CN115585213A - Modular vibration isolator with quasi-zero rigidity characteristic and vibration reduction platform thereof - Google Patents
Modular vibration isolator with quasi-zero rigidity characteristic and vibration reduction platform thereof Download PDFInfo
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- CN115585213A CN115585213A CN202211202197.8A CN202211202197A CN115585213A CN 115585213 A CN115585213 A CN 115585213A CN 202211202197 A CN202211202197 A CN 202211202197A CN 115585213 A CN115585213 A CN 115585213A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F13/00—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs
- F16F13/005—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising both a wound spring and a damper, e.g. a friction damper
- F16F13/007—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising both a wound spring and a damper, e.g. a friction damper the damper being a fluid damper
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
- F16F15/022—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using dampers and springs in combination
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
- F16F15/023—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using fluid means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
- F16F15/03—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using magnetic or electromagnetic means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
- F16F15/04—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using elastic means
- F16F15/06—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using elastic means with metal springs
- F16F15/067—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using elastic means with metal springs using only wound springs
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F6/00—Magnetic springs; Fluid magnetic springs, i.e. magnetic spring combined with a fluid
- F16F6/005—Magnetic springs; Fluid magnetic springs, i.e. magnetic spring combined with a fluid using permanent magnets only
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F2228/00—Functional characteristics, e.g. variability, frequency-dependence
- F16F2228/06—Stiffness
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Abstract
The invention belongs to the technical field related to vibration control equipment and discloses a modular vibration isolator with a quasi-zero stiffness characteristic, which comprises a damping unit, a positive stiffness unit and a negative stiffness unit, wherein the damping unit comprises an external cylinder body and an end cover thereof, an internal piston rod and an end cover thereof, an energy storage element and the like; the negative stiffness unit comprises two groups of annular permanent magnets, wherein one group of the annular permanent magnets are arranged in a repulsion mode and are respectively fixed on the inner wall of the cylinder body and the middle of the piston head, the other group of the annular permanent magnets are arranged in an attraction mode and are respectively fixed at two ends of the cylinder body and two ends of the piston head, and the two groups of the annular permanent magnets generate negative stiffness through relative movement; the positive stiffness unit comprises a metal pressure spring and an adjusting nut. By the aid of the vibration isolation device, a wider and stable quasi-zero stiffness interval can be realized, larger bearing capacity is provided, and better vibration isolation effect can be guaranteed; in addition, the compact structure can adapt to narrow installation space, the application universality is improved through the modular design, and the multi-degree-of-freedom vibration reduction requirement can be realized through arrangement and combination.
Description
Technical Field
The invention belongs to the technical field related to vibration control equipment, and particularly relates to a modular vibration isolator with a quasi-zero stiffness characteristic and a vibration damping platform thereof.
Background
The continuous periodic vibration in the flight process has great influence on airborne equipment such as a spectrum detector, a stabilized sight and the like, so that the operation precision of the carried equipment is influenced, the overall operation environment of the equipment is possibly worsened, and the structure is damaged. The problem of vibration suppression of airborne equipment has been a research hotspot of international academia for a long time, and most airborne equipment has the characteristics of large mass, limited installation space and the like, so that the design of related vibration isolators needs to simultaneously consider the two aspects of size and performance.
Aiming at the existing large-mass airborne equipment with limited installation space, the currently common damping means comprise three types: optimizing the structural form of the equipment, coating damping materials or installing vibration isolators and installing vibration absorbers to transfer the vibration response of the equipment. Most of the vibration isolators are designed based on rubber materials and wire meshes, the structure is simple, the requirements of large bearing capacity and compact installation space can be met, and the vibration isolation performance is not satisfactory. The high static and low dynamic characteristics of the quasi-zero stiffness vibration isolator can provide large bearing capacity, the vibration isolation bandwidth of a system can be effectively lengthened, and the quasi-zero stiffness vibration isolator correspondingly has high vibration isolation performance.
However, further research has shown that the quasi-zero stiffness vibration isolator in the prior art still has the following defects or shortcomings: the positive stiffness element and the negative stiffness element are formed by connecting positive and negative stiffness mechanisms in parallel, wherein for the negative stiffness serving as a core technology, the negative stiffness is mainly realized by methods such as a bending beam, a disc spring, a magnet, a cam roller, special materials and the like, and the positive stiffness element generally adopts a metal spring, and the positive stiffness element and the metal spring form a parallel connection structure in space. In fact, the parallel mechanisms of the above kind generally form a cubic shape, have a large volume and limited applicable scenes, and are difficult to meet the installation requirements of the vibration damping system of the airborne heavy equipment.
Disclosure of Invention
Aiming at the defects or requirements in the prior art, the invention aims to provide a modular vibration isolator with a quasi-zero stiffness characteristic and a vibration damping platform thereof, wherein the structural composition and the spatial layout of the whole device are redesigned, the combined magnetic negative stiffness is introduced into a damper, and a positive stiffness element is connected in parallel with the outer side of a cylinder body, so that a wider and stable quasi-zero stiffness interval can be realized, greater bearing is provided, a better vibration isolation effect can be ensured, the cost is low, and the power consumption is low; in addition, the compact structure can adapt to narrow installation space, the modular design can improve application universality, and the vibration reduction requirement of multiple degrees of freedom is realized through arrangement and combination.
To achieve the above object, according to one aspect of the present invention, there is provided a modular vibration isolator having a quasi-zero stiffness characteristic, the modular vibration isolator including a damping unit, a positive stiffness unit, and a negative stiffness unit arranged in parallel with each other, characterized in that:
the damping unit comprises a cylinder body, a piston rod, a floating piston plate and an energy storage spring, wherein the interior of the cylinder body is filled with damping liquid, the upper end of the cylinder body is provided with a cylinder body end cover, and a static sealing ring is arranged between the cylinder body end cover and the cylinder body; the piston rod is coaxially inserted and arranged in the cylinder body, and the lower end of the piston rod is provided with a piston rod end cover; the floating piston plate and the energy storage spring are sequentially arranged at the lower part of the piston rod end cover;
the positive stiffness unit comprises a metal compression spring and an adjusting nut, wherein the metal compression spring is integrally sleeved outside the cylinder body, one end of the metal compression spring is in contact with the tail of the piston rod, and the other end of the metal compression spring is in contact with the adjusting nut; the adjusting nut is in threaded connection with the outer side of the cylinder body, and changes the preload of the metal pressure spring by changing the position of the adjusting nut;
the negative stiffness unit comprises a permanent magnet at the upper end of the attraction group, a permanent magnet at the lower end of the repulsion group, a permanent magnet at the lower end of the attraction group and a positioning sleeve, wherein the permanent magnet at the upper end of the attraction group is fixedly connected with the end cover of the cylinder body, and the permanent magnet at the lower end of the attraction group is fixedly connected with the floating piston plate, so that a first magnet group which is oppositely arranged and mutually attracted up and down is formed; the rotor permanent magnet at the upper end of the attraction group and the rotor permanent magnet at the lower end of the attraction group are fixedly connected to the head part of the piston rod, and a second magnet group which is opposite to each other and mutually attracted is also formed; the repulsion group rotor permanent magnet and the repulsion group stator permanent magnet are fixed in the middle of the second magnet group and form a third magnet group which is horizontally opposite and mutually repulsive; in addition, the positioning sleeve is used for keeping the first magnet group, the second magnet group, the third magnet group and the piston rod to be coaxially and annularly arranged.
As a further preference, it is preferable for the piston rod to adopt a stepped configuration, wherein the outside diameter of the step near the head of the piston rod is larger than the inside diameter of the permanent magnets of the upper end stator of the attraction group, and the outside diameter of the end cover of the piston rod is larger than the inside diameter of the permanent magnets of the lower end stator of the attraction group.
As a further preference, the floating piston plate and the positioning sleeve preferably have relative movement therebetween and are connected by a dynamic seal ring; the stored energy spring is preferably compressed during installation, thereby increasing the damping fluid pressure inside the cylinder.
As a further preference, the first to third magnet groups are each separated from one another by a spacer, and the respective permanent magnets therein are preferably designed as hollow cylinders.
As a further preferred, for the first and second magnet sets, it is preferable that axial magnetization is adopted, and the upper and lower polarities of the permanent magnets are opposite, wherein the magnetization directions of the permanent magnet of the upper end of the attraction set and the permanent magnet of the upper end of the attraction set are up and N and the magnetization directions of the permanent magnet of the lower end of the attraction set and the permanent magnet of the lower end of the attraction set are up and S and N, and the outer ring of each permanent magnet is plated with a wear-resistant layer.
As a further preferred aspect, for the third magnet set, it is preferable that the height and the magnetic pole arrangement are the same, and radial magnetization with opposite internal and external polarities is adopted, wherein the magnetization direction of the repulsion group rotor permanent magnets is inner N and outer S, the outer ring thereof is plated with a wear-resistant layer, the magnetization direction of the repulsion group stator permanent magnets is inner S and outer N, and the inner ring is plated with a wear-resistant layer.
Preferably, the piston rod and the cylinder body are respectively provided with an external thread at the tail part, so that the piston rod and the cylinder body can be conveniently connected with different types of adapters.
According to another aspect of the invention, the invention further provides a corresponding single-freedom-degree vibration reduction platform, which is characterized in that the single-freedom-degree vibration reduction platform is formed by adopting four modular vibration isolators together and is used for realizing the vibration isolation characteristic in the vertical direction.
According to another aspect of the invention, the corresponding multi-degree-of-freedom vibration reduction platform is further provided, and is characterized in that the multi-degree-of-freedom vibration reduction platform is formed by adopting six modular vibration isolators together and is constructed into a Stewart platform.
Generally, compared with the prior art, the technical scheme of the invention mainly has the following technical advantages:
(1) The invention redesigns the structural composition and spatial layout of the whole modular shock absorber, realizes the configuration of the quasi-zero stiffness vibration isolator by introducing the magnetic negative stiffness into the interior of the shock absorber and connecting the positive stiffness spring on the cylinder body shell in parallel, has compact integral structure and can be applied to the shock absorption environment with limited installation space; meanwhile, the vibration isolator adopts a pure passive design, and has simple structure, low cost and low power consumption;
(2) The invention further carries out targeted improvement on the specific structure and arrangement mode of a plurality of key components such as the negative stiffness unit, wherein two groups of annular permanent magnets are adopted, one group of annular permanent magnets are arranged in a repulsion mode and are respectively fixed on the inner wall of the cylinder body and the middle part of the piston head, the other group of annular permanent magnets are arranged in an attraction mode and are respectively fixed on the end part of the cylinder body and the end part of the piston head, and the two groups of permanent magnets which are arranged in different modes generate negative stiffness through relative movement;
(3) The vibration isolator adopts a modular design, the joints at the two ends of the vibration isolator can be replaced, the vibration isolator can be suitable for different working scenes, meanwhile, various vibration reduction platforms are constructed through combination, diversified vibration reduction requirements can be met, and the universality of the application of the vibration isolator is obviously improved.
Drawings
Figure 1 is a cross-sectional view of the overall structure of a modular vibration isolator having a quasi-zero stiffness characteristic in accordance with the present invention;
FIG. 2 is a schematic diagram showing the modular vibration isolator of FIG. 1;
figure 3 is a graph showing negative stiffness versus displacement for a modular vibration isolator according to the present invention;
figure 4 is a single degree of freedom vibration damping platform constructed from four modular vibration isolators having a quasi-zero stiffness characteristic in accordance with a preferred embodiment of the present invention;
figure 5 is a multi-degree of freedom vibration attenuation platform constructed from six modular vibration isolators exhibiting quasi-zero stiffness characteristics in accordance with another preferred embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is an overall structural cross-sectional view of a modular vibration isolator having a quasi-zero stiffness characteristic in accordance with the present invention. As shown in fig. 1, the apparatus mainly includes components such as a damping unit, a positive stiffness unit, and a negative stiffness unit, which are arranged in parallel with each other, and will be specifically explained one by one.
Referring to fig. 2, a schematic diagram of a modular vibration isolator with quasi-zero stiffness according to the present invention is shown, wherein a base is connected to a lower end of the vibration isolator, a vibration displacement is expressed as x, a device is connected to an upper end of the vibration isolator, and a vibration displacement is expressed as y. The key negative stiffness unit adopts a combined magnetic negative stiffness structure and is composed of a repulsion type magnet group and an attraction type magnet group, and a wider stable negative stiffness interval can be realized.
For the damping unit, the damping unit comprises a cylinder body 12, a piston rod 1, a floating piston plate 14 and an energy storage spring 13, wherein the interior of the cylinder body 12 is filled with damping liquid 20, and the upper end of the cylinder body is provided with a cylinder body end cover 3; the piston rod 1 is coaxially inserted into the cylinder body 12, and the lower end of the piston rod is provided with a piston rod end cover 17; the floating piston plate 14 and the energy storage spring 13 are sequentially arranged at the lower part of the piston rod end cover 17.
For the positive stiffness unit, the positive stiffness unit comprises a metal pressure spring 2 and an adjusting nut 19, wherein the metal pressure spring 2 is integrally sleeved outside the cylinder body 12, one end of the metal pressure spring is in contact with the tail part of the piston rod 1, and the other end of the metal pressure spring is in contact with the adjusting nut 19; the adjusting nut 19 is screwed to the outside of the cylinder body 12 and changes the preload force of the metal compression spring 2 by changing its position. More specifically, the metal compression spring 2 is used for providing positive rigidity, the inner diameter of the metal compression spring is larger than the outer diameter of the cylinder 12, one end of the metal compression spring is in contact with the tail part of the piston rod 1, the other end of the metal compression spring is in contact with the adjusting nut 19, and the preload of the metal compression spring 2 is changed by changing the position of the adjusting nut 19.
For the negative stiffness unit, as one of the key components of the present invention, the negative stiffness unit includes an attraction group upper end stator permanent magnet 4, an attraction group lower end stator permanent magnet 10, an attraction group upper end mover permanent magnet 6, an attraction group lower end mover permanent magnet 9, an repulsion group mover permanent magnet 7, an repulsion group stator permanent magnet 8 and a positioning sleeve 11, wherein the attraction group upper end stator permanent magnet 4 is fixedly connected to the cylinder end cover 3, and the attraction group lower end stator permanent magnet is fixedly connected to the floating piston plate 14, thereby forming a first magnet group that is oppositely arranged and mutually attracted; the upper rotor permanent magnet 6 of the attraction group and the lower rotor permanent magnet 9 of the attraction group are fixedly connected to the head of the piston rod 1, and a second magnet group which is opposite to each other and mutually attracted is formed in the same way; the repulsion group rotor permanent magnet 7 and the repulsion group stator permanent magnet 8 are fixed in the middle of the second magnet group and form a third magnet group which is horizontally opposite and mutually repulsive; in addition, the positioning sleeve 11 is used for holding the first to third magnet sets and the piston rod to be coaxially and annularly mounted.
More specifically, referring to fig. 1 and 2, the cylinder 12 is filled with damping fluid 20, the outer side of the cylinder is connected to the adjusting nut 19 through a screw thread, and a static sealing ring 21 is installed between the cylinder end cover 3 and the cylinder 12. The piston rod 1 is inserted into the cylinder 12 and is prevented from leaking by the movable seal ring 15. The head of the piston rod 1 is mainly provided with a repulsion group rotor permanent magnet 7, an attraction group upper end rotor permanent magnet 6, a gasket 18, an attraction group lower end rotor permanent magnet 9 and a piston rod end cover 17, a piston rod head element is fixedly connected with the piston rod 2 through a screw 16, the repulsion group stator permanent magnet 8 is fixed on the inner side of the cylinder body 12, the height of the repulsion group stator permanent magnet is preferably consistent with that of the whole piston rod head, the axial position of the repulsion group stator permanent magnet is determined through a positioning sleeve 11, the repulsion group stator permanent magnet is installed coaxially with the piston rod 2, and an annular gap is reserved between the repulsion group stator permanent magnet and the piston rod head in the radial direction to serve as a flow channel of damping liquid 20. The locating sleeve 11 is fixedly connected with the cylinder body 12, the floating piston plate 14 and the locating sleeve 11 move relatively, but the relative movement displacement is small, the locating sleeve and the floating piston plate are connected through the movable sealing ring 15, and the energy storage spring 13 is compressed when being installed, so that the liquid pressure of the damping liquid 20 in the cylinder body 12 is increased.
In addition, the permanent magnet 4 of the upper stator of the attraction group is fixedly connected with the end cover 3 of the cylinder body, the permanent magnet 10 of the lower stator of the attraction group is fixedly connected with the floating piston plate 14, the permanent magnet 6 of the upper rotor of the attraction group and the permanent magnet 9 of the lower rotor of the attraction group are fixed at the head of the piston rod, the permanent magnet 7 of the repulsion group is fixed in the middle, and the three are separated by a gasket 18.
Through the design, when the piston rod 1 moves downwards relative to the cylinder 12 under pressure, the repelling group rotor permanent magnet 7 positioned at the head of the piston rod generates same-direction displacement relative to the repelling group stator permanent magnet 8, so that the piston rod 1 is under a downward acting force, meanwhile, the attracting group lower rotor permanent magnet 9 at the head of the piston rod is close to the attracting group lower stator permanent magnet 10, and the attraction force generated between the attracting group lower rotor permanent magnet and the attracting group upper rotor permanent magnet 6 is greater than the attraction force between the attracting group upper rotor permanent magnet and the upper stator permanent magnet 4, so that a downward acting force is also generated on the piston rod 1, and a negative stiffness effect is generated; when the piston rod 1 is pulled to move upwards relative to the cylinder 12, the negative stiffness unit also generates a force which is beneficial to the movement of the piston rod 1. By analogy, when the piston rod 1 is pulled upwards relative to the cylinder 12, the negative stiffness unit also generates a force that facilitates the movement of the piston rod. In addition, the metal compression spring is used for providing positive rigidity, the inner diameter of the metal compression spring is larger than the outer diameter of the cylinder body, one end of the metal compression spring is in contact with the tail of the piston rod, the other end of the metal compression spring is in contact with the adjusting nut, and the pre-loading force of the metal compression spring is changed by changing the position of the adjusting nut.
According to a preferred embodiment of the invention, the permanent magnets for realizing the negative rigidity effect are all hollow cylindrical, wherein the magnetization directions of the upper-end stator permanent magnet 4 of the attraction group and the upper-end rotor permanent magnet 6 of the attraction group are up N and down S, the magnetization directions of the lower-end rotor permanent magnet 9 of the attraction group and the lower-end stator permanent magnet 10 of the attraction group are up S and down N, and the outer rings are plated with a wear-resistant layer 5; the heights and the magnetic pole arrangement modes of the repulsion group rotor permanent magnet 7 and the repulsion group stator permanent magnet 8 are the same, radial magnetization with opposite internal and external polarities is adopted, wherein the magnetization direction of the repulsion group rotor permanent magnet 7 is internal N and external S, the outer ring is plated with a wear-resistant layer 5, the magnetization direction of the repulsion group stator permanent magnet 8 is internal S and external N, and the inner ring is plated with a wear-resistant layer 5, so that the abrasion degree caused by the flowing of the damping liquid 20 is reduced.
According to another preferred embodiment of the present invention, the piston rod 1 may adopt a step-like configuration, wherein the outer diameter of the step near the head of the piston rod is larger than the inner diameter of the stator permanent magnet 4 at the upper end of the attraction group, and the outer diameter of the end cover 17 of the piston rod is larger than the inner diameter of the stator permanent magnet 10 at the lower end of the attraction group, so as to prevent the attraction of the mover and the stator of the permanent magnet of the attraction group when the piston rod moves up and down.
Referring to fig. 3, a graph showing the change of negative stiffness with displacement of the modular vibration isolator with quasi-zero stiffness of the present invention is obtained by finite element simulation, and it can be known from the graph that the arrangement of the permanent magnets of the present invention can ensure a wider stable negative stiffness range, and the specific negative stiffness value can be changed by adjusting the structural parameters or the residual magnetization intensity, and then the quasi-zero stiffness with a wider stroke is realized by connecting the matched positive stiffness unit in parallel, so that the vibration isolation performance of the present invention can be effectively improved.
It should be noted that the modular vibration isolator with the quasi-zero stiffness characteristic is not limited to be used singly and can be used in combination, and the cylindrical platforms at the tail parts of the piston rod and the cylinder body are provided with external threads and can be connected with different types of adapters so as to construct different types of vibration isolation platforms and meet the requirements of vibration reduction with multiple degrees of freedom.
Specifically, referring to fig. 4, a single degree of freedom vibration damping platform constructed from four modular vibration isolators having a quasi-zero stiffness characteristic in accordance with a preferred embodiment of the present invention is shown. As can be seen from fig. 4, by using a plurality of sets of modular vibration isolators a to construct the single-degree-of-freedom vibration damping platform 23, a greater load can be provided while still maintaining good vertical vibration isolation characteristics.
Referring to fig. 5, a multiple degree of freedom vibration damping platform constructed from six modular vibration isolators exhibiting quasi-zero stiffness characteristics in accordance with another preferred embodiment of the present invention is shown. As can be seen from fig. 5, the form of the adapter 22 is not limited to one, and by changing the adapter into a spherical shape, the adapter can be used for constructing the Stewart platform 24, and accordingly, the adapter can be well applied to multi-degree-of-freedom vibration reduction.
In conclusion, the modular vibration isolator has the advantages that the combined magnetic negative stiffness is introduced into the damper, and the positive stiffness element is connected to the outer side of the cylinder body in parallel, so that a wider quasi-zero stiffness interval can be realized, a good vibration isolation effect is guaranteed while large bearing is provided, and the modular vibration isolator is simple in structure, low in cost and low in power consumption; the compact structure can meet the installation requirement of the vibration isolation system of the airborne heavy equipment; the modular design improves the application universality of the invention, can meet the requirement of vibration reduction with multiple degrees of freedom through arrangement and combination, and has wide application prospect.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. A modular vibration isolator having a quasi-zero stiffness characteristic, the modular vibration isolator including a damping unit, a positive stiffness unit, and a negative stiffness unit arranged in parallel with one another, characterized in that:
the damping unit comprises a cylinder body (12), a piston rod (1), a floating piston plate (14) and an energy storage spring (13), wherein the interior of the cylinder body (12) is filled with damping liquid (20), the upper end of the cylinder body is provided with a cylinder body end cover (3), and a static sealing ring (21) is arranged between the cylinder body end cover (3) and the cylinder body (12); the piston rod (1) is coaxially inserted into the cylinder body (12), and the lower end of the piston rod is provided with a piston rod end cover (17); the floating piston plate (14) and the energy storage spring (13) are sequentially arranged at the lower part of the piston rod end cover (17);
the positive stiffness unit comprises a metal pressure spring (2) and an adjusting nut (19), wherein the metal pressure spring (2) is integrally sleeved outside the cylinder body (12), one end of the metal pressure spring is in contact with the tail part of the piston rod (1), and the other end of the metal pressure spring is in contact with the adjusting nut (19); the adjusting nut (19) is in threaded connection with the outer side of the cylinder body (12) and changes the preload force of the metal pressure spring (2) by changing the position of the adjusting nut;
the negative stiffness unit comprises an upper stator permanent magnet (4) of the attraction group, a lower stator permanent magnet (10) of the attraction group, an upper rotor permanent magnet (6) of the attraction group, a lower rotor permanent magnet (9) of the attraction group, a repulsion rotor permanent magnet (7) of the repulsion group, a repulsion stator permanent magnet (8) of the repulsion group and a positioning sleeve (11), wherein the upper stator permanent magnet (4) of the attraction group is fixedly connected with the cylinder body end cover (3), and the lower stator permanent magnet of the attraction group is fixedly connected with the floating piston plate (14), so that a first magnet group which is oppositely arranged and mutually attracted up and down is formed; the upper rotor permanent magnet (6) and the lower rotor permanent magnet (9) of the attraction group are fixedly connected to the head of the piston rod (1) to form a second magnet group which is opposite to each other and mutually attracted; the repulsion group rotor permanent magnet (7) and the repulsion group stator permanent magnet (8) are fixed in the middle of the second magnet group and form a third magnet group which is horizontally opposite and mutually repulsive; in addition, the positioning sleeve (11) is used for keeping the first magnet group, the second magnet group, the third magnet group and the piston rod to be coaxially and annularly installed.
2. The modular vibration isolator of claim 1 characterized in that it is preferable for the piston rod (1) to adopt a stepped configuration in which the outer diameter of the step near the head of the piston rod is greater than the inner diameter of the attracting group upper end stator permanent magnet (4) and the outer diameter of the piston rod end cap (17) is greater than the inner diameter of the attracting group lower end stator permanent magnet (10).
3. The modular vibration isolator according to claim 1 or 2, characterized in that there is preferably relative movement between the floating piston plate (14) and the locating sleeve (11) and is connected by a dynamic seal (15); the energy-storing spring (13) is preferably compressed during installation, thereby increasing the damping hydraulic pressure inside the cylinder (12).
4. The modular vibration isolator of any one of claims 1 to 3 wherein the first to third magnet sets are spaced apart from each other by spacers (18) and wherein each permanent magnet is preferably designed in the form of a hollow cylinder.
5. The vibration isolator according to claim 4, wherein the first and second magnet sets are magnetized in the axial direction, and the polarities of the upper and lower permanent magnets are opposite, wherein the magnetization directions of the attracting set upper end stator permanent magnet (4) and the attracting set upper end mover permanent magnet (6) are up N and down S, the magnetization directions of the attracting set lower end mover permanent magnet (9) and the attracting set lower end stator permanent magnet (10) are up S and down N, and the outer ring of each permanent magnet is coated with a wear-resistant layer (5).
6. The modular vibration isolator according to claim 5, wherein for the third magnet set, it is preferable that the height and the magnetic pole arrangement are the same, and radial magnetization with opposite inner and outer polarities is adopted, wherein the magnetization direction of the repulsive set mover permanent magnets (7) is inner N outer S, the outer rings are coated with a wear resistant layer (5), the magnetization direction of the repulsive set stator permanent magnets (8) is inner S outer N, and the inner rings are coated with a wear resistant layer (5).
7. The modular vibration isolator according to any of the claims 1 to 6, characterized in that the respective tail parts of the piston rod (1) and the cylinder body (12) are provided with external threads for facilitating the connection with different types of adapters (22).
8. A single-dof vibration reduction platform, characterized in that the single-dof vibration reduction platform is formed by four modular vibration isolators according to any one of claims 1 to 7, and is used for realizing the vibration isolation characteristic in the vertical direction.
9. A multi-degree-of-freedom vibration-damping platform, which is formed by six modular vibration isolators according to any one of claims 1 to 7 and is constructed as a Stewart platform.
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| CN118461849A (en) * | 2024-07-09 | 2024-08-09 | 上海路博减振科技股份有限公司 | Negative-rigidity floating floor provided with diagonal bracing lead damper |
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| CN115585213B (en) | 2024-04-19 |
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