A semi-active quasi-zero stiffness vibration isolation device based on end force

Abstract

The present application relates to the field of vibration isolation technology, and in particular to a semi-active quasi-zero stiffness vibration isolation device based on end force, comprising a base; a vibration isolation seat arranged relative to the base; a negative stiffness mechanism comprising a first cylindrical structure, a first inner magnetic yoke column, a first outer ring permanent magnet and a first outer magnetic yoke cylinder, one end of the first outer magnetic yoke cylinder being fixedly connected to the vibration isolation seat, the first cylindrical structure being arranged in the first outer magnetic yoke cylinder, the first inner magnetic yoke column being passed through the interior of the first cylindrical structure, the first cylindrical structure comprising an inner magnetic ring frame, a first inner ring permanent magnet and a second inner ring permanent magnet, the first inner ring permanent magnet and the second inner ring permanent magnet being arranged on the inner magnetic ring frame; a voice coil motor mounted on the base, the voice coil motor being connected to the first inner magnetic yoke column; an end plate being fixedly connected to the other end of the first inner magnetic yoke column; and a positive stiffness mechanism being arranged between the end plate and the base. The first inner magnetic yoke column and the first outer magnetic yoke cylinder can effectively reduce magnetic leakage and improve the load capacity of the vibration isolation device.

Description

Technical Field

[0001] The present application relates to the field of vibration isolation technology, and in particular to a semi-active quasi-zero stiffness vibration isolation device based on end force. Background Art

[0002] Vibration isolation technology plays a vital role in modern engineering, widely used for vibration control in precision instruments, mechanical equipment, and building structures. While traditional passive vibration isolation systems offer simple structures and high reliability, their performance is limited by their natural frequency, making it difficult to achieve effective isolation at low frequencies. To overcome this limitation, quasi-zero-stiffness vibration isolation systems have emerged.

[0003] The core principle of a quasi-zero-stiffness vibration isolation system is to achieve extremely low dynamic stiffness near the equilibrium position through the mutual balance of positive and negative stiffness, thereby significantly reducing the system's natural frequency and expanding the vibration isolation frequency band. Currently, negative stiffness mechanisms mainly include magnetic negative stiffness mechanisms such as canted springs, magnetic springs, and pneumatic springs. Magnetic negative stiffness mechanisms typically use permanent magnets to generate negative stiffness. However, existing magnetic negative stiffness mechanisms suffer from severe magnetic flux leakage and low magnetic flux utilization, resulting in significant waste of magnetic field energy and poor load capacity of the entire vibration isolation system. Summary of the Invention

[0004] The present application aims to address, at least to a certain extent, one of the aforementioned technical problems in the prior art. To this end, the present application provides a semi-active, quasi-zero-stiffness vibration isolation device based on end force, which effectively addresses the problems of severe magnetic flux leakage and low magnetic flux utilization in the prior art, significantly improving vibration isolation performance and load capacity.

[0005] A semi-active quasi-zero stiffness vibration isolation device based on end force, comprising:

[0006] base;

[0007] a vibration isolation seat, arranged relative to and spaced from the base;

[0008] A negative stiffness mechanism is provided between the base and the vibration isolation seat, the negative stiffness mechanism includes a first cylindrical structure, a first inner magnetic yoke column, a first outer ring permanent magnet and a first outer magnetic yoke cylinder, one end of the first outer magnetic yoke cylinder is fixedly connected to the vibration isolation seat, the first cylindrical structure is provided inside the first outer magnetic yoke cylinder, the first inner magnetic yoke column is passed through the interior of the first cylindrical structure, the two ends of the first inner magnetic yoke column extend from the two ends of the first cylindrical structure, the first cylindrical structure includes an inner magnetic ring frame, a first inner ring permanent magnet and a second inner ring permanent magnet with opposite magnetization directions, the first inner ring permanent magnet and the second inner ring permanent magnet are parallel to the axial direction of the first outer magnetic yoke cylinder and are spaced apart on the inner magnetic ring frame, The first outer ring permanent magnet is arranged inside the first outer magnetic yoke tube and is concentric with the first outer magnetic yoke tube. The first outer ring permanent magnet and the first inner ring permanent magnet at least partially overlap in the radial direction of the first outer magnetic yoke tube. The first outer ring permanent magnet and the second inner ring permanent magnet are spaced apart in the axial direction of the first outer magnetic yoke tube. The magnetic properties of the first outer ring permanent magnet and the first inner ring permanent magnet are opposite, and the magnetic properties of the first outer ring permanent magnet and the second inner ring permanent magnet are the same. There is a movable gap between the inner wall of the first outer ring permanent magnet and the outer wall of the first cylindrical structure. The first inner magnetic yoke column and the first outer magnetic yoke tube form a closed magnetic circuit for the first inner ring permanent magnet and the second inner ring permanent magnet.

[0009] A voice coil motor is mounted on the base, and the voice coil motor is connected to one end of the first inner magnetic yoke column;

[0010] an end plate, the end plate being fixedly connected to the other end of the first inner magnetic yoke column, and the end plate being arranged relative to the base with a spacing therebetween;

[0011] A positive stiffness mechanism is provided between the end plate and the base.

[0012] In an optional or preferred embodiment, the voice coil motor comprises:

[0013] a second outer magnetic yoke tube, one end of the second outer magnetic yoke tube being connected to an end of the first outer magnetic yoke tube away from the vibration isolation seat;

[0014] a second cylindrical structure disposed inside the second outer magnetic yoke cylinder, the second cylindrical structure comprising a coil frame and two coils with opposite winding directions, the coil frame being disposed inside the second outer magnetic yoke cylinder and fixedly connected to the base, the two coils being arranged parallel to and spaced apart from each other on the coil frame along the axial direction of the second outer magnetic yoke cylinder;

[0015] a second inner magnetic yoke column, which is inserted into the interior of the second cylindrical structure, with two ends of the second inner magnetic yoke column extending from two ends of the second cylindrical structure, one end of the second inner magnetic yoke column being fixedly connected to the base, and the other end being connected to the first inner magnetic yoke column;

[0016] Two second outer ring permanent magnets with opposite magnetic properties are arranged inside the second outer magnetic yoke tube and remain concentric with the second outer magnetic yoke tube. The two second outer ring permanent magnets are arranged parallel and spaced along the axial direction of the second outer magnetic yoke tube. The two second outer ring permanent magnets are respectively aligned with the two coils along the radial direction of the second outer magnetic yoke tube. There is a movable gap between the inner wall of the two second outer ring permanent magnets and the outer wall of the second cylinder structure.

[0017] In an optional or preferred embodiment, the inner diameter and outer diameter of the second outer magnetic yoke cylinder are the same as the inner diameter and outer diameter of the first outer magnetic yoke cylinder, and the second outer magnetic yoke cylinder is integrally connected to the first outer magnetic yoke cylinder.

[0018] In an optional or preferred embodiment, the second inner magnetic yoke column is connected to the first inner magnetic yoke column via a magnetic isolation block, and a movable gap is provided between the outer wall of the magnetic isolation block and the inner walls of the first outer magnetic yoke tube and the second outer magnetic yoke tube that are integrally formed and connected.

[0019] In an optional or preferred embodiment, it also includes an outer magnetic ring frame with a cylindrical structure, and the outer magnetic ring frame is arranged inside the first outer magnetic yoke tube and the second outer magnetic yoke tube that are integrally connected. The outer magnetic ring frame remains coaxial with the first outer magnetic yoke tube and the second outer magnetic yoke tube that are integrally connected, and a first magnetic ring assembly groove and a second magnetic ring assembly groove are provided on the outer magnetic ring frame. The first outer ring permanent magnet is assembled in the first magnetic ring assembly groove, and the second magnetic ring assembly groove is provided with two layers, and two second outer ring permanent magnets are respectively assembled in the two layers of the second magnetic ring assembly groove.

[0020] In an optional or preferred embodiment, an avoidance hole is provided on the end plate, and a connecting leg is provided on the vibration isolation seat, and the connecting leg passes through the avoidance hole to connect the first outer magnetic yoke cylinder and the outer magnetic ring frame.

[0021] In an optional or preferred embodiment, three positive stiffness mechanisms are provided, and the three positive stiffness mechanisms are arranged circumferentially and spaced apart on the outer circumference of the first outer magnetic yoke tube and the second outer magnetic yoke tube that are integrally connected. The positive stiffness mechanism includes a first support rod, a second support rod, a third support rod, an outer compression spring sheet and an inner compression spring sheet. The first support rod is parallel to the second support rod and is arranged at intervals. The same end of the first support rod and the second support rod is connected by the outer compression spring sheet. The third support rod is provided between the first support rod and the second support rod and is parallel to the first support rod and the second support rod. The third support rod is fixed to the outer wall of the first outer magnetic yoke tube and the second outer magnetic yoke tube that are integrally connected through a connecting block. The inner compression spring sheet is provided at both ends of the third support rod, and the two ends of the inner compression spring sheet are respectively connected to the first support rod and the second support rod, and the inner compression spring sheet is parallel to the outer compression spring sheet. The outer compression spring sheets on the first support rod and the second support rod near the end plate are connected to the end plate, and the outer compression spring sheets on the first support rod and the second support rod near the base are connected to the base.

[0022] In an optional or preferred embodiment, a first slot extending horizontally is provided on the end plate, one end of the first slot extends to the edge of the end plate to form a first opening, a first block is provided on the outer compression spring sheet on the positive stiffness mechanism near one end of the end plate, and the first block is inserted into the first slot through the first opening, and a second slot extending horizontally is provided on the base, one end of the second slot extends to the edge of the base to form a second opening, a second block is provided on the outer compression spring sheet on the positive stiffness mechanism near one end of the base, and the second block is inserted into the second slot through the second opening.

[0023] In an optional or preferred embodiment, a third magnetic ring assembly groove and a fourth magnetic ring assembly groove are provided on the inner magnetic ring frame, the first inner ring permanent magnet includes a plurality of first fan-shaped magnetic blocks, at least two of the first fan-shaped magnetic blocks are assembled in the third magnetic ring assembly groove, and each of the first fan-shaped magnetic blocks is assembled into the first inner ring permanent magnet in the third magnetic ring assembly groove, the second inner ring permanent magnet includes a plurality of second fan-shaped magnetic blocks, at least two of the second fan-shaped magnetic blocks are assembled in the fourth magnetic ring assembly groove, and each of the second fan-shaped magnetic blocks is assembled into the second inner ring permanent magnet in the fourth magnetic ring assembly groove, adjacent two of the first fan-shaped magnetic blocks in the third magnetic ring assembly groove are separated by a first partition, and the first partition is an integral structure with the inner magnetic ring frame, and adjacent two of the second fan-shaped magnetic blocks in the fourth magnetic ring assembly groove are separated by a second partition, and the second partition is an integral structure with the inner magnetic ring frame.

[0024] In an optional or preferred embodiment, each of the first outer ring permanent magnets includes a plurality of third sector-shaped magnetic blocks, each of the third sector-shaped magnetic blocks is assembled into the first outer ring permanent magnet in the first magnetic ring assembly groove, and two adjacent third sector-shaped magnetic blocks in the first magnetic ring assembly groove are separated by a third partition, and the third partition is an integral structure with the outer magnetic ring frame; each of the second outer ring permanent magnets includes a plurality of fourth sector-shaped magnetic blocks, each of the fourth sector-shaped magnetic blocks is assembled into the second outer ring permanent magnet in the second magnetic ring assembly groove, and two adjacent fourth sector-shaped magnetic blocks in the second magnetic ring assembly groove are separated by a fourth partition, and the fourth partition is an integral structure with the outer magnetic ring frame.

[0025] Based on the above technical solution, the embodiments of the present application have at least the following beneficial effects: the negative stiffness mechanism in the present application adopts the first inner magnetic yoke column and the first outer magnetic yoke cylinder to construct a closed loop of guiding magnetic force inside and outside the first inner ring permanent magnet and the second inner ring permanent magnet. The first inner magnetic yoke column and the first outer magnetic yoke cylinder can effectively reduce leakage magnetic field, and the magnetic flux utilization rate is significantly improved, which solves the problem of serious waste of magnetic field energy in the prior art, thereby effectively improving the load capacity of the entire vibration isolation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present application is further described below with reference to the accompanying drawings and embodiments;

[0027] Figure 1 1 is a schematic structural diagram of a semi-active quasi-zero stiffness vibration isolation device based on end force provided in one embodiment of the present application;

[0028] Figure 2 yes Figure 1 A schematic diagram of a portion of the structure of the illustrated embodiment;

[0029] Figure 3 yes Figure 1 A schematic diagram of the structure of the embodiment shown in FIG. 1 without the end plates and the positive stiffness mechanism;

[0030] Figure 4 yes Figure 1 a side cross-sectional view of the illustrated embodiment;

[0031] Figure 5 yes Figure 1 A partial structural cross-sectional view of the embodiment shown;

[0032] Figure 6 yes Figure 1 A schematic structural diagram of the outer magnetic ring frame in the embodiment shown;

[0033] Figure 7 yes Figure 1 A schematic diagram of the positional relationship between the negative stiffness mechanism, the voice coil motor, and the magnetic isolation block in the illustrated embodiment;

[0034] Figure 8 yes Figure 1 A schematic diagram of the positional relationship among the first inner magnetic yoke column, the inner magnetic ring frame, the first inner ring permanent magnet, and the second inner ring permanent magnet in the illustrated embodiment;

[0035] Figure 9 yes Figure 1 A schematic structural diagram of the positive stiffness mechanism in the illustrated embodiment;

[0036] Figure 10 yes Figure 1 A schematic diagram of the magnetization direction of the first inner ring permanent magnet in the illustrated embodiment;

[0037] Figure 11 yes Figure 1 A schematic diagram of the magnetization direction of the second inner ring permanent magnet in the illustrated embodiment;

[0038] Figure 12 This is a schematic diagram of the distribution of magnetic lines of force in the design of traditional vibration isolation devices;

[0039] Figure 13 Schematic diagram of the magnetic field line distribution of the first inner ring permanent magnet and the second inner ring permanent magnet in this application;

[0040] Figure 14 It is a schematic diagram and a curve diagram of the numerical analysis of the magnetic field distribution of the first inner ring permanent magnet and the second inner ring permanent magnet using finite element simulation technology in this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] 1-base; 2-vibration isolation seat; 3-negative stiffness mechanism; 4-voice coil motor; 5-end plate; 6-positive stiffness mechanism; 7-magnetic isolation block; 8-outer magnetic ring frame; 10-second slot; 11-second opening; 20-connecting leg; 30-first cylinder structure; 31-first inner yoke column; 32-first outer ring permanent magnet; 33-first outer yoke cylinder; 40-second outer yoke cylinder; 41-second cylinder structure; 42-second inner yoke column; 43-second outer ring permanent magnet; 50-first slot; 51-first opening; 52-avoidance hole; 60-first support rod; 61-second support rod; 62-third support rod; 63-outer pressure spring; 6 4-inner compression spring; 65-connecting block; 66-first clamping block; 67-second clamping block; 80-annular support step; 81-first magnetic ring assembly groove; 82-second magnetic ring assembly groove; 83-third partition; 84-fourth partition; 301-inner magnetic ring frame; 301a-third magnetic ring assembly groove; 301b-fourth magnetic ring assembly groove; 301c-first partition; 301d-second partition; 302-first inner ring permanent magnet; 302a-first sector-shaped magnetic block; 303-second inner ring permanent magnet; 303a-second sector-shaped magnetic block; 320-third sector-shaped magnetic block; 411-coil frame; 412-coil; 430-fourth sector-shaped magnetic block. DETAILED DESCRIPTION

[0043] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0044] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0046] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0047] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0048] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0049] Vibration isolation technology plays a vital role in modern engineering, widely used for vibration control in precision instruments, mechanical equipment, and building structures. While traditional passive vibration isolation systems offer simple structures and high reliability, their performance is limited by their natural frequency, making it difficult to achieve effective isolation at low frequencies. To overcome this limitation, quasi-zero-stiffness vibration isolation systems have emerged.

[0050] The core principle of a quasi-zero-stiffness vibration isolation system is to achieve extremely low dynamic stiffness near the equilibrium position through the mutual balance of positive and negative stiffness, thereby significantly reducing the system's natural frequency and expanding the vibration isolation frequency band. Currently, negative stiffness mechanisms mainly include magnetic negative stiffness mechanisms such as canted springs, magnetic springs, and pneumatic springs. Magnetic negative stiffness mechanisms typically use permanent magnets to generate negative stiffness. However, existing magnetic negative stiffness mechanisms suffer from severe magnetic flux leakage and low magnetic flux utilization, resulting in significant waste of magnetic field energy and poor load capacity of the entire vibration isolation system.

[0051] Reference Figures 1 to 9 The semi-active quasi-zero stiffness vibration isolation device based on end force of the present invention includes a base 1, a vibration isolation seat 2, a negative stiffness mechanism 3, a voice coil motor 4, an end plate 5 and a positive stiffness mechanism 6.

[0052] Base 1 is a circular structure that supports the entire vibration isolation device. It has multiple threaded holes for connecting and securing other components. Vibration isolation mount 2 is spaced relative to base 1 and features standardized mounting interfaces on its upper surface, allowing for easy connection to various precision equipment requiring vibration isolation.

[0053] The negative stiffness mechanism 3 is provided between the base 1 and the vibration isolation seat 2. The negative stiffness mechanism 3 includes a first cylindrical structure 30, a first inner magnetic yoke column 31, a first outer ring permanent magnet 32 ​​and a first outer magnetic yoke cylinder 33. The first cylindrical structure 30 is provided inside the first outer magnetic yoke cylinder 33. The first cylindrical structure 30 includes an inner magnetic ring frame 301, a first inner ring permanent magnet 302 and a second inner ring permanent magnet 303 with opposite magnetization directions. Figure 10 、 Figure 11 The magnetization direction of the first inner ring permanent magnet 302 is parallel to the radial outward, and the magnetization direction of the second inner ring permanent magnet 303 is parallel to the radial inward, so that the magnetic properties of the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303 are opposite. The advantage of this magnetization method is that it can achieve rapid magnetization.

[0054] The first inner ring permanent magnet 302 and the second inner ring permanent magnet 303 are arranged on the inner magnetic ring frame 301 in parallel and at intervals along the axial direction of the first outer magnetic yoke tube 33. The first inner ring permanent magnet 302, the second inner ring permanent magnet 303 and the inner magnetic ring frame 301 together constitute the first cylinder structure 30. The first inner magnetic yoke column 31 is arranged inside the first cylinder structure 30, and the two ends of the first inner magnetic yoke column 31 extend from the two ends of the first cylinder structure 30.

[0055] In some embodiments, the first inner magnetic yoke column 31 is tightly fitted with the first cylindrical structure 30, the first inner magnetic yoke column 31 and the first cylindrical structure 30 remain concentric, and the first cylindrical structure 30 and the first outer magnetic yoke cylinder 33 remain concentric, that is, the central axes of the first inner magnetic yoke column 31, the first cylindrical structure 30 and the first outer magnetic yoke cylinder 33 coincide.

[0056] One end of the first outer magnetic yoke tube 33 is fixedly connected to the vibration isolation seat 2. In some embodiments, a connecting leg 20 is provided on the vibration isolation seat 2, and the vibration isolation seat 2 is fixedly connected to the upper end surface of the first outer magnetic yoke tube 33 through the connecting leg 20 by bolts.

[0057] The first outer ring permanent magnet 32 ​​is arranged inside the first outer magnetic yoke tube 33 and remains concentric with the first outer magnetic yoke tube 33. The first outer ring permanent magnet 32 ​​and the first inner ring permanent magnet 302 at least partially overlap along the radial direction of the first outer magnetic yoke tube 33. The first outer ring permanent magnet 32 ​​and the second inner ring permanent magnet 303 are arranged at intervals along the axial direction of the first outer magnetic yoke tube 33.

[0058] In the embodiment shown in the present application, the first outer ring permanent magnet 32 ​​and the first inner ring permanent magnet 302 completely overlap along the radial direction of the first outer magnetic yoke tube 33, that is, the first inner ring permanent magnet 302 is located inside the first outer ring permanent magnet 32, and the second inner ring permanent magnet 303 and the first outer ring permanent magnet 32 ​​are staggered with each other.

[0059] The first outer ring permanent magnet 32 ​​has opposite magnetic properties to the first inner ring permanent magnet 302, and the first outer ring permanent magnet 32 ​​has the same magnetic properties as the second inner ring permanent magnet 303. There is a movable gap between the inner wall of the first outer ring permanent magnet 32 ​​and the outer wall of the first cylindrical structure 30. The first inner magnetic yoke column 31 and the first outer magnetic yoke cylinder 33 form a closed magnetic circuit for the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303.

[0060] The voice coil motor 4 is mounted on the base 1 and is connected to one end of the first inner magnetic yoke column 31. The voice coil motor 4 works in conjunction with the negative stiffness mechanism 3 to achieve semi-active vibration isolation control. The end plate 5 is fixedly connected to the other end of the first inner magnetic yoke column 31, that is, the end plate 5 and the voice coil motor 4 are respectively located at both ends of the first inner magnetic yoke column 31, the end plate 5 and the base 1 are arranged relative to each other, and the positive stiffness mechanism 6 is arranged between the end plate 5 and the base 1.

[0061] Both the first inner magnetic yoke column 31 and the first outer magnetic yoke tube 33 are made of electrical pure iron DT4, which has high magnetic permeability. The magnetic field inside the first inner ring permanent magnet 302 and the magnetic field inside the second inner ring permanent magnet 303 are constrained, guided, and transmitted by the first inner magnetic yoke column 31. Therefore, the first inner magnetic yoke column 31 can effectively reduce the leakage of the magnetic field inside the first inner ring permanent magnet 302 and the magnetic field inside the second inner ring permanent magnet 303. Similarly, the magnetic field outside the first inner ring permanent magnet 302 and the magnetic field outside the second inner ring permanent magnet 303 are constrained, guided, and transmitted by the first outer magnetic yoke tube 33. Therefore, the first outer magnetic yoke tube 33 can effectively reduce the leakage of the magnetic field outside the first inner ring permanent magnet 302 and the magnetic field outside the second inner ring permanent magnet 303.

[0062] The present application shortens the length of the main magnetic circuit by the first inner magnetic yoke column 31 and the first outer magnetic yoke cylinder 33 to reduce magnetic resistance, enhance the magnetic field density in the core area, suppress magnetic leakage between the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303, and improve the utilization rate of magnetic energy. The first inner magnetic yoke column 31 and the first outer magnetic yoke cylinder 33 form a compact magnetic flux closed loop through magnetic yoke constraint.

[0063] The negative stiffness mechanism 3 in the present application uses the first inner magnetic yoke column 31 and the first outer magnetic yoke cylinder 33 to construct a closed loop of guiding magnetic force inside and outside the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303. The first inner magnetic yoke column 31 and the first outer magnetic yoke cylinder 33 can effectively reduce magnetic leakage, and the magnetic flux utilization rate is significantly improved, solving the problem of serious waste of magnetic field energy in the prior art, thereby effectively improving the load capacity of the entire vibration isolation device. By balancing positive stiffness and negative stiffness, the present application can achieve extremely low dynamic stiffness at the equilibrium position, greatly reducing the natural frequency. Compared with traditional passive vibration isolation systems, the vibration isolation frequency band is significantly expanded, especially in the low-frequency band. The vibration isolation effect is greatly improved.

[0064] The present application configures the interaction between the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303 and the first outer ring permanent magnet 32, and utilizes the nonlinear superposition of the end effect to achieve an inverse change relationship between the restoring force and the displacement within a preset displacement range. The coupling design of the positive stiffness mechanism 6 and the nonlinear negative stiffness mechanism 3 makes the vibration isolation device exhibit a quasi-zero stiffness characteristic near the equilibrium position, wherein the integrated voice coil motor 4 works in conjunction with the negative stiffness mechanism 3 to achieve semi-active vibration isolation control.

[0065] The voice coil motor 4 includes a second outer magnetic yoke tube 40, a second cylindrical structure 41, a second inner magnetic yoke column 42, and two second outer ring permanent magnets 43 of opposite magnetic properties. One end of the second outer magnetic yoke tube 40 is connected to the end of the first outer magnetic yoke tube 33 away from the vibration isolation seat 2. In the embodiment shown in this application, the inner and outer diameters of the second outer magnetic yoke tube 40 are the same as those of the first outer magnetic yoke tube 33. The second outer magnetic yoke tube 40 and the first outer magnetic yoke tube 33 are integrally formed and connected. That is, the negative stiffness mechanism 3 and the voice coil motor 4 share a single outer magnetic yoke tube. This improves the integration of the negative stiffness mechanism 3 and the voice coil motor 4 and makes the overall structure of the device more compact.

[0066] The second cylindrical structure 41 is disposed inside the second outer yoke cylinder 40, with a movable gap between the outer wall of the second cylindrical structure 41 and the inner wall of the second outer ring permanent magnet 43. In the embodiment shown in this application, the second cylindrical structure 41 and the second outer yoke cylinder 40 are concentrically disposed.

[0067] The second cylindrical structure 41 includes a coil frame 411 and two coils 412 with opposite winding directions. The coil frame 411 is arranged inside the second outer magnetic yoke tube 40 and fixedly connected to the base 1. The two coils 412 are arranged on the coil frame 411 in parallel with the axial direction of the second outer magnetic yoke tube 40 and at intervals. The second inner magnetic yoke column 42 is passed through the interior of the second cylindrical structure 41. The two ends of the second inner magnetic yoke column 42 extend from the two ends of the second cylindrical structure 41. One end of the second inner magnetic yoke column 42 is fixedly connected to the base 1, and the other end is connected to the first inner magnetic yoke column 31. The two second outer ring permanent magnets 43 are arranged inside the second outer magnetic yoke tube 40 and remain concentric with the second outer magnetic yoke tube 40. The two second outer ring permanent magnets 43 are arranged in parallel with the axial direction of the second outer magnetic yoke tube 40 and at intervals. The two second outer ring permanent magnets 43 are respectively aligned with the two coils 412 along the radial direction of the second outer magnetic yoke tube 40. When the coil 412 is energized, the generated magnetic field interacts with the magnetic field of the second outer ring permanent magnet 43. By controlling the magnitude and direction of the current in the coil 412, precise control of the active force can be achieved.

[0068] In the embodiment shown in the present application, the lower end of the second inner magnetic yoke column 42 is fixedly connected to the base 1 by bolts, the central axes of the second inner magnetic yoke column 42, the second cylindrical structure 41 and the second outer magnetic yoke cylinder 40 coincide, and the central axes of the second cylindrical structure 41 coincide with the first cylindrical structure 30.

[0069] The voice coil motor 4 can generate active control force in real time to achieve active vibration suppression, further improving the vibration isolation effect on the basis of quasi-zero stiffness passive vibration isolation, especially near the resonant frequency, where active control can effectively suppress resonance amplification.

[0070] The control system for voice coil motor 4 includes a displacement sensor, an observer, a controller, and a power amplifier. The displacement sensor monitors the displacement signal of vibration isolation mount 2 in real time, the observer measures the vibration velocity, the controller calculates the required control force based on the feedback signal, and the power amplifier drives coil 412 to generate the corresponding electromagnetic force. Through closed-loop control, active vibration suppression can be achieved.

[0071] To prevent magnetic field interference between the negative stiffness mechanism 3 and the voice coil motor 4, the second inner yoke post 42 is connected to the first inner yoke post 31 via a magnetic isolation block 7. A gap exists between the outer wall of the magnetic isolation block 7 and the inner walls of the integrally formed first and second outer yoke cylinders 33 and 40. Made of a non-magnetic aluminum alloy, the magnetic isolation block 7 effectively isolates the two magnetic circuits, ensuring the independence and stability of their respective magnetic fields. Specifically, the magnetic isolation block 7 is a cylindrical structure with a boss provided on the upper end of the second inner yoke post 42 and a boss provided on the lower end of the first inner yoke post 31. Grooves are provided on both the upper and lower end surfaces of the magnetic isolation block 7. The upper boss of the second inner yoke post 42 mates with the groove on the lower end surface of the magnetic isolation block 7, while the lower boss of the first inner yoke post 31 mates with the groove on the upper end surface of the magnetic isolation block 7. The second inner yoke post 42, the first inner yoke post 31, and the magnetic isolation block 7 are coaxially arranged.

[0072] In some embodiments, the semi-active quasi-zero stiffness vibration isolation device based on end force also includes an outer magnetic ring frame 8 with a cylindrical structure, and the outer magnetic ring frame 8 is arranged inside the first outer magnetic yoke tube 33 and the second outer magnetic yoke tube 40 that are integrally connected. The outer magnetic ring frame 8 remains coaxial with the first outer magnetic yoke tube 33 and the second outer magnetic yoke tube 40 that are integrally connected, wherein the outer wall of the lower end of the outer magnetic ring frame 8 is provided with an outwardly protruding annular support step 80, and the first outer magnetic yoke tube 33 and the second outer magnetic yoke tube 40 that are integrally connected are directly sleeved on the outside of the outer magnetic ring frame 8, and the lower end face of the second outer magnetic yoke tube 40 is docked with the annular support step 80 at the lower end of the outer magnetic ring frame 8 and fixed by bolts, so that a special outer magnetic ring frame 8 is provided inside the first outer magnetic yoke tube 33 and the second outer magnetic yoke tube 40 that are integrally connected to install the first outer ring permanent magnet 32 ​​and the second outer ring permanent magnet 43.

[0073] Specifically, a first magnetic ring assembly groove 81 is provided on the outer magnetic ring frame 8, and the first outer ring permanent magnet 32 ​​is assembled in the first magnetic ring assembly groove 81. Two layers of second magnetic ring assembly grooves 82 are provided on the outer magnetic ring frame 8, and two second outer ring permanent magnets 43 are respectively assembled in the two layers of second magnetic ring assembly grooves 82. The outer magnetic ring frame 8 provides an installation position for the first outer ring permanent magnet 32 ​​and the second outer ring permanent magnet 43, ensuring that the first outer ring permanent magnet 32 ​​and the second outer ring permanent magnet 43 are stably arranged inside the first outer magnetic yoke tube 33 and the second outer magnetic yoke tube 40 that are integrally formed and connected. In addition, the provision of the outer magnetic ring frame 8 simplifies the installation process of the first outer ring permanent magnet 32 ​​and the second outer ring permanent magnet 43, facilitates disassembly and replacement during maintenance, and reduces maintenance costs and difficulty.

[0074] In this application, the base 1, positive stiffness mechanism 6, end plate 5, first cylindrical structure 30, magnetic isolation block 7, and second cylindrical structure 41 collectively constitute the stator portion of the vibration isolation device, while the vibration isolation seat 2, the integrally molded first and second outer magnetic yoke cylinders 33 and 40, the outer magnetic ring frame 8, the first outer ring permanent magnet 32 ​​and the second outer ring permanent magnet 43 mounted on the outer magnetic ring frame 8 collectively constitute the mover portion of the vibration isolation device. During the vibration isolation process, the mover portion undergoes axial relative motion outside the stator portion.

[0075] like Figure 12 As shown in the figure, in the design of traditional vibration isolation devices, the divergence of magnetic lines of force leads to insufficient magnetic energy utilization and limited load capacity. The fundamental reason is that the magnetic resistance around the permanent magnet is unevenly distributed, and the magnetic lines of force preferentially choose low magnetic resistance paths to form a closed loop.

[0076] like Figure 13 As shown, in the present application, the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303 in the negative stiffness mechanism 3 are arranged axially and magnetized in opposite directions. The magnetomotive force of the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303 is used to drive the magnetic flux to form a closed loop along the high magnetic permeability path formed by the first inner magnetic yoke column 31 and the first outer magnetic yoke cylinder 33 and the second outer magnetic yoke cylinder 40 that are integrally connected. Therefore, the present application can generate magnetic field characteristics that are highly matched with the theoretical magnetic field distribution. The nonlinear effect of the end force of the first outer ring permanent magnet 32 ​​on the mover part with the relative position enables the mover part to provide a higher load supporting force at the midpoint of the working range, and this force is highly linear with respect to the change in the relative position of the mover part and the stator part.

[0077] Reference Figure 14Finite element simulation technology is used to numerically analyze the magnetic field distribution of the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303. By extracting the radial magnetic flux density component in the cylindrical coordinate system, two intervals of segment A and segment B with linear characteristics are identified. The simulation data show that the magnetic field intensity and displacement in these two intervals are in a stable linear relationship. Based on the electromagnetic field theory, the magnetic field distribution in the linear interval is equivalent to two virtual currents in opposite directions. According to the Ampere force principle, the Lorentz force generated in segment A is upward and has a negative slope relationship with the displacement. In segment B, since the magnetic field and the virtual current are in opposite directions at the same time, a negative slope characteristic of the force and displacement in the same direction is generated. Therefore, the mechanical superposition effect of the two intervals of segment A and segment B is manifested as a stable negative stiffness characteristic on a macroscopic scale, that is, Figure 14 Negative stiffness region in .

[0078] It should be noted that Figure 14 Br in the cylindrical coordinates refers to the air gap flux density, that is, the radial component of the magnetic field strength at a point on the extraction line in cylindrical coordinates. A refers to the vector magnetic potential, and the unit is Weber. It is used to describe the magnetic field distribution and can be visualized by drawing magnetic lines of force.

[0079] The right-hand rule analysis shows that the equivalent virtual current system can be physically realized as the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303. Therefore, the present application realizes the inverse change relationship between the restoring force and the displacement within the preset displacement range by configuring the interaction between the magnetic fields of the first inner ring permanent magnet 302 and the second inner ring permanent magnet 303 of the stator part and the equivalent current of the first outer ring permanent magnet 32 ​​in the mover part, and utilizing the nonlinear superposition of the end effects.

[0080] In the embodiment shown in this application, three positive stiffness mechanisms 6 are provided, spaced circumferentially around the outer circumference of the integrally formed first and second outer yoke cylinders 33, 40. Specifically, the three positive stiffness mechanisms 6 are spaced 120° apart around the outer circumference of the integrally formed first and second outer yoke cylinders 33, 40. The stiffness design of these three positive stiffness mechanisms 6 achieves the goal of offsetting positive and negative stiffness within the operating range, thereby producing quasi-zero stiffness.

[0081] Reference Figure 9Each positive stiffness mechanism 6 includes a first support rod 60, a second support rod 61, a third support rod 62, an outer compression spring 63 and an inner compression spring 64. The first support rod 60 is parallel to the second support rod 61 and is arranged at intervals. The same end of the first support rod 60 and the second support rod 61 is connected by the outer compression spring 63. The third support rod 62 is arranged between the first support rod 60 and the second support rod 61 and is parallel to the two. The third support rod 62 is connected to the first outer magnetic yoke cylinder integrally formed by the connecting block 65. 33 and the outer wall of the second outer magnetic yoke cylinder 40 are fixed. Inner compression springs 64 are provided at both ends of the third support rod 62. The ends of the inner compression springs 64 are respectively connected to the first support rod 60 and the second support rod 61. The inner compression springs 64 and the outer compression springs 63 are arranged in parallel to form a double-layer elastic connection structure. The outer compression springs 63 on the first support rod 60 and the second support rod 61 near the end plate 5 are connected to the end plate 5, and the outer compression springs 63 on the first support rod 60 and the second support rod 61 near the base 1 are connected to the base 1. The outer compression springs 63 and the inner compression springs 64 are both made of spring steel plates. The double spring arrangement of the outer compression springs 63 and the inner compression springs 64 can improve the lateral stiffness of the positive stiffness mechanism 6 and help improve the torsional stiffness of the entire device, resisting torsional deformation.

[0082] It should be noted that the positive stiffness of the positive stiffness mechanism 6 is directly related to the thickness of the compression spring. Therefore, the positive stiffness of the positive stiffness mechanism 6 will produce stiffness errors due to processing errors in the thickness of the compression spring. Therefore, the fewer the compression springs, the thicker the thickness of each compression spring of the positive stiffness mechanism 6 can be, the smaller the stiffness error caused by processing errors, and the easier it is to match a lower stiffness. Setting it to two positive stiffness mechanisms 6 will result in unstable degrees of freedom, and setting it to three is most reasonable.

[0083] To further optimize the connection between the positive stiffness mechanism 6 and the end plate 5 and the base 1, in some embodiments, a first horizontally extending slot 50 is provided on the end plate 5, one end of the first slot 50 extending to the edge of the end plate 5 to form a first opening 51. A first block 66 is provided on the outer compression spring piece 63 of the positive stiffness mechanism 6 near one end of the end plate 5. The first block 66 forms a sliding fit with the first slot 50 and is inserted into the first slot 50 through the first opening 51. A second horizontally extending slot 10 is provided on the base 1, one end of the second slot 10 extending to the edge of the base 1 to form a second opening 11. A second block 67 is provided on the outer compression spring piece 63 of the positive stiffness mechanism 6 near one end of the base 1 to form a second opening 11. The second block 67 forms a sliding fit with the second slot 10 and is inserted into the second slot 10 through the second opening 11. This block-slot connection method not only simplifies the assembly process of the positive stiffness mechanism 6, but also facilitates disassembly and replacement during maintenance.

[0084] To ensure reliable connection between the vibration isolation base 2 and the integrally formed first and second outer magnetic yoke tubes 33, 40, while also improving the overall compactness of the device, a clearance hole 52 is provided on the end plate 5. The connecting leg 20 provided on the vibration isolation base 2 passes through the clearance hole 52 to connect the first outer magnetic yoke tube 33 and the outer magnetic ring frame 8. Specifically, the connecting leg 20 is fixedly connected to the top end surface of the first outer magnetic yoke tube 33 and the top end surface of the outer magnetic ring frame 8 via bolts. The design of the clearance hole 52 not only provides a passage for the connecting leg 20 but also prevents interference with the connecting leg 20 by the end plate 5, thereby ensuring the normal operation of the device.

[0085] The inner magnetic ring frame 301 is provided with a third magnetic ring assembly groove 301a and a fourth magnetic ring assembly groove 301b. Each first inner ring permanent magnet 302 includes multiple first sector-shaped magnetic blocks 302a. At least two first sector-shaped magnetic blocks 302a are assembled in the third magnetic ring assembly groove 301a. Each first sector-shaped magnetic block 302a is assembled in the third magnetic ring assembly groove 301a to form a complete first inner ring permanent magnet 302. Each second inner ring permanent magnet 303 includes multiple second sector-shaped magnetic blocks 303a. At least two second sector-shaped magnetic blocks 303a are assembled in the fourth magnetic ring assembly groove 301b. Each second sector-shaped magnetic block 303a is assembled in the fourth magnetic ring assembly groove 301b to form a complete second inner ring permanent magnet 303.

[0086] This block setting method reduces manufacturing costs, facilitates magnetization processing and quality control, and at the same time, the block structure can effectively resist thermal stress caused by temperature changes, thereby improving product reliability and service life.

[0087] In the embodiment shown in this application, four first sector magnetic blocks 302a and four second sector magnetic blocks 303a are provided.

[0088] The two adjacent first sector-shaped magnetic blocks 302a in the third magnetic ring assembly groove 301a are separated by a first partition 301c, and the first partition 301c and the inner magnetic ring frame 301 are an integral structure. The two adjacent second sector-shaped magnetic blocks 303a in the fourth magnetic ring assembly groove 301b are separated by a second partition 301d, and the second partition 301d and the inner magnetic ring frame 301 are an integral structure.

[0089] The first outer ring permanent magnets 32 also employ a segmented structure. Each first outer ring permanent magnet 32 ​​includes multiple third sector-shaped magnetic segments 320, which can be four or six, depending on the specific application requirements. Each third sector-shaped magnetic segment 320 is assembled in the first magnetic ring assembly slots 81 to form a complete first outer ring permanent magnet 32. For example, in the embodiment shown in this application, four third sector-shaped magnetic segments 320 are provided.

[0090] Two adjacent third sector-shaped magnetic blocks 320 in the first magnetic ring assembly groove 81 are separated by a third partition plate 83 , and the third partition plate 83 and the outer magnetic ring frame 8 are an integral structure.

[0091] The second outer ring permanent magnets 43 in the voice coil motor 4 also employ a segmented structure. Each second outer ring permanent magnet 43 comprises multiple fourth sector-shaped magnetic segments 430, preferably four or six, depending on the specific application requirements. Each layer of second magnetic ring assembly slots 82 is composed of multiple fourth sector-shaped magnetic segments 430 to form a complete second outer ring permanent magnet 43. For example, in the embodiment illustrated herein, each layer of second outer ring permanent magnets 43 is composed of four fourth sector-shaped magnetic segments 430.

[0092] Two adjacent fourth sector-shaped magnetic blocks 430 in the second magnetic ring assembly groove 82 are separated by a fourth partition plate 84 , and the fourth partition plate 84 and the outer magnetic ring frame 8 are an integral structure.

[0093] This segmented design of the fan-shaped magnet not only reduces manufacturing costs but also facilitates magnetization processing and quality control of the permanent magnets. Furthermore, the segmented structure effectively resists thermal stress caused by temperature changes, improving product reliability.

[0094] In the present application, the first outer ring permanent magnet 32 ​​is concentrically arranged with the first inner ring permanent magnet 302 , and the second outer ring permanent magnet 43 is concentrically arranged with the coil 412 .

[0095] The first cylindrical structure 30 , the second cylindrical structure 41 and the magnetic isolation block 7 are coaxially arranged inside the first outer magnetic yoke cylinder 33 and the second outer magnetic yoke cylinder 40 which are integrally formed and connected.

[0096] In summary, the semi-active quasi-zero stiffness vibration isolation device based on end force of the present invention effectively solves the problems of severe magnetic leakage and low magnetic flux utilization in the prior art, significantly improves the vibration isolation performance and load capacity, and realizes wide-band, high-efficiency vibration control. It is particularly suitable for applications such as precision instruments and high-end equipment that have extremely high requirements for vibration isolation performance. Through the coupling design of the positive stiffness mechanism 6 and the nonlinear negative stiffness mechanism 3, the system exhibits quasi-zero stiffness characteristics near the equilibrium position, and the optimized magnetic circuit layout greatly improves the load-bearing capacity of the system. The device also integrates a voice coil motor 4, which can adjust the output force in real time according to the vibration signal.

[0097] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the technical field without departing from the purpose of the present application.

Claims

1. A semi-active quasi-zero stiffness vibration isolation device based on end force, characterized in that: include: base; a vibration isolation seat, arranged relative to and spaced from the base; A negative stiffness mechanism is provided between the base and the vibration isolation seat, the negative stiffness mechanism includes a first cylindrical structure, a first inner magnetic yoke column, a first outer ring permanent magnet and a first outer magnetic yoke cylinder, one end of the first outer magnetic yoke cylinder is fixedly connected to the vibration isolation seat, the first cylindrical structure is provided inside the first outer magnetic yoke cylinder, the first inner magnetic yoke column is passed through the interior of the first cylindrical structure, the two ends of the first inner magnetic yoke column extend from the two ends of the first cylindrical structure, the first cylindrical structure includes an inner magnetic ring frame, a first inner ring permanent magnet and a second inner ring permanent magnet with opposite magnetization directions, the first inner ring permanent magnet and the second inner ring permanent magnet are parallel to the axial direction of the first outer magnetic yoke cylinder and are spaced apart on the inner magnetic ring frame, The first outer ring permanent magnet is arranged inside the first outer magnetic yoke tube and is concentric with the first outer magnetic yoke tube. The first outer ring permanent magnet and the first inner ring permanent magnet at least partially overlap in the radial direction of the first outer magnetic yoke tube. The first outer ring permanent magnet and the second inner ring permanent magnet are spaced apart in the axial direction of the first outer magnetic yoke tube. The magnetic properties of the first outer ring permanent magnet and the first inner ring permanent magnet are opposite, and the magnetic properties of the first outer ring permanent magnet and the second inner ring permanent magnet are the same. There is a movable gap between the inner wall of the first outer ring permanent magnet and the outer wall of the first cylindrical structure. The first inner magnetic yoke column and the first outer magnetic yoke tube form a closed magnetic circuit for the first inner ring permanent magnet and the second inner ring permanent magnet. A voice coil motor is mounted on the base, the voice coil motor is connected to one end of the first inner magnetic yoke column, the voice coil motor includes a second outer magnetic yoke tube, a second cylinder structure, a second inner magnetic yoke column and two second outer ring permanent magnets with opposite magnetic properties, one end of the second outer magnetic yoke tube is connected to the end of the first outer magnetic yoke tube away from the vibration isolation seat, the inner diameter and outer diameter of the second outer magnetic yoke tube are the same as the inner diameter and outer diameter of the first outer magnetic yoke tube, the second outer magnetic yoke tube is integrally formed and connected to the first outer magnetic yoke tube, the second cylinder structure is arranged inside the second outer magnetic yoke tube, the second cylinder structure includes a coil frame and two coils with opposite winding directions, the coil frame is arranged inside the second outer magnetic yoke tube and is fixedly connected to the base, the two coils The rings are parallel to and spaced apart from each other along the axial direction of the second outer magnetic yoke cylinder and are arranged on the coil frame; the second inner magnetic yoke column is passed through the interior of the second cylindrical structure; the two ends of the second inner magnetic yoke column extend from the two ends of the second cylindrical structure; one end of the second inner magnetic yoke column is fixedly connected to the base, and the other end is connected to the first inner magnetic yoke column; the two second outer ring permanent magnets are arranged inside the second outer magnetic yoke cylinder and are concentric with the second outer magnetic yoke cylinder; the two second outer ring permanent magnets are parallel to and spaced apart along the axial direction of the second outer magnetic yoke cylinder; the two second outer ring permanent magnets are respectively aligned with the two coils along the radial direction of the second outer magnetic yoke cylinder; and there is a movable gap between the inner wall of the two second outer ring permanent magnets and the outer wall of the second cylindrical structure; an end plate, the end plate being fixedly connected to the other end of the first inner magnetic yoke column, and the end plate being arranged relative to the base with a spacing therebetween; A positive stiffness mechanism is provided between the end plate and the base, and three positive stiffness mechanisms are provided. The three positive stiffness mechanisms are arranged circumferentially and spaced apart on the outer periphery of the first outer magnetic yoke cylinder and the second outer magnetic yoke cylinder that are integrally connected. The positive stiffness mechanism includes a first support rod, a second support rod, a third support rod, an outer compression spring sheet and an inner compression spring sheet. The first support rod is parallel to the second support rod and is arranged at intervals. The same end of the first support rod and the second support rod is connected by the outer compression spring sheet. The third support rod is provided between the first support rod and the second support rod, and is connected to the first support rod and the second support rod. A support rod is parallel to the second support rod, and the third support rod is fixed to the outer wall of the first outer magnetic yoke tube and the second outer magnetic yoke tube that are integrally formed through a connecting block. The inner compression spring sheet is set at both ends of the third support rod, and the two ends of the inner compression spring sheet are respectively connected to the first support rod and the second support rod. The inner compression spring sheet is parallel to the outer compression spring sheet, and the outer compression spring sheet on the first support rod and the second support rod close to the end plate is connected to the end plate, and the outer compression spring sheet on the first support rod and the second support rod close to the base is connected to the base.

2. The semi-active quasi-zero stiffness vibration isolation device based on end force according to claim 1 is characterized in that: The second inner magnetic yoke column is connected to the first inner magnetic yoke column via a magnetic isolation block, and a movable gap is formed between the outer wall of the magnetic isolation block and the inner walls of the first outer magnetic yoke cylinder and the second outer magnetic yoke cylinder that are integrally formed and connected.

3. The semi-active quasi-zero stiffness vibration isolation device based on end force according to claim 1 is characterized in that: It also includes an outer magnetic ring frame with a cylindrical structure, which is arranged inside the first outer magnetic yoke tube and the second outer magnetic yoke tube that are integrally connected. The outer magnetic ring frame remains coaxial with the first outer magnetic yoke tube and the second outer magnetic yoke tube that are integrally connected. A first magnetic ring assembly groove and a second magnetic ring assembly groove are provided on the outer magnetic ring frame. The first outer ring permanent magnet is assembled in the first magnetic ring assembly groove. The second magnetic ring assembly groove is provided with two layers, and two second outer ring permanent magnets are respectively assembled in the two layers of the second magnetic ring assembly groove.

4. The semi-active quasi-zero stiffness vibration isolation device based on end force according to claim 3 is characterized in that: The end plate is provided with an avoidance hole, the vibration isolation seat is provided with a connecting leg, and the connecting leg passes through the avoidance hole to connect the first outer magnetic yoke cylinder and the outer magnetic ring frame.

5. The semi-active quasi-zero stiffness vibration isolation device based on end force according to claim 1, characterized in that: A first slot extending horizontally is provided on the end plate, one end of the first slot extends to the edge of the end plate to form a first opening, a first block is provided on the outer compression spring sheet on the positive stiffness mechanism near one end of the end plate, the first block is inserted into the first slot through the first opening, a second slot extending horizontally is provided on the base, one end of the second slot extends to the edge of the base to form a second opening, a second block is provided on the outer compression spring sheet on the positive stiffness mechanism near one end of the base, the second block is inserted into the second slot through the second opening.

6. The semi-active quasi-zero stiffness vibration isolation device based on end force according to claim 3 is characterized in that: The inner magnetic ring frame is provided with a third magnetic ring assembly groove and a fourth magnetic ring assembly groove, the first inner ring permanent magnet includes a plurality of first sector-shaped magnetic blocks, at least two of the first sector-shaped magnetic blocks are assembled in the third magnetic ring assembly groove, and each of the first sector-shaped magnetic blocks is assembled into the first inner ring permanent magnet in the third magnetic ring assembly groove, the second inner ring permanent magnet includes a plurality of second sector-shaped magnetic blocks, at least two of the second sector-shaped magnetic blocks are assembled in the fourth magnetic ring assembly groove, and each of the second sector-shaped magnetic blocks is assembled into the second inner ring permanent magnet in the fourth magnetic ring assembly groove, adjacent two first sector-shaped magnetic blocks in the third magnetic ring assembly groove are separated by a first partition, and the first partition and the inner magnetic ring frame are an integral structure, and adjacent two second sector-shaped magnetic blocks in the fourth magnetic ring assembly groove are separated by a second partition, and the second partition and the inner magnetic ring frame are an integral structure.

7. The semi-active quasi-zero stiffness vibration isolation device based on end force according to claim 6, characterized in that: Each of the first outer ring permanent magnets includes a plurality of third sector-shaped magnetic blocks, each of the third sector-shaped magnetic blocks is assembled into the first outer ring permanent magnet in the first magnetic ring assembly groove, and two adjacent third sector-shaped magnetic blocks in the first magnetic ring assembly groove are separated by a third partition, and the third partition is an integral structure with the outer magnetic ring frame; each of the second outer ring permanent magnets includes a plurality of fourth sector-shaped magnetic blocks, each of the fourth sector-shaped magnetic blocks is assembled into the second outer ring permanent magnet in the second magnetic ring assembly groove, and two adjacent fourth sector-shaped magnetic blocks in the second magnetic ring assembly groove are separated by a fourth partition, and the fourth partition is an integral structure with the outer magnetic ring frame.

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