An adjustable stiffness foil gas dynamic pressure bearing

Abstract

This invention provides an adjustable stiffness foil gas dynamic pressure bearing, comprising: a top foil, a first foil, an SMA foil group, a second foil, a bearing sleeve, a cooling plate, and a heat sink; wherein, the first foil and the second foil are each composed of two longitudinal beams connected at the ends of circumferentially distributed V-shaped beams, the circumferential length of the V-shaped beam of the first foil is less than the gap between two adjacent V-shaped beams of the second foil, and the V-shaped beam of the first foil is placed between the two V-shaped beams of the second foil; the SMA foil group is composed of a first SMA foil, an electrically controlled heating film, and a second SMA foil stacked sequentially, located in the middle of the first foil and the second foil, and its axial width is less than the axial width of the V-shaped beams of the first foil and the second foil; the cold end of the electrically controlled cooling plate is in close contact with the V-shaped beam of the second foil, and the hot end is connected to the heat sink; the top foil provides the bearing surface for the dynamic pressure gas film, and the bearing sleeve supports and fixes all components. This application achieves active adjustment of bearing stiffness by rapidly adjusting the elastic modulus of SMA foil through an electrically controlled heating film and cooling plate, thus solving the technical problem that existing foil gas dynamic bearings cannot cross critical speeds and ultra-high speed instability. The circumferentially spaced V-shaped beams enable the top foil and SMA foil group to participate in structural deformation as simply supported beams, improving impact resistance and durability. Under load, the top foil forms a V-shaped depression, producing a gas-gathering effect similar to that of grooved bearings, thereby improving the bearing's load-bearing capacity.

Description

Technical Field

[0001] This invention relates to the field of hydrodynamic bearing technology, specifically to an adjustable stiffness foil gas hydrodynamic bearing, which is particularly suitable for high-speed rotating mechanical equipment, such as fuel cell air compressors, blowers, and micro gas turbines. Background Technology

[0002] Foil hydrodynamic bearings are divided into radial bearings and thrust bearings, consisting of a top foil, elastic foils, and a bearing sleeve, utilizing high-pressure gas as the carrier supporting the rotor. However, the stiffness of existing bearings does not change with rotor speed, resulting in vibration amplitudes significantly exceeding the bearing clearance when the rotor speed approaches or equals the system's higher-order natural frequency, making it impossible to cross the critical speed. Furthermore, the smooth top foil and circumferentially uniform elastic structure cause the bearing's principal stiffness in the horizontal and vertical directions to be isotropic, while the cross stiffness exhibits antisymmetry, leading to subsynchronous instability of the rotor at high speeds. Thrust bearings are used to bear the axial force of the rotor system to suppress axial vibration and axial movement; however, in existing technology, thrust bearings have insufficient axial load-bearing capacity. Summary of the Invention

[0003] To address the aforementioned technical shortcomings, this application provides an adjustable stiffness foil gas dynamic bearing. Shape memory alloy foil serves as the bearing's elastic structure, and the elastic modulus of the shape memory alloy foil is rapidly adjusted via an electrically controlled heating film and cooling plates, thereby achieving active adjustment of the bearing stiffness. Furthermore, the combined design of the cooling plates and heat sinks effectively improves the bearing's heat dissipation, ensuring its stability during high-speed rotation. The sequentially distributed top foil, first foil, shape memory alloy foil group, and second foil participate in the structural deformation in the form of a simply supported beam, improving the bearing's resistance to impact loads and its durability. Simultaneously, the top foil, supported by the first foil, generates a gas-gathering effect similar to that of a grooved bearing, increasing the bearing's load-bearing capacity. The numerous technical effects of the preferred solutions among the various technical solutions provided by this invention are described below.

[0004] To achieve the above technical objectives, the present invention provides the following technical solution: an adjustable stiffness foil gas dynamic bearing, comprising: a top foil, a first foil, a shape memory alloy foil group, a second foil, a bearing sleeve, a cooling plate, and a heat sink.

[0005] Both the first and second foils consist of several circumferentially distributed beam structures connecting two longitudinal beams at the ends of the foils. The circumferential length of the beam structure of the first foil is independent of the circumferential length of the beam structure of the second foil. The circumferential gap between two adjacent beam structures of the first foil is independent of the circumferential gap between two adjacent beam structures of the second foil. The circumferential length of the beam structure of the first foil is less than the gap between two adjacent beam structures of the second foil. The beam structure of the first foil is positioned between the beam structures of the two second foils. The circumferential length of the beam structure of the second foil is less than the gap between two adjacent beam structures of the first foil. The beam structure of the second foil is positioned between the beam structures of the two first foils. The axial width of the first and second foils is equal to the axial width of the top foil and greater than the axial width of the shape memory alloy foil group. The end of the first foil is in a cantilever state relative to the shape memory alloy foil group.

[0006] The shape memory alloy foil assembly consists of a first shape memory alloy foil, a second shape memory alloy foil, and an electrically controlled heating film of equal length. The electrically controlled heating film is placed between the first and second shape memory alloy foils, and the axial width of the shape memory alloy foil assembly is less than the axial width of the beam structure of the first and second foils. The circumferential length of the electrically controlled heating film is equal to or less than the circumferential length of the first shape memory alloy foil. The electrically controlled heating film heats the first and second shape memory alloy foils by electricity, causing them to undergo a phase change, changing their elastic modulus and increasing their diameter, thereby adjusting the stiffness of the bearing.

[0007] Cooling fins and heat sinks are respectively placed on the cooling fin slots and heat sink slots on the bearing sleeve. The cooling fins are distributed circumferentially. The cold end of the electrically controlled cooling fin is located below the second foil. The beam structure closely adheres to the second foil and is fixed in the cooling fin slot on the bearing. The hot end of the cooling fin is closely attached to the heat sink. The heat sink has multiple vertical thin plates. The heat dissipation area is increased by multiple vertical thin plates to ensure temperature control of the bearing when it rotates at high speed.

[0008] One end of the top foil is fixed to the bearing sleeve, while the other end is free. The axial length of the top foil is less than or equal to the axial length of the first foil, the second foil, and the bearing sleeve. The top foil provides the bearing surface for the dynamic pressure air film.

[0009] The inner surface of the bearing sleeve has a cooling fin groove and a heat sink groove. The cooling fin groove is above the heat sink groove. The bearing sleeve supports and fixes the top foil, the first foil, and the second foil.

[0010] Preferably, the beam structure of the first foil and the second foil is a V-shaped beam, an arc-shaped beam, or a straight beam. The second foil has a hole corresponding to the beam structure with an enlarged ratio at the circumferential position of the beam structure of the first foil, so as to deform the beam structure of the first foil.

[0011] Preferably, the included angle of the V-shaped beam is modified according to actual needs, and the two sides of the V-shape are not parallel.

[0012] Preferably, the circumferential length at the axial midpoint of the beam structure of the first foil is greater than the circumferential length at its ends, so that the midpoint stiffness of the beam structure of the foil is greater than the support stiffness at both ends.

[0013] Preferably, the first foil and the second foil can be composed of a longitudinal beam and circumferentially distributed V-shaped beams.

[0014] Preferably, the first shape memory alloy foil and the second shape memory alloy foil are provided with circumferentially distributed shape memory alloy foil end grooves at both ends, so that the first shape memory alloy foil and the second shape memory alloy foil have high stiffness in the middle and low stiffness at both ends, and the shape memory alloy foil end grooves are located below the beam structure of the first foil.

[0015] Preferably, one or more electrically controlled heating films are distributed circumferentially, and the first shape memory alloy foil and the second shape memory alloy foil are heated globally or locally, causing the shape memory alloy material to undergo a phase change, changing its elastic modulus and expanding its diameter, thus producing a local preload effect.

[0016] Preferably, the top foil, the first foil, and the second foil are all made of shape memory alloy material.

[0017] Preferably, the top foil is arc-shaped and consists of one or multiple foils distributed circumferentially.

[0018] Preferably, the edge of the free end of the top foil is arc-shaped, V-shaped, or straight, and the orientation of the arc or V-shape is consistent with the direction of rotor rotation.

[0019] Preferably, the bearing can be removed from the cooling fins and heat sink.

[0020] According to another aspect of the present invention, an adjustable stiffness foil gas dynamic thrust bearing is also provided, comprising a thrust top foil, a thrust first foil, a thrust shape memory alloy foil group, a thrust second foil, and a thrust bearing sleeve, wherein the thrust top foil, the thrust first foil, the thrust shape memory alloy foil group, and the thrust second foil are fixed on the thrust bearing sleeve through thrust foil limiting holes.

[0021] Both the first and second thrust foils are composed of several thrust foil beam structures that are non-uniformly distributed circumferentially, connecting the inner and outer rings of the thrust foil. The circumferential length of the beam structure of the first thrust foil is less than the gap between two adjacent beam structures of the second thrust foil. The beam structure of the first thrust foil is placed between the beam structures of the two second thrust foils. The circumferential length of the beam structure of the second thrust foil is less than the gap between two adjacent beam structures of the first thrust foil. The beam structure of the second thrust foil is placed between the beam structures of the two first thrust foils. The several non-uniformly distributed beam structures divide the bearing circumferentially into multiple parts. The beam structure of the first part and the beam structure of the second part are separated by pre-drilled holes in the thrust foil. The pre-drilled holes of the first and second thrust foils are approximately in the same circumferential position.

[0022] The thrust shape memory alloy foil assembly consists of a first thrust shape memory alloy foil, a second thrust shape memory alloy foil, and a thrust electronically controlled heating film, all with identical structures. The shapes of the first and second thrust shape memory alloy foils are similar to those of the thrust top foil. The inner diameters of the first and second thrust shape memory alloy foils are larger than the inner diameter of the thrust foil beam structure, while the outer diameters are smaller than the outer diameter of the thrust foil beam structure. The thrust electronically controlled heating film is placed between the first and second thrust shape memory alloy foils.

[0023] The thrust top foil consists of an outer ring of the thrust top foil, a connecting beam of the thrust top foil, and a bearing surface of the thrust top foil. The outer diameter of the circumferentially distributed bearing surface of the top foil is less than or equal to the outer diameter of the thrust foil beam structure, and the inner diameter of the bearing surface of the top foil is greater than or equal to the inner diameter of the thrust foil beam structure. One end of the thrust top foil is located in the pre-reserved hole of the thrust foil. When subjected to air film load, the end of the top foil deforms in the pre-reserved hole of the thrust foil, forming a wedge shape.

[0024] Preferably, the thrust foil beam structure is a thrust foil V-shaped beam, a thrust foil arc-shaped beam, or a thrust foil straight beam, and the specific shape is set according to the pressure distribution of the thrust bearing.

[0025] Preferably, the included angle of the thrust foil V-beam is modified according to actual needs.

[0026] Preferably, the two sides of the thrust foil V-beam have different lengths and the circumferential widths on both sides.

[0027] Preferably, the second thrust foil has a hole corresponding to the enlarged thrust foil beam structure at the circumferential position of the thrust foil beam structure of the first thrust foil, so that the thrust foil beam structure of the first thrust foil can be deformed.

[0028] Preferably, the thrust foil of the first thrust foil is placed radially along the thrust bearing, or in the horizontal and vertical directions.

[0029] Preferably, the thrust-controlled heating film is a single or multiple films distributed circumferentially, which are electrically heated globally or locally to heat the first thrust shape memory alloy foil and the second thrust shape memory alloy foil, causing a phase change in the shape memory alloy material and altering its elastic modulus.

[0030] Preferably, the thrust top foil, the first thrust foil, and the second thrust foil are all made of shape memory alloy material.

[0031] Preferably, the shape of the top foil end is arc-shaped or V-shaped, which is set according to the gas film pressure distribution. The arc or V-shaped orientation of the top foil bearing surface is consistent with the rotor rotation direction to collect gas.

[0032] The present invention, by employing the aforementioned technology, offers the following advantages compared to existing technologies: It provides an adjustable stiffness foil gas dynamic bearing. The top foil, first foil, shape memory alloy foil assembly, and second foil are all processed from flat foils, eliminating the need for mold pressing and shaping, thus improving the bearing's manufacturability. By using the shape memory alloy foil as the bearing's elastic structure, the heating and cooling of the shape memory alloy foil are rapidly altered via an electrically controlled heating film and cooling plates, changing its elastic modulus and consequently altering the bearing's circumferential global or local support stiffness, thereby improving the bearing's overall stiffness. The anisotropic stiffness of the bearing and the reduced cross stiffness enable the rotor system to operate stably across critical speeds and ultra-high speeds. At the same time, the cooling fins and heat sinks increase the heat dissipation effect of the bearing and the temperature control speed of the shape memory alloy material. The circumferentially spaced beam structure in the first and second foils allows the top foil and the shape memory alloy foil group to participate in the deformation of the structure as simply supported beams, improving the bearing's resistance to impact loads and durability. Meanwhile, under load, the top foil, supported by the first foil, exhibits a V-shaped indentation, producing an air-gathering effect similar to that of a grooved bearing, thereby increasing the bearing's load-bearing capacity. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 An exploded view of the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0035] Figure 2 This is a front view of the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0036] Figure 3The bearing support structure diagram of the adjustable stiffness foil gas dynamic bearing provided by the present invention is shown.

[0037] Figure 4 A schematic diagram of the first foil of the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0038] Figure 5 A schematic diagram of the second foil of the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0039] Figure 6 A schematic diagram of the shape memory alloy foil assembly for the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0040] Figure 7 This is a partial enlarged view of the bearing sleeve of the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0041] Figure 8 This is a schematic diagram of the first foil pattern 1 of the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0042] Figure 9 This is a partial enlarged cross-sectional view of the adjustable stiffness foil gas dynamic bearing provided by the present invention (Style 1).

[0043] Figure 10 This is a schematic diagram of the first foil pattern 2 of the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0044] Figure 11 A schematic diagram of the bearing support structure of the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0045] Figure 12 This is a schematic diagram of the shape memory alloy foil pattern 1 for the adjustable stiffness foil gas dynamic bearing provided by the present invention.

[0046] Figure 13 Exploded view of the adjustable stiffness foil gas dynamic thrust bearing provided by the present invention.

[0047] Figure 14 A schematic diagram of the thrust foil of the adjustable stiffness foil gas dynamic thrust bearing provided by the present invention.

[0048] Figure 15 A schematic diagram of the thrust top foil of the adjustable stiffness foil gas dynamic thrust bearing provided by the present invention.

[0049] Figure 16 A schematic diagram of the adjustable stiffness foil gas dynamic thrust bearing provided by the present invention.

[0050] Figure 17 This is a schematic diagram of the thrust top foil style 1 of the adjustable stiffness foil gas dynamic thrust bearing provided by the present invention.

[0051] Figure 18 This is a schematic diagram of the thrust foil style 1 of the adjustable stiffness foil gas dynamic thrust bearing provided by the present invention.

[0052] Figure 19 This is a schematic diagram of the thrust shape memory alloy foil assembly style 1 for the adjustable stiffness foil gas dynamic thrust bearing provided by the present invention.

[0053] Figure 20 This is a schematic diagram of the thrust foil style 2 of the adjustable stiffness foil gas dynamic thrust bearing provided by the present invention.

[0054] The labels for the various figures in the diagram are as follows: 1-Top foil, 2-First foil, 3-Shape memory alloy foil group, 4-Second foil, 5-Bearing sleeve, 6-Cooling plate, 7-Heat sink, 11-Thrust bearing sleeve, 12-Thrust first foil, 13-Thrust shape memory alloy foil group, 14-Thrust second foil, 15-Thrust top foil, 16-Thrust first foil style 1, 17-Thrust shape memory alloy foil group style 1, 1 8-Thrust second foil style 1, 19-Thrust top foil style 1, 20-Thrust first foil style 2, 21-First foil longitudinal beam, 22-First foil V-shaped beam, 24-Straight beam, 31-First shape memory alloy foil, 32-Electrically controlled heating film, 33-Second shape memory alloy foil, 41-Second foil longitudinal beam, 42-Second foil V-shaped beam, 51-Cooling fin groove, 52-Heat sink groove, 121-Thrust foil Outer ring of the thrust foil, 122-V-shaped beam of the thrust foil, 123-Inner ring of the thrust foil, 124-Limiting hole of the thrust foil, 125-Pre-drilled hole of the thrust foil, 151-Outer ring of the thrust top foil, 152-Connecting beam of the thrust top foil, 153-Bearing surface of the thrust top foil, 154-End of the thrust top foil, 171-First shape memory alloy foil pattern 1 of the thrust, 172-Electrically controlled heating film of the thrust, 173-Second shape memory alloy foil of the thrust. Style 1, 181-Outer ring of first thrust foil style 1, 182-Crossbeam of first thrust foil style 1, 183-Inner ring of first thrust foil style 1, 184-Limiting hole of first thrust foil style 1, 185-Reserved hole of first thrust foil style 1, 191-Outer ring of top thrust foil style 1, 192-Connecting beam of top thrust foil style 1, 193-Bearing surface of top thrust foil style 1, 311-End groove of shape memory alloy foil. Detailed Implementation

[0055] 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.

[0056] In the description of this invention, it should be noted that, unless otherwise stated, "several" or "more than" means two or more; the terms "upper," "lower," "top," "bottom," "inner," "outer," "first," "second," 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.

[0057] In the description of this invention, it should be noted that, unless otherwise stated, the term "preload" should be interpreted broadly, that is, the air film thickness is not uniform in the radial direction of the bearing, for example, the bearing structure is preloaded during installation, or it can be formed during the bearing operation process and have the same effect as the preload. For those skilled in the art, the specific meaning of the above term in this invention can be understood according to the specific circumstances.

[0058] The adjustable stiffness foil gas dynamic bearing provided in the embodiments of this application will now be described.

[0059] like Figure 1 and Figure 2 As shown, an adjustable stiffness foil gas dynamic bearing includes: a top foil (1), a first foil (2), a shape memory alloy foil group (3), a second foil (4), a bearing sleeve (5), a cooling plate (6), and a heat sink (7).

[0060] like Figures 3 to 5As shown, both the first foil (2) and the second foil (4) are composed of several circumferentially distributed beam structures connecting two longitudinal beams (21, 41) at the ends of the foil. In this case, the beam structure is a V-shaped beam. The circumferential length of the V-shaped beam (22) of the first foil is not related to the circumferential length of the V-shaped beam (42) of the second foil. The circumferential gap between two adjacent V-shaped beams (22) of the first foil is not related to the circumferential gap between two adjacent V-shaped beams (42) of the second foil. The circumferential length of the V-beam (22) of the first foil is less than the gap between the V-beams (42) of the two adjacent second foils. The V-beam (22) of the first foil is placed between the V-beams (42) of the two second foils. The circumferential length of the V-beam (42) of the second foil is less than the gap between the V-beams (22) of the two adjacent first foils. The V-beam (42) of the second foil is placed between the V-beams (22) of the two first foils. The axial width of the first foil (2) and the second foil (4) is greater than or equal to the axial width of the top foil (1) and greater than the axial width of the shape memory alloy foil group (3). The end of the first foil (2) is in a cantilever state relative to the shape memory alloy foil group (3).

[0061] like Figure 6 As shown, the shape memory alloy foil group (3) is composed of a first shape memory alloy foil (31) and a second shape memory alloy foil (33) of the same length and an electrically controlled heating film (32). The electrically controlled heating film (32) is placed in the middle of the first shape memory alloy foil (31) and the second shape memory alloy foil (33), and the axial width of the shape memory alloy foil group (3) is less than the axial width of the V-shaped beam of the first foil and the second foil. The circumferential length of the electrically controlled heating film (32) is equal to or less than the circumferential length of the first shape memory alloy foil (31). When the electrically controlled heating film (32) is energized, it simultaneously heats the first shape memory alloy foil (31) and the second shape memory alloy foil (33), causing the shape memory alloy material to undergo a phase change, changing its elastic modulus and increasing its diameter value, thus producing a local preload effect.

[0062] like Figure 1 As shown, one end of the top foil (1) is fixed on the bearing sleeve (5), and the other end is free. The axial length of the top foil (1) is less than or equal to the axial length of the first foil (2), the second foil (4) and the bearing sleeve (5). The top foil (1) provides the bearing surface for the dynamic pressure air film.

[0063] like Figure 1 , Figure 2 , Figure 7 , Figure 9As shown, the cooling fins (6) are distributed circumferentially. The cold end of the electrically controlled cooling fins (6) is located below the V-shaped beam (42) of the second foil and is fixed in the cooling fin groove (51) on the bearing. The hot end of the cooling fins (6) is in close contact with the heat sink (7). The heat sink (7) has multiple vertical thin plates to increase the ventilation and heat dissipation area. The heat sink (7) is placed in the heat sink groove (52) of the bearing sleeve (5).

[0064] like Figure 4 and Figure 5 As shown, preferably, the axial width of the longitudinal beams (21, 41) of the first foil (2) and the second foil (4) is independent of the circumferential length of the V-beams (22, 42), and the two dimensions can be made the same or different.

[0065] Preferably, only one of the longitudinal beams (21, 41) of the first foil (2) and the second foil (4) is retained.

[0066] Preferably, the included angle of the V-shaped beam is modified according to actual needs, and the two sides of the V-shape are not parallel.

[0067] Preferably, such as Figures 8 to 10 As shown, the beam structure is a V-shaped beam, an arc beam or a straight beam. The V-shaped beam of the first foil (2) is replaced by a straight beam (24) or an arc beam. The replaced first foil (2) becomes the first foil style 1 and the first foil style 2. The second foil (4) has corresponding holes for the enlarged beam structure at the circumferential position of the beam structure of the first foil (2), so that the beam structure can be deformed.

[0068] Preferably, such as Figure 10 As shown, the circumferential length at the axial middle position of the beam structure of the first foil is greater than the circumferential length at its ends, which makes the middle stiffness of the beam structure of the foil greater than the support stiffness at both ends.

[0069] Preferably, such as Figure 11-12 As shown, circumferentially distributed shape memory alloy foil end grooves (311) are machined on both sides of the first shape memory alloy foil (31) and the second shape memory alloy foil (33), so that the first shape memory alloy foil (31) and the second shape memory alloy foil (33) have high stiffness in the middle and low stiffness at both ends. The shape memory alloy foil end grooves (311) are placed below the V-shaped beam (22) of the first foil.

[0070] Preferably, the electrically controlled heating film (32) is a single or multiple circumferentially distributed film, which heats the first shape memory alloy foil (31) and the second shape memory alloy foil (33) by global or local electric heating, causing the shape memory alloy material to undergo a phase change, changing its elastic modulus and expanding its diameter, thereby producing a local preload effect.

[0071] Preferably, the top foil (1), the first foil (2), and the second foil (4) are all made of shape memory alloy material.

[0072] Preferably, the top foil (1), the first foil (2), the shape memory alloy foil group (3), and the second foil (4) form a single structure or multiple structures distributed circumferentially.

[0073] Preferably, the edge of the free end of the top foil (1) is arc-shaped, V-shaped or straight, and the orientation of the arc or V-shape is consistent with the direction of rotor rotation.

[0074] Preferably, the bearing has removable cooling fins (6) and heat sinks (7).

[0075] Figure 13-15 As shown, an adjustable stiffness foil gas dynamic thrust bearing is composed of a thrust top foil (15), a thrust first foil (12), a thrust shape memory alloy foil group (13), a thrust second foil (14), and a thrust bearing sleeve (11). All components are fixed on the thrust bearing sleeve (11) through thrust foil limiting holes (124).

[0076] The first thrust foil (12) and the second thrust foil (14) are composed of several thrust foil beams that are not uniformly distributed in the circumference, connecting the inner ring (123) and the outer ring (121) of the thrust foil. In this case, the thrust foil beam structure is a thrust foil V-beam (122). The circumferential length of the thrust foil V-beam (122) of the first thrust foil (12) is less than the gap between the thrust foil V-beams (122) of the two adjacent second thrust foils (14). The thrust foil V-beam (122) of the first thrust foil (12) is placed between the thrust foil V-beams (122) of the two second thrust foils (14). The circumferential length of the thrust foil V-beam (122) of the second thrust foil (14) is less than the gap between the two adjacent second thrust foils (14). The gap between the thrust foil V-beams (122) of the first thrust foil (12) and the thrust foil V-beams (122) of the second thrust foil (14) are placed between the two thrust foil V-beams (122) of the first thrust foil (12); the several thrust foil V-beams (122) of the first thrust foil (12) and the second thrust foil (14) are non-uniformly distributed in the circumference, dividing the bearing circumferentially into multiple parts. The thrust foil V-beams of the first part and the thrust foil V-beams of the second part are separated by thrust foil reserved holes (125). The circumferential distance of the thrust foil reserved holes (125) is relatively large. The thrust foil reserved holes (125) of the first thrust foil (12) and the second thrust foil (14) are approximately in the same circumferential position.

[0077] The thrust top foil (15) consists of a thrust top foil outer ring (151), a thrust top foil connecting beam (152), and a thrust top foil bearing surface (153). The thrust top foil bearing surface (153) is connected to the thrust top foil outer ring (151) via the thrust top foil connecting beam (152). The outer diameter of the circumferentially distributed thrust top foil bearing surface (153) is less than or equal to the outer diameter of the thrust foil V-beam (122). The inner diameter of the thrust top foil bearing surface (153) is greater than or equal to the inner diameter of the thrust foil V-beam (122). One thrust top foil end (154) of the thrust top foil bearing surface (153) is located in the thrust foil reserved hole (125). When bearing the air film load, the thrust top foil end (154) deforms in the thrust foil reserved hole (125) to produce a wedge shape.

[0078] Preferably, the shape of the thrust top foil end (154) is arc-shaped or V-shaped, which is set according to the gas film pressure distribution. The arc-shaped or V-shaped orientation of the thrust top foil bearing surface (155) is consistent with the rotor rotation direction to gather gas.

[0079] Preferably, such as Figure 13-19 As shown, the thrust foil beam structure is a thrust foil V-shaped beam, a thrust foil arc-shaped beam, or a thrust foil straight beam. The specific shape is set according to the pressure distribution of the thrust bearing. The second thrust foil has a hole corresponding to the enlarged thrust foil beam structure at the circumferential position of the thrust foil beam structure of the first thrust foil, so that the thrust foil beam structure can be deformed. After the thrust foil V-shaped beam is replaced with the thrust foil straight beam, the first thrust foil, the thrust shape memory alloy foil group, the second thrust foil, and the thrust top foil can have the corresponding structures shown in the figure, such as thrust first foil style 1 (16), thrust shape memory alloy foil group style 1 (17), thrust second foil style 1 (18), and thrust top foil style 1 (19).

[0080] Preferably, the included angle of the thrust foil V-beam (122) is modified according to actual needs.

[0081] Preferably, the two sides of the thrust foil V-beam (122) have different lengths and different circumferential widths.

[0082] Preferably, such as Figure 20 As shown, the thrust foil is placed in a straight beam along the thrust bearing radially, or horizontally and vertically.

[0083] Preferably, the thrust top foil (15), the first thrust foil (12), and the second thrust foil (14) are all made of shape memory alloy material.

[0084] 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. An adjustable stiffness foil gas hydrodynamic bearing, characterized in that, include: Top foil, first foil sheet, shape memory alloy foil sheet group, second foil sheet, bearing sleeve, cooling plate, heat sink; among which, Both the first foil and the second foil are composed of several circumferentially distributed beam structures connecting two longitudinal beams at the ends of the foil. The circumferential length of the beam structure of the first foil is smaller than the gap between adjacent beam structures of the second foil, and is placed between adjacent beam structures of the second foil. The beam structure is a V-shaped beam, an arc beam, or a straight beam. The shape memory alloy foil assembly is composed of a first shape memory alloy foil, an electrically controlled heating film, and a second shape memory alloy foil stacked sequentially. It is located in the radial and axial middle of the first foil and the second foil, and its axial width is smaller than the axial width of the beam structure of the first foil and the second foil. The cold end of the electronically controlled cooling plate is located below the second foil and is in close contact with the beam structure of the second foil. The hot end of the cooling plate is in close contact with the heat sink. The heat sink is provided with multiple vertical thin plates to increase the heat dissipation area. The axial length of the top foil is less than or equal to the axial length of the first foil, the second foil, and the bearing sleeve. The top foil provides a bearing surface for the dynamic pressure gas film. The bearing sleeve supports and fixes the top foil, the first foil, the shape memory alloy foil group, the second foil, the cooling plate, and the heat sink.

2. The adjustable stiffness foil gas hydrodynamic bearing according to claim 1, characterized in that, The circumferential length at the axial midpoint of the V-shaped beam, arc beam, or straight beam is greater than the circumferential length at its ends, making its midpoint stiffness greater than the support stiffness at both ends; the second foil has a hole corresponding to the beam structure at an enlarged ratio at the circumferential position of the beam structure of the first foil, so that the beam structure of the first foil can be deformed; the end of the first foil is in a cantilever state relative to the shape memory alloy foil group.

3. The adjustable stiffness foil gas hydrodynamic bearing according to claim 1, characterized in that, The electrically controlled heating film is a single or multiple circumferentially distributed film, the circumferential length of which is equal to or less than the circumferential length of the first shape memory alloy foil. It can heat the first shape memory alloy foil and the second shape memory alloy foil globally or locally, causing the shape memory alloy material to undergo a phase change, thereby changing its elastic modulus and increasing its diameter to produce a local preload effect. The detachable cooling plate and the heat sink are distributed circumferentially and are located in the cooling plate groove and heat sink groove on the bearing sleeve, respectively. They work in conjunction with the electrically controlled heating film to regulate the temperature of the shape memory alloy foil group.

4. The adjustable stiffness foil gas hydrodynamic bearing according to claim 1, characterized in that, The top foil has an arc-shaped or segmented structure, with one end fixed to the bearing sleeve and the other end free; the edge of the free end is arc-shaped, V-shaped or straight, wherein the arc or V-shaped orientation is consistent with the rotor rotation direction.

5. The adjustable stiffness foil gas hydrodynamic bearing according to claim 1, characterized in that, The first shape memory alloy foil and the second shape memory alloy foil are provided with circumferentially distributed shape memory alloy foil end grooves on both sides, so that the stiffness in the middle is greater than the stiffness at both ends, and the shape memory alloy foil end grooves are placed below the beam structure of the first foil.

6. An adjustable stiffness foil gas dynamic thrust bearing, characterized in that, include: The thrust top foil, the first thrust foil, the thrust shape memory alloy foil assembly, the second thrust foil, and the thrust bearing sleeve; among which... Both the first thrust foil and the second thrust foil are composed of several thrust foil beam structures that are non-uniformly distributed circumferentially, connecting the inner and outer rings of the thrust foil. The circumferential length of the thrust foil beam structure of the first thrust foil is less than the gap between adjacent thrust foil beam structures of the second thrust foil, and is placed between two thrust foil beam structures of the second thrust foil. The thrust foil beam structure is a thrust foil V-shaped beam, a thrust foil arc-shaped beam, or a thrust foil straight beam. The thrust shape memory alloy foil assembly consists of a first thrust shape memory alloy foil, a second thrust shape memory alloy foil, and a thrust electrically controlled heating film with identical structures. The thrust electrically controlled heating film is placed between the first thrust shape memory alloy foil and the second thrust shape memory alloy foil. The thrust top foil includes an outer ring of the thrust top foil, a connecting beam of the thrust top foil, and a bearing surface of the thrust top foil; the outer diameter of the bearing surface of the circumferentially distributed thrust top foil is less than or equal to the outer diameter of the thrust foil beam structure, and its inner diameter is greater than or equal to the inner diameter of the thrust foil beam structure. The thrust top foil, the first thrust foil, the thrust shape memory alloy foil group, and the second thrust foil are fixed to the thrust bearing sleeve through the thrust foil limiting hole.

7. The adjustable stiffness foil gas dynamic thrust bearing according to claim 6, characterized in that, The two sides of the same side of the thrust foil V-beam have different lengths and the circumferential widths on both sides; the straight beam is placed radially along the thrust bearing, or horizontally and vertically; the specific shape of the thrust foil beam structure is set according to the pressure distribution of the thrust bearing; the second thrust foil has a hole corresponding to the enlarged thrust foil beam structure at the circumferential position of the thrust foil beam structure of the first thrust foil, so that the thrust foil beam structure can be deformed; The bearing is divided into multiple parts by several thrust foil beam structures that are not uniformly distributed in the circumference. The first part of the thrust foil beam structure and the second part of the thrust foil beam structure are separated by the pre-reserved holes in the thrust foil.

8. The adjustable stiffness foil gas dynamic thrust bearing according to claim 6, characterized in that, The inner diameter of the first thrust shape memory alloy foil and the second thrust shape memory alloy foil is larger than the inner diameter of the thrust foil beam structure, and their outer diameter is smaller than the outer diameter of the thrust foil beam structure; the thrust electronically controlled heating film is a single or multiple circumferentially distributed film that globally or locally heats the first thrust shape memory alloy foil and the second thrust shape memory alloy foil, thereby changing their elastic modulus and increasing their diameter value.

9. The adjustable stiffness foil gas dynamic thrust bearing according to claim 7, characterized in that, The shape of the thrust top foil end is arc-shaped or V-shaped, which is set according to the gas film pressure distribution; one end of the thrust top foil is supported by the thrust foil beam structure, and the other end of the thrust top foil is deformed in the pre-reserved hole of the thrust foil; the orientation of the arc or V-shape of the thrust top foil bearing surface is consistent with the rotor rotation direction.

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