Combined variable-rigidity permanent magnet thrust bearing based on follow-up auxiliary unit

Abstract

The invention belongs to the field of magnetic suspension bearings, and particularly relates to a combined variable-rigidity permanent magnet thrust bearing based on a follow-up auxiliary unit, which comprises a bearing unit, an auxiliary unit and a displacement adjusting assembly. The bearing has the advantages that the bearing has two working states, the relative displacement of the stator and the rotor of the auxiliary unit is adjusted to enable the auxiliary unit to have positive rigidity under the working condition of high bearing capacity, the overall bearing capacity is the superposition of the rigidity of the bearing unit and the bearing capacity of the auxiliary unit, the high bearing capacity is provided, and the equipment safety in the starting and accelerating states is guaranteed in the high bearing capacity state; under the low-rigidity working condition, the relative displacement of the stator and the rotor of the auxiliary unit is adjusted to enable the auxiliary unit to have negative rigidity, and part of rigidity is offset to reduce inherent frequency to achieve vibration reduction. The bearing adopts a split design, is easy to assemble and disassemble and is wide in application range.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation bearing design research, and relates to a design method for permanent magnet thrust bearings, specifically a combined variable stiffness permanent magnet thrust bearing based on a follow-up auxiliary unit. Background Technology

[0002] Traditional mechanical thrust bearings involve mechanical contact, which, especially in high-speed rotating systems, leads to problems such as short service life, insufficient load-bearing capacity, high noise, and high installation and maintenance costs. In contrast, permanent magnet thrust bearings are non-contact bearings with significant advantages such as frictionless operation, no lubrication, no pollution, low maintenance, and long service life. Permanent magnet thrust bearings are frequently used in rotating systems. When the external excitation frequency matches the structure's natural frequency, resonance occurs. This not only causes unnecessary stress and damage to structural components and connections, affecting equipment lifespan, but also generates noise and vibration pollution, threatening the comfort and safety of personnel and equipment. The load-bearing capacity characteristics of permanent magnet thrust bearings are considered linear within a certain operating range. Linear vibration isolation systems often use methods to lower the natural frequency to improve the system's vibration isolation capability. However, lowering the natural frequency also reduces the system stiffness, leading to a decrease in the system's load-bearing capacity. Therefore, there is an urgent need to provide a new type of combined variable stiffness permanent magnet thrust bearing based on a servo-assisted unit. Summary of the Invention

[0003] Purpose of the invention To address the inherent constraint between the natural frequency and load-bearing capacity of existing permanent magnet thrust bearings, this invention provides a combined variable stiffness permanent magnet thrust bearing based on a follower-assisted unit. This bearing, while meeting the load-bearing capacity requirements under operating conditions, can reduce its stiffness, thereby lowering its natural frequency and exhibiting excellent dynamic vibration reduction and isolation performance, thus meeting practical needs. The difference between this bearing and traditional permanent magnet thrust bearings lies in the fact that the force-displacement relationship in traditional bearings is approximately linear, while the force-displacement relationship in the combined variable stiffness permanent magnet thrust bearing with the follower-assisted unit is non-linear. That is, the working stiffness under complete operating conditions is not constant; its working stiffness varies depending on different operating conditions. This can reduce the first-order natural frequency under important operating conditions, broaden the vibration isolation frequency band, and optimize the vibration reduction and isolation performance of the permanent magnet thrust bearing.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A combined variable stiffness permanent magnet thrust bearing based on a follow-up auxiliary unit includes a load-bearing unit, an auxiliary unit, and a displacement adjustment assembly. The bearing unit includes a bearing unit stator and a bearing unit rotor. The bearing unit stator back iron of the bearing unit stator is equipped with a bearing unit stator magnetic ring assembly. The bearing unit rotor includes a rotating shaft and a bearing unit rotor magnetic ring assembly mounted on the rotating shaft. The number of bearing unit rotor magnetic ring assemblies is the same as that of the bearing unit stator magnetic ring assemblies, and their end face positions correspond one-to-one. The auxiliary unit includes an auxiliary unit stator and an auxiliary unit rotor. The auxiliary unit stator has an auxiliary unit stator back iron, and an auxiliary unit stator magnetic ring assembly is installed on the inner wall of the auxiliary unit stator back iron. The outer peripheral wall of the auxiliary unit stator back iron is provided with auxiliary unit mounting ears, and the auxiliary unit mounting ears are fixedly connected to a slider. The slider is equipped with a slide rail parallel to the axis of the auxiliary unit rotor, and the slider slides in cooperation with the slide rail. The auxiliary unit rotor includes a rotating shaft and an auxiliary unit rotor magnetic ring assembly installed on the rotating shaft. The number of auxiliary unit rotor magnetic ring assemblies is the same as that of the auxiliary unit stator magnetic ring assemblies, and their end face positions correspond one-to-one. The load-bearing unit stator, auxiliary unit stator, load-bearing unit rotor, and auxiliary unit rotor are coaxially arranged. The displacement adjustment assembly includes a hydraulic cylinder, a thrust plate, and a displacement sensor. The hydraulic cylinder is located on one side of the stator of the bearing unit; the thrust plate is fixedly located at the front end of the ejector rod of the hydraulic cylinder; and the displacement sensor is located at the end of the stator of the bearing unit, and the displacement sensor is located on the side closer to the stator of the auxiliary unit.

[0005] As a further description of the above solution, the bearing unit stator magnetic ring group is formed by axially stacking the bearing unit stator magnetic rings, and a first air gap is provided between adjacent bearing unit stator magnetic rings. The first air gap is pressed and fixed by a non-magnetic material partition. The bearing unit rotor magnetic ring assembly is formed by axially stacking the bearing unit rotor magnetic rings. A second air gap is provided between adjacent bearing unit rotor magnetic rings. The second air gap is pressed and fixed by a non-magnetic material partition. The auxiliary unit stator magnetic ring assembly is formed by axially stacking auxiliary unit stator magnetic rings, and a third air gap is provided between adjacent auxiliary unit stator magnetic rings. The third air gap is pressed and fixed by a non-magnetic material partition. The auxiliary unit rotor magnetic ring assembly is formed by axially stacking auxiliary unit rotor magnetic rings, and a fourth air gap is provided between adjacent auxiliary unit rotor magnetic rings. The fourth air gap is pressed and fixed by a non-magnetic material partition.

[0006] As a further description of the above scheme, the combined variable stiffness permanent magnet thrust bearing based on the follower auxiliary unit also includes a bearing unit base and an auxiliary unit base. The bearing unit stator is fixedly installed on the bearing unit base; the slide rail is fixedly installed on the auxiliary unit base; both ends of the bearing unit stator magnetic ring group and the auxiliary unit stator magnetic ring group are axially pressed and fastened by stator caps; both ends of the bearing unit rotor magnetic ring group and the auxiliary unit rotor magnetic ring group are axially pressed and fastened by rotor caps.

[0007] As a further description of the above scheme, the magnetization direction of the stator magnetic ring group of the bearing unit and the rotor magnetic ring group of the bearing unit is radial magnetization; and in the stator magnetic ring group of the bearing unit, each layer of the bearing unit stator magnetic ring is spliced ​​together with arc-shaped magnetic blocks of the same polarity, and the polarities of the bearing unit stator magnetic rings of adjacent layers are opposite. In the bearing unit rotor magnetic ring assembly, each layer of the bearing unit rotor magnetic ring is composed of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the bearing unit rotor magnetic rings of adjacent layers are opposite. Both the stator magnetic ring assembly and the rotor magnetic ring assembly of the bearing unit are periodically magnetized.

[0008] The magnetization direction of both the auxiliary unit stator magnetic ring group and the auxiliary unit rotor magnetic ring group is radial magnetization; and in the auxiliary unit stator magnetic ring group, each layer of auxiliary unit stator magnetic rings is composed of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the auxiliary unit stator magnetic rings in adjacent layers are opposite. In the auxiliary unit rotor magnetic ring group, each layer of the auxiliary unit rotor magnetic ring is composed of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the auxiliary unit rotor magnetic rings in adjacent layers are opposite; the auxiliary unit stator magnetic ring group and the auxiliary unit rotor magnetic ring group as a whole are periodically magnetized.

[0009] As a further description of the above solution, the bearing has two operating conditions, as follows: High load-bearing conditions: When the bearing is in the starting or acceleration state, the displacement sensor monitors the axial displacement of the bearing unit rotor and controls the hydraulic cylinder to drive the thrust plate to push the auxiliary unit stator and slider to move synchronously along the slide rail, so that the auxiliary unit stator and the auxiliary unit rotor maintain a preset relative position unchanged, the auxiliary unit is in a positive stiffness state, and the overall load is the superposition of the bearing unit stiffness and the auxiliary unit load-bearing capacity, so as to provide high load-bearing capacity. Low stiffness condition: When the bearing is running smoothly and there is a need for vibration or noise control, the displacement sensor collects the load-bearing capacity and axial displacement data of the bearing unit, calculates the relative displacement design value of the auxiliary unit stator and the auxiliary unit rotor required to make the auxiliary unit exhibit negative stiffness, and then controls the hydraulic cylinder to drive the thrust plate to push the auxiliary unit stator and slider along the slide rail to the relative displacement design value. The auxiliary unit is in a negative stiffness state, and the overall stiffness is the superposition and cancellation of the bearing unit stiffness and the auxiliary unit stiffness to reduce the natural frequency.

[0010] As a further description of the above scheme, the bearing unit shaft and the auxiliary unit shaft are axially fixed by flanges, and the bearing unit shaft and the auxiliary unit shaft are circumferentially fixed by splines.

[0011] As a further description of the above scheme, the stator back iron of the bearing unit, the stator back iron of the auxiliary unit, the bearing unit shaft and the auxiliary unit shaft are all made of magnetically conductive material.

[0012] As a further description of the above scheme, the number of magnetic rings in the bearing unit stator magnetic ring group, the bearing unit rotor magnetic ring group, the auxiliary unit stator magnetic ring group, and the auxiliary unit rotor magnetic ring group is at least two.

[0013] As a further description of the above scheme, the bearing unit stator, bearing unit rotor, auxiliary unit stator, and auxiliary unit rotor achieve radial stability through radial bearings.

[0014] Advantages and effects 1. Under high load conditions, this invention uses a hydraulic cylinder to keep the stator of the auxiliary unit in a preset relative position, maintaining the auxiliary unit in a positive stiffness state. The overall load is the superposition of the load-bearing capacity of the supporting unit and the auxiliary unit, providing high load-bearing capacity to ensure equipment safety during startup and acceleration. Under low stiffness conditions, the hydraulic cylinder uses a hydraulic cylinder to make the relative displacement between the stator and rotor of the auxiliary unit reach the design value. At this time, the overall stiffness is the superposition of the load-bearing unit and the auxiliary unit. The difference from traditional permanent magnet thrust bearings is that the force-displacement relationship of traditional permanent magnet thrust bearings is approximately linear, while the force-displacement relationship of the combined variable stiffness permanent magnet thrust bearing with follower auxiliary units is non-linear. That is, the working stiffness under complete working conditions is not constant, and its working stiffness varies according to different working conditions, thereby reducing the stiffness under the corresponding working conditions, thus reducing the natural frequency and widening the vibration isolation frequency band. While solving the contradiction between the system's load-bearing capacity and natural frequency, it achieves the effect of variable stiffness vibration reduction of permanent magnet thrust bearings.

[0015] 2. The bearing unit and auxiliary unit of this invention are connected by flange and spline. Axial fixation is achieved by connecting the flange with bolts, and circumferential fixation and torque and speed transmission are achieved by spline and keyway of bearing unit rotor. This split-combination design is easy to install and disassemble. The bearing unit and auxiliary unit can be used independently. The bearing unit and auxiliary unit can be replaced in different scenarios, and the application range is wide.

[0016] 3. The magnetic ring assembly of the present invention adopts a radial alternating magnetization method, which is conducive to improving the utilization rate of permanent magnets. The air gap space retained in the axial magnetic ring component can reduce magnetic leakage, increase the magnetic field utilization rate between the magnetic ring assemblies of the radial bearing unit stator magnetic ring assembly and the bearing unit rotor magnetic ring assembly, the auxiliary unit stator magnetic ring assembly and the auxiliary unit rotor magnetic ring assembly, and can be directly adsorbed on the bearing unit back iron, the bearing unit shaft, the auxiliary unit back iron and the auxiliary unit shaft, reducing the installation difficulty. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the descriptions below.

[0018] Figure 1 This is an axial sectional view of a combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to an embodiment of the present invention. Figure 2 This is an axial sectional view of the stator according to an embodiment of the present invention; Figure 3 This is an axial sectional view of the rotor according to an embodiment of the present invention; Figure 4 A comparison of the load-axial displacement relationship between a combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit and a traditional permanent magnet thrust bearing; Figure 5 A comparison of the stiffness-axial displacement relationship between a combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit and a traditional permanent magnet thrust bearing. Figure 6 This is a radial cross-sectional view of one layer of the magnetic ring in the bearing unit magnetic ring assembly according to an embodiment of the present invention; Figure 7 This is a radial cross-sectional view of one layer of the magnetic ring in the auxiliary unit magnetic ring assembly of this invention. Figure 8 This is a schematic diagram of the stator installation of the auxiliary unit according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the stator installation of the bearing unit according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1-Stabilizer of the load-bearing unit; 1001-Stabilizer back iron of the load-bearing unit; 1002-Stabilizer mounting ear of the load-bearing unit; 1003-Stabilizer base; 2-Stabilizer rotor; 21-Stabilizer shaft; 3-Auxiliary unit stator; 3001-Auxiliary unit base; 3002-Auxiliary unit mounting ear; 3003-Slider; 3004-Slide rail; 4-Auxiliary unit rotor; 41-Auxiliary unit shaft; 5-Hydraulic cylinder; 6-Bolt; 7-Stabilizer stator magnetic ring assembly; 71-Bearing... 72-First air gap interval; 8-Rotor magnetic ring assembly of the load-bearing unit; 81-Rotor magnetic ring of the load-bearing unit; 82-Second air gap interval; 9-Stator magnetic ring assembly of the auxiliary unit; 91-Stator magnetic ring of the auxiliary unit; 92-Third air gap interval; 10-Rotor magnetic ring assembly of the auxiliary unit; 101-Rotor magnetic ring of the auxiliary unit; 102-Fourth air gap interval; 11-Displacement sensor; 12-Flange; 13-Spline; 14-Bearing; 15-Thrust plate; 16-Stator cover; 17-Rotor cover. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0023] A combined variable stiffness permanent magnet thrust bearing based on a follow-up auxiliary unit includes a load-bearing unit, an auxiliary unit, and a displacement adjustment assembly. The bearing unit includes a bearing unit stator 1 and a bearing unit rotor 2. The bearing unit stator 1 has a bearing unit stator magnetic ring group 7 installed on the inner wall side of the bearing unit stator back iron 1001. The bearing unit rotor 2 includes a rotating shaft 21 and a bearing unit rotor magnetic ring group 8 installed on the rotating shaft 21. The number of bearing unit rotor magnetic ring groups 8 is the same as that of bearing unit stator magnetic ring groups 7, and their end face positions correspond one-to-one. The auxiliary unit includes an auxiliary unit stator 3 and an auxiliary unit rotor 4. The auxiliary unit stator 3 has an auxiliary unit mounting lug 3002 fixedly connected to a slider 3003, and a slide rail 3004 fixed to the auxiliary unit base 3001. The axial movement restriction of the auxiliary unit stator 3 is released through the cooperation of the slider 3003 and the slide rail 3004. An auxiliary unit stator magnetic ring assembly 9 is installed on the inner wall of the auxiliary unit stator back iron 31 of the auxiliary unit stator 3. The auxiliary unit rotor 4 includes a rotating shaft 41 and an auxiliary unit rotor magnetic ring assembly 10 mounted on the rotating shaft 41. The number of auxiliary unit rotor magnetic ring assemblies 10 and auxiliary unit stator magnetic ring assemblies 9 is the same, and their end face positions correspond one-to-one. The load-bearing unit stator 1, auxiliary unit stator 3, load-bearing unit rotor 2, and auxiliary unit rotor 4 are coaxially arranged. The displacement adjustment assembly includes a hydraulic cylinder 5, a thrust plate 15, and a displacement sensor 11. The hydraulic cylinder 5 is located on one side of the stator 1 of the bearing unit and is connected to the stator 1 of the bearing unit by bolts 6. The thrust plate 15 is fixedly located at the front end of the ejector rod of the hydraulic cylinder 5. The displacement sensor 11 is located at the end of the stator 1 of the bearing unit, and the displacement sensor 11 is located on the side close to the stator 3 of the auxiliary unit. Under high load conditions, the hydraulic cylinder 15 keeps the stator 3 of the auxiliary unit in a preset relative position, and the auxiliary unit maintains a positive stiffness state. The overall load is the superposition of the bearing capacity of the bearing unit and the bearing capacity of the auxiliary unit, providing high load capacity to ensure the safety of the equipment during startup and acceleration. Under low stiffness conditions, the hydraulic cylinder 5 makes the relative displacement between the stator 3 of the auxiliary unit and the rotor 4 of the auxiliary unit reach the design value. At this time, the overall stiffness is the superposition of the positive stiffness of the bearing unit and the negative stiffness of the auxiliary unit. The difference between this and traditional permanent magnet thrust bearings is that the force-displacement relationship of traditional permanent magnet thrust bearings is approximately linear, while the force-displacement relationship of the combined variable stiffness permanent magnet thrust bearing with follower auxiliary units is nonlinear. That is, the working stiffness under complete working conditions is not constant, and its working stiffness varies according to different working conditions, thereby reducing the stiffness under the corresponding working conditions, thereby reducing the natural frequency and widening the vibration isolation frequency band. While solving the contradiction between the system's load-bearing capacity and natural frequency, it achieves the effect of variable stiffness vibration reduction of permanent magnet thrust bearings.

[0024] The bearing unit stator magnetic ring group 7 of the present invention is formed by axially stacking bearing unit stator magnetic rings 71, and a first air gap 72 is provided between adjacent bearing unit stator magnetic rings 71, wherein the first air gap 72 is pressed and fixed by a non-magnetic material partition plate. The bearing unit rotor magnetic ring group 8 is formed by axially stacking bearing unit rotor magnetic rings 81. A second air gap 82 is provided between adjacent bearing unit rotor magnetic rings 81. The second air gap 82 is pressed and fixed by a non-magnetic material partition. The auxiliary unit stator magnetic ring group 9 is formed by axially stacking auxiliary unit stator magnetic rings 91, and a third air gap 92 is provided between adjacent auxiliary unit stator magnetic rings 91, wherein the third air gap 92 is pressed and fixed by a non-magnetic material partition; the auxiliary unit rotor magnetic ring group 10 is formed by axially stacking auxiliary unit rotor magnetic rings 101, and a fourth air gap 102 is provided between adjacent auxiliary unit rotor magnetic rings 101, wherein the fourth air gap 102 is pressed and fixed by a non-magnetic material partition.

[0025] The combined variable stiffness permanent magnet thrust bearing based on the follower auxiliary unit of the present invention further includes a bearing unit base 1003 and an auxiliary unit base 3001. The bearing unit stator 1 is fixedly mounted on the bearing unit base 1003 by the bearing unit stator mounting lug 1002; the slide rail 3004 is fixedly mounted on the auxiliary unit base 3001; both ends of the bearing unit stator magnetic ring group 7 and the auxiliary unit stator magnetic ring group 9 are axially pressed and fastened by the stator cover 16; wherein both ends of the bearing unit rotor magnetic ring group 8 and the auxiliary unit rotor magnetic ring group 10 are axially pressed and fastened by the rotor cover 17.

[0026] In this invention, the magnetization direction of the stator magnetic ring group 7 and the rotor magnetic ring group 8 of the bearing unit is radial magnetization; and in the stator magnetic ring group 7 of the bearing unit, each layer of the stator magnetic ring 71 of the bearing unit is spliced ​​together with arc-shaped magnetic blocks of the same polarity, and the polarities of the stator magnetic rings 71 of the bearing unit in adjacent layers are opposite. In the bearing unit rotor magnetic ring group 8, each layer of the bearing unit rotor magnetic ring 81 is made up of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the bearing unit rotor magnetic rings 81 in adjacent layers are opposite. Both the stator magnetic ring group 7 and the rotor magnetic ring group 8 of the bearing unit are periodically magnetized.

[0027] The magnetization direction of both the auxiliary unit stator magnetic ring group 9 and the auxiliary unit rotor magnetic ring group 10 is radial magnetization; and in the auxiliary unit stator magnetic ring group 9, each layer of the auxiliary unit stator magnetic ring 91 is made up of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the auxiliary unit stator magnetic rings 91 in adjacent layers are opposite. In the auxiliary unit rotor magnetic ring group 10, each layer of the auxiliary unit rotor magnetic ring 101 is made up of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the auxiliary unit rotor magnetic rings 101 in adjacent layers are opposite; the auxiliary unit stator magnetic ring group 9 and the auxiliary unit rotor magnetic ring group 10 are periodically magnetized as a whole.

[0028] The magnetic ring assembly of the present invention adopts a radial alternating magnetization method, which is beneficial to improving the utilization rate of permanent magnets. The air gap space retained in the axial magnetic ring component can reduce magnetic leakage and increase the magnetic field utilization rate between the magnetic ring assemblies 7 and 8 of the radial bearing unit stator magnetic ring assembly, 9 and 10 of the auxiliary unit stator magnetic ring assembly, and 10 of the auxiliary unit rotor magnetic ring assembly. It can also be directly adsorbed on the bearing unit back iron 1001, bearing unit rotating shaft 21, auxiliary unit back iron 31 and auxiliary unit rotating shaft 41, reducing the installation difficulty.

[0029] The bearing unit stator 1 of the present invention is fastened to the base or pedestal; and the bearing has two working conditions, as follows: 1. High load-bearing condition: When the bearing is in the starting, acceleration or other state, the displacement sensor 11 monitors the axial displacement of the rotor 2 of the bearing unit and controls the hydraulic cylinder 5 to drive the thrust disk 15 to push the auxiliary unit stator 3 and the slider 3003 to move synchronously axially along the slide rail 3004. The calculation is to keep the auxiliary unit stator 3 and the auxiliary unit rotor 4 in a preset relative position unchanged. The auxiliary unit is in a positive stiffness state. The overall load is the superposition of the stiffness of the bearing unit and the load-bearing capacity of the auxiliary unit to provide high load-bearing capacity. II. Low stiffness condition: When the bearing of the present invention is in a stable operating state and there is a need for vibration or noise control, the displacement sensor 11 collects the load-bearing capacity and axial displacement data of the load-bearing unit, calculates the relative displacement design value of the auxiliary unit stator 3 and the auxiliary unit rotor 4 required to make the auxiliary unit exhibit negative stiffness, and then controls the hydraulic cylinder 5 to drive the thrust disk 15 to push the auxiliary unit stator 3 and the slider 3003 along the slide rail 3004 to the relative displacement design value. The auxiliary unit is in a negative stiffness state, and the overall stiffness is the superposition and cancellation of the load-bearing unit stiffness and the auxiliary unit stiffness, so as to reduce the natural frequency and achieve vibration reduction.

[0030] The bearing unit shaft 21 and the auxiliary unit shaft 41 of this invention are axially fixed by flange 12, and circumferentially fixed by spline 13. The bearing unit and auxiliary unit are connected by flange 12 and spline 13. Axial fixation is achieved by connecting flange 12 with bolts 6, while circumferential fixation and torque and speed transmission are achieved by the keyway cooperation between spline 13 and the bearing unit rotor. This modular design facilitates installation and disassembly; both the bearing unit and auxiliary unit can be used independently, and they can be interchanged for different scenarios, making it widely applicable.

[0031] The stator back iron 1001 of the bearing unit, the stator back iron 31 of the auxiliary unit, the bearing unit rotating shaft 21 and the auxiliary unit rotating shaft 41 of the present invention are all made of magnetically conductive material.

[0032] In this invention, the bearing unit stator 1, the bearing unit rotor 2, the auxiliary unit stator 3, and the auxiliary unit rotor 4 achieve radial stability through a radial bearing 14.

[0033] This invention combines a load-bearing unit and an auxiliary unit. Under high load conditions, the rotor 2 of the load-bearing unit and the rotor 4 of the auxiliary unit undergo axial displacement, which in turn drives the magnetic ring assembly 8 of the load-bearing unit rotor and the magnetic ring assembly 10 of the auxiliary unit rotor to undergo axial displacement. Since the stator 3 of the auxiliary unit is not axially fixed, the relative displacement between the stator 3 and the rotor 4 of the auxiliary unit is made to reach the design value through the hydraulic cylinder 5. The auxiliary unit is in a positive stiffness state, and the overall load is the superposition of the stiffness of the load-bearing unit and the load-bearing capacity of the auxiliary unit, providing high load-bearing capacity to ensure the safety of the equipment during startup and acceleration. Under low stiffness conditions, the relative displacement between the stator 3 and the rotor 4 of the auxiliary unit is made to reach the design value through the hydraulic cylinder 5. The auxiliary unit is in a low thrust output and negative stiffness state. At this time, the overall stiffness is the superposition of the stiffness of the load-bearing unit and the auxiliary unit. The overall stiffness is significantly reduced, thereby reducing the stiffness under this condition and thus reducing the natural frequency, achieving the effect of variable stiffness vibration reduction.

[0034] The hydraulic cylinder 5 has a thrust plate 15 fixedly mounted at the front end of its ejector rod; the rotating shafts 31 and 41 are made of high magnetic permeability material and have a hollow internal structure, preferably steel. The load-bearing unit stator 1 and the auxiliary unit stator 3 are made of high magnetic permeability material.

[0035] The auxiliary stator magnetic ring group 9 has at least two groups. In order to minimize magnetic leakage between each group of magnetic rings, a certain axial air gap length is maintained between different magnetic ring groups. Each layer of magnetic rings can be clamped with a non-magnetic stainless steel gasket.

[0036] The number of stator magnetic ring groups 7 of the bearing unit is at least two. In order to minimize magnetic leakage between each group of magnetic rings, a certain axial air gap length is maintained between different magnetic ring groups. Each layer of magnetic rings can be clamped with stainless steel shims made of non-magnetic material.

[0037] According to the present invention, the number of magnetic rings in the auxiliary unit rotor magnetic ring group 10 is the same as the number of magnetic rings in the stator magnetic ring group 9, the number of magnetic rings in the bearing unit rotor magnetic ring group 8 is the same as the number of magnetic rings in the bearing unit stator magnetic ring group 7, and the end faces of each layer of magnetic rings are consistent.

[0038] like Figure 4 As shown in the simulation results, compared with traditional permanent magnet thrust bearings, this patent has multi-stage low stiffness and high load-bearing regions to meet the stiffness and load-bearing requirements of different constant speed cruise conditions as well as start-up and acceleration states. This patent divides the entire working range into two regions: low stiffness and high load-bearing. Furthermore, based on the specific service environment of the permanent magnet thrust bearing, the low stiffness region is further divided into multiple working condition zones. Moreover, the load-bearing capacity in the high load-bearing region is not reduced, and the load-bearing capacity and displacement curves exhibit an overall non-linear relationship, breaking through the limitation of the approximately linear relationship between the load-bearing capacity and displacement curves of traditional permanent magnet thrust bearings.

[0039] like Figure 5 As shown, simulation results indicate that the average stiffness of the traditional permanent magnet thrust bearing under operating conditions 1, 2, and 3 are 3.12 × 10⁻⁶. 7 N / m, 2.98×10 7 N / m, 2.72×10 7 N / m, the average stiffness of this patent under operating conditions 1, 2 and 3 is 0.64×10 N / m. 7 N / m, 0.51×10 7 N / m, 0.69×10 7 The stiffness (N / m) is reduced by 79.493%, 82.89%, and 74.57% respectively compared to traditional permanent magnet thrust bearings; in the entire 2-6mm low stiffness range, the average stiffness of traditional permanent magnet thrust bearings and this patented technology is 2.94×10 N / m. 7 N / m and 0.61×10 7 The N / m is reduced by 79.13% compared to traditional permanent magnet thrust bearings, thereby reducing vibration by lowering the natural frequency.

[0040] The combined variable stiffness permanent magnet thrust bearing based on the follow-up auxiliary unit of the present invention is suitable for vibration control and stable operation of propeller propulsion shaft system of large ferry. The specific installation and operation are as follows: the rotor of the permanent magnet thrust bearing is connected to the propeller shaft system interface, and the stator of the permanent magnet thrust bearing is connected to the main body of the large ferry. When the main body of the large ferry needs power, the propeller rotates, and the rotor 2 of the permanent magnet thrust bearing bearing unit moves axially relative to the stator 1 of the bearing unit. When the hull operates in a high-load condition zone, the auxiliary unit stator 3 moves with the auxiliary unit rotor 4 due to the attraction between them. The auxiliary unit is in a positive stiffness state, and the overall load is the superposition of the stiffness of the load-bearing unit and the load-bearing capacity of the auxiliary unit, providing high load-bearing capacity to ensure equipment safety during startup and acceleration. When the hull operates in a low-stiffness condition zone, the hydraulic cylinder 5 makes the relative displacement between the auxiliary unit stator 3 and the auxiliary unit rotor 4 reach the design value. The auxiliary unit is in a low-output force and negative stiffness state. At this time, the overall stiffness is largely offset by the superposition of the stiffness of the load-bearing unit and the auxiliary unit, thereby reducing the stiffness under this condition, thus reducing the natural frequency, reducing the vibration and noise of large ferries, achieving the effect of variable stiffness vibration reduction, and meeting the requirements of stability and comfort during ship operation.

[0041] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit, characterized in that, Includes a load-bearing unit, auxiliary units, and displacement adjustment components. The bearing unit includes a bearing unit stator (1) and a bearing unit rotor (2). The bearing unit stator back iron (1001) of the bearing unit stator (1) is equipped with a bearing unit stator magnetic ring group (7). The bearing unit rotor (2) includes a rotating shaft (21) and a bearing unit rotor magnetic ring group (8) installed on the rotating shaft (21). The number of the bearing unit rotor magnetic ring group (8) is the same as that of the bearing unit stator magnetic ring group (7), and their end face positions correspond one-to-one. The auxiliary unit includes an auxiliary unit stator (3) and an auxiliary unit rotor (4); the auxiliary unit stator (3) has an auxiliary unit stator back iron (31), an auxiliary unit stator magnetic ring assembly (9) is installed on the inner wall of the auxiliary unit stator back iron (31), and an auxiliary unit mounting ear (3002) is provided on the outer peripheral wall of the auxiliary unit stator back iron (31), the auxiliary unit mounting ear (3002) is fixedly connected to a slider (3003); the slider (3003) is fitted with a shaft that is connected to the auxiliary unit rotor (4). The slide rail (3004) is parallel to the linear direction, and the slider (3003) slides in cooperation with the slide rail (3004); the auxiliary unit rotor (4) includes a rotating shaft (41) and an auxiliary unit rotor magnetic ring group (10) mounted on the rotating shaft (41). The number of auxiliary unit rotor magnetic ring groups (10) is the same as that of auxiliary unit stator magnetic ring groups (9), and their end face positions correspond one-to-one; the bearing unit stator (1), auxiliary unit stator (3), bearing unit rotor (2), and auxiliary unit rotor (4) are coaxially arranged; The displacement adjustment assembly includes a hydraulic cylinder (5), a thrust plate (15), and a displacement sensor (11). The hydraulic cylinder (5) is located on one side of the stator (1) of the bearing unit. The thrust plate (15) is fixedly located at the front end of the ejector rod of the hydraulic cylinder (5). The displacement sensor (11) is located at the end of the stator (1) of the bearing unit, and the displacement sensor (11) is located on the side close to the stator (3) of the auxiliary unit.

2. The combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to claim 1, characterized in that, The bearing unit stator magnetic ring group (7) is formed by axially stacking the bearing unit stator magnetic rings (71). A first air gap (72) is provided between adjacent bearing unit stator magnetic rings (71). The first air gap (72) is pressed and fixed by a non-magnetic material partition. The bearing unit rotor magnetic ring group (8) is formed by axially stacking bearing unit rotor magnetic rings (81). A second air gap (82) is provided between adjacent bearing unit rotor magnetic rings (81). The second air gap (82) is pressed and fixed by a non-magnetic material partition. The auxiliary unit stator magnetic ring group (9) is formed by axially stacking auxiliary unit stator magnetic rings (91), and a third air gap (92) is provided between adjacent auxiliary unit stator magnetic rings (91). The third air gap (92) is pressed and fixed by a non-magnetic material partition. The auxiliary unit rotor magnetic ring group (10) is formed by axially stacking auxiliary unit rotor magnetic rings (101), and a fourth air gap (102) is provided between adjacent auxiliary unit rotor magnetic rings (101). The fourth air gap (102) is pressed and fixed by a non-magnetic material partition.

3. The combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to claim 1, characterized in that, It also includes a support unit base (1003) and an auxiliary unit base (3001). The support unit stator (1) is fixedly installed on the support unit base (1003); the slide rail (3004) is fixedly installed on the auxiliary unit base (3001); both ends of the support unit stator magnetic ring group (7) and the auxiliary unit stator magnetic ring group (9) are axially pressed and fastened by the stator cover (16); both ends of the support unit rotor magnetic ring group (8) and the auxiliary unit rotor magnetic ring group (10) are axially pressed and fastened by the rotor cover (17).

4. A combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to claim 1, characterized in that, The magnetization direction of the stator magnetic ring group (7) of the bearing unit and the rotor magnetic ring group (8) of the bearing unit is radial magnetization; and in the stator magnetic ring group (7) of the bearing unit, each layer of the bearing unit stator magnetic ring (71) is made up of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the bearing unit stator magnetic rings (71) of adjacent layers are opposite. In the bearing unit rotor magnetic ring group (8), each layer of the bearing unit rotor magnetic ring (81) is made up of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the bearing unit rotor magnetic rings (81) of adjacent layers are opposite; The stator magnetic ring group (7) of the bearing unit and the rotor magnetic ring group (8) of the bearing unit are both periodically magnetized. The magnetization direction of the auxiliary unit stator magnetic ring group (9) and the auxiliary unit rotor magnetic ring group (10) is radial magnetization; and in the auxiliary unit stator magnetic ring group (9), each layer of auxiliary unit stator magnetic rings (91) is made up of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the auxiliary unit stator magnetic rings (91) of adjacent two layers are opposite. In the auxiliary unit rotor magnetic ring group (10), each layer of the auxiliary unit rotor magnetic ring (101) is made up of arc-shaped magnetic blocks with the same polarity spliced ​​together, and the polarities of the auxiliary unit rotor magnetic rings (101) of adjacent two layers are opposite; the auxiliary unit stator magnetic ring group (9) and the auxiliary unit rotor magnetic ring group (10) are periodically magnetized as a whole.

5. A combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to claim 4, characterized in that, The bearing has two operating conditions, as detailed below: High load-bearing conditions: When the bearing is in the starting or acceleration state, the displacement sensor (11) monitors the axial displacement of the bearing unit rotor (2) and controls the hydraulic cylinder (5) to drive the thrust disk (15) to push the auxiliary unit stator (3) and the slider (3003) to move synchronously along the slide rail (3004), so that the auxiliary unit stator (3) and the auxiliary unit rotor (4) maintain the preset relative position unchanged, the auxiliary unit is in a positive stiffness state, and the overall load is the superposition of the bearing unit stiffness and the auxiliary unit load-bearing capacity to provide high load-bearing capacity; Low stiffness condition: When the bearing is running smoothly and there is a need for vibration or noise control, the displacement sensor (11) collects the load-bearing capacity and axial displacement data of the bearing unit, calculates the relative displacement design value of the auxiliary unit stator (3) and the auxiliary unit rotor (4) required to make the auxiliary unit exhibit negative stiffness, and then controls the hydraulic cylinder (5) to drive the thrust disk (15) to push the auxiliary unit stator (3) and the slider (3003) to move along the slide rail (3004) to the relative displacement design value. The auxiliary unit is in a negative stiffness state, and the overall stiffness is the superposition and cancellation of the bearing unit stiffness and the auxiliary unit stiffness to reduce the natural frequency.

6. A combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to claim 1, characterized in that, The bearing unit shaft (21) and the auxiliary unit shaft (41) are axially fixed by flange (12), and the bearing unit shaft (21) and the auxiliary unit shaft (41) are circumferentially fixed by spline (13).

7. A combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to claim 1, characterized in that, The stator back iron (1001) of the bearing unit, the stator back iron (31) of the auxiliary unit, the bearing unit shaft (21) and the auxiliary unit shaft (41) are all made of magnetic materials.

8. A combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to claim 1, characterized in that, The number of magnetic rings in the bearing unit stator magnetic ring group (7), the bearing unit rotor magnetic ring group (8), the auxiliary unit stator magnetic ring group (9), and the auxiliary unit rotor magnetic ring group (10) is at least two.

9. A combined variable stiffness permanent magnet thrust bearing based on a follower auxiliary unit according to claim 1, characterized in that, The bearing unit stator (1), bearing unit rotor (2), auxiliary unit stator (3) and auxiliary unit rotor (4) achieve radial stability through radial bearings (14).

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