Rare earth permanent magnet buffer shock insulation bearing and use method thereof

Abstract

The application relates to the technical field of bridge supports, in particular to a rare earth permanent magnetic buffering and shock insulation support and a use method thereof. The support comprises an upper seat plate, a middle seat plate, a lower seat plate, a shearing device and a plurality of permanent magnets; the permanent magnets are arranged on the upper seat plate, the middle seat plate, the lower seat plate and a limiting plate respectively and form a plurality of groups of matched magnetic rings; two magnetic rings in each group of matched magnetic rings are respectively located between the upper seat plate and the middle seat plate, between the middle seat plate and the lower seat plate or between the upper seat plate and the limiting plate, and the magnetic pole directions of the matched magnetic rings in each group are repulsive when the magnetic pole positions are one-to-one corresponding. The application utilizes the magnetic field repulsive force of the repulsive permanent magnets to form a non-contact elastic support and a magnetic hysteresis damping structure, realizes self-adaptive stiffness adjustment in normal service, and inhibits micro-vibration, so that the problems of poor long-term service durability and high maintenance cost of traditional shock insulation supports caused by material aging, shearing fatigue and medium leakage are solved.

Description

Technical Field

[0001] This invention relates to the field of bridge bearing technology, and in particular to a rare earth permanent magnet buffer and seismic isolation bearing and its application method. Background Technology

[0002] Currently, magnetic materials have been applied in the bridge field. Various publicly available designs primarily utilize the repulsive effect of conventional magnetic materials (electromagnets, etc.) to achieve functions such as energy absorption, buffering, vibration reduction, noise reduction, and damping adjustment in the bearings. These designs typically require the use of springs, coils, rubber, and other structures. CN206873281U discloses a novel bridge bearing that reduces the burden on the bearing's friction structure and corrects the bearing's posture during instability by correspondingly setting magnetic components (electromagnets) of the same polarity on the upper and lower bearing plates. CN119162909A discloses a bridge seismic isolation bearing that, through the... The force-counteracting mechanism of the bearing is equipped with electromagnets with mutually repelling magnetic poles on the guide shaft, thereby increasing the bearing strength in the horizontal direction and reducing the fatigue in the vertical direction; CN223189575U discloses a controllable damping variable stiffness seismic isolation bearing, which adjusts the horizontal stiffness and damping of the bearing by setting an electromagnetic damping mechanism (magnet, spring, coil) on the bearing and controlling the power supply of the electromagnetic damping mechanism using a seismic sensor and a central processing module; CN208201625U discloses a stable bridge bearing, which adjusts the horizontal stiffness and damping by setting the same polarity phase in the extension plate and the assembly cavity. Repulsive magnets increase the cushioning capacity and flexibility of the bearing; CN112962439A discloses a planar bridge bearing that significantly reduces bridge sway by using a slider and rotating column made of magnetic material (with opposite magnetic properties); CN211645971U discloses a bridge bearing with good vibration damping effect, which utilizes mutually repulsive magnetic blocks, damping oil, rubber seats, damping springs, and U-shaped elastic blocks to achieve good vibration damping effect; CN221566805U discloses a bridge bearing with multiple limiting support functions, which uses hydraulic dampers, spring dampers, and magnetic... The use of dampers enhances the cushioning effect of the bearing; CN108166381A discloses a bridge bearing vibration damping device based on piezoelectric ceramics, which uses magnetized metal particles placed between the upper and lower electrode plates of the device to achieve the effect of resisting and absorbing vibration energy by utilizing the reverse force generated when the magnetized metal particles are arranged in an orderly manner along the electric field direction in a strong electric field; CN223951603U discloses a bridge bearing with a stabilizing mechanism, which uses a support spring and a repulsive magnetic ring placed on the insert of the stabilizing mechanism to achieve the cushioning and stabilizing effect on the seesaw, thereby enhancing the overall stability; CN 110344320A discloses a magnetorheological elastomer bridge bearing, which adjusts the bearing stiffness and damping by setting a magnetorheological elastomer, an electromagnetic coil and an air rubber spring column on the bearing, thereby improving noise reduction and vibration reduction effects; CN205399195U discloses an electromagnetic anti-overturning bridge bearing, which provides an attractive force to the beam when the bearing is subjected to tensile stress by setting an electromagnetic chuck and a stress sensing mechanism on the bearing, thereby preventing the bridge from overturning.CN114717932A discloses a vibration-damping and insulating bridge bearing. By placing an upper positive magnet, a lower positive magnet, and a damping spring at the four corners of the bearing's inner cavity, electromagnetic damping is achieved, reducing the amplitude of the damping spring and minimizing damage to the internal structure.

[0003] In contrast, rare-earth permanent magnet materials enable non-contact magnetoelastic bearings with no internal mechanical friction contact parts. This eliminates issues such as material aging, shear fatigue, rubber cracking, lead creep, and damping medium leakage, significantly improving long-term service durability. The permanent magnet magnetic field can adaptively adjust the bearing stiffness, providing suitable support stiffness and effectively suppressing vibration. Under seismic loads, the magnetic repulsion and hysteresis damping efficiently dissipate seismic input energy, achieving adaptive stiffness changes and improving seismic isolation and vibration reduction effects. Furthermore, permanent magnet bearings are unaffected by dust, water vapor, or corrosive environments, making them highly adaptable to complex field conditions. They require no external power supply or active control, belonging to a passive seismic isolation and damping structure. Their simple structure requires no maintenance, has no consumable material losses, and boasts a long service life. The bearing stiffness, damping characteristics, and limit stroke can be flexibly adjusted through the arrangement of permanent magnets to meet the seismic and vibration reduction requirements of bridges with different spans, overcoming the shortcomings of traditional seismic isolation and damping bearings, such as non-adjustable stiffness, limited energy dissipation capacity, susceptibility to aging and deterioration, and high maintenance costs.

[0004] Currently, the application of rare earth permanent magnet materials in bridge bearings is limited. Some publicly disclosed designs only represent preliminary development and lack specific magnetic circuit design for the magnets used, resulting in limited improvement in the bearing's vibration reduction and seismic resistance. For example, CN117822423A discloses a magnetically attracted damping bridge bearing that uses bolts to fix neodymium iron boron magnets in slots on the lower bearing plate to achieve magnetic damping of the inner spherical cap liner. CN217419296U discloses an adaptive quick-installation vibration-damping and limiting magnetic damping bearing that uses two magnetic damping devices (permanent magnets) in the bearing's displacement direction. Using magnets and springs, electromagnetic eddy currents are used to achieve vibration reduction; CN217810483U discloses a seismic isolation road bridge bearing, which uses the repulsive effect of magnetic blocks (strong magnets) with the same magnetic poles on the damping sliding member and the sliding seat to relieve the pressure under the bearing; CN206873281U and CN107090769A disclose a bridge bearing, which uses magnetic components (permanent magnets or electromagnets) with the same magnetic poles and correction components on the upper and lower bearing plates to reduce the burden on the friction structure and achieve automatic reset of instability under small external forces.

[0005] Furthermore, from an overall perspective, in the currently disclosed designs of bearings that utilize magnetic materials, the role of magnetic materials is mostly auxiliary. The bearings as a whole still rely mainly on springs, hydraulic systems, etc., for vibration damping and isolation. Moreover, magnetic buffer devices are usually external devices, lacking improvements from the perspective of the bearing as a whole.

[0006] Therefore, there is an urgent need to propose a new rare-earth permanent magnet buffer isolation bearing and fixing method to solve the problems of poor long-term service durability and high maintenance costs of traditional isolation bearings due to material aging, shear fatigue and medium leakage. Summary of the Invention

[0007] In view of this, the present invention aims to propose a rare earth permanent magnet buffer isolation bearing and its application method to solve the problems of poor long-term service durability and high maintenance cost of traditional isolation bearings due to material aging, shear fatigue and medium leakage.

[0008] This application utilizes a ring-shaped symmetrical arrangement of paired magnetic rings with opposite magnetic poles and corresponding positions on the upper, middle, lower, and limiting plates. By leveraging the nonlinear characteristics of the repulsive force of permanent magnet magnetic fields, the bearing adaptively adjusts its stiffness during normal service to suppress micro-vibrations. Simultaneously, during earthquakes, the automatic shearing of shear pins releases the slippage. The slip resistance generated by the relative motion of the paired magnetic rings, combined with the magnetic domain rotation and hysteresis damping caused by eddy current effects, efficiently dissipates seismic energy. Thus, without the need for external power supply, mechanical friction contact, or easily aging components such as rubber hydraulic fluid, it achieves a fully passive, maintenance-free, long-life seismic isolation function applicable to different bridge spans. This overcomes the technical contradictions of existing bearings, such as unadjustable stiffness, limited energy dissipation capacity, reliance on elastic components, and high maintenance costs.

[0009] The technical solution of this invention is implemented as follows:

[0010] One object of the present invention is to disclose a rare earth permanent magnet buffer and seismic isolation bearing, comprising an upper bearing plate, a middle bearing plate, a lower bearing plate, and a shearing device, and further comprising:

[0011] Several permanent magnets are respectively disposed on the upper seat plate, the middle seat plate, the lower seat plate and the limiting plate of the shearing device, and the permanent magnets form multiple sets of paired magnetic rings;

[0012] The two magnetic rings in each pair of magnetic rings are located between the upper seat plate and the middle seat plate, between the middle seat plate and the lower seat plate, or between the upper seat plate and the limiting plate, respectively. The magnetic poles of each pair of magnetic rings are of the same polarity and repel each other, and their magnetic pole positions correspond one-to-one.

[0013] Optionally, the permanent magnet is a high-performance rare-earth permanent magnet material.

[0014] Optionally, the magnetic performance level of the permanent magnet is 52SH or higher.

[0015] Optionally, the permanent magnets are arranged in a Halbach array.

[0016] Optionally, the permanent magnets are symmetrically and uniformly arranged in a ring on the upper seat plate, middle seat plate, lower seat plate and limiting plate.

[0017] Optionally, the shearing device further includes a shearing pin and a positioning screw, which are designed to be shearable under seismic loads to release relative slippage between the upper seat plate, the middle seat plate, and the lower seat plate.

[0018] Optional, also includes:

[0019] A polymer material slide plate, wherein the polymer material slide plate is mixed with anisotropic magnetic powder and shaped by an external magnetic field, so that the polymer material slide plate is magnetic.

[0020] Optionally, the permanent magnet includes a small magnetorheological damper, which is connected to a magnetic field control system for actively or semi-actively adjusting the damping force.

[0021] Another object of the present invention discloses a rare earth permanent magnet buffer and seismic isolation bearing and its usage method. The method of using the rare earth permanent magnet buffer and seismic isolation bearing, based on any one of the above claims, includes the following steps:

[0022] Under the normal service load of the bridge, the upper seat plate, middle seat plate and lower seat plate will be relatively displaced, which will cause the magnetic pole spacing between each pair of magnetic rings to change. The magnetic repulsion force of the like poles of the permanent magnets will generate non-contact elastic support, and the support stiffness will be adaptively adjusted with the load.

[0023] When an earthquake occurs and the horizontal force exceeds a preset threshold, the shear pin and / or positioning screw will shear and break, allowing relative sliding between the upper seat plate, the middle seat plate and the lower seat plate.

[0024] During the sliding process, the upper, middle and lower seat plates drive the paired magnetic rings to generate relative motion, so that the magnetic repulsion force of the paired magnetic rings provides sliding resistance. At the same time, the irreversible movement of the magnetic domains inside the permanent magnet and the eddy current effect generate magnetic hysteresis damping, which together dissipates the seismic input energy.

[0025] Compared with existing technologies, the rare-earth permanent magnet buffer and seismic isolation bearing and its application method of the present invention have the following advantages:

[0026] 1. This invention provides elastic support and damping energy dissipation by setting permanent magnets on the upper plate, middle plate, lower plate and limiting plate to form multiple sets of paired magnetic rings. The magnetic poles of each set of paired magnetic rings are of the same polarity and repel each other, and the magnetic pole positions correspond one-to-one. It eliminates the need for elastic components that are prone to aging or leakage, such as springs, rubber, and hydraulic oil. This solves the problems of poor long-term service durability and high maintenance costs of traditional seismic isolation bearings due to material aging, shear fatigue and medium leakage.

[0027] 2. This invention arranges permanent magnets in a symmetrical ring according to a Halbach array, so that when the paired magnetic rings undergo relative displacement of the support, the magnetic repulsive force instantaneously and passively changes the support stiffness and damping with the changes in displacement and velocity, thus forming a passive adaptive stiffness adjustment structure. Combined with the shearing release of the shearing device under seismic load, when the upper, middle and lower support plates slip, the magnetic ring repulsive force simultaneously provides sliding resistance and hysteresis damping, effectively dissipating seismic energy. This solves the contradiction in existing magnetic supports where magnets are mostly auxiliary, lack overall magnetic circuit design, and cannot simultaneously take into account normal vibration reduction and seismic energy dissipation.

[0028] 3. This invention adopts a fully permanent magnet passive structure, which requires no external power supply, no sensors or control system, and has no internal mechanical friction contact parts. It is unaffected by dust, water vapor, or corrosive environments, and requires no maintenance or consumables. At the same time, by adjusting the number and arrangement of permanent magnets in the paired magnetic rings, it can flexibly adapt to the seismic and vibration reduction requirements of bridges with different spans. It solves the problems of existing electromagnetic or active control bearings that rely on external energy, have complex control logic, poor field adaptability, and traditional passive bearings with non-adjustable stiffness and limited energy consumption capacity. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 A schematic diagram of a rare earth permanent magnet buffer and seismic isolation bearing;

[0031] Figure 2 This is a magnified view of a portion of the support.

[0032] Explanation of reference numerals in the attached figures

[0033] 1. Upper seat plate; 2. Middle seat plate; 3. Lower seat plate; 4. Limiting plate; 5. Shear pin; 6. Positioning screw; 7. Permanent magnet; 8. Polymer material sliding plate; 9. Stainless steel sliding plate. Detailed Implementation

[0034] To make the technical means and objectives and effects of the present invention easier to understand, the embodiments of the present invention will be described in detail below with reference to specific illustrations.

[0035] like Figures 1 to 2As shown, this invention provides a rare-earth permanent magnet buffer and vibration isolation bearing and its usage method, including an upper bearing plate 1, a middle bearing plate 2, a lower bearing plate 3, a shearing device, and several permanent magnets 7. The shearing device includes a limiting plate 4, a shearing pin 5, and a positioning screw 6. The permanent magnets 7 are respectively disposed on the upper bearing plate 1, the middle bearing plate 2, the lower bearing plate 3, and the limiting plate 4, forming multiple sets of paired magnetic rings. The two magnetic rings in each set of paired magnetic rings are respectively located between the upper bearing plate 1 and the middle bearing plate 2, between the middle bearing plate 2 and the lower bearing plate 3, or between the upper bearing plate 1 and the limiting plate 4, and the magnetic poles of each set of paired magnetic rings are of the same polarity and repel each other, with their positions corresponding one-to-one.

[0036] This design achieves passive adaptive stiffness adjustment by setting paired magnetic rings with the same magnetic poles repulsive in direction and corresponding in position on the upper bearing plate 1, middle bearing plate 2, lower bearing plate 3, and limiting plate 4. It can provide flexible support under small vibrations and automatically increase stiffness under large displacements, effectively suppressing high-frequency micro-vibrations of the bridge. At the same time, it uses the magnetic repulsion force to form a non-contact elastic support, completely avoiding the aging and leakage problems of traditional rubber and hydraulic components, and significantly improving long-term durability. In the event of an earthquake, the shear pin 5 and the positioning screw 6 automatically shear off, releasing the sliding degree of freedom. In addition to providing sliding resistance, the paired magnetic rings also generate hysteresis damping through magnetic domain rotation and eddy current effect, efficiently dissipating seismic energy, extending the structural vibration period, and reducing the peak displacement. The overall structure has no external power supply and no mechanical friction, and has excellent maintenance-free operation and adaptability to complex environments. Furthermore, the flexible adjustment of the number and arrangement of magnets can adapt to different bridge requirements, overcoming the shortcomings of existing bearings such as non-adjustable stiffness, limited energy consumption, and easy deterioration. At the same time, it provides progressive limit protection to prevent over-limit displacement.

[0037] The permanent magnet 7 can be made of conventional magnetic materials, but is preferably made of high-performance rare-earth permanent magnet materials. The magnetic performance grade of the high-performance rare-earth permanent magnet material can be selected according to the actual working conditions, such as one or more of the N-series, M-series, H-series, SH-series, UH-series, or EH-series. In a preferred embodiment, the magnetic performance grade of the high-performance rare-earth permanent magnet material is 52SH or higher, such as 52SH, 53UH, or 54EH, to ensure stable magnetic performance over a wide temperature range (-40℃ to 120℃). It should be understood that in high-temperature environments or under special requirements, higher-grade permanent magnet materials, such as 48UH or 50EH, can also be selected, and the specific grade does not constitute a limitation of the present invention.

[0038] To enhance magnetic field utilization efficiency and reduce magnetic leakage, the permanent magnets 7 are preferably arranged in a Halbach array. A Halbach array refers to a near-sinusoidal magnetic field distribution where the magnetization directions of adjacent permanent magnets 7 rotate sequentially at fixed angles (e.g., 90°, 45°, or 30°), forming a strong unilateral magnetic field with low magnetic leakage. In one specific embodiment, the rotation period of the Halbach array is four magnets (i.e., magnetization directions are sequentially 0°, 90°, 180°, and 270°). In another optional embodiment, eight magnets can be used to form a complete cycle (each magnet rotates 45°). This arrangement concentrates the magnetic field between paired magnetic rings on opposite sides, significantly improving the repulsive force while reducing magnetic field interference to the external environment (such as reinforcing bars and prestressed tendons).

[0039] Meanwhile, permanent magnets 7 are symmetrically and uniformly arranged in a ring pattern on the upper seat plate 1, middle seat plate 2, lower seat plate 3, and limiting plate 4, that is, evenly distributed along the circumference of the central axis of the support, forming one or more sets of concentric rings. The radial spacing between adjacent magnetic rings can be adjusted according to the support size, for example, from 10mm to 50mm. Through the symmetrical ring arrangement, the support can generate a uniform repulsive force when subjected to load in any horizontal direction, solving the problem of local stress concentration and uneven force distribution in existing supports under eccentric loading.

[0040] Furthermore, the number of permanent magnets 7 in the paired magnetic rings can be adjusted according to the vibration reduction and isolation requirements of the actual working conditions. For example, for small-span bridges (such as those below 20m), each magnetic ring can contain 4 permanent magnets 7; for medium-span bridges (20m-50m), each magnetic ring can contain 8 or 12 permanent magnets 7; for large-span bridges or bridges in high-intensity seismic zones, each magnetic ring can contain 16 or more permanent magnets 7 to provide sufficient magnetic repulsion and damping. The shape of the permanent magnets 7 can be square, fan-shaped, or arc-shaped, and its thickness (magnetization direction) is preferably 5mm to 30mm, more preferably 10mm to 20mm. This setting allows for flexible adjustment of the number, shape, and thickness of the permanent magnets 7 in the paired magnetic rings according to the bridge span, solving the problem that the stiffness and damping of traditional bearings are not adjustable and cannot be differentiated for different bridges.

[0041] In addition to the limiting plate 4, the shearing device also includes shear pins 5 and positioning screws 6. Under normal service conditions, shear pins 5 and positioning screws 6 fix the upper seat plate 1, middle seat plate 2, and lower seat plate 3 relatively, limiting their horizontal relative displacement within an allowable range (e.g., ±5mm to ±10mm). Shear pins 5 and positioning screws 6 are configured to shear under seismic loads: when the horizontal force generated by an earthquake exceeds a preset threshold (e.g., 10% to 30% of the vertical bearing capacity of the support), shear pins 5 and / or positioning screws 6 shear and break, thereby releasing the relative slippage between the upper seat plate 1, middle seat plate 2, and lower seat plate 3. The preset threshold can be calibrated by adjusting the material (e.g., 45 steel, 40Cr), diameter (e.g., 6mm to 20mm), or number of shear pins 5. The setting of shear pin 5 and positioning screw 6 restricts displacement during normal service and automatically shears off and releases slippage when an earthquake exceeds the threshold, which solves the contradiction that the bearing working mode cannot be automatically switched between normal use and earthquake conditions, and that traditional bearings are either too stiff to dissipate energy or too flexible to bear load stably.

[0042] The magnetic repulsion force of the paired magnetic rings constitutes a non-contact elastic support structure. Unlike traditional rubber or steel springs, this support requires no mechanical contact, thus eliminating issues such as rubber aging, shear fatigue, or permanent spring deformation. During normal service (e.g., vehicle traffic, wind-induced vibration, temperature changes), minute horizontal or vertical relative displacements occur between the upper seat plate 1 and the middle seat plate 2, and between the middle seat plate 2 and the lower seat plate 3. Due to the repulsion of like magnetic poles, the repulsive force between the magnetic rings increases non-linearly with decreasing distance. This design allows the support to exhibit low dynamic stiffness under minor vibrations, ensuring comfort; while automatically increasing stiffness under larger displacements to limit excessive displacement. The entire process requires no external sensors or controllers, achieving passive adaptive stiffness adjustment.

[0043] During a strong earthquake, shear pin 5 is sheared, resulting in significant relative slippage between the upper bearing plate 1, middle bearing plate 2, and lower bearing plate 3. During this relative motion, the paired magnetic rings, in addition to generating static repulsive force, also experience hysteresis damping due to the irreversible motion of magnetic domains and eddy current effects. This hysteresis damping is related to the relative velocity; the higher the velocity, the greater the energy dissipation. The magnetic repulsive force of the paired magnetic rings and the hysteresis damping together constitute the slip resistance structure and the hysteresis damping energy dissipation structure, equivalent to a damper connected in series inside the support. By rationally designing the number, arrangement, and magnetic properties of the magnets, the effective damping ratio of the support can reach 10% to 25%, far exceeding that of traditional pot bearings (approximately 2% to 5%), thereby effectively dissipating seismic input energy, prolonging the structural vibration period, and reducing acceleration response.

[0044] Based on the above embodiments, the support also includes a polymer material sliding plate 8 and a stainless steel sliding plate 9. The polymer material sliding plate 8 is typically made of polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), or polyetheretherketone (PEEK). To further enhance the magnetic field coupling effect, in one variation, the polymer material sliding plate 8 is internally mixed with anisotropic magnetic powder (e.g., HDDR neodymium iron boron magnetic powder) and oriented by an external magnetic field, giving the polymer material sliding plate 8 its own magnetic properties. Specifically, the magnetic powder and polymer granules are uniformly mixed at a mass ratio (5% to 30%), and a 1T to 2T directional magnetic field is applied during injection molding or compression molding, causing the easy magnetization axis of the magnetic powder to align along a specified direction. This arrangement of the sliding plate generates an additional magnetic field in a direction perpendicular to the friction surface, forming an auxiliary repulsive circuit with the permanent magnets 7 on the upper and lower seat plates 3, further improving the pull-out resistance and horizontal restoring force of the support.

[0045] In another alternative implementation, the permanent magnet 7 can be entirely or partially replaced with a small magnetorheological damper. The small magnetorheological damper includes a cylinder, piston, magnetorheological fluid, and excitation coil, and is connected to a magnetic field control system, including a controller, an acceleration sensor, and an adjustable power supply. The magnetic field control system allows for active or semi-active adjustment of the damping force based on the real-time seismic response. For example, low damping can be maintained during small to medium-sized earthquakes to allow support slippage and energy dissipation; during large earthquakes, damping can be increased to limit peak displacement. The response time of the magnetorheological damper is typically less than 10 ms, significantly faster than that of a mechanical friction damper. In a hybrid scheme, some of the magnetic rings can be retained as permanent magnets 7, while others can be replaced with magnetorheological dampers, forming a hybrid passive / semi-active seismic isolation system of "permanent magnet-magnetorheological".

[0046] To accommodate earthquakes of varying intensities, shear devices can include multi-stage shear pins. For example, a first-stage shear pin (small diameter, shear force F1) is used for normal light winds or minor earthquakes, allowing limited slippage of the support; a second-stage shear pin (large diameter, shear force F2 > F1) is used for design earthquakes; and a third stage is a limiting block or stop, serving as the ultimate limit. This hierarchical design gives the support multi-stage stiffness and damping characteristics.

[0047] To effectively limit excessive rotation of the middle seat plate 2 even after the shear pin 5 has broken, the inner edge of the limiting plate 4 is provided with an annular boss that forms a clearance fit with the outer side of the neck of the middle seat plate 2. When the rotation angle of the middle seat plate 2 exceeds a preset value, such as 0.05 rad, the boss contacts the neck of the middle seat plate 2, providing a mechanical anti-rotation force. At the same time, since the permanent magnets 7 are arranged in a symmetrical annular pattern, the uneven gap between the magnetic rings caused by rotation will generate a restoring torque, which helps to limit the rotation angle.

[0048] To ensure that the mating magnetic rings remain effectively aligned within the designed maximum sliding stroke and to prevent magnetic pair failure due to excessive offset, this invention further optimizes the dimensions of the permanent magnet in the sliding direction and the number of magnetic ring layers. Specifically, the width of the permanent magnet 7 in the allowable sliding direction of the support is set to be sufficiently large, for example, 60mm to 100mm, so that even if the designed maximum slip occurs (e.g., ±50mm), the mating magnetic rings still maintain an alignment width of at least 10mm, thereby ensuring the continued effectiveness of magnetic repulsion and hysteresis damping. Furthermore, based on the annular symmetrical arrangement, multiple rows of magnetic rings are arranged radially, such as inner and outer concentric magnetic rings; when the support experiences a large horizontal displacement causing partial misalignment of the outer magnetic rings, the inner magnetic rings still maintain a large alignment area, forming a redundant magnetic circuit, further ensuring that the magnetic pair is always in an effective working state. Through the synergistic design of the above-mentioned large width dimension and multiple redundant rows, the magnetic coupling reliability of the support under extreme sliding conditions is significantly improved.

[0049] The rare-earth permanent magnet buffer and seismic isolation bearing provided by this invention is assembled in the factory. During installation, the lower bearing plate 3 is first fixed to the pier or cap beam with anchor bolts, and then the middle bearing plate 2 and the upper bearing plate 1 are placed in sequence, ensuring that the magnetic pole positions of the paired magnetic rings correspond one-to-one. The limiting plate 4 is temporarily fixed to the middle bearing plate 2 with positioning screws 6, and shear pins 5 are inserted. Finally, the upper bearing plate 1 is connected to the beam. The entire installation process does not require magnetization or special protection of the permanent magnet 7; only care should be taken to avoid strong impacts that could cause the magnet to break. During use, since the permanent magnet 7 does not have aging or magnetic leakage problems (the performance degradation of neodymium iron boron is less than 1% within 100 years at normal temperature), the bearing is basically maintenance-free. If the magnet needs to be replaced, the limiting plate 4 can be removed, the worn or demagnetized magnet can be taken out and replaced with a new one of the same specifications, which is simple to operate.

[0050] Another object of the present invention is to provide a rare earth permanent magnet buffer and seismic isolation bearing and a method of using the same. The rare earth permanent magnet buffer and seismic isolation bearing based on any of the above-mentioned methods includes the following steps:

[0051] Step 1 (Normal Service Stage): Under the normal service load of the bridge, the upper bearing plate 1, the middle bearing plate 2 and the lower bearing plate 3 are relatively displaced, which causes the magnetic pole spacing between each pair of magnetic rings to change. The magnetic repulsion force of the like poles of the permanent magnet 7 is used to generate non-contact elastic support, and the bearing stiffness is adaptively adjusted with the load.

[0052] Step 2 (Earthquake Triggering Stage): When an earthquake occurs and the horizontal force exceeds the preset threshold, the shear pin 5 and / or the positioning screw 6 will break under shear force, releasing the relative slippage between the upper seat plate 1, the middle seat plate 2 and the lower seat plate 3.

[0053] Step 3 (Sliding Energy Dissipation Stage): During the sliding process, the upper seat plate 1, the middle seat plate 2 and the lower seat plate 3 drive the paired magnetic rings to generate relative motion, so that the magnetic repulsion force of the paired magnetic rings provides sliding resistance. At the same time, the irreversible motion of the magnetic domains inside the permanent magnet 7 and the eddy current effect generate magnetic hysteresis damping, which together dissipates the seismic input energy.

[0054] Through the above steps, the support of the present invention can adaptively adjust stiffness and suppress micro-vibrations during normal service, and automatically switch to energy-consuming working mode when an earthquake occurs, realizing a fully passive, maintenance-free seismic isolation function.

[0055] The present invention achieves the following beneficial effects:

[0056] The Halbach array and its symmetrical ring arrangement concentrate the magnetic field in the effective working area inside the support, reducing the leakage flux to less than 20% of that of traditional arrangements and improving material utilization.

[0057] The repulsion of like poles and hysteresis damping of the paired magnetic rings enable the support to have both elastic support and energy dissipation functions, solving the structural redundancy problem of traditional supports that require separate rubber pads and dampers.

[0058] The graded design of the shear pin 5 enables the support to automatically switch working modes under normal use and seismic conditions, achieving passive intelligent response.

[0059] The adjustable number and performance level of permanent magnets allow the bearings to be customized according to the bridge span, site type and seismic fortification level, resulting in good engineering adaptability.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rare-earth permanent magnet buffer and seismic isolation bearing, comprising an upper bearing plate (1), a middle bearing plate (2), a lower bearing plate (3), and a shearing device, characterized in that, Also includes: Several permanent magnets (7) are respectively disposed on the upper seat plate (1), the middle seat plate (2), the lower seat plate (3) and the limiting plate (4) of the shearing device, and the permanent magnets (7) form multiple sets of paired magnetic rings; The two magnetic rings in each pair of magnetic rings are located between the upper seat plate (1) and the middle seat plate (2), between the middle seat plate (2) and the lower seat plate (3), or between the upper seat plate (1) and the limiting plate (4), and the magnetic poles of each pair of magnetic rings are of the same polarity and repel each other, and the magnetic pole positions correspond one to one.

2. The rare-earth permanent magnet buffer and seismic isolation bearing according to claim 1, characterized in that, The permanent magnet (7) is a high-performance rare earth permanent magnet material.

3. The rare-earth permanent magnet buffer and seismic isolation bearing according to claim 1, characterized in that, The permanent magnet (7) has a magnetic performance level of 52SH or higher.

4. The rare-earth permanent magnet buffer and seismic isolation bearing according to claim 1, characterized in that, The permanent magnet (7) is arranged in a Halbach array.

5. The rare-earth permanent magnet buffer and seismic isolation bearing according to claim 1, characterized in that, The permanent magnets (7) are arranged symmetrically and evenly in a ring on the upper seat plate (1), middle seat plate (2), lower seat plate (3) and limiting plate (4).

6. The rare-earth permanent magnet buffer and seismic isolation bearing according to claim 5, characterized in that, The shearing device also includes a shearing pin (5) and a positioning screw (6), which are designed to be shearable under seismic loads to release the relative slippage between the upper seat plate (1), the middle seat plate (2) and the lower seat plate (3).

7. The rare-earth permanent magnet buffer and seismic isolation bearing according to claim 1, characterized in that, Also includes: The polymer material slide plate (8) is mixed with anisotropic magnetic powder and shaped by an external magnetic field, so that the polymer material slide plate (8) has magnetic properties.

8. The rare-earth permanent magnet buffer and seismic isolation bearing according to claim 1, characterized in that, The permanent magnet (7) includes a small magnetorheological damper, which is connected to a magnetic field control system for actively or semi-actively adjusting the damping force.

9. A rare-earth permanent magnet buffer and seismic isolation bearing and its application method, characterized in that, The rare-earth permanent magnet buffer and seismic isolation bearing based on any one of claims 1 to 8 includes the following steps: Under the normal service load of the bridge, the upper seat plate (1), the middle seat plate (2) and the lower seat plate (3) will be relatively displaced, which will cause the magnetic pole spacing between each pair of magnetic rings (8) to change. The magnetic repulsion force of the like poles of the permanent magnet (7) will generate non-contact elastic support, and the support stiffness will be adaptively adjusted with the load. When an earthquake occurs and the horizontal force exceeds a preset threshold, the shear pin (5) and / or the positioning screw (6) will shear and break, allowing relative sliding between the upper seat plate (1), the middle seat plate (2) and the lower seat plate (3). During the sliding process, the upper seat plate (1), the middle seat plate (2) and the lower seat plate (3) drive the paired magnetic rings to generate relative motion. The magnetic repulsion force of the paired magnetic rings provides sliding resistance. At the same time, the irreversible movement of the magnetic domains inside the permanent magnet (7) and the eddy current effect generate magnetic hysteresis damping, which together dissipates the earthquake input energy.

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