Composite bearing apparatus and axial load bearing method

Abstract

The present application relates to thrust bearing technical field, particularly to a kind of composite bearing equipment and its axial load supporting method, bearing equipment includes axial permanent magnetic levitation bearing device and magnetic medium lubrication thrust roller bearing device;Axial permanent magnetic levitation bearing device is used to generate repulsion type magnetic levitation force;Magnetic medium lubrication thrust roller bearing device includes upper thrust roller seat, lower thrust roller seat, magnetic conducting ring, magnetic lubricating medium and several rollers;Upper thrust roller seat and lower thrust roller seat are made of ferromagnetic material, and roller is fixed on lower thrust roller seat by magnetic force;Roller below is also provided with the permanent magnetic block or the roller positioning reverse permanent magnetic block that is arranged along circumference interval, separated by non-magnetic interval block;By forming circumferential magnetic circuit chain, magnetic lubricating medium is adsorbed on the surface of roller.By this bearing equipment and its axial load supporting method, static load can be supported, dynamic load can also be supported, and roller damage can be avoided.

Description

Technical Field

[0001] This invention relates to the field of thrust bearing technology, and in particular to a composite load-bearing device and its axial load support method. Background Technology

[0002] Large hydroelectric power generation equipment primarily uses sliding bearings to bear axial loads in its thrust bearings. Their advantages include high load-bearing capacity and, with proper hydrodynamic lubrication design, a theoretical lifespan approaching infinity. However, traditional thrust sliding bearings have the following disadvantages: 1. Due to the viscous friction of the lubricating medium, traditional thrust sliding bearings suffer large losses, with absolute values ​​ranging from 600kW to 1500kW depending on the speed and capacity.

[0003] 2. Heavy oil mist pollution: Due to the agitation of the rotor, the lubricating oil escapes to the outside in a mist form, causing environmental pollution.

[0004] 3. The auxiliary oil supply circulation system is complex, including cooling oil and water pipelines, coolers, pumps, motors and other pipeline circulation systems.

[0005] 4. The static friction during start-up and shutdown is large, requiring an auxiliary high-pressure oil system for assisted start-up and shutdown to avoid wear.

[0006] Among the existing technologies, Chinese invention patent document CN101662180A discloses a method that uses permanent magnet levitation bearings, angular contact ball bearings, and sliding bearings arranged separately to share loads. The angular contact ball bearings use standard parts, and the sliding bearings use common lubricating media. Chinese invention patent document CN105952796A discloses a sliding bearing that uses magnetic fluid to fill the moving and stationary gear rings to form magnetic fluid lubrication. Chinese utility model patent document CN203362830U discloses a method that uses magnetic levitation thrust bearings and ceramic ball bearings arranged separately to share unidirectional thrust. Chinese utility model patent document CN205446397U discloses a method that uses radial magnetic levitation bearings to reduce some of the radial force in the fixed direction and reduce the load on rolling bearings. Chinese utility model patent document CN213655476U discloses a method that uses rolling balls installed in rotor slots as protective bearings for permanent magnet levitation radial bearings. Chinese utility model patent document CN201487054U discloses a sliding bearing in which the main shaft is suspended and centered by a magnetic fluid. Chinese invention patent document CN107299938A discloses a method that uses electromagnetic windings to generate a repulsive magnetic field, and fills the shaft and bearing bush with magnetic fluid to form a sliding bearing and seal it.

[0007] In the above technical solutions, some use electromagnetic or permanent magnet levitation bearings combined with standard rolling bearings for joint load bearing or magnetic levitation bearing for rolling bearing protection, while others utilize magnetic fields combined with magnetic fluids to form sliding bearings for lubrication and load bearing. No specific performance improvements were made to the roller bearings. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes a composite load-bearing device and its axial load support method, which can withstand both static and dynamic loads. Furthermore, it employs magnetic force to fix the rollers, fully utilizing the magnetic lubricating medium dispersed around the rollers to ensure effective lubrication. It also provides high damping when subjected to impact loads, preventing roller damage.

[0009] This invention is achieved by adopting the following technical solution: A composite load-bearing device includes an axial permanent magnet levitation load-bearing device and a magnetic medium lubricated thrust roller load-bearing device; the axial permanent magnet levitation load-bearing device includes a non-magnetic stationary base plate and a non-magnetic rotating ring plate; the non-magnetic stationary base plate and the non-magnetic rotating ring plate are respectively provided with permanent magnet blocks on opposite sides to generate repulsive magnetic levitation force, and a gap C3 is formed. The magnetic medium lubricated thrust roller bearing device includes an upper thrust roller seat, a lower thrust roller seat, a magnetic ring, a magnetic lubricating medium, and several rollers. Both the upper and lower thrust roller seats are made of ferromagnetic material and are respectively fixed to a non-magnetic rotating ring plate and a non-magnetic stationary base plate, forming a gap C1 between them. The rollers are positioned between the upper and lower thrust roller seats and are magnetically fixed to the lower thrust roller seat. The upper thrust roller seat also has an upper thrust seat raceway, forming a gap C2 between the rollers and the upper thrust seat raceway. Below each roller, there is a corresponding roller positioning permanent magnet block or roller positioning reverse permanent magnet block. Several roller positioning permanent magnet blocks and several roller positioning reverse permanent magnet blocks are arranged alternately along the circumference and separated by non-magnetic spacers. The magnetic ring is set at the lower part of the roller positioning permanent magnet block and the roller positioning reverse permanent magnet block. By forming a circumferential magnetic circuit chain, the magnetic lubricating medium is adsorbed onto the roller surface.

[0010] Gap C3 > Gap C1 > Gap C2.

[0011] The axial permanent magnet maglev bearing device further includes an upper thrust maglev base and a lower thrust maglev base. The permanent magnet block includes an upper maglev base permanent magnet block disposed on the upper thrust maglev base and a lower maglev base permanent magnet block disposed on the lower thrust maglev base. The magnetization directions of the upper maglev base permanent magnet block and the lower maglev base permanent magnet block are opposite in the axial direction, and a gap C3 is formed between them.

[0012] The lower thrust roller seat is also provided with a boss corresponding to the roller; the roller is magnetically fixed to the center line of the boss and rotates around this center line.

[0013] The circumferential magnetic circuit chain consists of several sets of single magnetic circuit chains. Each set of single magnetic circuit chains includes a first magnetic circuit chain and a second magnetic circuit chain. The first magnetic circuit chain starts from the roller positioning permanent magnet block, passes upward through the lower thrust roller seat, passes through the roller, passes through the boss or the magnetic lubrication medium between two adjacent rollers to reach the next roller, passes downward through the lower thrust roller seat and the roller positioning reverse permanent magnet block in sequence, and then returns to the initial roller positioning permanent magnet block circumferentially through the lower magnetic guide ring to form a complete closed magnetic circuit. The second magnetic circuit chain starts from the roller positioning permanent magnet block, moves upward within the lower thrust roller seat circumferentially, passes downward through the roller positioning reverse permanent magnet block, and returns to the initial roller positioning permanent magnet block circumferentially through the lower magnetic guide ring to form a complete closed magnetic circuit.

[0014] The lower thrust roller seat is also provided with several arc grooves.

[0015] The circular arc grooves are connected to the non-magnetic spacers.

[0016] The lower thrust roller seat is also provided with a groove that matches the bottom of the roller.

[0017] A wedge-shaped gap is formed between the two end faces of the roller and the lower thrust roller seat.

[0018] A method for supporting axial load in a composite load-bearing device: In a static state, the static load is supported by an axial permanent magnet levitation bearing device; during operation, when the rotor axial load increases slightly along the direction of gravity, both gaps C3 and C2 decrease, the magnetic levitation force increases, and the rollers do not contact the upper thrust seat raceway and are not subjected to force; when the axial load increases significantly along the direction of gravity, the gaps C3 and C2 decrease significantly, and the rollers contact the upper thrust seat raceway through the magnetic lubrication medium on the top surface of the rollers and bear part of the axial load; when the axial load is in the opposite direction of gravity, both gaps C3 and C2 increase, and the magnetized rollers attract the upper thrust roller seat, thereby limiting the upward displacement of the rotor axis.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This equipment, through integrated and modular design, fully utilizes the low-consumption and high-efficiency load-bearing characteristics of the axial permanent magnet levitation bearing device, combined with a refined magnetic circuit design, enabling the rollers to form a "magnetic" positioning within the magnetic circuit channel, replacing the traditional mechanical cage that is easily damaged by impact forces. It fully utilizes the magnetic lubricating medium dispersed around the rollers, ensuring effective lubrication, low loss, and low heat generation, overcoming the disadvantages of high loss and the need for an additional circulating system for heat dissipation in magnetohydrodynamic (MHD) lubricated sliding bearings. Furthermore, the magnetic lubricating medium provides the necessary stiffness and damping to withstand impact forces and prevent roller damage, allowing this equipment to adapt to varying loads and impact loads. Compared to traditional mechanical cage and cageless roller bearings, it significantly extends the roller life.

[0020] Based on this equipment, the unit is easy and quick to start, and no external lubrication medium is required. The axial permanent magnet levitation bearing device fully bears the static load, while the magnetic medium lubricated thrust roller bearing device only bears the dynamic load that changes in axial direction during equipment operation. It can also bear a certain radial load with low contact stress, achieving the goals of reduced consumption, no oil contamination, high load capacity, and high efficiency of the thrust bearing.

[0021] 2. This invention integrates magnetic levitation and rollers into one unit, ensuring that the change trend of each gap value is exactly the same, avoiding the influence of thermal elastic deformation between the arrangement distances, which would cause inconsistent gap changes. It occupies little space and is easy to install and disassemble.

[0022] 3. The boss facilitates better positioning of the rollers.

[0023] 4. The single magnetic circuit chain includes the first magnetic circuit chain and the second magnetic circuit chain, which has a more reasonable magnetic flux distribution, enhances the magnetic constraint capability of the roller in the axial and radial directions, and improves the stability and load-bearing capacity of the overall system.

[0024] 5. The circular arc groove can increase the magnetic resistance λ1 of the second magnetic circuit and decrease the magnetic flux Φ1 of the second magnetic circuit, allowing most of the magnetic flux to pass through the first magnetic circuit.

[0025] 6. The groove design reduces the magnetic resistance of the first magnetic circuit chain, allowing most of the magnetic flux to pass through it. The magnetic lubricant adheres to the roller around the roller on the magnetic circuit formed by the roller positioning permanent magnet block. The bottom of the roller is the main path of the first magnetic circuit chain. The magnetic lubricant at the bottom of the roller, between the roller and the groove, serves two purposes: lubrication and filling the gap between the roller and the lower thrust roller seat.

[0026] 7. The wedge-shaped clearance helps to mitigate the radial instability of the permanent magnet levitation bearing. The radial force generated during operation is borne by the wedge-shaped oil film formed by the magnetic lubrication medium on the roller end face. The permanent magnet levitation bearing includes an upper thrust levitation seat, a lower thrust levitation seat, an upper levitation seat permanent magnet block, and a lower levitation seat permanent magnet block.

[0027] 8. In a static state, the axial static load is borne by the axial permanent magnet levitation bearing device. When the unit is running, the levitation force can be controlled by adjusting the gaps C3 and C2 to ensure that the rollers only contact the upper thrust seat raceway when the axial load is large, achieving efficient load bearing and reducing wear. When the dynamic load increases in the opposite direction of gravity, the rollers exert an attractive force on the upper thrust roller seat, limiting its displacement, preventing abnormal rotor lifting, and improving the safety and stability of the system operation. Attached Figure Description

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a cross-sectional structural diagram of DD in this invention, i.e., a schematic diagram of the circumferential magnetic circuit chain; Figure 3 This is an enlarged schematic diagram of region B in this invention, i.e., a schematic diagram of a single magnetic circuit chain; Figure 4 This is a schematic diagram of the equivalent magnetic circuit of a single magnetic circuit chain in this invention; Figure 5 This is an enlarged schematic diagram of region A in this invention, i.e., a schematic diagram of the distribution of the magnetic lubricating medium; Marked in the image: 1. Upper thrust roller seat; 2. Upper thrust magnetic levitation seat; 3. Non-magnetic rotating ring plate; 4. Upper magnetic levitation seat permanent magnet block; 6. Roller positioning permanent magnet block; 7. Magnetic ring; 8. Lower thrust magnetic levitation seat; 9. Non-magnetic stationary base plate; 10. Lower thrust roller seat; 11. Roller; 12. Magnetic lubricating medium; 15. Non-magnetic spacer block; 16. Arc groove; 17. Groove; 18. Boss; 19. Lower magnetic levitation seat permanent magnet block; 20. Roller positioning reverse permanent magnet block; 21. Upper thrust seat raceway. Detailed Implementation Example 1 As a basic embodiment of the present invention, the present invention includes a composite bearing device, comprising an axial permanent magnet levitation bearing device and a magnetic medium lubricated thrust roller bearing device. The axial permanent magnet levitation bearing device includes a non-magnetic stationary base plate 9 and a non-magnetic rotating ring plate 3. Permanent magnet blocks are respectively provided on opposite sides of the non-magnetic stationary base plate 9 and the non-magnetic rotating ring plate 3 to generate a repulsive magnetic levitation force, and gaps C3 are formed therein.

[0029] The magnetic medium lubricated thrust roller bearing device includes an upper thrust roller seat 1, a lower thrust roller seat 10, a magnetic ring 7, a magnetic lubricating medium 12, and several rollers 11. Both the upper thrust roller seat 1 and the lower thrust roller seat 10 are made of ferromagnetic material and are respectively fixed to a non-magnetic rotating ring plate 3 and a non-magnetic stationary base plate 9, forming a gap C1 between them. The rollers 11 are disposed between the upper thrust roller seat 1 and the lower thrust roller seat 10 and are magnetically fixed to the lower thrust roller seat 10. The upper thrust roller seat 1 is also provided with an upper thrust seat raceway 21, forming a gap C2 between the rollers 11 and the upper thrust seat raceway 21.

[0030] Below each roller 11, there is a corresponding roller positioning permanent magnet block 6 or roller positioning reverse permanent magnet block 20. A plurality of roller positioning permanent magnet blocks 6 and a plurality of roller positioning reverse permanent magnet blocks 20 are arranged alternately in the circumferential direction, separated by non-magnetic spacers 15. The magnetic ring 7 is disposed at the lower part of the roller positioning permanent magnet blocks 6 and roller positioning reverse permanent magnet blocks 20. Through the above structure, a circumferential magnetic circuit chain can be formed, allowing the magnetic lubricating medium 12 to be adsorbed onto the surface of the roller 11.

[0031] Example 2 In a preferred embodiment of the present invention, the present invention includes a composite bearing device, comprising an axial permanent magnet levitation bearing device and a magnetic medium lubricated thrust roller bearing device. The axial permanent magnet levitation bearing device includes a non-magnetic stationary base plate 9 and a non-magnetic rotating ring plate 3. Permanent magnet blocks are respectively provided on opposite sides of the non-magnetic stationary base plate 9 and the non-magnetic rotating ring plate 3 to generate a repulsive magnetic levitation force, forming a gap C3. Specifically, the axial permanent magnet levitation bearing device further includes an upper thrust magnetic levitation seat 2 and a lower thrust magnetic levitation seat 8. The permanent magnet blocks include an upper magnetic levitation seat permanent magnet block 4 disposed on the upper thrust magnetic levitation seat 2 and a lower magnetic levitation seat permanent magnet block 19 disposed on the lower thrust magnetic levitation seat 8. The magnetization directions of the upper magnetic levitation seat permanent magnet block 4 and the lower magnetic levitation seat permanent magnet block 19 are opposite in the axial direction, forming a gap C3 between them.

[0032] The magnetic medium lubricated thrust roller bearing device includes an upper thrust roller seat 1, a lower thrust roller seat 10, a magnetic ring 7, a magnetic lubricating medium 12, and several rollers 11. Both the upper thrust roller seat 1 and the lower thrust roller seat 10 are made of ferromagnetic material and are respectively fixed to a non-magnetic rotating ring plate 3 and a non-magnetic stationary base plate 9, forming a gap C1 between them. The rollers 11 are positioned between the upper thrust roller seat 1 and the lower thrust roller seat 10 and are magnetically fixed to the lower thrust roller seat 10. Specifically, the lower thrust roller seat 10 has a boss 18 corresponding to the roller 11. The roller 11 is magnetically fixed to the center line of the boss 18 and rotates around this center line. The upper thrust roller seat 1 also has an upper thrust seat raceway 21, forming a gap C2 between the roller 11 and the upper thrust seat raceway 21. The order of gaps is: gap C3 > gap C1 > gap C2.

[0033] Below each roller 11, there is a corresponding roller positioning permanent magnet block 6 or roller positioning reverse permanent magnet block 20. Several roller positioning permanent magnet blocks 6 and several roller positioning reverse permanent magnet blocks 20 are arranged alternately in the circumferential direction, separated by non-magnetic spacers 15. The magnetic ring 7 is located at the lower part of the roller positioning permanent magnet blocks 6 and roller positioning reverse permanent magnet blocks 20. By forming a circumferential magnetic circuit chain, the magnetic lubricating medium 12 is adsorbed onto the surface of the roller 11.

[0034] Example 3 In another preferred embodiment of the present invention, the present invention includes a composite bearing device, comprising an axial permanent magnet levitation bearing device and a magnetic medium lubricated thrust roller bearing device. The axial permanent magnet levitation bearing device includes a non-magnetic stationary base plate 9 and a non-magnetic rotating ring plate 3. Permanent magnet blocks are respectively provided on opposite sides of the non-magnetic stationary base plate 9 and the non-magnetic rotating ring plate 3 to generate a repulsive magnetic levitation force, and gaps C3 are formed therein.

[0035] The magnetic medium lubricated thrust roller bearing device includes an upper thrust roller seat 1, a lower thrust roller seat 10, a magnetic ring 7, a magnetic lubricating medium 12, and several rollers 11. Both the upper thrust roller seat 1 and the lower thrust roller seat 10 are made of ferromagnetic material and are respectively fixed to a non-magnetic rotating ring plate 3 and a non-magnetic stationary base plate 9, forming a gap C1 between them. The rollers 11 are disposed between the upper thrust roller seat 1 and the lower thrust roller seat 10 and are magnetically fixed to the lower thrust roller seat 10. The upper thrust roller seat 1 is also provided with an upper thrust seat raceway 21, forming a gap C2 between the rollers 11 and the upper thrust seat raceway 21.

[0036] Below each roller 11, there is a corresponding roller positioning permanent magnet block 6 or roller positioning reverse permanent magnet block 20. A plurality of roller positioning permanent magnet blocks 6 and a plurality of roller positioning reverse permanent magnet blocks 20 are arranged alternately in the circumferential direction, separated by non-magnetic spacers 15. The magnetic ring 7 is disposed at the lower part of the roller positioning permanent magnet blocks 6 and the roller positioning reverse permanent magnet blocks 20.

[0037] The above structure forms a circumferential magnetic circuit chain. This circumferential magnetic circuit chain consists of several sets of single magnetic circuit chains, each set including a first magnetic circuit chain and a second magnetic circuit chain. The first magnetic circuit chain begins with the roller positioning permanent magnet block 6 moving upwards through the lower thrust roller seat 10, passing through the roller 11, then through the boss 18 or the magnetic lubrication medium 12 between two adjacent rollers 11 to reach the next roller 11. From the next roller 11, it moves downwards sequentially through the lower thrust roller seat 10 and the roller positioning reverse permanent magnet block 20, then returns circumferentially to the initial roller positioning permanent magnet block 6 via the lower magnetic guide ring 7, forming a complete closed magnetic circuit. The second magnetic circuit chain begins with the roller positioning permanent magnet block 6 moving upwards within the lower thrust roller seat 10 circumferentially, then moving downwards through the roller positioning reverse permanent magnet block 20, and finally returning circumferentially to the initial roller positioning permanent magnet block 6 via the lower magnetic guide ring 7, forming a complete closed magnetic circuit.

[0038] The circumferential magnetic circuit chain allows the magnetic lubricating medium 12 to be adsorbed onto the surface of the roller 11.

[0039] Example 4 In another preferred embodiment of the present invention, the present invention includes a composite bearing device, as described in the appendix to the specification. Figure 1 The system includes an axial permanent magnet levitation bearing device and a magnetic medium lubricated thrust roller bearing device. The axial permanent magnet levitation bearing device includes a non-magnetic stationary base plate 9, a non-magnetic rotating ring plate 3, and a permanent magnet levitation bearing. The permanent magnet levitation bearing includes an upper thrust levitation seat 2, a lower thrust levitation seat 8, several upper levitation seat permanent magnet blocks 4, and several lower levitation seat permanent magnet blocks 19. The upper thrust levitation seat 2 is mounted on the non-magnetic rotating ring plate 3, and the lower thrust levitation seat 8 is mounted on the non-magnetic stationary base plate 9. The upper levitation seat permanent magnet blocks 4 are respectively mounted on the upper thrust levitation seat 2, and the lower levitation seat permanent magnet blocks 19 are respectively mounted on the lower thrust levitation seat 8. Along the axial direction, the upper levitation seat permanent magnet blocks 4 and the lower levitation seat permanent magnet blocks 19 are arranged in groups, with opposite magnetization directions in the axial direction, forming a gap C3 between them. The magnetic pole directions of two adjacent upper levitation seat permanent magnet blocks 4 are opposite in the axial direction.

[0040] The magnetic medium lubricated thrust roller bearing device includes an upper thrust roller seat 1, a lower thrust roller seat 10, a magnetic ring 7, a magnetic lubricating medium 12, and several rollers 11. Both the upper thrust roller seat 1 and the lower thrust roller seat 10 are made of ferromagnetic material. The upper thrust roller seat 1 is fixed to a non-magnetic rotating ring plate 3, and the lower thrust roller seat 10 is fixed to a non-magnetic stationary base plate 9. A gap C1 is formed between the upper thrust roller seat 1 and the lower thrust roller seat 10.

[0041] The roller 11 is disposed between the upper thrust roller seat 1 and the lower thrust roller seat 10. Specifically, the upper thrust roller seat 1 and the lower thrust roller seat 10 are respectively provided with mounting grooves on opposite sides. The mounting groove of the lower thrust roller seat 10 is also provided with a boss 18 corresponding to the roller 11. The roller 11 is magnetically fixed to the center line of the boss 18 and rotates around this center line. The mounting groove of the upper thrust roller seat 1 is also provided with an upper thrust seat raceway 21, and a gap C2 is formed between the roller 11 and the upper thrust seat raceway 21. Wedge-shaped gaps are respectively formed between the two end faces of the roller 11 and the inner wall of the mounting groove of the lower thrust roller seat 10. Among them, gap C3 > gap C1 > gap C2.

[0042] Below each roller 11, there is a corresponding roller positioning permanent magnet block 6 or roller positioning reverse permanent magnet block 20. A plurality of roller positioning permanent magnet blocks 6 and a plurality of roller positioning reverse permanent magnet blocks 20 are arranged alternately in the circumferential direction, separated by non-magnetic spacers 15. The magnetic ring 7 is disposed at the lower part of the roller positioning permanent magnet blocks 6 and the roller positioning reverse permanent magnet blocks 20.

[0043] The above structure allows for the formation of a circumferential magnetic circuit. Refer to the attached instruction manual. Figure 2 The circumferential magnetic circuit chain consists of several sets of single magnetic circuit chains, and each set of single magnetic circuit chains includes a first magnetic circuit chain and a second magnetic circuit chain. (Refer to the appendix of the instruction manual.) Figure 3 The first magnetic circuit chain starts from the roller positioning permanent magnet block 6, passes upward through the lower thrust roller seat 10, then through the roller 11, and reaches the next roller 11 via the boss 18 or the magnetic lubrication medium 12 between two adjacent rollers 11. For example, it reaches the next boss 18 circumferentially at point H, then passes downward through the next roller 11 in contact with it, successively through the lower thrust roller seat 10 and the roller positioning reverse permanent magnet block 20, and returns to the initial roller positioning permanent magnet block 6 circumferentially at point G via the lower magnetic guide ring 7, forming a complete closed magnetic circuit. The second magnetic circuit chain starts from the roller positioning permanent magnet block 6, moves upward within the lower thrust roller seat 10 at point E circumferentially, passes through point F, passes downward through the roller positioning reverse permanent magnet block 20, and returns to the initial roller positioning permanent magnet block 6 circumferentially at point G via the lower magnetic guide ring 7, forming a complete closed magnetic circuit. A simplified magnetic circuit diagram is attached to the instruction manual. Figure 4 As shown, under the action of magnetic potential θ, the first magnetic circuit chain DEHKFGD and the second magnetic circuit chain DEFGD are formed.

[0044] To reduce the magnetic flux Φ1 of the second magnetic circuit chain, several arc grooves 16 are provided on the lower thrust roller seat 10, and the arc grooves 16 are respectively connected to the non-magnetic spacer blocks 15. The magnetic resistance λ1 of the second magnetic circuit chain is increased by opening the arc grooves 16. Several grooves 17 matching the bottom of the roller 11 are also provided on the lower thrust roller seat 10. By setting the grooves 17, the magnetic resistance passing through the first magnetic circuit chain is reduced, allowing most of the magnetic flux to pass through the first magnetic circuit chain. The magnetic lubricating medium 12 is attached around the roller 11 on the magnetic circuit formed by the roller positioning permanent magnet block 6. The bottom of the roller 11 is the main path of the first magnetic circuit chain. The magnetic lubricating medium 12 at the bottom of the roller 11 is between the roller 11 and the grooves 17, which serves to lubricate and fill the gap between the roller 11 and the lower thrust roller seat 10, further reducing the magnetic resistance of the first magnetic circuit chain.

[0045] The groove 17 and the boss 18 are the main paths of the first magnetic circuit chain. The center line of the boss 18 is the machining axis of the groove 17. The roller 11 is fixed on the center line of the boss 18 and rotates around this center line. The roller 11 is fixed by magnetic force to roll along the rotation axis, replacing the traditional mechanical fixing cage.

[0046] Example 5 As another preferred embodiment of the present invention, the present invention includes an axial load support method for a composite load-bearing device, which is implemented based on the composite load-bearing device described in any of the embodiments 1 to 4 above. Specifically, in the static state, the static load in the static state is supported by an axial permanent magnet levitation load-bearing device. When the unit is running, when the rotor axial load increases slightly along the direction of gravity, both gaps C3 and C2 decrease, the magnetic levitation force increases, and the roller 11 does not contact the upper thrust seat raceway 21 and is not under force. When the axial load increases significantly along the direction of gravity, the gaps C3 and C2 decrease significantly, and the roller 11 contacts the upper thrust seat raceway 21 through the magnetic lubrication medium 12 on the top surface of the roller 11 and bears part of the axial load. When the axial load is in the opposite direction of gravity, both gaps C3 and C2 increase, and the magnetized roller 11 attracts the upper thrust roller seat 1 made of ferromagnetic material, thereby limiting the upward displacement of the rotor axis. The radial instability of the permanent magnet levitation bearing is caused by the radial force generated during operation, which is borne by the wedge-shaped oil film formed by the magnetic lubrication medium 12 on the end face of the roller 11.

[0047] In summary, any other corresponding modifications made by those skilled in the art after reading this invention document, without requiring creative mental effort, based on the technical solutions and concepts of this invention, are all within the scope of protection of this invention.

Claims

1. A composite load-bearing device, characterized in that: It includes an axial permanent magnet magnetic levitation bearing device and a magnetic medium lubricated thrust roller bearing device; the axial permanent magnet magnetic levitation bearing device includes a non-magnetic stationary base plate (9) and a non-magnetic rotating ring plate (3); the non-magnetic stationary base plate (9) and the non-magnetic rotating ring plate (3) are respectively provided with permanent magnet blocks on opposite sides to generate repulsive magnetic levitation force and form a gap C3; The magnetic medium lubricated thrust roller bearing device includes an upper thrust roller seat (1), a lower thrust roller seat (10), a magnetic ring (7), a magnetic lubricating medium (12), and several rollers (11); the upper thrust roller seat (1) and the lower thrust roller seat (10) are both made of ferromagnetic material and are respectively fixed on a non-magnetic rotating ring plate (3) and a non-magnetic stationary base plate (9), forming a gap C1 between them; the rollers (11) are arranged between the upper thrust roller seat (1) and the lower thrust roller seat (10) and are fixed on the lower thrust roller seat (10) by magnetic force; the upper thrust roller seat (1) is also provided with an upper thrust seat raceway (21), and a gap C2 is formed between the rollers (11) and the upper thrust seat raceway (21); Below each roller (11) is a corresponding roller positioning permanent magnet block (6) or roller positioning reverse permanent magnet block (20). A number of roller positioning permanent magnet blocks (6) and a number of roller positioning reverse permanent magnet blocks (20) are arranged alternately in the circumferential direction, separated by non-magnetic spacer blocks (15). The magnetic ring (7) is set at the lower part of the roller positioning permanent magnet block (6) and the roller positioning reverse permanent magnet block (20). The roller positioning permanent magnet block (6), the lower thrust roller seat (10), the roller positioning reverse permanent magnet block (20), the magnetic ring (7) and the roller (11) cooperate to form a circumferential magnetic circuit chain, and the magnetic lubricating medium (12) is attracted to the surface of the roller (11) by relying on the circumferential magnetic circuit chain.

2. The composite load-bearing device according to claim 1, characterized in that: Gap C3 > Gap C1 > Gap C2.

3. The composite load-bearing device according to claim 2, characterized in that: The axial permanent magnet levitation bearing device also includes an upper thrust levitation seat (2) and a lower thrust levitation seat (8). The permanent magnet block includes an upper levitation seat permanent magnet block (4) set on the upper thrust levitation seat (2) and a lower levitation seat permanent magnet block (19) set on the lower thrust levitation seat (8). The magnetization directions of the upper levitation seat permanent magnet block (4) and the lower levitation seat permanent magnet block (19) are opposite in the axial direction, and a gap C3 is formed between them.

4. A composite load-bearing device according to claim 2, characterized in that: The lower thrust roller seat (10) is also provided with a boss (18) corresponding to the roller (11); the roller (11) is fixed to the center line of the boss (18) by magnetic force and rotates around this center line.

5. A composite load-bearing device according to claim 4, characterized in that: The circumferential magnetic circuit chain is composed of several sets of single magnetic circuit chains. Each set of single magnetic circuit chains includes a first magnetic circuit chain and a second magnetic circuit chain. The first magnetic circuit chain passes upward from the roller positioning permanent magnet block (6) through the lower thrust roller seat (10) and then through the roller (11). It passes through the boss (18) or the magnetic lubrication medium (12) between two adjacent rollers (11) to reach the next roller (11). After passing through the next roller (11), it passes downward through the lower thrust roller seat (10) and the roller positioning reverse permanent magnet block (20) in sequence. Then, it returns to the initial roller positioning permanent magnet block (6) circumferentially through the lower magnetic guide ring (7) to form a complete closed magnetic circuit. The second magnetic circuit chain moves upward from the roller positioning permanent magnet block (6) in the lower thrust roller seat (10) circumferentially, then passes downward through the roller positioning reverse permanent magnet block (20). Finally, it returns to the initial roller positioning permanent magnet block (6) circumferentially through the lower magnetic guide ring (7) to form a complete closed magnetic circuit.

6. A composite load-bearing device according to claim 1 or 5, characterized in that: The lower thrust roller seat (10) is also provided with several arc grooves (16).

7. A composite load-bearing device according to claim 6, characterized in that: The circular arc groove (16) is connected to the non-magnetic spacer block (15).

8. A composite load-bearing device according to claim 7, characterized in that: The lower thrust roller seat (10) is also provided with a groove (17) that matches the bottom of the roller (11).

9. A composite load-bearing device according to claim 8, characterized in that: A wedge-shaped gap is formed between the two end faces of the roller (11) and the lower thrust roller seat (10).

10. The axial load support method for a composite load-bearing device according to claim 1, characterized in that: In a static state, the static load is borne by an axial permanent magnet levitation bearing device; When the unit is running, when the rotor axial load increases slightly along the direction of gravity, the gaps C3 and C2 decrease, the magnetic levitation force increases, and the roller (11) does not contact the upper thrust seat raceway (21) and is not subjected to force. When the axial load increases significantly along the direction of gravity, the gaps C3 and C2 decrease significantly, and the roller (11) contacts the upper thrust seat raceway (21) through the magnetic lubrication medium (12) on the top surface of the roller (11) and bears part of the axial load. When the axial load is in the opposite direction of gravity, the gaps C3 and C2 increase, and the magnetized roller (11) attracts the upper thrust roller seat (1), thereby limiting the upward displacement of the rotor.

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