Quasi-zero stiffness vibration isolator based on bounded magnetic constant force

Abstract

A quasi-zero stiffness vibration isolator based on bounded magnetic constant force comprises a rack, a magnetic shaft fixedly arranged in parallel on the rack, a slide rail with a slide block, and a sleeve and a retainer which are sequentially sleeved on the magnetic shaft, wherein the retainer is fixedly connected with the slide block, the sleeve is in non-contact with the magnetic shaft, and corresponding repulsive permanent magnet groups are arranged on both sides of the slide block and positions opposite to end faces of the rack to form a mechanical boundary. The quasi-zero stiffness vibration isolator has a compact structure form and stable vibration isolation effect while realizing high static stiffness and low dynamic stiffness.

Description

Technical Field

[0001] This invention relates to a technology in the field of vibration control, specifically a quasi-zero stiffness vibration isolator based on bounded magnetic constant force. Background Technology

[0002] Existing quasi-zero stiffness technology often achieves this by superimposing positive and negative stiffness. Since this design requires the simultaneous introduction of positive and negative stiffness elements, its assembly structure is usually complex and its operating conditions are relatively harsh. In addition, the parallel arrangement of positive and negative stiffness elements occupies most of the space in the vibration isolator. When the vibration isolation system is miniaturized, the positive and negative stiffness elements are prone to changes in assembly position and constraint failure during deformation, which seriously affects the vibration isolation performance. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies that cannot achieve quasi-zero stiffness and thus vibration isolation through a single structure, as well as the problem that vibration isolators that rely on material deformation to provide restoring force cannot avoid material fatigue failure. It proposes a quasi-zero stiffness vibration isolator based on bounded magnetic constant force, which achieves high static stiffness and low dynamic stiffness while having a compact structural form and stable vibration isolation effect.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to a quasi-zero stiffness vibration isolator based on bounded magnetic constant force, comprising: a frame, a magnetic shaft fixedly arranged in parallel thereon, a slide rail with a slider, and a sleeve and a retainer sequentially sleeved on the magnetic shaft, wherein: the retainer is fixedly connected to the slider, the sleeve is not in contact with the magnetic shaft, and corresponding mutually repulsive permanent magnet groups are provided on both sides of the slider and at the position of the opposite end face of the frame to form a mechanical boundary.

[0006] Technical effect

[0007] This invention achieves constant force by inducing magnetic field distortion through magnetic shaft friction caused by a sleeve; it utilizes mutually repulsive permanent magnets to form a mechanical boundary, limiting the range of the constant force; the constant force is coupled with the mechanical boundary, resulting in high static stiffness and low dynamic stiffness. Compared with existing quasi-zero stiffness vibration isolators, it eliminates the need for positive and negative stiffness elements, avoiding the failure risks caused by complex assembly and the superposition of positive and negative stiffness; this technology does not rely on the deformation of elastic elements to generate load-bearing capacity and restoring force, thus avoiding material fatigue failure. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of the present invention;

[0009] Figure 2 This is an exploded view of the components of the present invention;

[0010] Figure 3 This is a schematic cross-sectional view of the magnetic shaft structure;

[0011] Figure 4 This is a schematic diagram of the cage structure of the magnetic constant force mechanism;

[0012] In the diagram: 1. Frame; 2. Mutually exclusive permanent magnet; 3. Magnetic shaft; 4. Sleeve; 5. Cage; 6. Slide rail; 7. Slider; 8. Mounting slot; 9. Mounting hole.

[0013] Figure 5 This is a schematic diagram of the vibration isolation performance test scheme;

[0014] Figure 6 Performance test diagram for quasi-zero stiffness vibration isolators;

[0015] In the figure: 1) Time domain results of the 2-20Hz frequency sweep test; 2) Frequency domain results of the 2-20Hz frequency sweep test;

[0016] Figure 7 Force-displacement test curves for magnetic constant force mechanisms and vibration isolators;

[0017] In the figure: 1) Force-displacement curve between the sleeve and the radially magnetized magnetic shaft; 2) Force-displacement curve of the vibration isolator under the coupling effect of constant magnetic force and repulsive magnets. Detailed Implementation

[0018] like Figures 1-4 As shown, this embodiment relates to a quasi-zero stiffness vibration isolator based on constant force rather than the superposition of positive and negative stiffness, including: a frame 1, a magnetic shaft 3 fixedly arranged in parallel on it, a slide rail 6 with a slider 7, and a sleeve 4 and a retainer 5 sequentially sleeved on the magnetic shaft 3, wherein: the retainer 5 is fixedly connected to the slider 7, the sleeve 4 has no contact with the magnetic shaft 3, and corresponding mutually repulsive permanent magnet groups 2 are provided on both sides of the slider 7 and at the position facing the frame 1 to form a mechanical boundary.

[0019] like Figure 3 As shown, the magnetic shaft 3 is a cylindrical structure, including a magnetized part and a non-magnetized part, which together form a magnetic shaft.

[0020] The magnetized portion is magnetized radially, and its magnetic field distribution characteristics are that the two ends of the magnetic axis are non-uniform, while the center of the magnetic axis is uniform.

[0021] The unmagnetized portion is made of a non-ferrous metal with no magnetic permeability, preferably aluminum, and its function is to provide guidance and constraint.

[0022] The magnetic shaft is encased in an aluminum shell.

[0023] The sleeve 4 is a hollow cylindrical structure with an inner diameter larger than the outer diameter of the magnetic shaft. When the sleeve approaches the magnetic shaft along the axial direction, the magnetic lines of force of the magnetic shaft preferentially pass through the sleeve, which will cause the magnetic field of the magnetic shaft to be distorted. Specifically, the uniform magnetic field in the center of the magnetic shaft will be distorted into a non-uniform magnetic field.

[0024] The sleeve is made of a highly magnetically permeable material, preferably soft iron.

[0025] The retainer 5 is a symmetrical structure with a mounting groove 8 for fixing the sleeve 4 and a mounting hole 9 for fixing the vibration-isolated mass. When the sleeve 4 and the retainer 5 move along the magnetic axis 3, the distance between the mutually repulsive permanent magnets 2 changes simultaneously.

[0026] like Figure 5 As shown, this embodiment illustrates a vibration isolation experimental method based on the aforementioned vibration isolator. A computer-controlled vibration controller generates a sweep frequency signal with an amplitude of 1.5 mm and a frequency range of 2-20 Hz. The sweep frequency signal is amplified by a power amplifier and then drives the vibration table to move. The vibration isolator is installed on the vibration table, and the vibration signals of the isolated mass and the vibration table are measured by an accelerometer and transmitted to the vibration controller as negative feedback. A data acquisition unit collects the accelerometer signals in real time and saves them in a computer.

[0027] When the load mass is set to 1.2 kg, the vibration excitation amplitude is 1.5 mm, and the frequency sweep test is performed from 2 to 20 Hz, the time-domain results of the vibration test are as follows: Figure 6 As shown in (a), the vibration response is much lower than the vibration excitation as the frequency increases; the frequency domain results of the vibration test are as follows. Figure 6 As shown in (b), the vibration isolator has an initial vibration isolation frequency of 3.6 Hz and has a wide frequency isolation effect.

[0028] like Figure 7 As shown, the static test results of the vibration isolator are as follows. As can be seen from the figure, the magnetic constant force mechanism composed of sleeve 4 and magnetic shaft 3 has significant constant force characteristics, and the magnitude of the magnetic constant force is 14.5 N. After the magnetic constant force mechanism is coupled with the mutually repulsive permanent magnet 2, the vibration isolator forms a force-displacement curve with mechanical boundaries, and has significant high static and low dynamic characteristics.

[0029] Compared with existing technologies, this device does not rely on the superposition of positive and negative stiffness and material deformation. It uses non-contact magnetic force to realize the design of a quasi-zero stiffness vibration isolator, which has good broadband vibration isolation capability.

[0030] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A quasi-zero stiffness vibration isolator based on bounded magnetic constant force, characterized in that, include: The frame, the magnetic shaft and the slide rail with the slider are fixedly mounted on it, and the sleeve and the retainer are sequentially sleeved on the magnetic shaft. The retainer is fixedly connected to the slider, the sleeve is not in contact with the magnetic shaft, and the slider is provided with corresponding mutually repulsive permanent magnet groups on both sides and the opposite end face of the frame to form a mechanical boundary. The magnetic shaft is a cylindrical structure, consisting of a magnetized part and a non-magnetized part, which together form a magnetic shaft. The magnetized portion is magnetized radially, and its magnetic field distribution characteristics are that the two ends of the magnetic axis are non-uniform, while the center of the magnetic axis is uniform. The unmagnetized portion is made of a non-ferrous metal with no magnetic permeability and is used to provide guidance and constraint; The sleeve is a hollow cylindrical structure with an inner diameter larger than the outer diameter of the magnetic shaft. When the sleeve approaches the magnetic shaft along the axial direction, the magnetic lines of force of the magnetic shaft preferentially pass through the sleeve, which will cause the magnetic field of the magnetic shaft to be distorted. Specifically, the uniform magnetic field in the center of the magnetic shaft will be distorted into a non-uniform magnetic field. The cage is a symmetrical structure with a mounting groove for fixing the sleeve and mounting holes for fixing the vibration-isolated mass. When the sleeve and the cage move along the magnetic axis, the spacing between the mutually repulsive permanent magnets changes simultaneously.

2. The quasi-zero stiffness vibration isolator based on bounded magnetic constant force according to claim 1, characterized in that, The sleeve is made of a highly magnetically permeable material.

3. A quasi-zero stiffness vibration isolation experimental method based on the vibration isolator according to claim 1 or 2, characterized in that, The computer-controlled vibration controller generates a sweep frequency signal, which is amplified by a power amplifier to drive the vibration table. A quasi-zero stiffness isolator is installed on the vibration table, and the vibration signals of the isolated mass and the vibration table are measured by an accelerometer and transmitted to the vibration controller as negative feedback. The accelerometer signal is then collected in real time by a data acquisition device and stored in the computer.

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