Double-ring multi-layer overlapped dynamic pressure thrust bearing

Abstract

The invention discloses a double-ring multi-layer overlapped dynamic pressure thrust bearing which comprises a bearing bottom plate, a damping fin, a bearing gasket and a bearing top foil which are overlapped, the damping fin, the bearing gasket and the bearing top foil are axially symmetrical and are arranged in an inner ring and an outer ring, and each ring is surrounded by a plurality of foils at intervals in the circumferential direction; the bearing bottom plate enables each damping fin to form a simply supported beam supporting structure in the circumferential direction, the bearing gaskets are supported at the middle portions of the damping fins and the bearing top foil in the circumferential direction, inclined planes are formed at the two ends of the bearing top foil in the circumferential direction, and the thickness of the inner-ring bearing gasket of each bearing gasket is larger than that of the outer-ring bearing gasket of each bearing gasket. The double-ring multi-layer overlapped dynamic pressure thrust bearing is adopted, the supporting rigidity of the inner ring bearing lamination is larger than that of the outer ring bearing lamination, and the variable-rigidity damping characteristic is achieved. According to the bearing, the starting and stopping service life of the bearing is prolonged; and the bearing also has the capability of self-adaptive adjustment according to load change, the stability of the bearing is improved, and the power consumption of the bearing is lower.

Description

Technical Field

[0001] The invention relates to a supporting element of a shaft system structure, and in particular to a gas dynamic pressure thrust bearing with a stacked structure. Background Art

[0002] Bearings are components in mechanical shafting systems that support the rotation of the rotor (shaft). Depending on the direction of the force they support, they can be divided into radial bearings, which bear radial forces, and thrust bearings, which bear axial forces. Thrust bearings provide axial support for the rotor, reducing axial movement and ensuring its axial reliability. Among them, dynamic pressure thrust bearings utilize the wedge-shaped space formed between the rotor carrier plate and the bearing surface to generate a wedge-shaped dynamic pressure effect. As the rotor speed increases, the viscosity of the gas draws the surrounding gas into the wedge-shaped space between the rotor and the bearing. As the air pressure within the wedge-shaped space increases, a dynamic pressure film forms between the rotor and the bearing when the bearing speed reaches a certain value, isolating the rotor from the bearing and providing load-bearing lubrication. Once stable gas lubrication is achieved, the dynamic pressure effect increases the bearing's load capacity as the rotor speed increases. Furthermore, utilizing the dynamic pressure film to support loads significantly reduces friction. Compared to bearings with other operating principles, hydrodynamic thrust bearings offer numerous advantages, including oil-free operation, pollution-free operation, low operating resistance, simple structure, and low mechanical losses. These advantages offset many of the shortcomings of traditional liquid bearings, sliding oil bearings, and rolling bearings, and have led to their widespread application in high-speed rotating machinery and precision machining. They are particularly popular in applications such as food processing, brewing, and data centers. Driven by the demands of energy conservation, emission reduction, and environmental protection, hydrodynamic thrust bearings offer a promising market and future.

[0003] Currently, hydrodynamic foil thrust bearings are widely used as axial support elements for high-speed rotors. While they offer advantages, they also present disadvantages. Optimizing and improving the stability and reliability of hydrodynamic foil thrust bearings is a crucial issue. Bearing load, damping, and takeoff speed are crucial parameters for bearings. For example, in refrigeration centrifugal compressors, changes in operating conditions alter the compressor's intake and exhaust ports, and so do bearing load and support conditions. The bearing's load, vibration reduction, and damping under varying operating conditions are crucial for ensuring rotor system stability. For example, during operating mode switching, when the compressor intake superheat is low, centrifugal compressors are prone to liquid hammer. This can cause the compressor rotor to become unstable, leading to irreversible damage to the rotor and bearings. In this situation, excellent bearing damping performance is essential. Furthermore, during certain startup conditions, reducing the bearing's takeoff speed and minimizing rotor dry friction time for a faster takeoff are also important measures to enhance the life of hydrodynamic foil thrust bearings.

[0004] The basic structure of the existing dynamic pressure foil thrust bearing includes a bearing bottom plate, a supporting wave foil and a load-carrying top foil. The supporting wave foil located in the middle of the bearing is generally a ring-shaped load-carrying tile. In the starting stage of the bearing, the top foil area of the existing dynamic pressure foil thrust bearing is in full contact with the rotor load-carrying disc, that is, the contact area is large, the starting resistance is large, and a large starting torque is required. The bearing power consumption is large during starting, the take-off speed is relatively high, the time of dry friction between the bearing and the rotor is long, and the start-stop life of the bearing is reduced; the thrust bearing with the wave foil structure has poor damping characteristics of the wave foil used for vibration reduction, and the stability is not enough; and the existing bearing with a single ring of load-carrying tiles does not have the ability of self-adaptive adjustment with the change of load, that is, the load-carrying area cannot be self-adaptively adjusted and changed, and the corresponding bearing power consumption will be higher.

[0005] Therefore, how to overcome the defects of the existing dynamic pressure foil thrust bearing, such as poor load damping characteristics, no load self-adaptive adjustment capability, large friction torque in the starting process and influence on start-stop life, is a technical problem to be solved in the field. SUMMARY

[0006] In order to solve the technical problems of the existing dynamic pressure foil thrust bearing, such as poor load damping characteristics, no load self-adaptive adjustment capability and large friction torque in the starting process, a double-ring multi-layer superimposed dynamic pressure thrust bearing with good load damping characteristics, load self-adaptive adjustment capability, short take-off time of the bearing in the starting process, small friction torque and prolonged start-stop life is provided.

[0007] To solve the technical problem, the double-ring multi-layer superimposed dynamic pressure thrust bearing provided by the present application comprises a bearing bottom plate, a damping sheet, a load-carrying gasket and a load-carrying top foil which are stacked in sequence; the damping sheet, the load-carrying gasket and the load-carrying top foil are arranged in a double ring which is axially symmetrical and has an inner ring and an outer ring, and each ring is circumferentially spaced and surrounded by multiple foils; the bearing bottom plate supports each damping sheet in a simply supported beam structure in the circumferential direction, the load-carrying gasket is supported at the circumferential middle part of the damping sheet and the load-carrying top foil, so that the two ends of each load-carrying top foil in the circumferential direction form an inclined surface, and the thickness of the inner ring load-carrying gasket is greater than that of the outer ring load-carrying gasket.

[0008] The bearing utilizes a radially arranged, stacked structure of inner and outer ring foils. The inner and outer ring damping fins have the same thickness, but the outer ring damping fin's support span is greater than the inner ring damping fin's. Consequently, the outer ring damping fin's stiffness is lower than the inner ring damping fin's. Furthermore, the inner ring bearing shim is thicker than the outer ring bearing shim, while the inner and outer ring bearing top foils maintain the same thickness. This ensures that the bearing's inner ring bearing fins have greater support stiffness than the outer ring bearing fins. During rotor startup, the stiffer inner ring bearing fins receive priority, facilitating rapid air film formation. This means that the bearing's inner ring bearing top foil contacts the rotor carrier disc first, while the larger outer ring bearing top foil has not yet contacted the rotor disc. This reduces the contact area between the bearing and the rotor disc, lowering friction and the frictional torque required for rotor startup. This reduces the speed required for the bearing to take off, enabling faster rotor takeoff. This reduces the rotor's dry friction time and improves the bearing's start-up and shutdown life. As rotor speed increases, aerodynamic axial forces increase. Under the compressive action of the axial force, the inner ring damping plate, supported between the two support bosses of the bearing baseplate, deforms downward. At this point, the outer ring bearing top foil begins to contact the rotor bearing disc and exert its load-bearing function, thereby increasing the bearing's load-bearing area. At the same operating speed, the increased load-bearing area increases the bearing capacity of the entire thrust bearing, enabling the bearing to autonomously adapt to changes in load and improve its load-bearing reliability. The inner and outer ring damping plates of the present invention are arranged between the two support bosses of the bearing baseplate to form a simply supported beam support structure. Compared to the corrugated foil vibration damping plates of existing thrust bearings, their damping characteristics and adaptive adjustment capabilities are superior, resulting in higher bearing stability.

[0009] Preferably, one surface of the bearing base plate is evenly distributed with radially arranged support bosses, the number of the support bosses corresponds to the number of damping plates in a circle, and two adjacent support bosses make each damping plate form a simply supported beam support structure along the circumferential direction.

[0010] By uniformly disposing radial support bosses along the circumference of the bearing baseplate, the bearing baseplate and the support bosses, which serve as the support structure, can be manufactured integrally. The radial arrangement of the support bosses allows for different support spans for the inner and outer ring damping plates, thereby achieving different support stiffnesses for the inner and outer ring damping plates, thereby achieving the objectives of the present invention.

[0011] Preferably, the damping plate is fan-shaped, with its two circumferential ends respectively arranged on two adjacent supporting bosses, and the damping plate is first fixedly connected to the supporting bosses with a radial edge facing the side of the bearing rotation direction.

[0012] The damping sheet is made into a fan shape, which can be suitable for the inclined shape of the radially arranged support boss, that is, the two side edges of the fan-shaped circumferential edge are radial, which is convenient for corresponding connection with the support boss to form reliable support. The radial edge on one side of the damping sheet is fixedly connected with the support boss, and the radial edge on the other side is not fixedly welded with the support boss, but only abuts against the surface of the support boss, which is a free end, and is convenient for deformation and expansion of the damping sheet. That is, when the damping sheet is deformed under impact load, the free expansion of the damping sheet can be ensured to improve the damping characteristics of the bearing.

[0013] Preferably, the damping sheet is fixed by spot welding with the support boss, the welding spots are uniformly distributed along the radial edge of the damping sheet, the number of the welding spots is equal to or greater than six, and the gap distance between the welding spots is 2-5 mm; the thickness of the inner and outer ring damping sheets of the damping sheet is the same, and the thickness is 0.1-0.5 mm. The damping sheet is spot welded with the support boss, which can ensure the flatness of the welding; the number of the welding spots is selected according to the size of the bearing to ensure the reliability of the welding.

[0014] Preferably, the inner and outer ring bearing pads of the bearing pad are correspondingly welded on the circumferential middle part of the upper surface of the inner and outer ring damping sheets of the damping sheet, the thickness of the outer ring bearing pad is 0.05-0.01 mm, and the thickness of the inner ring bearing pad is 0.02-0.06 mm thicker than that of the outer ring bearing pad.

[0015] The bearing pad is welded on the circumferential middle part of the upper surface of the damping sheet to ensure the flatness of the welding and play a better supporting role. Limiting the thickness of the inner ring bearing pad to be 0.02-0.06 mm thicker than that of the outer ring bearing pad can increase the rigidity of the inner ring bearing pad, which is convenient for the inner ring bearing pad to preferentially bear the axial force during the starting process of the rotor.

[0016] Preferably, the bearing top foil is in a fan shape, the inner and outer ring bearing top foil bearing areas of the bearing top foil are greater than the areas of the corresponding inner and outer ring bearing pads, the circumferential length of each bearing top foil is greater than the circumferential length of the corresponding overlapping bearing pad, and the radial edge on one side of the bearing top foil is fixedly connected with the support boss, and the radial edge on the other side of the bearing top foil abuts against the free end of the damping sheet.

[0017] The bearing top foil is made into a fan shape, which can be suitable for the inclined shape of the radially arranged support boss, and the two side edges of the fan-shaped circumferential edge are also radial, which is convenient for corresponding connection with the support boss. The inner and outer ring bearing top foil bearing areas of the bearing top foil are greater than the areas of the corresponding inner and outer ring bearing pads, so that the bearing top foil directly contacts and bears the rotor bearing disc. The radial edge on one side of the bearing top foil is fixedly connected with the support boss, and the radial edge on the other side is not fixedly connected with the support boss, but only abuts against the surface of the support boss, which is a free end, and is convenient for deformation and expansion of the bearing top foil. That is, when the bearing top foil is deformed under impact load, the free movement of the bearing top foil can be ensured to improve the damping characteristics of the bearing.

[0018] Preferably, the bearing top foil is first bent into a radial edge facing the bearing rotation direction, and the bent edge of the bent structure is fixedly connected to the supporting boss for welding to avoid the outside of the fixed connection area of ​​the damping plate.

[0019] The radial edge of the load-bearing top foil that needs to be fixed is made into a bent structure. When the load-bearing top foil is welded and fixed to the supporting boss of the bearing base plate, the bent structure is used to avoid the welding end of the damping plate below, that is, the welding platform of the load-bearing top foil is outside the welding area of ​​the damping plate to prevent the two from overlapping and affecting the free expansion and contraction of the damping plate and the load-bearing top foil.

[0020] Preferably, the load-bearing top foil includes the welding platform, the wedge-shaped air inlet plane, the top foil load-bearing area, and the wedge-shaped exhaust plane, and the tail end of the wedge-shaped exhaust plane is in contact with the free end of the damping plate; the thickness of the inner and outer ring load-bearing top foils is the same, which is 0.1-0.25mm.

[0021] After the bearing of the present invention is installed, each circumferential end of the support top foil forms downwardly inclined surfaces. This means that the support top foil forms a wedge-shaped air intake plane, a top foil support area, and a wedge-shaped air exhaust plane. When the bearing is assembled with the rotor, the wedge-shaped air intake and exhaust planes at each end of the support top foil form air intake and exhaust wedge spaces with the surface of the rotor support plate. When the rotor rotates, air is drawn in through the air intake wedge space and exhausted through the exhaust wedge space. This facilitates the establishment of a dynamic pressure gas model between the bearing and the rotor support plate, reduces friction and wear, and facilitates heat dissipation from the bearing.

[0022] Preferably, the wedge heights of the wedge-shaped air inlet planes and the wedge heights of the wedge-shaped air exhaust planes of the inner and outer ring bearing top foils are the same, and the wedge height H2 is the same as the thickness H1 of the bearing gasket.

[0023] According to the size of the bearing, keeping the wedge height of the wedge-shaped air inlet plane of the inner and outer ring bearing top foils the same as the wedge height of the wedge-shaped air exhaust plane, and the wedge height H2 and the thickness H1 of the bearing gasket the same, can more effectively establish a dynamic pressure gas model between the bearing and the rotor bearing plate, reduce friction and wear, and dissipate heat from the bearing.

[0024] Preferably, the number of foils per circle is 4-8. The number of foils constituting each circle in the bearing of the present invention can be selected based on the specific size of the bearing. The purpose is to ensure reasonable bearing support stiffness, reduce rotor starting friction torque, maintain the bearing's ability to adapt to load changes, and improve bearing load reliability.

[0025] The double-ring multi-layer superimposed dynamic pressure thrust bearing provided by the application has different support stiffness of the inner and outer rings of the bearing, and has a variable stiffness damping characteristic. During the starting process of the rotor, the inner ring with strong support stiffness is in contact with the rotor to bear the load, the contact area is small, and the friction resistance is reduced, so that the rotor can take off quickly. That is, the dry friction time of the rotor is short, and the starting and stopping life of the bearing is improved; as the aerodynamic axial force increases, the outer ring bearing top foil starts to contact and bear the rotor, and then the contact area of the bearing is increased, and the bearing capacity of the bearing is improved, so that the bearing has the ability to adaptively adjust according to the change of the axial load, and the stability of the bearing is improved. Since the damping sheet of the application has better damping characteristics than the wave foil structure of the existing bearing, and has a double-ring bearing area that can adaptively adjust changes, the power consumption of the bearing will be lower. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is an exploded schematic view of the double-ring multi-layer superimposed dynamic pressure thrust bearing of the application.

[0027] Figure 2 It is a front view of the double-ring multi-layer superimposed dynamic pressure thrust bearing of the application.

[0028] Figure 3 It is Figure 2 a structure schematic view in which the bearing top foil is removed;

[0029] Figure 4 It is Figure 3 a structure schematic view in which the bearing gasket is removed;

[0030] Figure 5 It is Figure 1 a perspective view of the bearing bottom plate in the application;

[0031] Figure 6 It is Figure 1 a schematic view of the bearing top foil in the application;

[0032] Figure 7 It is Figure 2 a projection schematic view of the outer ring bearing laminates in the A-A direction of the application;

[0033] Figure 8 It is Figure 2 a projection schematic view of the inner ring bearing laminates in the B-B direction of the application.

[0034] In the figure:

[0035] 1-bearing top foil, 101-inner ring bearing top foil, 102-outer ring bearing top foil, 103-welding platform,

[0036] 104-wedge-shaped air inlet plane, 105-top foil bearing area, 106-wedge-shaped air outlet plane;

[0037] 2 - bearing pad, 201 - inner ring bearing pad, 202 - outer ring bearing pad;

[0038] 3 - damping sheet, 301 - inner ring damping sheet, 302 - outer ring damping sheet, 303 - welding spot;

[0039] 4 - bearing base plate, 401 - support boss, 402 - fixing pin hole, 403 - bearing hole. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is described in detail below in combination with the drawings and examples. It should be understood that the following specific examples are only used to explain the present application and do not constitute limitation to the present application.

[0041] As shown in Figures 1 to 4 , the embodiment of the double-ring multi-layer compound dynamic pressure thrust bearing provided by the present application comprises a bearing base plate 4, a damping sheet 3, a bearing pad 2 and a bearing top foil 1 which are stacked in sequence. The bearing base plate 4 is disc-shaped, while the damping sheet 3 comprises an inner ring damping sheet 301 and an outer ring damping sheet 302, i.e. arranged in axial symmetry in double rings; the bearing pad 2 comprises an inner ring bearing pad 201 and an outer ring bearing pad 202, arranged in axial symmetry in double rings; and the bearing top foil 1 comprises an inner ring bearing top foil 101 and an outer ring bearing top foil 102, arranged in axial symmetry in double rings. The inner ring and the outer ring are both composed of multiple foils which are spaced and circled in circumferential direction, and constitute the inner and outer ring bearing stack assemblies arranged in radial direction. Please refer to Figure 7 、 Figure 8 , the bearing base plate 4 is supported by the support structure on its surface, so that each of the inner ring damping sheet 301 and the outer ring damping sheet 302 is supported as a simply supported beam in circumferential direction; the inner ring bearing pad 201 is supported at the intermediate part of the inner ring damping sheet 301 and the inner ring bearing top foil 101 in circumferential direction; the outer ring bearing pad 202 is supported at the intermediate part of the outer ring damping sheet 302 and the outer ring bearing top foil 102 in circumferential direction, so that each of the bearing top foils 1 has an inclined surface at both ends in circumferential direction, and the thickness of the inner ring bearing pad 201 of the bearing pad 2 is greater than that of the outer ring bearing pad 202.

[0042] In this embodiment, as shown in Figure 4 、 Figure 5As shown, the disc-shaped bearing base plate 4 has a bearing hole 403 at its center. The surface of the bearing base plate 4 is evenly distributed with radially arranged support bosses 401, and the number of the support bosses corresponds to the number of damping plates 3 in a circle, that is, six. The two ends of each damping plate 3 are arranged on two adjacent support bosses 401, so that each damping plate 3 forms a simply supported beam support structure along the circumferential direction. The support bosses 401 radially arranged on the surface of the bearing base plate 4 can manufacture the bearing base plate 4 disc and the support bosses 401 used as a support structure as one piece. The radial setting of the support bosses 401 can make the support spans of the inner ring damping plate 301 and the outer ring damping plate 302 different, such as Figure 7 、 Figure 8 As shown, the support span L1 of the outer ring damping plate 302 is greater than the support span L2 of the inner ring damping plate 301, so that the support stiffness of the inner ring damping plate 301 is greater than the support stiffness of the outer ring damping plate 302, thereby achieving the purpose of the present invention. In addition, the outer circumference of the bearing base plate 4 is also provided with a fixing pin hole 402 for installation.

[0043] like Figure 1 、 Figure 4 As shown, the damping plate 3 is fan-shaped, and its two ends in the circumferential direction are respectively arranged on two adjacent support bosses 401. The inner ring damping plate 301 and the outer ring damping plate 302 are both made into fan-shaped, which can be adapted to the inclined side shape of the radially arranged support boss 401. At the same time, the two sides of the fan-shaped circumference are also radial, which facilitates the corresponding connection with the support boss to form a reliable support. The radial edge of the damping plate 3 facing the bearing rotation direction is first spot-welded to the surface of the support boss 401 (as shown in FIG. Figure 7 、 Figure 8 As shown), the radial edge on the other side is not welded to the support boss, but is only abutted against the surface of the support boss, which is a free end to facilitate deformation and expansion of the damping plate. That is, when the damping plate 3 is deformed by an impact load, the free expansion and contraction of the damping plate 3 can be guaranteed to improve the damping characteristics of the bearing. The damping plate 3 is fixed to the support boss 401 by spot welding, and the welding points 303 are evenly distributed along the radial edge of the damping plate 3. The number of welding points is equal to or greater than six, and the gap distance between the welding points is 2-5mm; the inner and outer ring damping plates of the damping plate 3 have the same thickness, which is 0.1-0.5mm. The damping plate 3 and the support boss 401 are spot welded to ensure the flatness of the welding; the number of welding points can be selected according to the size of the bearing to ensure the reliability of the welding.

[0044] like Figure 1 、 Figure 3 、 Figure 7 and Figure 8As shown, the inner ring bearing pad 201 and the outer ring bearing pad 202 of the bearing pad 2 are ultrasonically welded to the middle part of the circumferential surface of the inner ring damping sheet 301 and the outer ring damping sheet 302 of the damping sheet 3. The thickness of the outer ring bearing pad 202 is 0.05-0.01mm, and the thickness of the inner ring bearing pad 201 is 0.02-0.06mm thicker than that of the outer ring bearing pad 202. The bearing pad 2 is welded to the middle part of the surface of the damping sheet 3, so as to ensure the welding flatness and play a better supporting role, and facilitate the formation of the inclined surface of the two ends of the bearing top foil 1 downward. Limiting the thickness of the inner ring bearing pad 201 to be 0.02-0.06mm thicker than that of the outer ring bearing pad 202 can increase the bearing stiffness of the inner ring bearing stack, so as to preferentially bear the axial force by the inner ring bearing stack during the starting process of the rotor.

[0045] As shown in Figure 1 , Figure 2 , Figure 7 and Figure 8 , the inner ring bearing top foil 101 and the outer ring bearing top foil 102 of the bearing top foil 1 are both fan-shaped, the bearing area of the inner and outer ring bearing top foils is larger than that of the corresponding inner ring bearing pad 201 and outer ring bearing pad 202, and the circumferential length of each ring bearing top foil 1 is larger than that of the underlying bearing pad 2. The radial edge of the bearing top foil 1 on the side facing the rotating direction of the bearing is welded and fixed with the supporting boss 401, and the radial edge on the other side of the bearing top foil 1 is in contact with the free end of the damping sheet 3. The bearing top foil 1 is made into a fan shape, which can be adapted to the shape of the inclined side of the radially arranged supporting boss, and the two side edges of the circumferential fan shape are also radial, which facilitates the corresponding connection with the supporting boss 401. The bearing area of the bearing top foil 1 is larger than that of the bearing pad 2, so that the bearing top foil 1 directly contacts and bears the rotor bearing disc. The radial edge on one side of the bearing top foil 1 is fixedly connected with the supporting boss, and the radial edge on the other side is not fixed with the supporting boss, but only abuts against the surface of the supporting boss, which is a free end, facilitating the deformation and expansion of the bearing top foil 1. That is, when the bearing top foil 1 is deformed by impact load, the free expansion of the bearing top foil 1 can also be ensured, so as to improve the damping characteristics of the bearing. Please refer to Figure 6 As shown, the radial edge of the bearing top foil 1 on the side facing the rotating direction of the bearing is in a bending structure, and the bending edge of the bending structure is a welding platform 103 which is welded and fixedly connected with the supporting boss 401 (please refer to Figure 7), to avoid the outside of the damping sheet 3 fixed connection area. The radial edge of the bearing top foil 1 is made into a bending structure, when the bearing top foil 1 is welded and fixed with the support boss of the bearing bottom plate 4, the bending structure avoids the welding end of the underlying damping sheet 3, that is, makes the welding platform 103 of the bearing top foil 1 outside the welding area of the damping sheet 3, so as to avoid the overlap of the two, which affects the free expansion of the damping sheet 3 and the bearing top foil 1. The bearing top foil 1 comprises a welding platform 103, a wedge-shaped air inlet plane 104, a top foil bearing area 105, and a wedge-shaped air outlet plane 106. The tail end of the wedge-shaped air outlet plane 106 is attached to the free end of the damping sheet 3. The thickness of the inner ring bearing top foil 101 and the outer ring bearing top foil 102 is the same, which is 0.1-0.25mm.

[0046] As shown in Figure 2 , Figure 7 , Figure 8 When the bearing is assembled, the symmetry centers of the damping sheet 3, the bearing pad 2 and the bearing top foil 1 are coincident, forming a bearing laminated assembly, and the symmetry centers of the bearing top foil 1 and the two adjacent support bosses are coincident. The circumferential ends of the bearing top foil 1 form downward inclined surfaces, that is, the bearing top foil 1 forms a wedge-shaped air inlet plane 104, a top foil bearing area 105 and a wedge-shaped air outlet plane 106. When the bearing and the rotor are assembled, the wedge-shaped air inlet plane 104 and the wedge-shaped air outlet plane 106 at both ends of the bearing top foil 1 form an air inlet wedge-shaped space and an air outlet wedge-shaped space between the surface of the rotor bearing disc. When the rotor rotates, it is convenient to bring in gas through the air inlet wedge-shaped space and discharge gas through the air outlet wedge-shaped space. This is conducive to establishing a dynamic pressure gas mode lubrication bearing between the bearing and the rotor bearing disc, reducing friction and wear, and facilitating heat dissipation of the bearing. The wedge-shaped height of the wedge-shaped air inlet plane of the inner and outer ring bearing top foil and the wedge-shaped height of the wedge-shaped air outlet plane are the same, which is H2, and the wedge-shaped height H2 and the thickness H1 of the bearing pad 2 are the same. According to the size of the bearing, keeping the wedge-shaped height of the wedge-shaped air inlet plane of the inner and outer ring bearing top foil and the wedge-shaped height of the wedge-shaped air outlet plane the same and the wedge-shaped height H2 and the thickness H1 of the bearing pad 2 the same can more effectively establish a dynamic pressure gas mode lubrication bearing between the bearing and the rotor bearing disc, reduce friction and wear, and dissipate heat of the bearing.

[0047] As shown in Figure 1 , Figure 2 In the present embodiment, the damping sheet 3, the bearing pad 2 and the bearing top foil 1 constituting the inner ring or the outer ring are all six pieces. According to the size of the bearing, the foil pieces of each ring can be 4-8 pieces. The number of foil pieces constituting each ring in the bearing of the present application can be selected, the purpose is to make the bearing support stiffness reasonable, facilitate to reduce the rotor starting friction torque, maintain the performance of self-adapting load change of the bearing, and improve the reliability of the bearing bearing.

[0048] The present application adopts the bearing structure of double-foil laminated bearing structure with inner and outer rings arranged in the radial direction. Since the thickness of the inner and outer ring damping sheets 3 is the same, but the support span LI of the outer ring damping sheet 302 is greater than the support span L2 of the inner ring damping sheet 301, the stiffness of the outer ring damping sheet is less than that of the inner ring damping sheet. In addition, the thickness of the inner ring bearing pad 201 is greater than that of the outer ring bearing pad 202, while the thickness of the inner and outer ring bearing top foil 1 remains the same, so that the support stiffness of the inner ring bearing stack of the bearing is greater than that of the outer ring bearing stack. During the starting process of the rotor, the inner ring bearing stack with higher stiffness is preferentially loaded, which is beneficial to the rapid formation of the gas film, that is, the bearing inner ring bearing top foil 101 is in contact with the rotor bearing disc first and is loaded, and the larger area outer ring bearing top foil 102 has not yet contacted the rotor bearing disc, thereby reducing the contact area of the bearing and the rotor bearing disc, and the friction force between the two is reduced, so that the rotor starting friction torque is reduced, thereby reducing the required rotating speed of the bearing take-off, and the rotor can take off quickly, that is, the rotor dry friction time is reduced, and the bearing start-stop life is improved. With the increase of the rotating speed of the rotor, the aerodynamic axial force increases, and under the compression action of the axial force, the inner ring damping sheet 301 supported in the middle of the two support bosses of the bearing bottom plate deforms downward, at this time the outer ring bearing top foil 102 starts to contact the rotor bearing disc and plays a bearing role, that is, the bearing area increases. At the same bearing working speed, the increase of the bearing area can improve the bearing capacity of the entire thrust bearing, so that the bearing can adapt to the load change and improve the reliability of the bearing. The inner and outer ring damping sheets in the present application are arranged between the two support bosses of the bearing bottom plate in a simply supported beam support structure, and the damping characteristics are relatively better than those of the existing thrust bearing wave foil damping sheet, and the stability of the bearing is higher. Compared with the poor damping characteristics and the inability to adaptively adjust changes of the existing wave foil structure, the bearing of the present application has lower bearing power consumption.

[0049] Techniques, methods, and devices known to those of ordinary skill in the relevant art should be considered within the scope of the present specification. Any specific values in the present specification should be interpreted as merely illustrative and not limiting on the present application.

[0050] The above description is only a specific implementation of the present application. It should be noted that any modification, equivalent replacement and change made within the spirit and framework of the present application should be included in the protection scope of the present application.

Claims

1. A double-ring multi-layered dynamic pressure thrust bearing, characterized in that: It includes a stacked bearing base plate, a damping plate, a load-bearing gasket and a load-bearing top foil; the damping plate, the load-bearing gasket and the load-bearing top foil are all arranged in a double circle with an inner and outer circle axially symmetrical, and each circle is surrounded by multiple foils at intervals in the circumferential direction; the bearing base plate makes each damping plate form a simply supported beam support structure along the circumferential direction, and the load-bearing gasket is supported on the middle part of the damping plate and the load-bearing top foil in the circumferential direction, so that the two ends of each load-bearing top foil in the circumferential direction form an inclined surface, and the thickness of the inner ring load-bearing gasket of the load-bearing gasket is greater than the thickness of the outer ring load-bearing gasket.

2. The double-ring multi-layered dynamic pressure thrust bearing according to claim 1, characterized in that: The surface of the bearing base plate is evenly distributed with radially arranged support bosses, the number of which corresponds to the number of the damping plates in one circle, and two adjacent support bosses make each damping plate form a simply supported beam support structure along the circumferential direction.

3. The double-ring multi-layered dynamic pressure thrust bearing according to claim 1, characterized in that: The damping plate is fan-shaped, and its two circumferential ends are respectively arranged on two adjacent supporting bosses, and the damping plate is first fixedly connected to the supporting bosses on the radial edge facing the side of the bearing rotation direction.

4. The double-ring multi-layered dynamic pressure thrust bearing according to claim 3, characterized in that: The damping plate is fixed to the supporting boss by spot welding, the welding points are evenly distributed along the radial edge of the damping plate, the number of welding points is equal to or greater than six, and the welding point gap distance is 2-5mm; the inner and outer ring damping plates of the damping plate have the same thickness, which is 0.1-0.5mm.

5. The double-ring multi-layered dynamic pressure thrust bearing according to claim 1, characterized in that: The load-bearing gasket is fixedly connected to the middle part of the circumferential surface of the damping plate. The thickness of the outer ring load-bearing gasket is 0.05-0.01 mm, and the thickness of the inner ring load-bearing gasket is 0.02-0.06 mm thicker than that of the outer ring load-bearing gasket.

6. The double-ring multi-layered dynamic pressure thrust bearing according to claim 1, characterized in that: The load-bearing top foil is fan-shaped, and the load-bearing area of ​​the load-bearing top foil is larger than the area of ​​the load-bearing gasket. The circumferential length of each load-bearing top foil is larger than the circumferential length of the load-bearing gasket. The load-bearing top foil is first fixedly connected to the support boss on the radial edge on the side facing the bearing rotation direction, and the radial edge on the other side of the load-bearing top foil is in contact with the free end of the damping plate 3.

7. The double-ring multi-layered dynamic pressure thrust bearing according to claim 6, characterized in that: The bearing top foil is first bent into a radial edge facing the bearing rotation direction, and the bent edge of the bent structure is fixedly connected to the supporting boss as a welding platform to avoid the outside of the damping plate fixed connection area.

8. The double-ring multi-layered dynamic pressure thrust bearing according to claim 7, characterized in that: The load-bearing top foil includes the welding platform, wedge-shaped air inlet plane, top foil load-bearing area, and wedge-shaped exhaust plane. The tail end of the wedge-shaped exhaust plane is in contact with the free end of the damping plate. The thickness of the inner and outer ring load-bearing top foils is the same, which is 0.1-0.25mm.

9. The double-ring multi-layered dynamic pressure thrust bearing according to claim 8, characterized in that: The wedge height of the wedge-shaped air inlet plane of the supporting top foil is the same as the wedge height of the wedge-shaped air exhaust plane, and the wedge height is the same as the thickness of the supporting gasket.

10. The double-ring multi-layered dynamic pressure thrust bearing according to claim 1, characterized in that: The number of foils per circle is 4-8.

Images