A vibration isolator and method of adjusting a vibration isolator

Abstract

The present application relates to the technical field of vibration isolation, and provides a vibration isolator and a method for adjusting the vibration isolator. The vibration isolator comprises a support frame, a first fixed frame, a second fixed frame, a third fixed frame, a first permanent magnet, a second permanent magnet, a first coil, a second coil, a third coil, a transmission shaft, a third permanent magnet and a mass to be isolated. The vibration isolator provided by the present application can realize high static-low dynamic stiffness and variable stiffness and damping characteristics. The vibration isolator is completely composed of electromagnetic coils and permanent magnets, and eliminates linear springs, leaf springs and other contact type mechanical elastic elements in the existing vibration isolator, so that the influence of factors such as fatigue, humidity and lubrication can be avoided, the shortcomings that the traditional high static-low dynamic stiffness vibration isolator cannot change the initial isolation frequency and the damping and stiffness adjustment speed is slow are solved, the structure is simple and compact, the volume is small, the maintenance is convenient, the generated force is large, and more complex working conditions can be coped with.

Description

Technical Field

[0001] This invention relates to the field of vibration isolation technology, and more particularly to a vibration isolator and a method for adjusting the vibration isolator. Background Technology

[0002] Vibration is widespread in mechanical systems. With the continuous advancement of science and technology, the operating environment of mechanical structures is becoming increasingly complex, while the demands for structural safety, reliability, and high precision are also increasing. To meet the increasingly stringent requirements of actual vibration control, high static and low dynamic stiffness vibration isolation technology has received increasing attention. High static-low dynamic stiffness vibration isolators are mostly composed of parallel combinations of positive and negative stiffness, possessing both high static stiffness and low dynamic stiffness. Under the premise of meeting high load-bearing capacity and static stability, they have low dynamic stiffness, low natural frequency, and a wide vibration isolation bandwidth, making them well-suited for low-frequency vibration isolation problems.

[0003] In a high static and low dynamic stiffness vibration isolation system with parallel positive and negative stiffness, the system's dynamic characteristics and vibration isolation performance largely depend on the mechanical properties of the negative stiffness element. Currently, there are many ways to achieve negative stiffness, such as mechanical springs, rubber, plates, cams, permanent magnets, and electromagnets, but most are passive implementations and have limitations when facing complex and variable operating conditions.

[0004] In recent years, semi-active vibration isolation has been widely studied to address complex operating conditions by altering the system's damping and stiffness. Compared to active vibration isolation, it requires no external energy from actuators, is relatively easy to control, and is low-cost and readily implemented.

[0005] For example, patent application number 202410154171.3 discloses a negative stiffness magnetic vibration isolator based on metal rubber, which adjusts the negative stiffness by controlling the current in the coil. The electromagnetic coil is wound around a movable metal rubber, forming magnetic poles with the metal rubber to generate negative stiffness with the upper and lower magnets. This solution uses a single coil, and its drawback is a relatively small range of stiffness adjustment. Summary of the Invention

[0006] The purpose of this invention is to provide a vibration isolator and a method for adjusting the vibration isolator, so as to solve the problem that the unreasonable structure of the vibration isolator in the prior art leads to a small stiffness adjustment range.

[0007] To achieve the above objectives, according to a first aspect of the present invention, a vibration isolator is provided, comprising: a support frame; a first fixed frame and a second fixed frame, both fixedly connected to the support frame and spaced apart along a first direction; a third fixed frame, fixedly connected to the support frame and located between the first and second fixed frames; a first permanent magnet and a second permanent magnet, respectively fixedly mounted on the first and second fixed frames; both the first and second permanent magnets having clearance holes; a first coil and a second coil, the first coil being fixedly mounted on the first fixed frame and located on the outer periphery of the first permanent magnet. The second coil is fixedly mounted on the second fixed frame and located on the outer periphery of the second permanent magnet; the third coil is mounted on the third fixed frame and located between the first coil and the second coil; the drive shaft is connected to the first fixed frame and the second fixed frame through a linear bearing, and the drive shaft can move relative to the support frame in a first direction; the drive shaft passes sequentially through the clearance holes of the first permanent magnet and the second permanent magnet; the third permanent magnet is fixedly mounted on the drive shaft and is arranged opposite to the third coil, and the third permanent magnet can move relative to the third coil in the first direction; the vibration-isolated mass block is fixedly connected to the upper end of the drive shaft.

[0008] Furthermore, the vibration isolator also includes a negative resistance branch circuit, which is connected to the third coil. The negative resistance branch circuit includes fixed resistors R1 and R2, operational amplifier O, and variable resistor R. S One end of the third coil is grounded, and the other end is connected to the inverting input terminal - of operational amplifier O. One end of the fixed resistor R1 is grounded, and the other end is connected to the non-inverting input terminal + of operational amplifier O. The two ends of another fixed resistor R2 are connected between the non-inverting input terminal + and the output terminal of operational amplifier O, respectively. The variable resistor R... S Connect it between the inverting input terminal and the output terminal of operational amplifier O; the fixed resistors R1 and R2 have the same resistance value.

[0009] Furthermore, the support frame includes a base and multiple brackets, which are arranged in a circumferential array on the upper surface of the base and are all fixedly connected to the base. The first fixing frame includes a lower fixing disc, a lower magnet fixing bracket, and a lower coil retainer. The lower fixing disc is fixedly connected to the multiple brackets and is located above the base. The lower magnet fixing bracket is fixedly connected to the lower fixing disc, and the lower coil retainer is fixedly connected to the lower magnet fixing bracket. The lower magnet fixing bracket has a first annular surrounding plate. The lower coil retainer and the inner side of the first annular surrounding plate together form an installation space for installing the first permanent magnet, and the lower coil retainer and the outer side of the first annular surrounding plate together form an installation space for installing the first coil. The second fixing frame includes an upper fixing disc, an upper magnet fixing frame, and an upper coil retainer. The upper fixing disc is fixedly connected to multiple supports and is located above the lower coil retainer. The upper magnet fixing frame is fixedly connected to the upper fixing disc, and the upper coil retainer is fixedly connected to the upper magnet fixing frame. The upper magnet fixing frame has a second annular surrounding plate. The upper coil retainer and the inner side of the second annular surrounding plate together form an installation space for installing the second permanent magnet, and the outer side of the upper coil retainer and the second annular surrounding plate together form an installation space for installing the second coil. The third fixing frame includes a coil clamp, which is fixedly connected to multiple supports. The coil clamp has a clamping space for clamping the third coil.

[0010] Furthermore, the vibration isolator also includes: a first connecting member, which is L-shaped and has connecting holes for mounting bolts; the first connecting member includes a first connecting plate and a second connecting plate connected at right angles; the first connecting plate is bolted to the bracket, and the second connecting plate is bolted to the base; each bracket is fixed to the base by two first connecting members; and a second connecting member, which is L-shaped and has connecting holes for mounting bolts; the second connecting member includes a third connecting plate and a fourth connecting plate connected at right angles; the third connecting plate is bolted to the bracket, and the fourth connecting plate is bolted to the upper or lower fixed disc. The system is bolted together. The upper fixed disc is connected to multiple brackets one-to-one via multiple second connecting parts, and the lower fixed disc is also connected to multiple brackets one-to-one via multiple second connecting parts. The linear bearings include an upper linear bearing and a lower linear bearing. The upper fixed disc has a first mounting hole, and the upper magnet mounting bracket also includes a first annular mounting plate that passes through the first mounting hole. An upper linear bearing that mates with the drive shaft is installed in the first mounting hole. The lower fixed disc has a second mounting hole, and the lower magnet mounting bracket also includes a second annular mounting plate that passes through the second mounting hole. A lower linear bearing that mates with the drive shaft is installed in the second mounting hole.

[0011] Furthermore, the first, second, and third permanent magnets are all made of neodymium iron boron; the first, second, and third permanent magnets are all axially magnetized; and the magnetization directions of two adjacent permanent magnets among the first, second, and third permanent magnets are opposite.

[0012] Furthermore, the thickness of the first permanent magnet is greater than that of the second permanent magnet; the thickness of the first permanent magnet is greater than that of the third permanent magnet.

[0013] Furthermore, the polarity of the current in the first coil and the second coil is always the same.

[0014] Furthermore, the third permanent magnet moves relative to the third coil along with the drive shaft. No additional current is supplied to the third coil; the damping force is generated by the induced current.

[0015] According to a second aspect of the present invention, a method for adjusting a vibration isolator is provided. The vibration isolator is as described above. The stiffness adjustment method includes the following steps: when the object to be isolated vibrates, the third permanent magnet moves vertically relative to the first and second permanent magnets in the axial direction, causing a change in the air gap between the third permanent magnet and the first and second permanent magnets. As the air gap changes, the force between the permanent magnets also changes, thereby generating a high static-low dynamic stiffness characteristic. The three permanent magnet poles are arranged opposite each other, and the first and second coils are controlled by a DSPACE controller based on the acceleration signals of the base and the isolated mass block. The variable stiffness characteristic of the vibration isolator is achieved by adjusting the magnitude and direction of the current in the coils. When a positive current is applied to the first and second coils, the repulsive forces generated by the first and second coils and the first and second permanent magnets are superimposed, increasing the stiffness of the vibration isolator. When a reverse current is applied to the first and second coils, the attractive forces generated by the first and second coils cancel out the repulsive forces generated by the first and second permanent magnets, decreasing the stiffness of the vibration isolator. When external vibration occurs, the third permanent magnet and the third coil undergo relative up-and-down motion, and the third coil generates an induced current, producing a damping force that opposes the relative motion between the third permanent magnet and the third coil.

[0016] Furthermore, the vibration isolator is the aforementioned vibration isolator, and the stiffness adjustment method includes the following steps: when the resistance values ​​of the fixed resistor R1 and the fixed resistor R2 are the same, the resistance value generated by the operational amplifier O is equivalent to the variable resistor R. S The negative value of the resistance reduces the resistance in the third coil of the vibration isolator, increases the induced current, and enhances the electromagnetic damping effect.

[0017] Compared with the prior art, the present invention has two sets of electromagnetic coils wound around the outer periphery of two fixed magnets, respectively. Compared with a single coil, the two sets of coils can achieve a wider range of stiffness adjustment. The positive stiffness can also be adjusted by changing the direction of the current. At the same time, since the two sets of electromagnetic coils are a certain distance away from the central moving magnet, the influence of eddy currents generated by the relative motion between the magnet and the electromagnetic coils on the control current can be reduced.

[0018] The vibration isolator provided by this invention is a high static-low dynamic stiffness vibration isolator structure with variable stiffness and damping. The positive and negative stiffness of this structure are entirely generated by permanent magnets and electromagnetic coils, unlike structures that use contact-type mechanical elastic elements such as linear springs and leaf springs to provide positive stiffness. This avoids the influence of factors such as fatigue, humidity, and lubrication. The stiffness and damping of the vibration isolator can be changed in real time, effectively widening the system's vibration isolation frequency band, reducing the vibration peak value in the isolator's resonant frequency range, and decreasing the vibration transmissibility within the vibration isolation frequency range.

[0019] Based on the implementation methods provided in the above aspects, this application can be further combined to provide more implementation methods. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a three-dimensional structural schematic diagram of a vibration isolator provided in an optional embodiment of the present invention;

[0022] Figure 2 for Figure 1 A cross-sectional view of the vibration isolator in the diagram;

[0023] Figure 3 This diagram illustrates the simultaneous application of positive excitation current to the first and second coils and the repulsive force generated between the magnets; the solid arrows represent the repulsive force.

[0024] Figure 4 This diagram illustrates the attractive force generated when the first and second coils are simultaneously supplied with reverse excitation currents, and the repulsive force generated between the magnets; solid arrows represent repulsive forces, and dashed arrows represent attractive forces.

[0025] Figure 5 A circuit diagram of the negative resistance branch circuit of the vibration isolator provided in an optional embodiment of the present invention;

[0026] Figure 6 Stiffness-displacement curves of vibration isolators under different currents;

[0027] Figure 7 The amplitude-frequency curves show the changes in vibration amplitude of the vibration isolator with and without damping, as a function of frequency.

[0028] Explanation of icon numbers:

[0029] 1. Base; 2. First connecting piece; 3. Bracket; 4. Second connecting piece; 5. Upper fixed disc; 6. Lower fixed disc; 7. Lower magnet fixing bracket; 8. Lower coil retainer; 9. Lower linear bearing; 10. Drive shaft; 11. Upper linear bearing; 12. Upper magnet fixing bracket; 13. Upper coil retainer; 14. First permanent magnet; 15. First coil; 16. Second permanent magnet; 17. Second coil; 18. Third permanent magnet; 19. Third coil; 20. Coil clamp; 21. Vibration-isolated mass block. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0031] like Figures 1 to 5As shown, the present invention provides a vibration isolator, comprising: a support frame; a first fixed frame and a second fixed frame, both fixedly connected to the support frame and spaced apart along a first direction; a third fixed frame, fixedly connected to the support frame and located between the first and second fixed frames; a first permanent magnet 14 and a second permanent magnet 16, respectively fixedly mounted on the first and second fixed frames; both the first and second permanent magnets 14 and 16 having clearance holes; a first coil 15 and a second coil 17, the first coil 15 being fixedly mounted on the first fixed frame and located on the outer periphery of the first permanent magnet 14, and the second coil 17 being fixedly mounted on the second fixed frame. The third coil 19 is located on the outer periphery of the second permanent magnet 16; the third coil 19 is mounted on the third fixed frame and is located between the first coil 15 and the second coil 17; the drive shaft 10 is connected to the first fixed frame and the second fixed frame through a linear bearing, and the drive shaft 10 can move relative to the support frame in the first direction; the drive shaft 10 passes through the clearance hole of the first permanent magnet 14 and the clearance hole of the second permanent magnet 16 in sequence; the third permanent magnet 18 is fixedly mounted on the drive shaft 10 and is arranged opposite to the third coil 19, and the third permanent magnet 18 moves relative to the third coil 19 in the first direction; the vibration-isolated mass block 21 is fixedly connected to the upper end of the drive shaft 10.

[0032] When the vibration isolation object vibrates, the third permanent magnet 18 will move up and down relative to the first permanent magnet 14 and the second permanent magnet 16 in the axial direction under the drive of the transmission shaft 10, which will change the air gap between the third permanent magnet 18 and the first permanent magnet 14 and the second permanent magnet 16. As the air gap changes, the force between the permanent magnets will also change, thus producing a high static-low dynamic stiffness characteristic.

[0033] Three permanent magnets are arranged with their magnetic poles facing each other. The variable stiffness characteristic of the vibration isolator is achieved by using a DSPACE controller to control the magnitude and direction of the current flowing through the first coil 15 and the second coil 17 based on the acceleration signals of the base 1 and the vibration-isolated mass block 21. When a positive current flows through the first coil 15 and the second coil 17, the repulsive forces generated by the first coil 15 and the second coil 17 and the first permanent magnet 14 and the second permanent magnet 16 are superimposed, increasing the stiffness of the vibration isolator. When a reverse current flows through the first coil 15 and the second coil 17, the attractive forces generated by the first coil 15 and the second coil 17 cancel out the repulsive forces generated by the first permanent magnet 14 and the second permanent magnet 16, decreasing the stiffness of the vibration isolator. When external vibration occurs, the third permanent magnet 18 and the third coil 19 move up and down relative to each other. The third coil 19 generates an induced current, producing a damping force that opposes the relative movement between the third permanent magnet 18 and the third coil 19.

[0034] like Figure 5As shown, the vibration isolator also includes a negative resistance branch circuit, which is connected to the third coil 19. The negative resistance branch circuit includes fixed resistors R1 and R2, operational amplifier O, and variable resistor R. S One end of the third coil 19 is grounded, and the other end is connected to the inverting input terminal - of operational amplifier O. One end of the fixed resistor R1 is grounded, and the other end is connected to the non-inverting input terminal + of operational amplifier O. The two ends of another fixed resistor R2 are connected between the non-inverting input terminal + and the output terminal of operational amplifier O, respectively. The variable resistor R... S Connect it between the inverting input terminal and the output terminal of operational amplifier O; the fixed resistors R1 and R2 have the same resistance value.

[0035] When the fixed resistors R1 and R2 have the same resistance, the operational amplifier O generates a resistance equivalent to the variable resistor R. S The negative value of the resistance reduces the resistance in the third coil 19 of the vibration isolator, increases the induced current, and enhances the electromagnetic damping effect.

[0036] like Figure 1 and Figure 2 As shown, the support frame includes a base 1 and multiple brackets 3. The multiple brackets 3 are arranged in a circumferential array on the upper surface of the base 1, and all of the multiple brackets 3 are fixedly connected to the base 1. The first fixing frame includes a lower fixing disc 6, a lower magnet fixing bracket 7, and a lower coil retainer 8. The lower fixing disc 6 is fixedly connected to the multiple brackets 3 and is located above the base 1. The lower magnet fixing bracket 7 is fixedly connected to the lower fixing disc 6, and the lower coil retainer 8 is fixedly connected to the lower magnet fixing bracket 7. The lower magnet fixing bracket 7 has a first annular surrounding plate. The lower coil retainer 8 and the inner side of the first annular surrounding plate together form an installation space for installing the first permanent magnet 14, and the lower coil retainer 8 and the outer side of the first annular surrounding plate together form an installation space for installing the first coil 15. The second fixing frame... The device includes an upper fixed disc 5, an upper magnet fixing frame 12, and an upper coil retainer 13. The upper fixed disc 5 is fixedly connected to multiple supports 3 and is located above the lower coil retainer 8. The upper magnet fixing frame 12 is fixedly connected to the upper fixed disc 5, and the upper coil retainer 13 is fixedly connected to the upper magnet fixing frame 12. The upper magnet fixing frame 12 has a second annular surrounding plate. The upper coil retainer 13 and the inner side of the second annular surrounding plate together form an installation space for installing a second permanent magnet 16, and the upper coil retainer 13 and the outer side of the second annular surrounding plate together form an installation space for installing a second coil 17. The third fixing frame includes a coil clamp 20, which is fixedly connected to multiple supports 3 and has a clamping space for clamping a third coil 19. This invention further optimizes the structure of the vibration isolator by optimizing the structures of the first, second, and third fixing frames, facilitating the processing and assembly of the vibration isolator.

[0037] In the optional embodiments not shown in this application, the structures of the first fixing frame, the second fixing frame, the third fixing frame, and the support frame can also be modified according to actual needs, as long as their functions can be achieved.

[0038] like Figure 1 and Figure 2 As shown, the vibration isolator further includes: a first connecting member 2, which is L-shaped and has connecting holes for mounting bolts. The first connecting member 2 includes a first connecting plate and a second connecting plate connected at right angles. The first connecting plate is bolted to the bracket, and the second connecting plate is bolted to the base. Each bracket 3 is fixed to the base 1 by two first connecting members 2; and a second connecting member 4, which is L-shaped and has connecting holes for mounting bolts. The second connecting member 4 includes a third connecting plate and a fourth connecting plate connected at right angles. The third connecting plate is bolted to the bracket 3, and the fourth connecting plate is bolted to the upper fixed disc 5 or the lower fixed disc 6. The upper fixed disc 5 is connected to multiple brackets 3 one-to-one via multiple second connecting pieces 4, and the lower fixed disc 6 is also connected to multiple brackets 3 one-to-one via multiple second connecting pieces 4. The linear bearings include an upper linear bearing 11 and a lower linear bearing 9. The upper fixed disc 5 has a first mounting hole, and the upper magnet fixing bracket 12 also includes a first annular mounting plate passing through the first mounting hole. An upper linear bearing 11, which mates with the drive shaft 10, is installed in the first mounting hole. The lower fixed disc 6 has a second mounting hole, and the lower magnet fixing bracket 7 also includes a second annular mounting plate passing through the second mounting hole. A lower linear bearing 9, which mates with the drive shaft 10, is installed in the second mounting hole. This further optimizes the structure of the vibration isolator, facilitating its processing and assembly.

[0039] Optionally, the first permanent magnet 14, the second permanent magnet 16, and the third permanent magnet 18 are all made of neodymium iron boron. Neodymium iron boron has the advantage of strong magnetism.

[0040] Optionally, such as Figure 3 and Figure 4 As shown, the first permanent magnet 14, the second permanent magnet 16, and the third permanent magnet 18 are all axially magnetized; the magnetization directions of two adjacent permanent magnets among the first permanent magnet 14, the second permanent magnet 16, and the third permanent magnet 18 are opposite.

[0041] Optionally, the thickness of the first permanent magnet 14 is greater than that of the second permanent magnet 16; the thickness of the first permanent magnet 14 is greater than that of the third permanent magnet 18. In this way, the thickness of the first permanent magnet 14, located at the bottom of the entire vibration isolator, is slightly greater than the thickness of the second permanent magnet 16 and the third permanent magnet 18, which will generate an upward magnetic force difference. When the vibration isolator bears a mass equal to the difference, the middle third permanent magnet 18 just returns to the equilibrium position.

[0042] Optionally, the current polarity in the first coil 15 and the second coil 17 is always the same.

[0043] Optionally, the third permanent magnet 18 moves relative to the third coil 19 along with the transmission shaft 10. No additional current is supplied to the third coil 19, and the damping force is generated by the induced current.

[0044] This invention also provides a method for adjusting a vibration isolator, wherein the vibration isolator is one of the above-described or below-described vibration isolators. The stiffness adjustment method includes the following steps: when the object being isolated vibrates, the third permanent magnet 18 will move relative to the first permanent magnet 14 and the second permanent magnet 16 in the axial direction, causing the air gap between the third permanent magnet 18 and the first permanent magnet 14 and the second permanent magnet 16 to change. As the air gap changes, the force between the permanent magnets also changes, thereby producing a high static-low dynamic stiffness characteristic; the three permanent magnet poles are arranged opposite each other, and the magnitude and direction of the current flowing into the first coil 15 and the second coil 17 are controlled by the DSPACE controller according to the acceleration signals of the base 1 and the isolated mass block 21. To achieve the variable stiffness characteristic of the vibration isolator; when a positive current is applied to the first coil 15 and the second coil 17, the repulsive forces generated by the first coil 15 and the second coil 17 and the first permanent magnet 14 and the second permanent magnet 16 are superimposed, and the stiffness of the vibration isolator increases; when a reverse current is applied to the first coil 15 and the second coil 17, the attractive forces generated by the first coil 15 and the second coil 17 cancel out the repulsive forces generated by the first permanent magnet 14 and the second permanent magnet 16, and the stiffness of the vibration isolator decreases; when external vibration occurs, the third permanent magnet 18 and the third coil 19 produce relative up-down movement, and the third coil 19 generates an induced current, generating a damping force that opposes the relative movement between the third permanent magnet 18 and the third coil 19.

[0045] Optionally, the stiffness adjustment method further includes the following steps: when the values ​​of fixed resistor R1 and fixed resistor R2 are the same, the resistance generated by operational amplifier O is equivalent to that of variable resistor R. S The negative value of the resistance reduces the resistance in the third coil 19 of the vibration isolator, increases the induced current, and enhances the electromagnetic damping effect.

[0046] This invention belongs to the field of low-frequency vibration isolation structure technology, and in particular relates to a high static-low dynamic stiffness vibration isolator structure with variable stiffness and damping, which is suitable for low-frequency vibration isolation of mechanical systems.

[0047] This invention provides a variable stiffness, variable damping vibration isolator constructed using a combination of electromagnetic coils and permanent magnets, exhibiting high static-low dynamic stiffness characteristics, particularly suitable for low-frequency vibrations in the 0.5-70Hz range. Compared to existing technologies, this invention presents a novel vibration isolator structure that achieves high static-low dynamic stiffness as well as variable stiffness and variable damping characteristics. The invention uses an electromagnetic coil paired with a permanent magnet as the stiffness adjustment element; its positive and negative stiffness are entirely generated by the permanent magnet and the electromagnetic coil. The variable stiffness characteristic can be achieved by changing the magnitude and direction of the current in the electromagnetic coil. Compared to traditional vibration isolators, this invention offers a wider isolation frequency band and allows for real-time adjustment. By designing the height, thickness, inner and outer diameters of the central electromagnetic coil, as well as the negative resistance parameters in the branch circuits, the vibration isolator can generate appropriate damping force during operation to cope with vibrations at different frequencies. Within the resonance range, reducing the negative resistance value can increase the damping force, reducing the resonance peak; within the isolation range, appropriately increasing the resistance can reduce the damping force, thereby improving the vibration isolation effect. This vibration isolator is entirely composed of electromagnetic coils and permanent magnets, eliminating the need for contact-type mechanical elastic elements such as linear springs and leaf springs found in existing vibration isolators. This avoids the effects of fatigue, humidity, and lubrication. It overcomes the shortcomings of traditional high static-low dynamic stiffness vibration isolators, such as the inability to change the initial isolation frequency and the slow adjustment speed of damping and stiffness. Compared to other vibration suppression methods, the magnetic ring of this invention is nested within the electromagnetic coil, resulting in a simple, compact structure, small size, easy maintenance, and a large force, enabling it to handle more complex working conditions.

[0048] In the illustrated specific embodiment of the present invention, the electromagnetic coil includes a first coil 15, a second coil 17, and a third coil 19.

[0049] like Figure 1 and Figure 2 As shown, the vibration isolator provided by the present invention is a high static-low dynamic stiffness vibration isolator with variable stiffness and damping. It consists of three parts: the main structure of the variable stiffness vibration isolator, the electromagnetic damping element, and the branch circuit. The variable stiffness vibration isolator includes a base 1, an L-shaped first connecting piece 2, a bracket 3, an L-shaped second connecting piece 4, an upper fixed disc 5, a lower fixed disc 6, a lower magnet fixing frame 7, a lower coil baffle 8, a lower linear bearing 9, a transmission shaft 10, an upper linear bearing 11, an upper magnet fixing frame 12, an upper coil baffle 13, a first permanent magnet 14, a first coil 15, a second permanent magnet 16, a second coil 17, a third permanent magnet 18, and a vibration-isolated mass block 21.

[0050] In an optional embodiment of the present invention, the first permanent magnet 14, the second permanent magnet 16, and the third permanent magnet 18 are all ring-shaped permanent magnets.

[0051] The bracket 3 is vertically fixed to the base 1 via an L-shaped first connector 2. There are four brackets 3 arranged in a circular array on the base. The upper fixed disc 5 and the lower fixed disc 6 are fixed to the bracket 3 via an L-shaped second connector 4. The first permanent magnet 14 is fixed to the lower magnet mounting bracket 7, and the lower magnet mounting bracket 7 is fastened to the lower fixed disc 6 with bolts. The first coil 15 is wound around the lower magnet mounting bracket 7 and arranged coaxially and in the same plane as the first permanent magnet 14. The lower coil retainer 8 is fixed above the lower magnet mounting bracket 7 with screws to prevent relative movement of the first coil 15 during operation. The lower linear bearing 9 is interference-fitted with the central hole of the lower magnet mounting bracket 7. The lower end of the drive shaft 10 is slidably fitted with the lower linear bearing 9. The upper linear bearing 11 above the lower linear bearing 9 is slidably fitted on the upper end of the drive shaft 10. The upper linear bearing 11 is interference-fitted with the center hole of the upper magnet mounting bracket 12. The upper fixed disc 5 is fastened to the upper magnet mounting bracket 12. The upper coil baffle 13 is fixed below the upper magnet mounting bracket 12. The relationship between the second permanent magnet 16 and the second coil 17 and the upper magnet mounting bracket 12 is the same as the relationship between the first permanent magnet 14 and the first coil 15 and the lower magnet mounting bracket 7. The third permanent magnet 18 is fixed to the drive shaft 10 by welding and is located between the first permanent magnet 14 and the second permanent magnet 16. The vibration-damping mass block 21 is fixed to the upper end of the drive shaft by a nut and moves with the drive shaft 10. When the vibration-isolated object vibrates, the third permanent magnet 18 will move up and down relative to the first permanent magnet 14 and the second permanent magnet 16 in the axial direction, causing a change in the air gap between the third permanent magnet 18 and the first permanent magnet 14 and the second permanent magnet 16. As the air gap changes, the force between the permanent magnets also changes, resulting in a high static-low dynamic stiffness characteristic. The three permanent magnet poles are arranged opposite each other. The variable stiffness characteristic of the vibration isolator can be achieved by using the DSPACE controller to control the magnitude and direction of the current flowing through the first coil 15 and the second coil 17 based on the acceleration signals of the base 1 and the vibration-isolated mass block 21. When a positive current is applied, the repulsive forces generated by the first coil 15 and the second coil 17 and the first permanent magnet 14 and the second permanent magnet 16 are superimposed, increasing the stiffness of the vibration isolator. When a reverse current is applied, the attractive forces generated by the first coil 15 and the second coil 17 cancel out the repulsive forces generated by the first permanent magnet 14 and the second permanent magnet 16, decreasing the stiffness of the vibration isolator.

[0052] The electromagnetic damping element includes a third coil 19 and a coil clamp 20. The coil clamp 20 is fixed to the middle of the bracket 3 by a nut. The third coil 19 is fixed by the coil clamp 20 in a position coaxial and in the same plane as the third permanent magnet 18 in its equilibrium position. When external vibration occurs, the third permanent magnet 18 will generate relative vertical movement with the third coil 19. The third coil 19 will generate an induced current, thereby generating a force that opposes the relative movement between the third permanent magnet 18 and the third coil 19. Since this force is a variable related to the speed of motion, it can be regarded as a damping force.

[0053] like Figure 5 As shown, the branch circuit adopts a negative resistance branch circuit, forming a closed loop by connecting it across the two ends of the third coil 19. The third coil 19 can be equivalent to a coil resistance R in the loop. e and coil inductance l e The positive impedance and negative resistance branch circuit, formed by series connection, consists of two fixed resistors R1 and R2 of equal value, an operational amplifier O, and a variable resistor R. S The configuration is as follows: One end of the third coil 19 is grounded, and the other end is connected to the inverting input terminal (-) of operational amplifier O. One end of the fixed resistor R1 is grounded, and the other end is connected to the non-inverting input terminal (+) of operational amplifier O. The two ends of another fixed resistor R2 are connected between the non-inverting input terminal (+) and the output terminal of operational amplifier O, respectively. The variable resistor R... S Connected between the inverting input and output terminals of operational amplifier O. When the fixed resistors R1 and R2 have the same value, the resistance generated by operational amplifier O is equivalent to that of the variable resistor R. S The negative value of the resistance can effectively reduce the resistance in the third coil 19, thereby increasing the induced current and enhancing the electromagnetic damping effect.

[0054] like Figure 3 As shown, the vibration isolator provided by the present invention includes three permanent magnets. The three permanent magnets are all made of neodymium iron boron, which has strong magnetic properties. All three permanent magnets are axially magnetized, and the magnetization directions of two adjacent permanent magnets are opposite.

[0055] Optionally, such as Figure 2 As shown, the thickness of the first permanent magnet 14 located below the entire vibration isolator is slightly greater than the thickness of the second permanent magnet 16 and the third permanent magnet 18. This will generate an upward magnetic force difference. When the vibration isolator bears a mass equal to the difference, the middle third permanent magnet 18 will just return to the equilibrium position.

[0056] Optionally, the current polarity in the first coil 15 and the second coil 17 is always the same.

[0057] Optionally, the third permanent magnet 18 moves relative to the third coil 19 along with the drive shaft, and no additional current is supplied to the third coil 19; the damping force is generated by the induced current.

[0058] The following describes a single use of the present invention with reference to the accompanying drawings:

[0059] Example 1: With the stiffness unchanged, only the damping of the vibration isolator is changed.

[0060] The vibration isolator is fixed between the vibration source and the object being isolated. The first coil 15 and the second coil 17 are supplied with currents of the same magnitude and in the same direction. With the vibration of the excitation platform and the radial constraint of the lower linear bearing 9 and the upper linear bearing 11 on the transmission shaft 10, the third permanent magnet 18 will generate axial vertical relative motion with the third coil 19. The amplitude of this motion depends on the external excitation of the excitation platform. This induces an electromotive force in the third coil 19, the magnitude of which is related to the speed of the third permanent magnet 18. When the third coil 19 is connected to an external circuit, an induced current is generated. According to Ampere's law, this generates an Ampere force that opposes the movement of the third permanent magnet 18. Since this force is velocity-dependent, it can also be considered a type of electromagnetic damping force. This force hinders the vibration of the controlled object, achieving the effect of vibration suppression.

[0061] The negative resistance branch circuit reduces the resistance in the third coil 19, increasing the induced current and thus the damping force. However, excessive damping weakens the vibration isolation effect of this invention; therefore, a variable resistor R is added to the branch circuit. S When the external vibration frequency approaches the natural frequency of the vibration isolator, the isolator will resonate, and its vibration amplitude will increase significantly. In this case, the resistance needs to be reduced to increase the damping force and reduce the resonance peak. When the external vibration frequency is greater than √2 times the natural frequency of the vibration isolator, the isolator enters its operating range, and the vibration amplitude decreases significantly. In this case, the resistance needs to be increased to reduce the damping force and enhance the vibration isolation capability of the isolator. Frequency response simulations of this invention were performed using MATLAB software. Figure 7 ,Depend on Figure 7 It can be seen that, compared with the scheme without damping, the resonance peak value is significantly reduced after adding damping elements.

[0062] Example 2: With the damping unchanged, only the stiffness of the vibration isolator is changed.

[0063] The vibration isolator is fixed between the vibration source and the object being isolated. Vibration is transmitted to the base platform. The third permanent magnet 18 will move relative to the first permanent magnet 14 and the second permanent magnet 16. The air gap between the middle magnet and the upper and lower magnets changes. The attractive or repulsive force between the permanent magnets generally increases as the air gap decreases and decreases as the air gap increases. Therefore, the third permanent magnet 18 will experience a nonlinear force due to its vertical movement, thus exhibiting high static stiffness and low dynamic stiffness characteristics. When the first coil 15 and the second coil 17 are loaded with the rated positive excitation current, such as... Figure 3 As shown, the coupling of the third coil 19 with the magnetic ring will generate a repulsive electromagnetic force, which, combined with the repulsive force generated by the magnetic rings at both ends, will increase the resultant force applied to the middle magnetic ring and the equivalent stiffness of the system; when the first coil 15 and the second coil 17 are loaded with the rated reverse excitation current, as Figure 4 As shown, the coupling of the third coil 19 with the magnetic ring will generate an attractive electromagnetic force, which cancels out the repulsive force generated by the magnetic rings at both ends. The resultant force applied to the middle magnetic ring and the equivalent stiffness of the system will both decrease. The invention was modeled and simulated using the simulation software MAXWELL, and the stiffness characteristics of the vibration isolator when positive and negative currents are applied, as well as different currents, were obtained. Figure 6 ,Depend on Figure 6 It can be seen that the vibration isolator provided by the present invention has high static-low dynamic stiffness characteristics, and the stiffness can be adjusted by changing the direction and magnitude of the current in the first coil 15 and the second coil 17.

[0064] At this point, the present invention can achieve dynamic adjustment of stiffness and damping, and has the characteristics of fast response speed, large force, simple structure and easy maintenance. It has a good vibration isolation effect for low-frequency vibration isolation of mechanical systems.

[0065] The beneficial effects of this invention are:

[0066] Compared with existing technologies, a novel vibration isolator structure has been designed. This invention utilizes the change in the air gap between a moving magnet and two fixed magnets to generate a nonlinear force, achieving high static-low dynamic stiffness characteristics. An electromagnetic coil paired with a permanent magnet is used as the stiffness adjustment element. Variable stiffness characteristics can be achieved by changing the magnitude and direction of the current in the coil. Simultaneously, the resistance in the branch circuit can be changed to adjust the induced current in the central electromagnetic coil, generating a changing electromagnetic force to achieve variable damping characteristics. Compared to traditional vibration isolator structures, this design offers a wider isolation frequency band and allows for real-time adjustment. Even when the external circuit is inoperable, the isolator can still provide passive vibration isolation, exhibiting high robustness. This vibration isolator is entirely composed of an electromagnetic coil and a permanent magnet, overcoming the shortcomings of traditional high static-low dynamic stiffness vibration isolators, such as the inability to change the initial isolation frequency and slow damping and stiffness adjustment speed.

[0067] The vibration isolation system can generate appropriate damping force during operation by designing the height, thickness, inner and outer diameters of the central electromagnetic coil, as well as the parameters of the negative resistance in the branch circuit, taking into account actual manufacturing errors and structural dimensions. The adjustable range of the central electromagnetic coil dimensions is: height 20-30mm, thickness 15-30mm, inner diameter 13-15mm, and outer diameter varies with the inner diameter and thickness. The adjustable range of the negative resistance in the branch circuit is -2 to -30Ω. For vibrations at different frequencies, the magnitude of the negative resistance can be changed to generate a larger damping force in the resonance range to reduce the resonance peak, and a smaller damping force in the isolation range to improve the vibration isolation effect.

[0068] Compared to other vibration control methods, the magnetic ring of this invention is nested in the electromagnetic coil, which has a simple and compact structure, small size, easy maintenance, and generates a large force, and can cope with various complex working conditions.

[0069] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0070] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

Claims

1. A vibration isolator, characterized in that, include: Support frame; A first fixing frame and a second fixing frame are both fixedly connected to the support frame and are spaced apart along a first direction; A third fixing frame is fixedly connected to the support frame and is located between the first fixing frame and the second fixing frame; The first permanent magnet (14) and the second permanent magnet (16) are respectively fixedly installed on the first fixed frame and the second fixed frame; both the first permanent magnet (14) and the second permanent magnet (16) are provided with clearance holes; The first coil (15) and the second coil (17) are fixedly mounted on the first fixed frame and located on the outer periphery of the first permanent magnet (14). The second coil (17) is fixedly mounted on the second fixed frame and located on the outer periphery of the second permanent magnet (16). The third coil (19) is mounted on the third fixing frame and is located between the first coil (15) and the second coil (17); A drive shaft (10) is connected to the first fixed frame and the second fixed frame via a linear bearing. The drive shaft (10) can move relative to the support frame along the first direction. The drive shaft (10) passes sequentially through the clearance hole of the first permanent magnet (14) and the clearance hole of the second permanent magnet (16). The third permanent magnet (18) is fixedly mounted on the transmission shaft (10) and is arranged opposite to the third coil (19). The third permanent magnet (18) moves relative to the third coil (19) along the first direction. The vibration-isolated mass block (21) is fixedly connected to the upper end of the transmission shaft (10).

2. The vibration isolator according to claim 1, characterized in that, The vibration isolator also includes a negative resistance branch circuit, which is connected to the third coil (19). The negative resistance branch circuit includes fixed resistors R1 and R2, an operational amplifier O, and a variable resistor R. S One end of the third coil (19) is grounded, and the other end is connected to the inverting input terminal - of operational amplifier O. One end of the fixed resistor R1 is grounded, and the other end is connected to the non-inverting input terminal + of operational amplifier O. The two ends of another fixed resistor R2 are connected between the non-inverting input terminal + and the output terminal of operational amplifier O, respectively. The variable resistor R S Connected between the inverting input terminal and the output terminal of operational amplifier O; the fixed resistors R1 and R2 have the same resistance value.

3. The vibration isolator according to claim 1, characterized in that, The support frame includes a base (1) and multiple brackets (3). The multiple brackets (3) are arranged in a circumferential array on the upper surface of the base (1), and the multiple brackets (3) are fixedly connected to the base (1). The first fixing frame includes a lower fixing disc (6), a lower magnet fixing frame (7), and a lower coil baffle (8). The lower fixing disc (6) is fixedly connected to a plurality of brackets (3). The lower fixing disc (6) is located above the base (1). The lower magnet fixing frame (7) is fixedly connected to the lower fixing disc (6). The lower coil baffle (8) is fixedly connected to the lower magnet fixing frame (7). The lower magnet fixing frame (7) has a first annular surrounding plate. The lower coil baffle (8) and the inner side of the first annular surrounding plate together form an installation space for installing the first permanent magnet (14). The lower coil baffle (8) and the outer side of the first annular surrounding plate together form an installation space for installing the first coil (15). The second fixing frame includes an upper fixing disc (5), an upper magnet fixing frame (12), and an upper coil baffle (13). The upper fixing disc (5) is fixedly connected to a plurality of brackets (3). The upper fixing disc (5) is located above the lower coil baffle (8). The upper magnet fixing frame (12) is fixedly connected to the upper fixing disc (5). The upper coil baffle (13) is fixedly connected to the upper magnet fixing frame (12). The upper magnet fixing frame (12) has a second annular surrounding plate. The upper coil baffle (13) and the inner side of the second annular surrounding plate together form an installation space for installing the second permanent magnet (16). The upper coil baffle (13) and the outer side of the second annular surrounding plate together form an installation space for installing the second coil (17). The third fixing frame includes a coil clamp (20), which is fixedly connected to a plurality of supports (3), and the coil clamp (20) has a clamping space for clamping the third coil (19).

4. The vibration isolator according to claim 3, characterized in that, The vibration isolator also includes: The first connector (2) is L-shaped and has a connecting hole for mounting bolts. The first connector (2) includes a first connecting plate and a second connecting plate connected at right angles. The first connecting plate is connected to the bracket by bolts, and the second connecting plate is connected to the base by bolts. Each bracket (3) is fixed to the base (1) by two first connectors (2). The second connector (4) is L-shaped and has connecting holes for mounting bolts. The second connector (4) includes a third connecting plate and a fourth connecting plate connected at right angles. The third connecting plate is connected to the bracket by bolts, and the fourth connecting plate is connected to the upper fixed disc (5) or the lower fixed disc (6) by bolts. The upper fixed disc (5) is connected to multiple brackets (3) one by one through multiple second connectors (4), and the lower fixed disc (6) is connected to multiple brackets (3) one by one through multiple second connectors (4). The linear bearing includes an upper linear bearing (11) and a lower linear bearing (9); The upper fixed disc (5) is provided with a first assembly hole, and the upper magnet fixing bracket (12) also includes a first annular mounting plate. The first annular mounting plate passes through the first assembly hole, and an upper linear bearing (11) that cooperates with the transmission shaft (10) is installed in the first assembly hole. The lower fixed disc (6) is provided with a second mounting hole, and the lower magnet fixing bracket (7) also includes a second annular mounting plate. The second annular mounting plate passes through the second mounting hole, and a lower linear bearing (9) that cooperates with the transmission shaft (10) is installed in the second mounting hole.

5. The vibration isolator according to claim 1, characterized in that, The first permanent magnet (14), the second permanent magnet (16), and the third permanent magnet (18) are all made of neodymium iron boron; The first permanent magnet (14), the second permanent magnet (16), and the third permanent magnet (18) are all axially magnetized; The magnetization directions of two adjacent permanent magnets among the first permanent magnet (14), the second permanent magnet (16), and the third permanent magnet (18) are opposite.

6. The vibration isolator according to claim 1, characterized in that, The thickness of the first permanent magnet (14) is greater than that of the second permanent magnet (16); The thickness of the first permanent magnet (14) is greater than that of the third permanent magnet (18).

7. The vibration isolator according to claim 1, characterized in that, The polarity of the current in the first coil (15) and the second coil (17) is always the same.

8. The vibration isolator according to claim 1, characterized in that, The third permanent magnet (18) moves relative to the third coil (19) along with the transmission shaft (10). No additional current is passed through the third coil (19), and the damping force is generated by the induced current.

9. A method for adjusting a vibration isolator, characterized in that, The vibration isolator is the vibration isolator according to any one of claims 1 to 8, and the stiffness adjustment method includes the following steps: When the vibration isolation object vibrates, the third permanent magnet (18) will move up and down relative to the first permanent magnet (14) and the second permanent magnet (16) in the axial direction, causing the air gap between the third permanent magnet (18) and the first permanent magnet (14) and the second permanent magnet (16) to change. As the air gap changes, the force between the permanent magnets will also change, thus producing a high static-low dynamic stiffness characteristic. The three permanent magnet poles are arranged opposite each other. The variable stiffness characteristics of the vibration isolator are realized by using the DSPACE controller to control the magnitude and direction of the current supplied to the first coil (15) and the second coil (17) according to the acceleration signal of the base (1) and the vibration isolating mass block (21). When a positive current is applied to the first coil (15) and the second coil (17), the repulsive forces generated by the first coil (15) and the second coil (17) with the first permanent magnet (14) and the second permanent magnet (16) are superimposed, and the stiffness of the vibration isolator increases. When reverse current is applied to the first coil (15) and the second coil (17), the attraction between the first coil (15) and the second coil (17) cancels out the repulsion between the first permanent magnet (14) and the second permanent magnet (16), and the stiffness of the vibration isolator decreases. When external vibration occurs, the third permanent magnet (18) and the third coil (19) generate relative up-down movement. The third coil (19) generates an induced current, which generates a damping force that opposes the relative movement between the third permanent magnet (18) and the third coil (19).

10. The method for adjusting a vibration isolator according to claim 9, characterized in that, The vibration isolator is the vibration isolator according to claim 2, and the stiffness adjustment method includes the following steps: When the fixed resistors R1 and R2 have the same resistance, the operational amplifier O generates a resistance equivalent to the variable resistor R. S The negative value of the resistance reduces the resistance in the third coil (19) of the vibration isolator, increases the induced current, and enhances the electromagnetic damping effect.

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