Load self-adaptive vibration isolator and floating slab track

Abstract

The invention discloses a load self-adaptive vibration isolator and a floating slab track, the load self-adaptive vibration isolator comprises a steel spring vibration isolator and a negative stiffness structure, the negative stiffness structure comprises a stroke platform, a ball screw bearing, a screw, a Halbach magnetic array, a support table and a base, and the top surface of the stroke platform is fixedly connected with a cover plate; the ball screw bearing penetrates through a center hole in the bottom face of the stroke platform and is fixedly connected with the stroke platform. The Halbach magnetic array comprises an inner shell, a coil and an outer shell, a plurality of grooves for placing the first arc-shaped magnets are uniformly formed in the inner shell in the circumferential direction, a plurality of grooves for placing the second arc-shaped magnets are uniformly formed in the outer shell in the circumferential direction, the coil is tightly attached to the inner wall of the outer shell, and a gap is formed between the coil and the outer wall of the outer shell; the center of the inner shell is fixedly connected with the lower part of the screw; the lower end of the lead screw is rotationally installed on the supporting table. The supporting table is fixedly installed on the base, and the lower portion of the shell is embedded in a groove reserved in the base. According to the device, load self-adaption is achieved, and low-frequency vibration under the variable load condition can be effectively restrained.

Description

Technical Field

[0001] The invention relates to the field of floating plate tracks, and in particular to a load-adaptive vibration isolator and a floating plate track. Background Art

[0002] With the development of modern science and technology, the vibration problem of urban rail transit has become increasingly prominent, which not only seriously affects the surrounding environment and people's daily life, but also seriously interferes with the normal operation of precision instruments and equipment. Therefore, it is necessary to take vibration reduction and noise reduction measures to reduce the negative impact caused by urban rail transit.

[0003] Among the various vibration reduction technologies currently available, steel spring floating slab track is the most important means to suppress the harm of rail transit vibration. However, since the floating slab track vibration isolation system is a linear system, it can be proved by vibration isolation theory that, whether it is active vibration isolation or passive vibration isolation, only when the excitation frequency is greater than The system will only have a vibration isolation effect when the system natural frequency is greater than 100 times. However, for low-frequency vibrations, such as vibration frequencies of 5Hz to 15Hz, the traditional steel spring floating plate system cannot effectively isolate, and the system response may even exceed the design specification requirements of the floating plate track (the response of the floating plate system cannot exceed 3mm).

[0004] Therefore, the most effective method is to reduce the natural frequency of the system to achieve low-frequency vibration reduction. At present, the most effective means to reduce the natural frequency is quasi-zero stiffness vibration isolation, which can maintain the load-bearing capacity while maintaining low stiffness during vibration. However, since urban rail transit is a variable load system during operation, the traditional quasi-zero stiffness is not applicable and may even cause vibration amplification. Summary of the invention

[0005] In order to solve the problems existing in the prior art, one object of the present invention is to provide a load-adaptive vibration isolator that can achieve low stiffness and quasi-zero stiffness under variable load conditions. Another object of the present invention is to provide a floating plate track using the load-adaptive vibration isolator that can achieve low stiffness and quasi-zero stiffness characteristics within different load ranges while maintaining the load-bearing capacity.

[0006] To this end, the present invention adopts the following technical solutions: A load adaptive vibration isolator comprises a steel spring vibration isolator and a negative stiffness structure installed in the spring vibration isolator, wherein the steel spring vibration isolator comprises a steel spring, a fastener and a cover plate, wherein the upper end of the steel spring is fixedly connected to the cover plate, the fastener is used to fix the cover plate and the floating plate, and the negative stiffness structure comprises a stroke platform, a ball screw bearing, a screw, a Halbach magnetic array, a support platform and a base, wherein: The top surface of the stroke platform is fixedly connected to the cover plate; the bottom surface of the stroke platform is an annular surface, the ball screw bearing passes through the center hole of the annular surface and is fixedly connected to the bottom surface of the stroke platform, and when the stroke platform moves vertically, the screw rotates relative to the ball screw bearing; The Halbach magnetic array comprises an inner shell, a coil and an outer shell, wherein the inner shell is uniformly formed with a plurality of grooves for accommodating the first arc-shaped magnet in the circumferential direction, and the outer shell is uniformly formed with a plurality of grooves for accommodating the second arc-shaped magnet in the circumferential direction, and the number of grooves on the inner shell and the outer shell is the same, and the coil is arranged close to the inner wall of the outer shell and forms a gap with the outer wall of the inner shell; The lower part of the screw rod passes through the central hole of the inner shell, and the two are fixedly connected so that the inner shell can rotate synchronously with the screw rod; The lower end of the screw rod is rotatably connected to a bearing installed in the support platform to ensure the rotation of the screw rod. The support platform is fixed on the base, and the lower part of the shell is embedded in a groove reserved on the base to achieve fixation.

[0007] Preferably, the number of the first arc-shaped magnets and the second arc-shaped magnets is the same and is a multiple of 4, and each group of 4 arc-shaped magnets corresponds to a low stiffness or quasi-zero stiffness interval.

[0008] Preferably, in the initial state, the distance between the top of the screw rod and the lower surface of the top surface of the stroke platform is 1-2 cm.

[0009] Preferably, the negative stiffness structure has a height of 28-32 cm and a width of 10-14 cm.

[0010] The present invention also protects a floating plate track, comprising a track, a track fastener, a floating plate and the above-mentioned load-adaptive vibration isolator, wherein a plurality of load-adaptive vibration isolators are spaced apart on both sides of the floating plate along the line direction.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention converts the periodic restoring torque generated by the interaction of the Halbach magnetic array into a periodic negative stiffness restoring force in the vertical direction through a ball screw bearing, and forms a load-adaptive restoring force after superposition with the linear restoring force of the steel spring, so that the vibration isolator can maintain low stiffness or quasi-zero stiffness at different load positions, thereby achieving load-bearing and low-frequency vibration isolation in different load ranges.

[0012] 2. The floating slab track equipped with the load-adaptive vibration isolator of the present invention realizes load adaptation and can better suppress the low-frequency vibration of the floating slab track under variable load conditions.

[0013] 3. The vibration isolator of the present invention has a simple structure and is easy to manufacture; the negative stiffness structure is slender and can directly replace the existing steel spring vibration isolator, and the magnitude of the restoring force generated by the negative stiffness structure can also be adjusted according to the load-bearing requirements.

[0014] 4. Because the Halbach array generates a stronger magnetic field when rotating, the copper coil can generate more electrical energy when cutting the magnetic flux lines compared to ordinary arrangements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of an embodiment of a load adaptive vibration isolator of the present invention; Figure 2 yes Figure 1 Schematic diagram of the exploded structure of the medium load adaptive vibration isolator; Figure 3 yes Figure 2 Structural schematic diagram of medium negative stiffness structure; Figure 4 yes Figure 2 Schematic diagram of the internal structure of the medium negative stiffness structure; Figure 5 is a schematic diagram of the angles through which the first arc magnet and the second arc magnet rotate relative to the initial position; Figure 6 is a schematic diagram of magnet periodic torque of a load adaptive vibration isolator according to an embodiment of the present invention; Figure 7 is a comparison diagram between theoretical calculation and simulation results of the torque generated by the magnet of the load adaptive vibration isolator according to one embodiment of the present invention; Figure 8 is a schematic diagram of a load-adaptive restoring force of a load-adaptive vibration isolator according to an embodiment of the present invention; Fig. 9 It is a schematic diagram of a floating plate track structure according to an embodiment of the present invention; Fig.10 is a simulation result of a rail train according to an embodiment of the present invention; In the figure: 1. Steel spring isolator 2. Negative stiffness structure 3. Stroke platform 4. Ball screw bearing 5. Screw 6. Inner shell 7. First arc-shaped magnet 8. Outer shell 9. Second arc-shaped magnet 10. Support table 11. Base 12. Cover 13. Bolts 14. Fasteners 15. Steel spring 16. Copper coil. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0017] Figure 1 to Figure 4 An embodiment of the load-adaptive vibration isolator of the present invention is shown. As shown in the figure, the load-adaptive vibration isolator includes a steel spring vibration isolator 1 and a ball screw-Halbach negative stiffness structure (hereinafter referred to as the negative stiffness structure 2). The steel spring vibration isolator 1 includes a steel spring 15, a fastener 14 and a cover plate 12. The upper end of the steel spring 15 is fixedly connected to the cover plate 12, and the fastener 14 is used to fix the cover plate 12 and the floating plate; the negative stiffness structure 2 is installed under the cover plate 12 and inside the steel spring 15.

[0018] Specifically, the negative stiffness structure 2 includes a stroke platform 3 , a ball screw bearing 4 , a screw 5 , a Halbach magnetic array, a support platform 10 and a base 11 .

[0019] The top surface of the stroke platform 3 is fixedly connected to the cover plate 12 to achieve synchronous movement with the steel spring vibration isolator 1; the bottom surface of the stroke platform 3 is an annular surface, the ball screw bearing 4 passes through the center hole of the annular surface and is fixedly connected to the bottom surface of the stroke platform 3, and when the stroke platform 3 moves vertically, the screw 5 rotates relative to the ball screw bearing 4.

[0020] The Halbach magnetic array includes an inner shell 6, a coil 16 and an outer shell 8. The inner shell 6 is evenly formed with a plurality of grooves for accommodating the first arc-shaped magnet 7 in the circumferential direction, and the outer shell 8 is evenly formed with a plurality of grooves for accommodating the second arc-shaped magnet 9 in the circumferential direction. The number of grooves on the inner shell 6 and the outer shell 8 is the same. The coil 16 is arranged close to the inner wall of the outer shell 8 and forms a gap with the outer wall of the inner shell 6.

[0021] The lower part of the screw rod 5 passes through the central hole of the inner shell 6 , and the two are fixedly connected so that the inner shell 6 can rotate synchronously with the screw rod 5 .

[0022] The lower end of the screw rod 5 is rotatably connected to a bearing installed in the support platform 10 to ensure the rotation of the screw rod 5. The support platform 10 is fixedly mounted on the base 11, and the lower part of the housing 8 is embedded in a groove reserved on the base 11 to achieve fixation.

[0023] When the steel spring isolator 1 is stimulated, the stroke platform 3 moves vertically, thereby driving the ball screw bearing 4 vertically, the inner shell 6 rotates, and the first arc magnet 7 interacts with the second arc magnet 9 to provide a periodic reaction torque, which is then converted into a vertical periodic negative stiffness restoring force through the screw bearing 4. After coupling with the steel spring, it can offset part of the positive stiffness restoring force of the steel spring, that is, providing negative stiffness for the steel spring isolator 1.

[0024] In the load-adaptive vibration isolator of the present invention, the number of the first arc magnet and the second arc magnet is the same and is a multiple of 4, and each group of four arc magnets corresponds to a low stiffness or quasi-zero stiffness interval. Each cycle of the periodic negative stiffness restoring force corresponds to a quasi-zero stiffness interval under a load condition.

[0025] When the load on the stroke platform 3 changes, the screw rod 5 can drive the inner shell 6 to rotate to the corresponding quasi-zero stiffness interval to achieve low stiffness requirements under different load positions, thereby realizing load-adaptive low-frequency vibration isolation of the floating plate track.

[0026] At the same time, when the inner shell 6 rotates, the Halbach array formed by the arc-shaped magnet 7 thereon can enable the copper coil 16 on the outer shell 8 to generate electrical energy and connect to the external circuit to collect, store and utilize the generated electrical energy, thereby realizing the capture of vibration energy.

[0027] The periodic moment (torque) generated by the load adaptive isolator can be adjusted by adjusting the spacing between the first arc magnets 7, the spacing between the second arc magnets 9, the logarithm of the magnets and the arrangement (magnetization direction of the magnets). The ball screw bearing 4 then converts the moment into a vertical negative stiffness reaction force, and by coupling with the steel spring, it can offset part of the positive stiffness restoring force of the steel spring.

[0028] In the load adaptive vibration isolator of the present invention, the inner shell 6 is connected to the screw rod 5 by mortise and tenon joints, and is coupled to each other, so as to ensure that the inner shell can rotate synchronously with the screw rod when the screw rod rotates. The inner shell and the outer shell are made of aluminum alloy or plastic.

[0029] In the load adaptive vibration isolator of the present invention, the magnetization directions of the second arc-shaped magnet in the outer shell and the first arc-shaped magnet in the inner shell are arranged in three ways, namely radial to radial, tangential to radial and tangential to tangential.

[0030] See also Figure 5 , assuming that the initial rotation angle of the arc magnet is After rotation, the angles between the two sides (two sections) of the first arc-shaped magnet and the initial position are and , the angles between the two sides of the second arc magnet and the initial position are and .

[0031] When the magnetization direction is arranged in different ways, the calculation formula of the periodic torque generated by the negative stiffness structure 2 is as follows: Radial to Radial: , ; Tangential (outer) to radial (inner): , ; , ; ; Tangential to tangential: , ; .

[0032] in: It is the torque generated when magnets with tangential magnetization directions rotate relative to each other. It is the torque generated by two tangential surfaces when the magnets with tangential magnetization directions rotate relative to each other. It is the torque generated by the tangent plane of the axial surface when the magnets with tangential and radial magnetization directions rotate relative to each other; It is the torque generated by two sections when the magnets with tangential and radial magnetization directions rotate relative to each other; It is the force exerted by the axial surface on the axial surface when the magnets with tangential magnetization directions rotate relative to each other; is the relative magnetic permeability of vacuum; denotes the integration of the angles of the external and internal magnets, respectively; is the rotation angle of the screw; denote the integration of the heights of the external and internal magnets, respectively; denote the integration of the radial lengths of the external and internal magnets, respectively; is the charge on the magnet; Indicates Internal magnets; Indicates an external magnet; are the inner diameter and outer diameter of the first arc-shaped magnet and the inner diameter and outer diameter of the second arc-shaped magnet respectively; The height of the upper surface and the height of the lower surface of the first arc-shaped magnet and the height of the upper surface and the height of the lower surface of the second arc-shaped magnet respectively; is the number of magnet pairs in the entire magnet array.

[0033] For the convenience of engineering application, the charges of the internal and external magnets are selected to be equal, that is, , then: The torque calculation equation of the Halbach magnetic array is: .

[0034] Figure 6 The figure shows the torque generated by the negative stiffness structure of the load adaptive vibration isolator of one embodiment of the present invention when it moves. As shown in the figure, one rotation can generate 4 cycles of torque, and the cycle length is .

[0035] The relationship between the rotation angle of the inner housing (screw) and the vertical displacement of the stroke platform (ball screw bearing) is as follows: , Among them is Inner shell rotation angle, is the initial rotation angle, usually set to 0; is the rotation period, For the rotation time, is the vertical displacement, is the screw lead.

[0036] Vertical restoring force generated by the Halbach negative stiffness structure The calculation formula is: , in, is the friction coefficient of the ball screw, is the relative torque generated when the entire Halbach magnet array rotates.

[0037] The total restoring force of the load adaptive isolator is: , is the stiffness coefficient of the spring.

[0038] It can be seen that different quasi-zero stiffness intervals correspond to different load-bearing intervals. Therefore, when the load changes, the vibration isolator can have a good load adaptive effect.

[0039] In the load-adaptive vibration isolator of the present invention, in the initial state, the distance between the top of the screw rod 5 and the lower surface of the top surface of the stroke platform 3 is 1-2 cm. The size of the steel spring vibration isolator is equivalent to that of the original vibration isolator, the height of the negative stiffness structure is 28 cm-32 cm, and the width is 10 cm-14 cm, which can be adjusted according to engineering requirements.

[0040] Figure 7 The figure shows the comparison between the theoretical calculation results and the finite element simulation results of the Halbach magnetic array of the Halbach negative stiffness structure in one embodiment of the present invention. It can be seen that the two results are highly similar, which proves the accuracy of the theoretical analysis.

[0041] Figure 8 The figure is a schematic diagram of the restoring force of a load-adaptive isolator according to an embodiment of the present invention. It can be seen that under different load conditions, multiple low-stiffness intervals can be formed, thereby achieving load adaptation.

[0042] Fig. 9 The figure shows a floating plate track using the above-mentioned load adaptive vibration isolator, including a track 21, a track fastener 22, a floating plate 23 and the load adaptive vibration isolator, wherein: a plurality of load adaptive vibration isolators are arranged at intervals on both sides of the floating plate 23 along the line direction.

[0043] The load adaptive vibration isolator of the present invention can directly replace the original steel spring vibration isolator and be installed on the existing floating plate track.

[0044] Fig.10 The figure shows the simulation result of a rail train according to an embodiment of the present invention. The rail train simulation model uses a three-car model (three carriages), and its parameters are: the weight of the train distributed to each vibration isolator is 1.5 tons, the stiffness of the steel spring vibration isolator is 7300KN / m, and the damping is 16000ngs / m; the parameters of the C40 concrete used for the floating slab are: elastic modulus is 3.25e10pa, density is 2500kg / m 3 , Poisson's ratio is 0.2; the vehicle speed is 70km / h.

[0045] It can be seen from the simulation results that when the train is under rated load, the displacement response of the floating plate track using the load adaptive isolator of the present invention is smaller than that of the floating plate track using the steel spring isolator, that is, the isolator system of the present invention is superior to the steel spring isolator system.

Claims

1. A load adaptive vibration isolator, comprising a steel spring vibration isolator and a negative stiffness structure installed in the spring vibration isolator, the steel spring vibration isolator comprising a steel spring, a fastener and a cover plate, the upper end of the steel spring is fixedly connected to the cover plate, the fastener is used to fix the cover plate and the floating plate, characterized in that: The negative stiffness structure (2) comprises a stroke platform (3), a ball screw bearing (4), a screw (5), a Halbach magnetic array, a support platform (10) and a base (11), wherein: The top surface of the stroke platform (3) is fixedly connected to the cover plate (12); the bottom surface of the stroke platform (3) is an annular surface, the ball screw bearing (4) passes through the center hole of the annular surface and is fixedly connected to the bottom surface of the stroke platform (3); when the stroke platform 3 moves vertically, the screw (5) rotates relative to the ball screw bearing (4); The Halbach magnetic array comprises an inner shell (6), a coil (16) and an outer shell (8); the inner shell (6) is uniformly formed with a plurality of grooves in the circumferential direction for accommodating the first arc-shaped magnet (7); the outer shell (8) is uniformly formed with a plurality of grooves in the circumferential direction for accommodating the second arc-shaped magnet (9); the number of grooves on the inner shell (6) and the outer shell (8) is the same; the coil (16) is arranged in close contact with the inner wall of the outer shell (8) and forms a gap with the outer wall of the inner shell (6); The lower part of the screw rod (5) passes through the central hole of the inner shell (6), and the two are fixedly connected so that the inner shell (6) can rotate synchronously with the screw rod (5); The lower end of the screw rod (5) is rotatably connected to a bearing installed in a support platform (10) to ensure the rotation of the screw rod (5); the support platform (10) is fixedly mounted on the base (11), and the lower part of the housing (8) is embedded in a groove reserved on the base (11) to achieve fixation.

2. The load adaptive vibration isolator according to claim 1, characterized in that: The number of the first arc-shaped magnets and the second arc-shaped magnets is the same and is a multiple of 4, and each group of 4 arc-shaped magnets corresponds to a low stiffness or quasi-zero stiffness interval.

3. The load adaptive vibration isolator according to claim 1, characterized in that: In the initial state, the distance between the top of the screw rod (5) and the lower surface of the top surface of the stroke platform (3) is 1 to 2 cm.

4. The load adaptive vibration isolator according to claim 1, characterized in that: The negative stiffness structure (2) has a height of 28-32 cm and a width of 10-14 cm.

5. The load adaptive vibration isolator according to claim 1, characterized in that: The inner shell (6) is connected to the screw rod (5) by mortise and tenon joints.

6. The load adaptive vibration isolator according to claim 1, characterized in that: The inner shell and the outer shell are made of aluminum alloy or plastic.

7. A floating plate track, characterized in that: It comprises a track (21), a track fastener (22), a floating plate (23), and the load-adaptive vibration isolator according to any one of claims 1 to 4, wherein a plurality of load-adaptive vibration isolators are arranged at intervals on both sides of the floating plate (23) along the line direction.

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