A gas dynamic pressure bearing with tiltable foil

Abstract

This application relates to the field of gas bearing technology and provides a foil-tiltable gas hydrodynamic bearing, comprising: a bearing sleeve, a first foil, an auxiliary support foil, and a top foil; the first foil is composed of several interconnected upper and lower triangular structures formed by pressing metal plates, wherein the upper triangular structure is inverted and connected to the lower triangular structure, and there is a certain gap between the two intermediate beams connecting the upper and lower triangular structures; the auxiliary support foil is installed between the two intermediate beams; after the first foil structure bears a load, the two intermediate beams bend and deform inward to compress the auxiliary support foil, while generating a certain frictional damping; the upper triangular structure rotates to the left or right according to the load direction, and the lower triangular structure deforms to both sides and transfers the load to the adjacent upper and lower triangular structures; the upper surface of the first foil contacts the top foil surface, and the lower surface of the first foil contacts the inner surface of the bearing sleeve; the auxiliary support foil support is inserted into the inclined groove in the bearing sleeve; the bearing sleeve supports the first foil, and the first foil supports the top foil; one end of the first foil and the arc-shaped top foil are free, and the other end is fixed together on the bearing sleeve. Compared to traditional gas foil bearings, the rotatable characteristic of the first foil in this application is beneficial for adjusting the local deformation of the top foil and improving the operational stability of the gas foil bearing.

Description

Technical Field

[0001] This invention relates to the field of radial gas dynamic bearing technology, and more specifically to a foil-tiltable gas dynamic bearing. Background Technology

[0002] Gas dynamic bearings utilize the gas dynamic effect to generate a high-pressure gas film, providing contactless lubrication to support the rotor. They have advantages such as oil-free lubrication and high-efficiency output. Compared with oil-lubricated bearings, they are more widely used in high-speed, light-load rotating equipment such as high-speed air circulators, oil-free turbochargers, and fuel cell air compressors.

[0003] However, a very large velocity gradient exists along the thickness direction of the gas film between the high-speed rotor and the stationary top foil surrounding the hydrodynamic film, causing the gas film to generate an excitation of approximately 0.5 times the rotational speed. This excitation acts on the rotor, and when the excitation frequency is close to the system frequency, it can cause subsynchronous resonance in the rotor, severely affecting system stability and preventing the gas hydrodynamic bearing-supported rotor system from reaching higher speeds. To eliminate the influence of subsynchronous excitation on the rotor system, an integrated tilting pad gas hydrodynamic bearing is a good approach. Its structure features multi-lobed pads, and its tilting capability around the pivot point breaks the continuity of the gas film. However, the low damping and low load-bearing capacity of the metal pads in this type of bearing limit its application. Summary of the Invention

[0004] To address the aforementioned technical shortcomings, this application provides a foil-type tiltable gas dynamic bearing, which retains the advantage of high load capacity of foil bearings while also possessing the characteristic of rotating in the direction of the load after the foil structure deforms, thus solving the technical problem of poor stability in existing gas dynamic bearing systems. The numerous technical effects of the preferred solutions among the many technical solutions provided by this invention are described below.

[0005] To achieve the above-mentioned technical objectives, the present invention provides the following technical solutions:

[0006] The present invention provides a foil tiltable gas dynamic bearing, comprising: a bearing sleeve, a first foil, an auxiliary support foil, and a top foil.

[0007] In one embodiment, the first foil is composed of several interconnected upper and lower triangular structures formed by pressing metal plates. The upper triangular structure is inverted and connected to the lower triangular structure. There is a certain gap between the two intermediate beams connected to the upper and lower triangular structures. After the first foil bears a load, the upper and lower triangular structures generate radial and circumferential displacements. The two intermediate beams bend and deform inward. The upper triangular structure rotates to the left or right according to the load direction, and the lower triangular structure deforms to both sides to transfer the load to the adjacent upper and lower triangular structures. The upper surface of the first foil is in contact with the top foil surface, and the lower surface of the first foil is in contact with the bearing sleeve surface. One end of the first foil is free, and the other end is fixed to the bearing sleeve. The fixing method adopts various fixing methods such as welding, insertion of limit pins, hinge, screws, and adhesive.

[0008] In one embodiment, the upper and lower triangular structures in the first foil are replaced by a metal plate pressed into an upper and lower connected structure of one or two other shapes, such as a polygonal combination.

[0009] In one embodiment, the auxiliary support foil is made of pressed metal plate and consists of auxiliary support vertical beams and supports. The supports are inserted into the groove of the bearing sleeve. The auxiliary support foil has the effect of a cantilever beam, which improves the support of the upper triangular structure of the first foil. There is a certain gap between the auxiliary support vertical beams, which can withstand the compression of the middle beam of the first foil and generate a certain deformation, while providing support for the middle beam of the first foil.

[0010] In one embodiment, the top foil is formed by pressing a metal plate into an arc shape, with one end of the top foil being free and the other end being fixed to the bearing sleeve together with the end of the first foil.

[0011] In one embodiment, the bearing sleeve is an annular metal part, and the inner surface of the bearing sleeve is provided with a wire-cut axial through groove or pin hole. When the support structure is used, the groove is used to fix the support structure and the first foil and the top foil, and the first foil and the top foil can be directly welded to the bearing sleeve.

[0012] Optionally, a gap is left in the middle of the upper and lower triangular structures to place an auxiliary support structure to improve the bending stiffness of the upper and lower triangular structures. The auxiliary support structure is made of metal plate pressed and folded, and is placed between the two beams. The auxiliary support structure has a gap in the middle and deforms inward after being loaded by the two beams. The lower part of the auxiliary support structure is inserted into the groove of the bearing sleeve for fixation. The auxiliary support structure can be made of other materials or have other structural shapes to achieve the supporting and damping effects of the upper and lower triangular structures.

[0013] Optionally, the upper and lower triangular structures in the first foil can be replaced by other shapes of connected structures formed by pressing metal plates, such as combinations of the same or different types of shapes: upper part rectangular - lower part triangular structure. Alternatively, other materials or 3D printing can be used to form the upper and lower triangular structures.

[0014] Optionally, the first foil is made of pressed metal and has a certain supporting rigidity, and auxiliary supporting foils may not be used.

[0015] Optionally, the first foil can be segmented circumferentially to form a multi-lobed bearing structure, or the first foil can be segmented axially and a certain circumferential misalignment angle can be set. Both methods are used to adjust the distribution of the upper and lower triangular structures.

[0016] Optionally, the upper and lower triangular structures can be configured by changing the size of the structure and the distribution along the axial and circumferential directions, forming a distribution pattern where the middle of the axial direction is high and the two ends are low, or the circumferential direction is divided into several parts, each of which is high in the middle and low at both ends, so as to reasonably arrange the foil support stiffness and air film thickness distribution.

[0017] Optionally, the upper and lower triangular structures can be made by reducing the local structural size and placing a similarly shaped foil below the foil to form a two-layer structure.

[0018] This invention provides a foil-type tiltable gas dynamic bearing, wherein several upper and lower triangular structures are connected in parallel to form a first foil, supporting a flexible arc-shaped top foil. The top foil and the first foil are fixed together on the bearing sleeve. There is a gap between the upper and lower triangular structures, and an auxiliary support foil is placed in the gap. When the first foil bears a load, the hypotenuse beam of the lower triangular structure moves to both sides and transmits the load, while the hypotenuse beam of the upper triangular structure moves towards the center and rotates around the middle beam as a fulcrum. Therefore, the first foil has radial and circumferential displacement, which adjusts the contour distribution of the gas film and is beneficial to the stability of the system. Attached Figure Description

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a front view of a foil-tiltable gas dynamic bearing provided in an embodiment of the present invention.

[0021] Figure 2 An exploded view of a foil-tiltable gas dynamic bearing provided in an embodiment of the present invention.

[0022] Figure 3 This is a partial enlarged view of the first foil of a foil-tiltable gas dynamic bearing provided in an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the top foil of a tiltable gas dynamic bearing provided in an embodiment of the present invention.

[0024] Figure 5 This is a partially enlarged view of the auxiliary support foil of a tiltable gas dynamic bearing provided in an embodiment of the present invention.

[0025] Figure 6 This is a schematic diagram of a bearing sleeve for a foil-tiltable gas dynamic pressure bearing, provided as an embodiment of the present invention.

[0026] Figure 7 This is a partially enlarged view of a foil-tiltable gas dynamic bearing auxiliary support foil deformation structure provided in an embodiment of the present invention.

[0027] Figure 8 This is a schematic diagram of a bearing sleeve with an auxiliary support structure for the deformation of a foil-tiltable gas dynamic bearing, provided as an embodiment of the present invention.

[0028] Figure 9 This is a front view of a foil-supported gas dynamic bearing with tiltable foil, provided as an embodiment of the present invention.

[0029] Figure 10 An exploded view of an unsupported foil bearing for a tiltable gas dynamic bearing provided in an embodiment of the present invention.

[0030] Figure 11 An exploded view of a foil-tiltable gas dynamic bearing according to an embodiment of the present invention, showing the circumferential distribution of the first foil.

[0031] Figure 12 This is a front view of a foil-tiltable gas dynamic bearing according to an embodiment of the present invention, showing the first foil circumferentially distributed.

[0032] Figure 13 An exploded view of a foil-tiltable gas dynamic bearing according to an embodiment of the present invention, showing the axial distribution of the first foil.

[0033] Figure 14 This is a front view of a foil-tiltable gas dynamic bearing according to an embodiment of the present invention, showing the axial distribution of the first foil.

[0034] The labels in the attached figures are as follows:

[0035] 1-Bearing sleeve, 2-First foil, 3-Top foil, 4-Auxiliary support foil, 5-Auxiliary support foil deformation structure, 6-First type of foil deformation structure, 7-Second type of foil deformation structure, 11-Slanted groove of bearing sleeve, 12-Pin hole of bearing sleeve, 13-Straight groove of bearing sleeve, 21-Upper and lower triangular structures, 22-Bottom beam, 31-Top main body, 32-Top foil bending beam, 33-Top foil fixing beam, 41-Auxiliary support vertical beam, 42-Support, 211-Top beam of upper triangular structure, 212-Side beam of upper triangular structure, 213-Middle beam, 214-Side beam of lower triangular structure. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] In the description of this invention, it should be noted that, unless otherwise stated, "a number" means two or more; the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and 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 of this invention. Furthermore, the terms "main," "auxiliary," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance; "first," "second," etc., are used for descriptive purposes only. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0038] Please refer to the accompanying drawings for a description of the foil gas bearing provided in the embodiments of this application.

[0039] like Figure 1 and Figure 2 As shown, the foil gas bearing includes: a bearing sleeve 1, a first foil 2, a top foil 3, and an auxiliary support foil 4.

[0040] like Figure 3As shown, the first foil 2 is composed of several interconnected upper and lower triangular structures 21 formed by pressing the entire metal plate with a folding machine. Adjacent upper and lower triangular structures 21 are connected into a whole by a bottom beam 22. The first foil 2 can be used as a whole structure or as a single structure. The upper triangular structure is inverted and connected to the lower triangular structure. The top beam 211 of the upper triangular structure is flat, which can ensure a large contact area when in contact with the top foil. The side beams 212 of the upper triangle are connected to the side beams 214 of the lower triangular structure by middle beams 213. There is a certain gap between the two middle beams 213 connected to the upper and lower triangular structures. After the foil 2 bears the load, the upper and lower triangular structures 21 will generate radial and circumferential displacements. The two intermediate beams 213 bend and deform inward. The upper triangular structure rotates to the left or right according to the load direction. The top beams 211 of the adjacent upper triangular structures after deformation do not interfere with each other. The lower triangular structure deforms to both sides to transfer the load to the adjacent upper and lower triangular structures 21. The upper surface of the first foil 2 contacts the lower surface of the top foil 3, and the lower surface of the first foil 2 contacts the inner surface of the bearing sleeve 1. One end of the first foil 2 is free, and the other end is fixed to the bearing sleeve 1. The fixing method adopts various fixing methods such as welding, slot-limiting pin, hinge, screw, and adhesive.

[0041] Furthermore, the upper and lower triangular structures 21 in the first foil 2 are replaced by upper and lower connected structures formed by pressing metal plates into one or two other shapes.

[0042] like Figure 4 As shown, the top foil 3 is composed of an arc-shaped top foil body 31 made of metal plate, a top foil bending beam 32 and a top foil fixing beam 33. The top foil fixing beam 33 is fixed together with the end of the foil 2 on the bearing sleeve 1.

[0043] like Figure 5 As shown, the auxiliary support foil 4 is formed by pressing and folding a metal plate, and consists of an auxiliary support vertical beam 41 and a support 42. The height of the auxiliary support vertical beam 41 is greater than the height of the side beam 214 of the lower triangular structure and lower than the height of the top beam 211 of the upper triangular structure. The support 42 is separated to both sides and inserted into the inclined groove 11 in the bearing sleeve 1. This method can restrict the movement of the support 42 and form a "cantilever beam" effect, which improves the support of the upper triangular structure of the first foil 2. There is a certain gap between the auxiliary support vertical beams 41. After being squeezed by the middle beam 213 of the foil, it can produce a certain deformation, which provides support for the middle beam 213 of the foil.

[0044] like Figure 6 As shown, the bearing sleeve 1 is a circular metal part with an axial inclined groove 11 machined on its inner surface by wire cutting. The circumferential distribution of the inclined groove 11 is consistent with the circumferential distribution of the upper and lower triangular structures 21.

[0045] like Figure 7 As shown, the auxiliary support foil deformation structure 5 can replace the auxiliary support foil 4, and its height requirement is the same as that of the auxiliary support foil 4. This structure is fixed in the slot 13 by a pin shaft. The bearing sleeve deformation structure is adapted to the auxiliary support deformation structure 5, as shown. Figure 8 As shown.

[0046] Furthermore, by selecting suitable materials and sizes, the first foil 2 can have sufficient structural support rigidity, and the auxiliary support foil 4 can be omitted. Figure 9 and Figure 10 As shown.

[0047] Furthermore, the first foil 2 is segmented circumferentially to form a multi-lobed first foil deformation structure 6. Simultaneously, the circumferentially segmented first foil 2 remains straight, creating a preload effect after being installed into the bearing sleeve. Figure 11 and Figure 12 As shown, or the first foil is segmented along the axial direction to form a second foil deformation structure 7, and a certain circumferential misalignment angle is set, such as... Figure 11 and Figure 14 As shown, two methods are used to adjust the upper and lower triangular structures to form a distribution pattern where the middle of the axial direction is high and the two ends are low, or the circumferential direction is divided into several parts, with each part having a high middle and low two ends, so as to reasonably arrange the foil support stiffness and air film thickness distribution.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, alterations, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A foil-plate tiltable gas dynamic bearing, characterized in that, include: The bearing sleeve (1), the first foil (2), the auxiliary support foil (4), and the top foil (3) are arranged in parallel. The first foil (2) is composed of several interconnected upper and lower triangular structures (21) made of metal plate. The upper triangular structure is inverted and connected to the lower triangular structure. There is a certain gap between the two intermediate beams (213) connecting the upper and lower triangular structures. The auxiliary support foil (4) is installed between the two intermediate beams (213). After the first foil (2) bears the load, the two intermediate beams (213) bend and deform inward, squeezing the auxiliary support foil (4) and generating a certain frictional damping. It is affected by the intermediate beams (213). The upper triangular structure rotates to the left or right according to the load direction, and the lower triangular structure deforms to both sides and transmits the load to the adjacent upper and lower triangular structures (21). The radial inner surface of the first foil (2) contacts the radial outer surface of the top foil (3), and the radial outer surface of the first foil (2) contacts the radial inner surface of the bearing sleeve (1). The support (42) of the auxiliary support foil (4) is inserted into the inclined groove (11) of the bearing sleeve. The bearing sleeve (1) supports the first foil (2), and the first foil (2) supports the top foil (3). One end of the first foil (2) and the top foil (3) are free, and the other end is fixed together on the bearing sleeve (1).

2. The gas dynamic bearing according to claim 1, characterized in that, The auxiliary support foil (4) is made of metal plate and consists of auxiliary support vertical beam (41) and support (42). The support (42) is inserted into the inclined groove (11) of the bearing sleeve. The auxiliary support foil (4) has the effect of cantilever beam, which improves the support of the upper triangular structure of the first foil (2). There is a certain gap between the auxiliary support vertical beams (41). After being squeezed by the middle beam (213) of the first foil (2), it can produce a certain deformation and at the same time provide support for the middle beam (213) of the first foil (2).

3. The gas dynamic bearing according to claim 1, characterized in that, The upper and lower triangular structures (21) in the first foil (2) are replaced by upper and lower triangular structures made by 3D printing.

4. The gas dynamic bearing according to claim 1, characterized in that, The auxiliary support foil (4) is replaced by an auxiliary support foil deformation structure (5), which is formed by pressing and folding a metal plate and is placed between the two beams. The auxiliary support foil deformation structure (5) has a gap in the middle and deforms under the load of the two intermediate beams (213). The lower part of the auxiliary support foil deformation structure (5) is inserted into the straight groove (13) of the bearing sleeve for fixation.

5. The gas dynamic bearing according to claim 1, characterized in that, The first foil (2) is segmented along the circumferential direction to form a multi-lobed foil deformed body, or the first foil (2) is segmented along the axial direction and a certain circumferential misalignment angle is set. Both methods are used to adjust the distribution of the upper and lower triangular structures (21).

6. The gas dynamic bearing according to claim 1, characterized in that, The upper and lower triangular structures (21) are arranged in a reasonable manner by changing the size of the structure and the distribution along the axial and circumferential directions, forming a distribution with the middle of the axial direction being high and the two ends being low, or the circumferential direction being divided into several parts, each part having the middle of the circumferential direction being high and the two ends being low, thus supporting the stiffness and air film thickness distribution of the first foil (2).

7. The gas dynamic bearing according to claim 1, characterized in that, The bearing sleeve (1) is a circular metal part. The inner surface of the bearing sleeve is provided with an axial through groove or pin hole. When the auxiliary support foil (4) is used, the groove is used to fix the auxiliary support foil (4), the first foil (2), and the top foil (3). The first foil (2) and the top foil (3) can be directly fixed on the bearing sleeve.

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