position radially opposite to the cut-off portion of the flat foil (1), and the two cut-off corrugated foil portions are spliced ​​together. A continuous annular curve is circumscribed around the multiple peaks (11), with the center of the annular curve being point O. The distance between the two intersections of the annular curve and the X-axis is the length x' of the outer periphery of the corrugated foil (2) along the X direction, and the distance between the two intersections of the annular curve and the Y-axis is the length y' of the outer periphery of the corrugated foil (2) along the Y direction, with x' ≥ y'. Before and after the excision, the radially inner convex surfaces of the multiple troughs (12) are tangent to the outer peripheral surface of the flat foil (1); the heights of the wave peaks (11) in the multiple wave foils (2) are all equal. Before the removal, the radially convex surfaces of the multiple peaks (11) are located on the same second circumcircle (16), and the center of the second circumcircle (16) is located at point O, such that after the removal, x' > y'.

8. The bearing foil assembly according to claim 7, characterized in that: The rotor shaft (17) is located on the inner periphery of the flat foil (1) and in the projection plane in the vertical plane, the minimum distance between the rotor shaft (17) and the inner periphery of the flat foil (1) on the X-axis is the side gap (18), and the minimum distance between the rotor shaft (17) and the inner periphery of the flat foil (1) on the Y-axis is the top gap (19). The side gap (18) is greater than the top gap (19), and the ratio between the side gap (18) and the top gap (19) is the wedge ratio.

9. A bearing assembly, characterized in that: The assembly includes the bearing foil assembly according to any one of claims 1-6 or the bearing foil assembly according to claim 7 or 8, and further includes a bearing housing (20) having a shaft hole in which the bearing foil assembly is disposed to support the rotor shaft (17).

10. The bearing assembly according to claim 9, characterized in that: In the projection plane of the vertical plane, the inner circumference of the bearing seat (20) is provided with a first receiving groove (21) at the axial side of the X-axis, and the inner circumference of the bearing seat (20) is provided with a second receiving groove (22) at the axial side of the X-axis. The first lower end of the upper half of the flat foil (1) is connected to the first upper end of the lower half of the flat foil (1) opposite to it by a first connecting part (23). The first connecting part (23) is a protruding structure protruding toward the first receiving groove (21). The first connecting part (23) is inserted into the first receiving groove (21) to form a fixed end. The second lower end of the upper half of the flat foil (1) is connected to the second upper end of the lower half of the flat foil (1) opposite to it by a second connecting part (24). The second connecting part (24) is a protruding structure protruding toward the second receiving groove (22). The second connecting part (24) is inserted into the second receiving groove (22) to form a free end.

11. The bearing assembly according to claim 10, characterized in that: The third lower end of the upper half of the corrugated foil (2) is connected to the third upper end of the lower half of the corrugated foil (2) opposite to it by a third connecting part (25). The third connecting part (25) is a protruding structure protruding toward the first receiving groove (21). The third connecting part (25) is inserted into the first receiving groove (21) to form a fixed end of the corrugated foil. The fourth lower end of the upper half of the corrugated foil (2) is connected to the fourth upper end of the lower half of the corrugated foil (2) opposite to it by a fourth connecting part (26). The fourth connecting part (26) is a protruding structure protruding toward the second receiving groove (22). The fourth connecting part (26) is inserted into the second receiving groove (22) to form a free end of the corrugated foil.

12. An air compressor, characterized in that: The bearing assembly comprising any one of claims 9-11 further comprises a rotor shaft (17) wherein the bearing assembly supports the rotor shaft (17).

13. The air compressor according to claim 12, characterized in that: When the flat foil includes a free end, a fixed end, a corrugated foil, and a fixed end, the rotor shaft (17) rotates in a direction such that the lower half of the flat foil (1) rotates from the free end to the fixed end. The rotation direction of the rotor shaft (17) is such that the lower half of the structure of the corrugated foil (2) rotates from the free end of the corrugated foil to the fixed end of the corrugated foil.

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