Split bearing unit and dynamic pressure gas thrust foil bearing

Abstract

This invention discloses a split-type bearing unit and a hydrodynamic gas thrust foil bearing. The bearing unit includes a fan-shaped annular bearing housing, flat sheet-shaped support foils, and a fan-shaped annular top foil. The bearing housing has several narrow slots, in which the support foils are embedded. One end of the top foil is fixed to the bearing unit by a gasket, and the other end is suspended above the exposed end of the support foil in the narrow slot. The bearing made from this bearing unit allows the flat sheet-shaped support foils to be directly inserted into the narrow slots of the bearing housing, providing elastic support for the top foil. Simultaneously, the flexible combination of different support foils can achieve nonlinear stiffness, and the multiple contact areas between the different support foils and the top foil provide good damping.

Description

Technical Field

[0001] This invention relates to the field of hydrodynamic gas bearing manufacturing, and more particularly to a split bearing unit and a hydrodynamic gas thrust foil bearing. Background Technology

[0002] A hydrodynamic gas bearing is a passive sliding hydrodynamic bearing that uses air or other gases as the lubricating medium. A foil hydrodynamic gas bearing is a rigid hydrodynamic bearing with an additional elastic support structure. It typically consists of a top layer of foils that form a lubricating gas film and a bottom layer of elastic foils with a certain stiffness and Coulomb damping characteristics.

[0003] Based on the foil structure configuration, traditional foil hydrodynamic gas bearings can be mainly divided into cantilever type and corrugated foil type. Cantilever foil bearings consist of multiple leaf-shaped arc-shaped foils, one end hinged and the other free, stacked sequentially to form an elastic foil structure. Without a bottom supporting foil, the bearing's stiffness and load-bearing capacity are relatively low. The forming process of the arc-shaped foils generally requires the use of molds. Corrugated foil bearings use a corrugated foil strip formed by multiple arched structures connected sequentially as an elastic support structure, possessing higher foil stiffness and load-bearing capacity. The processing of the corrugated foil structure also requires hydraulic forming with molds, and its variable parameter design and processing process is costly.

[0004] The multi-flat support plate type thrust foil bearing proposed in this application provides a support structure with a simple manufacturing process, which can provide sufficient stiffness and load-bearing capacity. It has many relatively independent contact points with the top foil, which can provide good damping, and it is convenient to design and manufacture foil hydrodynamic gas bearings with different parameters and stiffness distributions. Summary of the Invention

[0005] Based on the above problems, the problem to be solved by the present invention is to provide a split bearing unit and a dynamic pressure gas thrust foil bearing that is simple to manufacture, low in cost, has a strong load-bearing capacity, and has flat sheet support foil.

[0006] One of the technical solutions of the present invention is as follows:

[0007] A split bearing unit includes a bearing housing with a fan-shaped annular straight structure, a support foil with a straight sheet structure, a top foil with a fan-shaped annular straight structure, and a gasket.

[0008] Several narrow, beveled grooves are provided on one surface of the bearing housing in a clockwise square pattern;

[0009] The support foil includes an embedded end and an extended end. The embedded end of the support foil is inserted into the narrow groove, and the extended end is exposed on the surface of the bearing seat.

[0010] The top foil includes a fixed end in the clockwise direction and a free end in the counterclockwise direction. The fixed end is fixedly disposed on the surface of the bearing seat by the gasket and close to the clockwise side of the bearing seat. The free end of the top foil is suspended above the extension end of the support foil.

[0011] Preferably, in the split bearing unit, the narrow groove is parallel to the counterclockwise side of the bearing housing, and the distance between two adjacent narrow grooves is equal, or the narrow grooves are distributed radially along the bearing unit, and the arc angle of two adjacent narrow grooves is equal.

[0012] Preferably, in the split bearing unit, each of the two axial ends of the support foil is provided with a lug. After the support foil is inserted into the narrow groove, the lug is exposed on the outer and inner rings of the bearing housing and serves as a limiting function on the inner and outer rings of the bearing housing, respectively.

[0013] Preferably, in the split bearing unit, multiple notches are formed along the longitudinal direction on the straight edge of the extended end.

[0014] Preferably, in the split bearing unit, each of the supporting foils includes a main fin and multiple auxiliary fins; the embedded end of the auxiliary fin is flush with and fitted to the embedded end of the main fin, the extended end of the auxiliary fin is closely fitted to the extended end of the main fin, and the lug of the auxiliary fin is flush with and fitted to the lug of the main fin.

[0015] Preferably, in the split bearing unit, when the number of auxiliary fins is greater than two times the number of main fins, the auxiliary fins in the middle layer are lower than the auxiliary fins at both ends.

[0016] Preferably, in the split bearing unit, the surface of the bearing housing is divided into a support plate area and a non-support plate area in a clockwise direction; the support plate area is provided with the support foil, and the non-support plate area has no support foil.

[0017] Preferably, in the split bearing unit, on the surface of the bearing housing, the distance between the extended end of the support foil and the surface of the bearing housing decreases gradually from high to low in a clockwise direction.

[0018] Preferably, in the split bearing unit, the density of the support foil in the outer radius region of the bearing housing is higher than the density of the support foil in the inner radius region of the bearing housing.

[0019] The second technical solution of the present invention is as follows:

[0020] A dynamic pressure gas thrust foil bearing includes a bearing mounting base plate with an annular structure, an annular retaining ring, and a plurality of the aforementioned split bearing units; the plurality of the split bearing units are arranged and fixedly disposed on the bearing mounting base plate in a circumferential distribution, and the annular retaining ring securely fastens the plurality of the split bearing units together; the inner and outer diameters of the split bearing units are respectively consistent with the inner and outer diameters of the bearing mounting base plate.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The flat sheet structure of the support foil is directly inserted into the narrow groove of the bearing unit, which can play an elastic support role for the top foil; at the same time, it has the tendency to slide in the circumferential direction.

[0023] 2. The bearing has a simple structure and manufacturing process, high rigidity and load-bearing capacity, and good damping performance. The flexible combination of support foils can achieve nonlinear stiffness. Multiple contact areas between different support foils and the top foil provide good damping. At the same time, the bearing can easily change various parameters to obtain different bearing performance.

[0024] 3. The bearing can adjust the inlet wedge clearance by adjusting the height of the auxiliary support plate along the circumferential direction, and adjust the radial stiffness distribution by adjusting the radial division of the main support plate or the shape of the overhanging end of the auxiliary support plate. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the assembly of a split bearing unit in one embodiment;

[0026] Figure 2 A schematic diagram of a partial structure of a split bearing unit with equally spaced and parallel narrow slots and bearing housing surfaces configured as support and non-support areas.

[0027] Figure 3 A partial structural diagram of a split bearing unit with parallel, equally spaced narrow slots and supporting foils including main fins and multiple auxiliary fins.

[0028] Figure 4 A schematic diagram of a flat, sheet-like support foil structure;

[0029] Figure 5 A schematic diagram of a support foil structure that is flat and sheet-like with a notch at the extended end;

[0030] Figure 6a , 6b These are schematic diagrams of the supporting foil, including the main fin and multiple auxiliary fins.

[0031] Figure 7A schematic diagram of a partial structure of a split bearing unit with narrow slots and rounded corners, and with support foils of different densities along the inner and outer radius regions of the bearing.

[0032] Figure 8 A schematic diagram of a partial structure of a split bearing unit with equally spaced and parallel narrow slots and a gradient decrease in the distance between the extended ends of the support foils and the surface of the bearing housing.

[0033] Figure 9 A schematic diagram of a partial structure of a split bearing unit with narrow slots and rounded corners, and the surface of the bearing housing is divided into a support area and a non-support area.

[0034] Figure 10 This is a schematic diagram of the assembly of a hydrodynamic gas thrust foil bearing structure that includes a split-type bearing unit. Detailed Implementation

[0035] The preferred embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0036] Example 1

[0037] like Figures 1 to 5 As shown, the split bearing unit 10 in this embodiment includes a bearing housing 300 with a fan-shaped annular straight structure, a support foil group 200 composed of several straight sheet-like support foils 210, a top foil 100 with a fan-shaped annular straight structure, and a gasket 400. Several narrow grooves 310 are formed on the inner wall of the bearing housing 300. These narrow grooves 310 are parallel to the counterclockwise (g-direction) side 302 of the bearing housing 300, and the distance between adjacent narrow grooves 210 is equal.

[0038] The support foil group 200 is composed of several support foils 210. Each support foil 210 includes an insert end 212 and an extension end 211. The insert end 212 of the support foil 210 is inserted into the narrow groove 310, and the extension end 211 is exposed on the surface of the bearing seat 300. Each narrow groove 320 has the same depth in the bearing seat 300.

[0039] Since the support foil 210 has a flat sheet structure, the corresponding narrow groove 320 is set as an oblique straight groove structure in the clockwise direction (g direction). The inclination angle formed by the narrow groove 320 and the surface of the bearing unit allows for the elastic support of the support foil 210. Each of the two axial ends of the support foil 210 is provided with a lug 202. After the support foil 210 is inserted into the narrow groove 310, the lug 210 is exposed on the outer ring 304 and inner ring 303 of the bearing housing 300, and serves as a limiting element on the inner ring 303 and outer ring 302 of the bearing housing 300.

[0040] The top foil 100 has a fan-shaped, annular, straight structure. The arc length, inner diameter, and outer diameter of the top foil 100 are consistent with the arc length, inner diameter, and outer diameter of the bearing housing 300. The top foil 100 includes a fixed end 120 and a free end 110. The clockwise (g-direction) side of the top foil 100 is the fixed end 120, and the counterclockwise (h-direction) side of the top foil 100 is the free end 110. The fixed end 120 is fixedly disposed on the surface of the bearing housing 300 by a gasket 400 and is close to the clockwise (g-direction) side 301 of the bearing housing 300. The free end 110 of the top foil 100 is exposed above the extension end 211 of the support foil 210, and the inner surface of the top foil 100 does not contact the extension end 211 of the support foil 210, so that the top foil 100 and the surface of the bearing housing 300 form an inclined angle. Under high-speed operation of the thrust disc, this tilt angle generates an initial dynamic pressure effect. After the top foil 100 deforms, it comes into contact with multiple support foils 210, thereby bearing a large axial load. In addition, the extension end 211 of the support foil 210 will undergo bending deformation, and the end face of the extension end 211 will also undergo circumferential slippage relative to the inner surface of the top foil 100. Therefore, compared with the corrugated foil bearing, the deformation and slippage of the flat sheet structure support foil 210 are not affected by the adjacent support foils 210.

[0041] Better, such as Figure 5 As shown, multiple notches 201 are made along the longitudinal direction on the straight edge of the extended end 211 of the support foil 210 with the above-mentioned flat sheet structure. These notches 210 divide the cut edge where the extended end 211 of the support foil 210 is located into multiple small segments. The axial length of each segment can be designed according to the requirements to form different axial stiffness distributions.

[0042] Better, such as Figure 2 As shown, along the circumference of the bearing unit 300, from clockwise direction g to counterclockwise direction h, the surface of the bearing housing 300 is divided into support area II and non-support area I. Support area II is provided with several support foils 210, while non-support area I is not provided with corresponding support foils 210. That is to say, the area on the surface of the bearing housing 300 in the counterclockwise direction h is support area II (also known as the high-pressure area), which is provided with several support foils 210; the area on the surface of the bearing housing 300 in the clockwise and counterclockwise directions g is non-support area I, which is not provided with support foils 210.

[0043] Furthermore, such as Figure 3As shown, the flat, sheet-like support foil 210 and the corresponding narrow grooves 310 on the bearing unit 300 are uniformly and parallelly distributed along the circumference. On each bearing unit 300, the width of the narrow grooves 310 is slightly smaller from the counterclockwise direction h to the clockwise direction g. Along the circumference of the bearing unit 300, from the clockwise direction g to the counterclockwise direction h, the support foil 210 first gradually increases in size and then remains constant to form a wedge-shaped converging gap.

[0044] Example 2

[0045] like Figure 6a and 6b As shown, the difference between this embodiment and Embodiment 1 is that the supporting foil 210 is different. Specifically:

[0046] Each support foil 210 includes a main fin 230 and multiple auxiliary fins 220; during installation, a main fin 230 and multiple auxiliary fins 220 are installed as a group in a narrow slot 320 of the bearing housing 300.

[0047] The main fin 230 and multiple auxiliary fins 220 each have an insert end 212 and an extension end 211. (Since the insert end of the main fin 230 and the insert end of the auxiliary fin 220 have the same structure and function, this embodiment uses the same identification number, such as insert end 212; of course, under the premise of no ambiguity, the identification of the insert end of the auxiliary fin 220 can also use other identification numbers, such as 212', 212a, etc.). The insert end 212 of the auxiliary fin 220 is flush with and attached to the insert end 212 of the main fin 230, and the extension end 211' of the auxiliary fin 220 is attached to the extension end 211 of the main fin 230. Both the extension end 211' of the auxiliary fin 220 and the extension end 211 of the main fin 230 can contact the outer wall of the top foil 100, or both extension ends 211 of the main fin 230 can contact the outer wall of the top foil 100, while the extension end 211' of the auxiliary fin 220 does not contact the outer wall of the top foil 100. Furthermore, the lugs 202 of the auxiliary fin 220 and the lugs 202 of the main fin 230 (since the lugs of the main fin 230 and the lugs of the auxiliary fin 220 have the same structure, size, and function, this embodiment uses the same identification number, such as lug 202; of course, without ambiguity, the identification of the lugs of the auxiliary fin 220 can also use other identification numbers, such as 202', 202a, etc.) are fitted flush with each other.

[0048] The main fin 230 described above has the same structure as the flat sheet-like support foil 210 in Embodiment 1. The insertion end of the auxiliary fin 220 is the same as the insertion end of the main fin 230, both being straight. The end face of the extension end 211' of the auxiliary fin 220 can be straight, zigzag, or arc-shaped. Normally, the spacing between the auxiliary fins is smaller than that between the main fins, but the extension end 211' of the auxiliary fin 220 must also be exposed on the inner wall of the bearing seat 300, that is, placed in the central through hole 310 of the bearing seat 300.

[0049] The extended end 211' of the auxiliary fin 220 is a straight edge, supported on the waist of the extended end 211 of the main fin 230, to improve the support stiffness of the main fin 230. The height of the auxiliary fin 230 will also affect the support stiffness. Therefore, along the circumferential direction, the auxiliary fin 230 can be set to vary in height according to a certain pattern to achieve the purpose of variable stiffness distribution.

[0050] The extended end 211' of the auxiliary fin 220 is a broken edge or a curved edge. Different edge forms can create different axial stiffness distributions, and the main purpose is to enhance the support stiffness of the central region.

[0051] Since there are a large number of auxiliary fins 230, namely two or more, all auxiliary fins 220 can be arranged on the same side of the main fin 230, or multiple auxiliary fins 220 can be arranged on both sides of the main fin 230 respectively.

[0052] Specifically, when the number of main fins 230 and auxiliary fins 220 is greater than two, the auxiliary fins 220 are not necessarily arranged in a high-low order. The auxiliary fins 220 in the middle layer can be lower than the auxiliary fins 220 on both sides. The main fins 230 will only contact the extension ends 211' of some auxiliary fins 220 after undergoing a certain bending deformation. This can achieve the effect of nonlinear stiffness. In this way, the fin group composed of main fins 230 and auxiliary fins 220 will slip between layers during the bending deformation process, which has a damping effect.

[0053] Example 3

[0054] The difference between this embodiment and Embodiment 1 is that:

[0055] like Figures 7 to 10 As shown, the narrow slots 310 of the bearing housing 300 are radially distributed along the bearing unit 300, and the arc angles of two adjacent narrow slots 310 are equal.

[0056] For this type of bearing housing 300 design, such as Figure 7 As shown, the distribution density of the support foils 210 in the outer radius region A can be increased relative to the inner radius region B to improve the support stiffness and overcome the disadvantage of large span between adjacent support foils 210 in the outer radius region.

[0057] Better, such as Figure 8 As shown, from the counterclockwise direction h to the clockwise direction g, the distance between the extension end 211 of the support foil 210 and the surface of the bearing housing 300 decreases gradually from the high region M to the low region N. Furthermore, the distance from the extension end 211 of the support foil 210 to the surface of the bearing housing 300 is equal in the high region M, while the distance from the extension end 211 of the support foil 210 to the surface of the bearing housing 300 decreases gradually along the clockwise direction g in the low region N. In this way, the support foils 210 on the bearing housing 300 are all radially distributed. The width between two adjacent support foils 210 near the inner ring 303 of the bearing housing 300 is slightly smaller, and gradually increases from g to h along the circumferential direction of the bearing housing 300 before remaining constant, forming a wedge-shaped converging gap. At this time, the radial length of each straight support foil 210 can be kept consistent, thereby reducing the manufacturing difficulty of the support foil 210 and making it easier for mass production.

[0058] Example 4

[0059] In this embodiment, the split bearing unit 10 of Embodiment 1 is selected. In the split bearing unit 10, the support foil 210 of Embodiment 2 is selected, which includes a main fin 230 and multiple auxiliary fins 220.

[0060] like Figure 10 As shown, a hydrodynamic gas thrust foil bearing 20 includes a hollow annular bearing mounting base plate 12, an annular retaining ring 11, and six split bearing units 10. The six split bearing units 10 are arranged and fixedly mounted on the bearing mounting base plate 12 in a circumferential distribution, and the annular retaining ring 11 securely fastens the six split bearing units 10 together. The inner and outer diameters of the split bearing units 10 are respectively consistent with the inner and outer diameters of the bearing mounting base plate 12. That is, it is composed of... Figure 10 After the components in section (a) are assembled, the following is obtained: Figure 10 The dynamic pressure gas thrust foil bearing 20 is shown in (b).

[0061] This type of bearing features flat, straight support foils that are directly inserted into narrow slots within the bearing unit, providing elastic support for the top foil. It also exhibits a tendency for circumferential sliding. Furthermore, the bearing has a simple structure and manufacturing process, high stiffness and load-bearing capacity, and good damping performance. The flexible combination of support foils allows for nonlinear stiffness, and multiple contact areas between the support foil groups and between the main support foil and the top foil provide excellent damping. Additionally, the bearing's parameters can be easily varied to achieve different bearing performance characteristics. Therefore, the inlet wedge clearance can be adjusted by changing the height of the auxiliary support foil circumferentially, and the radial stiffness distribution can be adjusted by radially dividing the main support foil or changing the shape of the overhanging ends of the auxiliary support foil.

[0062] It should be understood that the above description of the preferred embodiments of the present invention is quite detailed, but it should not be considered as a limitation on the scope of patent protection of the present invention. The scope of patent protection of the present invention shall be determined by the appended claims.

Claims

1. A split-type bearing unit, characterized in that, The split bearing unit includes a bearing housing with a fan-shaped annular straight structure, a support foil with a straight sheet structure, a top foil with a fan-shaped annular straight structure, and a gasket. Several narrow, beveled grooves are formed on one surface of the bearing housing in a clockwise direction; The support foil includes an embedded end and an extended end. The embedded end of the support foil is inserted into the narrow groove, and the extended end is exposed on the surface of the bearing seat. The top foil includes a fixed end in the clockwise direction and a free end in the counterclockwise direction. The fixed end is fixedly disposed on the surface of the bearing seat by the gasket and close to the clockwise side of the bearing seat. The free end of the top foil is exposed above the extension end of the support foil. The two axial ends of the support foil are each provided with a lug. After the support foil is inserted into the narrow groove, the lug is exposed on the outer and inner rings of the bearing seat and serves as a limiting function on the inner and outer rings of the bearing seat. Each support foil includes a main fin and multiple auxiliary fins. The embedded end of the auxiliary fin is flush with the embedded end of the main fin, and the extended end of the auxiliary fin is close to the extended end of the main fin. The lug of the auxiliary fin is flush with the lug of the main fin.

2. The split bearing unit according to claim 1, characterized in that, The narrow groove is parallel to the counterclockwise side of the bearing housing, and the distance between two adjacent narrow grooves is equal; or the narrow grooves are distributed radially along the bearing unit, and the arc angle of two adjacent narrow grooves is equal.

3. The split bearing unit according to claim 1, characterized in that, Multiple notches are made along the longitudinal direction on the straight edge of the extended end.

4. The split bearing unit according to claim 1, characterized in that, The surface of the bearing housing is divided into a support plate area and a non-support plate area in a clockwise direction; the support plate area is provided with the support foil, and the non-support plate area has no support foil.

5. The split bearing unit according to claim 1, characterized in that, On the surface of the bearing housing, the distance between the extended ends of the support foil and the surface of the bearing housing decreases gradually from high to low in a clockwise direction.

6. The split bearing unit according to claim 1, characterized in that, The density of the support foil in the outer radius region of the bearing housing is higher than the density of the support foil in the inner radius region of the bearing housing.

7. A hydrodynamic gas thrust foil bearing, characterized in that, The bearing includes a bearing mounting base plate with an annular structure, an annular retaining ring, and several split bearing units as described in any one of claims 1 to 6; the several split bearing units are arranged and fixedly disposed on the bearing mounting base plate in a circumferential distribution, and the annular retaining ring securely fastens the several split bearing units together; the inner and outer diameters of the split bearing units are respectively consistent with the inner and outer diameters of the bearing mounting base plate.

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