Beam-column support quasi-zero stiffness vibration isolation device

Abstract

The application discloses a bunching cantilever support quasi-zero stiffness vibration isolation device, which comprises a base, a linear motion assembly, a negative stiffness structure assembly and a positive stiffness structure assembly, wherein the linear motion assembly is vertically arranged on the base, and a negative stiffness structure with a single stable negative stiffness and a positive stiffness structure with a nonlinear gradually hardening positive stiffness are arranged in series on the linear motion assembly. The application adopts a bunching cantilever structure to provide a single stable negative stiffness, repulsion magnets to provide a nonlinear positive stiffness, and utilizes the nonlinear positive stiffness to modulate the single stable negative stiffness to achieve quasi-zero stiffness. The design of the vibration isolator does not depend on a double stable negative stiffness structure and a strictly linear stiffness structure. The nonlinear positive stiffness is adjustable. When the negative stiffness changes, the quasi-zero stiffness can still be achieved by adjusting the nonlinear positive stiffness structure. The load is borne by the negative stiffness structure and the positive stiffness structure together, and the rated load of the vibration isolation device can be changed by adjusting the initial configuration of the negative stiffness structure and the positive stiffness structure.

Description

Technical Field

[0001] This invention relates to a technology in the field of vibration isolation, specifically a cantilever support quasi-zero stiffness vibration isolation device. Background Technology

[0002] Existing vibration isolators use linear springs as load-bearing elements, and their vibration isolation initiation frequency is... Low-frequency vibrations are often several times their natural frequency. While using soft springs can lower the natural frequency of a vibration isolator, it can cause large static deformation, making it difficult for existing linear vibration isolators to effectively isolate low-frequency vibrations. Quasi-zero stiffness vibration isolators use nonlinear stiffness elements to support the load. The nonlinearity of stiffness allows quasi-zero stiffness isolators to simultaneously possess high static stiffness and low dynamic stiffness, thus achieving a balance between high load-bearing capacity and low natural frequency. Existing quasi-zero stiffness vibration isolators typically utilize bistable negative stiffness to offset linear positive stiffness to achieve quasi-zero stiffness. Typical bistable negative stiffness structures include: inclined spring structures, attractive or repulsive magnets, Euler buckling beams, convex-roller structures, etc. The design requirements for a quasi-zero stiffness isolator, which connects a bistable negative stiffness structure in parallel with a linear spring, are highly demanding, depending on both the bistable negative stiffness structure and the strictly linear stiffness structure. If the negative stiffness of the negative stiffness structure changes due to assembly issues, fatigue, or wear, the quasi-zero stiffness characteristic disappears, requiring replacement of the linear spring and re-matching of the negative stiffness structure to restore it. The load is borne by the linear spring, and the rated load of the quasi-zero stiffness isolator can be changed by adjusting the compression of the linear spring; however, this rated load adjustment method has the disadvantage of a narrow adjustment range. Existing technologies for achieving quasi-zero stiffness isolation using cantilever plates cannot adjust the stiffness of their linear stiffness mechanism, making it difficult to adjust the matching range. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, this invention proposes a cantilever-supported quasi-zero stiffness vibration isolation device. It employs a cantilever structure to provide monostable negative stiffness and a repulsive magnet to provide nonlinear positive stiffness. Quasi-zero stiffness is achieved by modulating the monostable negative stiffness with the nonlinear positive stiffness. The design of the isolator does not rely on a bistable negative stiffness structure or a strictly linear stiffness structure. The nonlinear positive stiffness is adjustable; when the negative stiffness changes, quasi-zero stiffness can still be achieved by adjusting the nonlinear positive stiffness structure without replacing components. The load is shared by both the negative and positive stiffness structures, and the rated load of the vibration isolation device can be changed by adjusting the initial configuration of the negative and positive stiffness structures. Compared to existing quasi-zero stiffness vibration isolators that rely on bistable negative stiffness structures and strictly linear stiffness structures, this invention offers a wider load adjustment range and a more compact structure.

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

[0005] This invention relates to a cantilever support quasi-zero stiffness vibration isolation device, comprising: a base, a linear motion component, a negative stiffness structure component, and a positive stiffness structure component, wherein: the linear motion component is vertically mounted on the base, and the negative stiffness structure having monostable negative stiffness and the positive stiffness structure having nonlinear gradually hardening positive stiffness are connected in series on the linear motion component.

[0006] The linear motion component includes a guide rod, a linear bearing, and a bearing housing. One end of the guide rod is connected to the base via a thread, and the other end is connected to the linear bearing via a spline. Under the constraint of the guide rod, the bearing housing can only move linearly and cannot rotate around itself.

[0007] The linear bearing is a splined linear bearing, and the spline shape matches the guide rod.

[0008] The bearing housing has a central hole, and the linear bearing is embedded in the bearing housing to form an interference fit.

[0009] The negative stiffness component includes: a cantilever beam, a ball bearing, a variable diameter protrusion, and a clamping block. The variable diameter protrusion is sleeved on the bottom end of the linear motion component. The cantilever beam is clustered and arrayed. One end is fixed to the top end of the linear motion component by the clamping block. The other end is provided with a ball bearing and contacts the variable diameter protrusion. The radius of the protrusion can be changed by rotating the variable diameter protrusion, thereby adjusting the negative stiffness.

[0010] The positive stiffness component includes: 6 auxiliary permanent magnets, 1 main permanent magnet, and a sleeve. The auxiliary permanent magnets are interference-fitted into the bearing housing. The main permanent magnet is sleeved on the guide rod through the sleeve. The height of the main permanent magnet from the base is adjusted by the limiting nut, which can change the repulsive force between the auxiliary permanent magnets and the main permanent magnet, thereby adjusting the positive stiffness.

[0011] The aforementioned quasi-zero stiffness vibration isolation refers to: rotating the variable diameter convex body to change the convex body radius to generate negative stiffness in the negative stiffness component, or adjusting the limit nut to change the repulsive force between the permanent magnets to adjust the positive stiffness so as to match the negative stiffness, using nonlinear positive stiffness to modulate the monostable negative stiffness to achieve quasi-zero stiffness, and adjusting the rated load of the quasi-zero stiffness vibration isolator.

[0012] Technical effect

[0013] This invention utilizes a repulsive magnet to modulate the monostable negative stiffness provided by a cantilever structure, achieving a quasi-zero stiffness vibration isolator design. This breaks free from the constraints of bistable negative stiffness structures and strictly linear stiffness structures on existing quasi-zero stiffness vibration isolator designs, resulting in a more flexible design and a more compact structure. The nonlinear positive stiffness structure has adjustable stiffness, enabling the matching of different negative stiffnesses to achieve quasi-zero stiffness without replacing components, making operation convenient and highly reliable. The rated load of the vibration isolator is shared by the negative stiffness structure and the positive stiffness structure, and the rated load can be varied by adjusting the configuration of the negative stiffness structure and the positive stiffness structure. The adjustable range of the rated load is larger than that of existing quasi-zero stiffness vibration isolators. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the quasi-zero stiffness vibration isolation device of the present invention;

[0015] Figure 2 This is a schematic diagram of the assembly of the cantilever structure and the second permanent magnet.

[0016] Figure 3 This invention does not include Figure 2 Assembly diagram of some structures;

[0017] Figure 4 This is a top sectional view of the variable diameter convex body;

[0018] Figure 5 Force-displacement curves of the quasi-zero stiffness vibration isolation device, positive stiffness component, and negative stiffness component of the present invention;

[0019] Figure 6 This is a force-displacement relationship diagram of the positive stiffness component of the present invention under different heights of the large permanent magnets;

[0020] Figure 7 This is a force-displacement relationship diagram of the negative stiffness component of the present invention under different rotation angles of the variable diameter protrusions;

[0021] Figure 8 This is a comparison diagram of the rated load adjustment range between the quasi-zero stiffness vibration isolation device of the present invention and existing quasi-zero stiffness realization methods;

[0022] In the diagram: 1. Base, 2. Variable diameter protrusion, 3. First nut, 4. Cantilever beam, 5. Bearing seat, 6. Clamping block, 7. First bolt, 8. Guide rod, 9. Second nut, 10. Second permanent magnet, 11. Ball bearing, 12. Spline bearing, 13. Third nut, 14. Sleeve, 15. First permanent magnet, 16. Fourth nut, 17. Fifth nut, 18. Linear bearing. Detailed Implementation

[0023] like Figures 1-3As shown in the figure, this embodiment relates to a cantilever support quasi-zero stiffness vibration isolation device, including: a base 1, a linear motion component, a negative stiffness structure component, and a positive stiffness structure component, wherein: the linear motion component is vertically arranged on the base 1, and the negative stiffness structure with monostable negative stiffness and the positive stiffness structure with nonlinear gradually hardening positive stiffness are connected in series on the linear motion component.

[0024] The linear motion assembly includes a guide rod 8 and a linear bearing 18 and a bearing housing 5 disposed thereon, wherein the linear bearing 18 and the bearing housing 5 are fixedly connected.

[0025] The bearing housing 5 is provided with a central hole for embedding the linear bearing 18 and forming an interference fit; the bearing housing 5 can only move linearly and cannot rotate around itself under the constraint of the guide rod 8.

[0026] The guide rod 8 has a thread at one end for connecting to the base 1, and a spline at the other end for fitting the linear bearing 18.

[0027] The linear bearing 18 is preferably a splined linear bearing 18, the spline shape of which matches the guide rod 8.

[0028] The negative stiffness component includes: a cantilever beam 4, a ball bearing 11, a variable diameter protrusion 2, and a clamping block 6, wherein: the variable diameter protrusion 2 is sleeved on the bottom end of the linear motion component, one end of the cantilever beam 4 is fixedly set on the top end of the linear motion component by the clamping block 6, and the other end is provided with a ball bearing 11 and in contact with the variable diameter protrusion 2, and the negative stiffness is adjusted by rotating the variable diameter protrusion 2.

[0029] Preferably, there are three cantilever beams 4, which are evenly distributed around the bearing seat 5 in a circumferential direction.

[0030] The ball bearing 11 can roll along the surface of the variable diameter protrusion 2.

[0031] like Figure 4 As shown, the variable diameter protrusion 2 has an outer surface that gradually increases in distance from the central axis along the circumferential direction, and a through hole is provided in the center for nesting the linear bearing 18, which is fitted with the guide rod 8.

[0032] The guide rod 8 is provided with a nut for pressing the variable diameter protrusion 2 against the upper surface of the base 1. When the nut is loosened, the variable diameter protrusion 2 can be rotated and adjusted to change the radius at the contact position between the protrusion and the ball bearing 11, thereby adjusting the negative stiffness.

[0033] The positive stiffness component includes: a first permanent magnet 15, six second permanent magnets 10, and a sleeve 14, wherein: the first permanent magnet 15 is movably mounted on the linear motion component via the sleeve 14, and the second permanent magnets 10 are fixedly mounted on one end of the linear motion component.

[0034] The second permanent magnet 10 is specifically disposed on the bottom surface of the bearing seat 5, and has countersunk holes distributed in a circumferential array. The second permanent magnet 10 is interference-fitted into the countersunk holes.

[0035] The first permanent magnet 15 is provided with a central hole for embedding the sleeve 14, and the sleeve 14 is provided with threads to be screwed onto the guide rod 8.

[0036] The guide rod 8 is provided with a limiting nut for limiting the position of the first permanent magnet 15. Adjusting the limiting nut changes the height of the first permanent magnet 15 from the base 1, which can change the repulsive force between the second permanent magnet 10 and the first permanent magnet 15 and adjust the positive stiffness.

[0037] Except for the second permanent magnet 10 and the first permanent magnet 15, the components of the vibration isolation device are preferably made of low magnetic permeability materials.

[0038] like Figure 5 As shown, the negative stiffness component can provide monostable negative stiffness, and the positive stiffness component can provide nonlinear gradually hardening positive stiffness. The load of the quasi-zero stiffness vibration isolation device is borne jointly by the negative stiffness structure and the positive stiffness structure.

[0039] like Figure 6 As shown, the quasi-zero stiffness vibration isolation device can adjust its positive stiffness by changing the position of the first permanent magnet 15.

[0040] like Figure 7 As shown, the quasi-zero stiffness vibration isolation device can change its negative stiffness by rotating the variable diameter protrusion 2.

[0041] like Figure 8 As shown, the quasi-zero stiffness vibration isolation device can adjust the positive stiffness by adjusting the position of the first permanent magnet 15 and change the negative stiffness by rotating the variable diameter protrusion 2, thereby achieving rated load adjustment.

[0042] like Figure 8 As shown, compared to existing quasi-zero stiffness vibration isolators that design a bistable negative stiffness structure in parallel with a linear spring, the vibration isolation device described above uses a nonlinear gradually hardening positive stiffness component to modulate a single negative stiffness structure component to achieve quasi-zero stiffness. It does not depend on a bistable negative stiffness structure or a strictly linear stiffness structure, and its design is flexible with a wide rated load adjustment range.

[0043] Compared with the prior art, the present invention utilizes the repulsive force between the first permanent magnet 15 and the second permanent magnet 10 to provide nonlinear gradually hardening positive stiffness, and uses the variable diameter protrusion 2 to support and concentrate the cantilever beam 4 to provide monostable negative stiffness, thus realizing a quasi-zero stiffness vibration isolator that does not rely on a bistable negative stiffness structure, making the design more flexible. The nonlinear positive stiffness provided by the first permanent magnet 15 and the second permanent magnet 10 is adjustable. When the negative stiffness provided by the negative stiffness structure changes due to assembly, structural fatigue, or other issues, quasi-zero stiffness vibration isolation can still be achieved without replacing any components, making operation convenient and highly reliable. The rated load of the vibration isolation device is jointly borne by the negative stiffness structure and the positive stiffness structure. The rated load can be changed by adjusting the position of the first permanent magnet 15 and the rotation angle of the variable diameter protrusion 2. The adjustable range of the rated load is larger than that of existing quasi-zero stiffness vibration isolators.

[0044] 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 bundle of cantilevered support quasi-zero stiffness vibration isolation devices characterized in that, The application relates to a quasi-zero stiffness vibration isolator. The linear motion assembly comprises a guide rod, a linear bearing and a bearing seat, wherein one end of the guide rod is connected with the base through screw threads, the other end is connected with the linear bearing through a spline, and the bearing seat can only move linearly under the constraint of the guide rod and cannot rotate around itself. The negative stiffness structure assembly comprises a cantilever beam, a ball bearing, a variable-diameter convex body and a clamping block, wherein the variable-diameter convex body is sleeved at the bottom end of the linear motion assembly, the cantilever beams are distributed in an array, one end is fixedly arranged at the top end of the linear motion assembly through the clamping block, the other end is provided with the ball bearing and is in contact with the variable-diameter convex body, the radius of the convex body can be changed by rotating the variable-diameter convex body, so that the negative stiffness can be adjusted. The linear bearing is a linear bearing with a spline, and the shape of the spline is matched with the guide rod.

2. The cantilevered quasi-zero stiffness vibration isolation device according to claim 1, characterized in that, The bearing seat is provided with a central hole, and the linear bearing is embedded in the bearing seat to form an interference fit.

3. The beam-plated cantilevered support quasi-zero stiffness vibration isolation device of claim 1, wherein, The variable-diameter convex body gradually increases in distance from the outer surface to the central axis in the circumferential direction, is provided with a through hole in the center for nesting the linear bearing, and is sleeved with the guide rod.

4. The beam-plated cantilevered support quasi-zero stiffness vibration isolation device of claim 1, wherein, The positive stiffness structure assembly comprises six auxiliary permanent magnet bodies, one main permanent magnet body and a sleeve, wherein the auxiliary permanent magnet bodies are embedded in the bearing seat with interference, the main permanent magnet body is sleeved on the guide rod through the sleeve and is adjusted in height from the base through a limiting nut, the repulsive force between the auxiliary permanent magnet bodies and the main permanent magnet body can be changed, and the positive stiffness can be adjusted.

5. The beam-plated cantilevered support quasi-zero stiffness vibration isolation device of claim 1, wherein, The guide rod is provided with a nut for pressing the variable-diameter convex body on the upper surface of the base, when the nut is loosened, the variable-diameter convex body can be adjusted in rotation, the radius at the contact position of the convex body and the ball bearing is changed, and the negative stiffness is adjusted.

6. The beam-plated cantilevered support quasi-zero stiffness vibration isolation device of claim 5, wherein, The quasi-zero stiffness vibration isolation refers to that the variable-diameter convex body changes the radius of the convex body to make the negative stiffness structure assembly generate negative stiffness or adjust the limiting nut to change the repulsive force between the permanent magnet bodies to adjust the positive stiffness, so that the positive stiffness matches the negative stiffness, the quasi-zero stiffness is realized by modulating the monostable negative stiffness with the nonlinear positive stiffness, and the rated load of the quasi-zero stiffness vibration isolator is adjusted.

7. The beam-plated cantilevered support quasi-zero stiffness vibration isolation device of claim 6, wherein, ​

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