CN111734779A - Ultralow frequency air spring vibration isolator based on radial magnetization magnetic ring negative stiffness structure - Google Patents
Ultralow frequency air spring vibration isolator based on radial magnetization magnetic ring negative stiffness structure Download PDFInfo
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- CN111734779A CN111734779A CN202010606305.2A CN202010606305A CN111734779A CN 111734779 A CN111734779 A CN 111734779A CN 202010606305 A CN202010606305 A CN 202010606305A CN 111734779 A CN111734779 A CN 111734779A
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- air chamber
- vibration isolator
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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
- F16F13/002—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising at least one fluid spring
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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
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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
- F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
- F16F9/02—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using gas only or vacuum
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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
- F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
- F16F9/32—Details
- F16F9/34—Special valve constructions; Shape or construction of throttling passages
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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
- F16F2222/00—Special physical effects, e.g. nature of damping effects
- F16F2222/12—Fluid damping
- F16F2222/126—Fluid damping using gases
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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
- F16F2228/063—Negative stiffness
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- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Vibration Prevention Devices (AREA)
Abstract
An ultralow frequency air spring vibration isolator based on a radial magnetization magnetic ring negative stiffness structure belongs to the technical field of precision vibration isolation, and comprises a double-chamber air spring vibration isolator and a negative stiffness magnetic spring, wherein the negative stiffness magnetic spring is coaxially nested in a main air chamber of the double-chamber air spring vibration isolator, an annular rubber pad is arranged at the bottom of the main air chamber, and 2-10 throttling holes are uniformly formed between the main air chamber and an additional air chamber; the negative-stiffness magnetic spring comprises an inner fixed magnetic ring, a movable magnetic ring and an outer fixed magnetic ring which are magnetized along the radial direction and are coaxially nested, and the centers of the axial heights of the inner fixed magnetic ring and the outer fixed magnetic ring are positioned on the same horizontal line; the invention has low natural frequency, large damping coefficient, high integration level and stability, can avoid rigid collision between the impact disturbance excitation guide actuating magnetic ring and the bottom of the main air chamber, and realizes the low-frequency/ultralow-frequency vibration isolation effect of precision instruments and equipment.
Description
Technical Field
The invention belongs to the technical field of precise vibration reduction, and particularly relates to an ultralow-frequency air spring vibration isolator based on a radial magnetized magnetic ring negative stiffness structure.
Background
In the processes of adjustment, test and experiment of precision instruments and equipment, low-frequency vibration interference in the environment becomes one of key problems influencing the research effect, and the equipping of a large-load-bearing air spring vibration isolator for the precision instruments and equipment gradually becomes a main technical means for inhibiting environmental micro-vibration in the field of large-scale ultra-precision engineering, but the following problems still exist in the research of the air spring vibration isolator:
(1) the natural frequency of the air spring vibration isolator is high, and the low-frequency/ultralow-frequency vibration interference in the environment cannot be inhibited. The existing air spring vibration isolator can achieve large bearing and medium-high frequency vibration suppression effects, but the volume of a cavity needs to be increased for achieving low-frequency/ultralow-frequency vibration suppression, so that the manufacturing cost and the using space are increased, and the low-frequency vibration suppression effect is less obvious along with the increase of the volume of the cavity, so that the air spring vibration isolator is difficult to isolate vibration below 1Hz in actual use.
(2) The system damping of the air spring vibration isolator is small, so that the stable adjustment time under the impact disturbance is long, and the resonance peak value is high. The air spring vibration isolator is a non-contact spring which is characterized in that compressed gas is filled into a flexible membrane, elastic support is realized by utilizing the compressibility of the gas, mechanical friction does not exist, the structural damping of the flexible membrane is used as a main damping source of the air spring vibration isolator, the damping coefficient is small, so that the vibration energy attenuation is slow under the excitation of impact disturbance, the system stability adjustment time is long, and the resonance peak value is high.
(3) The air spring vibration isolator with the parallel magnetic negative stiffness structure has low integration level and poor stability. The magnetic negative stiffness structure is connected with the air spring vibration isolator in parallel, so that the inherent frequency can be reduced under the condition of ensuring the large bearing of the air spring vibration isolator, and the low-frequency/ultralow-frequency vibration isolation effect with large bearing is realized. However, the existing low-frequency vibration isolator formed by connecting the cubic permanent magnet negative stiffness structure and the air spring vibration isolator in parallel has large volume and low system integration level, and the stiffness value of the negative stiffness structure is influenced by the floating height of the air spring vibration isolator; for the air spring vibration isolator with the nested coaxial magnetic ring negative stiffness structure, the coaxial magnetic ring negative stiffness structure is arrayed along the axial direction, so that the gravity center height of the vibration isolator can be improved in a mode of increasing the negative stiffness value, and the stability of the vibration isolator is reduced.
(4) The air spring vibration isolator with the parallel magnetic negative stiffness structure has no corresponding protection measure on impact disturbance excitation. The large-amplitude impact disturbance excitation causes rigid collision between the moving magnet and the fixed magnet of the magnetic negative stiffness structure, and between the moving magnet and the fixed magnet fixing piece, so that the magnet is easily damaged or broken.
Patent No. CN201310142491.9 discloses a positive and negative stiffness parallel damper. According to the technical scheme, the magnetic negative stiffness structure is coaxially arranged in the air spring vibration isolator cavity to form the positive and negative stiffness parallel connection vibration absorber, the magnetic negative stiffness structure is formed by two coaxial magnetic rings magnetized reversely along the radial direction, the structure is compact, and the influence of the floating height of the air spring vibration isolator on the stiffness value of the negative stiffness magnetic spring is not required to be considered. The technical scheme is characterized in that: 1) the magnetic negative stiffness structure axial array leads the positive and negative stiffness parallel shock absorber to have high gravity center and poor stability in a mode of increasing the negative stiffness value; 2) the magnetic negative stiffness structure is in a non-contact action mode, and the damping characteristic of the air spring vibration isolator is not improved; 3) under the excitation of impact disturbance, the magnetic negative stiffness structure has no corresponding protective measures.
Patent numbers CN201610914596.5 and CN201610914512.8 disclose a magnetic negative stiffness structure to reduce the natural frequency of the air spring vibration isolator, the magnetic negative stiffness structure is composed of three cubic permanent magnets with the same magnetization direction and arranged along a vertical equal gap array, and the stiffness value can be adjusted by changing the gap of the permanent magnets. The technical scheme is characterized in that: 1) the large floating height can increase the gap of the permanent magnet for the large-load air spring vibration isolator, so that the rigidity value of the magnetic negative rigidity structure is very small, and the effect of reducing the natural frequency of the air spring vibration isolator is not obvious; 2) the structural damping of the elastic membrane is small; 3) the air spring vibration isolator and the magnetic negative stiffness structure are arranged in a split manner, so that the system integration level is low and the volume is large; 4) under the excitation of impact disturbance, the magnetic negative stiffness structure has no corresponding protective measures.
Patent No. CN201810853079.0 discloses a quasi-zero stiffness vibration isolator with parallel positive and negative stiffness. According to the technical scheme, the magnetic negative stiffness structure is formed by the coaxial double magnetic rings magnetized in the axial direction, and the magnetic rings are convenient to axially magnetize and process; the magnetic ring gap is vertical to the rising and falling movement direction of the positive rigidity supporting element, so that the influence of the floating height of the positive rigidity supporting element on the rigidity value of the magnetic negative rigidity structure is not required to be considered. The technical scheme is characterized in that: 1) the magnetic negative stiffness structure is in a non-contact action mode, and the damping characteristic of the air spring vibration isolator is not improved; 2) the magnetic negative stiffness structure increases the negative stiffness value in an axial array mode to reduce the stiffness of the positive stiffness supporting element, and the axial array mode causes high gravity center and poor stability of the vibration isolator; 3) the magnetic negative stiffness structures are uniformly distributed on the left side and the right side of the positive stiffness supporting element, and the system is low in integration level and large in size.
In conclusion, through the innovation of the vibration isolation structure and the principle, the magnetic negative stiffness structure which has high integration degree, high stability, large damping and easy processing and is not influenced by the floating height of the positive stiffness supporting element is provided to offset the positive stiffness value of the large-bearing air spring vibration isolator, so that the magnetic negative stiffness structure has great significance for further improving the low-frequency vibration isolation performance of the micro-vibration isolation platform, increasing the structural damping and quickly attenuating the vibration energy.
Disclosure of Invention
The invention aims to solve the problems that the inherent frequency of a large-bearing air spring vibration isolator is high and cannot meet the low-frequency/ultralow-frequency vibration isolation requirement of precision instruments and equipment, the stable adjustment time under impact disturbance is long due to small damping coefficient, the resonance peak value is high, and a negative stiffness magnetic spring has no corresponding protective measures under the excitation of the impact disturbance, and provides an ultralow-frequency air spring vibration isolator based on a radial magnetization magnetic ring negative stiffness structure.
The technical solution of the invention is as follows:
an ultralow frequency air spring vibration isolator based on a radial magnetization magnetic ring negative stiffness structure comprises an air spring vibration isolator and a negative stiffness magnetic spring, wherein the negative stiffness magnetic spring is coaxially nested in the air spring vibration isolator, the overall structure is in axial symmetry, the air spring vibration isolator comprises a main air chamber, an elastic membrane, an inner compression ring and an outer compression ring, the outer end of the annular elastic membrane is tightly pressed and fixed on the main air chamber by the outer compression ring, and the top end of the inner compression ring supports a vibration isolation load; the air spring vibration isolator further comprises an additional air chamber, the additional air chamber is fixedly installed right below the main air chamber, an air inlet is formed in the side wall of the additional air chamber, 2-10 throttling holes are uniformly formed between the main air chamber and the additional air chamber, the main air chamber is made of aluminum alloy, titanium alloy or austenitic stainless steel which are not or weakly magnetic, and an annular rubber pad is arranged at the bottom of the main air chamber; the negative-stiffness magnetic spring comprises a fixed magnetic ring fixing piece, an inner fixed magnetic ring, a moving magnetic ring mounting piece, a moving magnetic ring and an outer fixed magnetic ring which are coaxially nested outwards along the radius of the axis, the fixed magnetic ring fixing piece and the moving magnetic ring mounting piece are made of non-magnetic or weakly-magnetic aluminum alloy, titanium alloy or austenitic stainless steel, the axial height centers of the inner fixed magnetic ring, the moving magnetic ring and the outer fixed magnetic ring are positioned on the same horizontal line, and a gap is formed between the bottom of the inner fixed magnetic ring and the bottom of the main air chamber; the inner fixed magnetic ring, the movable magnetic ring and the outer fixed magnetic ring are magnetized along the radial direction, and the magnetization directions of the inner fixed magnetic ring and the outer fixed magnetic ring are the same and are opposite to the magnetization direction of the movable magnetic ring; the inner fixed magnetic ring is fixedly arranged on the outer wall of the fixed magnetic ring fixing piece, the bottom of the fixed magnetic ring fixing piece is fixedly connected with the bottom of the main air chamber, a gap is arranged between the inner fixed magnetic ring and the movable magnetic ring mounting piece in the radial direction, the movable magnetic ring is fixedly arranged on the outer wall of the movable magnetic ring mounting piece, the inner end of the annular elastic film is pressed and fixed at the top end of the movable magnetic ring mounting piece through the inner pressure ring, a gap is arranged between the movable magnetic ring and the outer fixed magnetic ring in the radial direction, and the.
Preferably, the orifice is circular, elliptical, or polygonal in shape.
Preferably, the diameter of the circumcircle of the throttle hole is 1 mm-10 mm.
Preferably, the inner fixed magnetic ring, the outer fixed magnetic ring and the movable magnetic ring are permanent magnets or electromagnets.
Preferably, the volume of the additional air chamber is no more than 3 times the volume of the main air chamber.
Preferably, the elastic membrane is formed by vulcanizing a rubber material and a nylon cord or a polyester cord.
Preferably, the rubber pad is formed by vulcanizing a rubber material and a nylon cord or a polyester cord.
The technical innovation and the good effect of the invention are as follows:
(1) the technical scheme can realize the large bearing and near-zero frequency vibration isolation effects of the air spring vibration isolator, and simultaneously realize the characteristic of high integration degree. According to the invention, on one hand, the rigidity value and the inherent frequency of the air spring vibration isolator are reduced by serially connecting the additional air chambers, on the other hand, the near-zero frequency vibration isolation effect under the condition of large bearing is realized by coaxially nesting the negative rigidity magnetic spring in the main air chamber of the air spring vibration isolator, the micro-vibration interference of the full frequency band in the environment where the ultra-precise instrument and equipment is located is effectively isolated, and meanwhile, the integration level of the system is improved. This is one of the innovative points of the present invention from the prior art.
(2) The throttling hole damping and the eddy current damping generated by the invention can effectively accelerate the vibration energy attenuation and shorten the system stabilization time. Orifices with different shapes, sizes and numbers are arranged between the main air chamber and the additional air chamber so as to introduce orifice damping and increase system damping; in addition, under disturbance excitation, eddy current damping generated in the main air chamber and the fixed magnetic ring fixing frame can effectively restrain the motion of the brake magnetic ring relative to the fixed magnetic ring, quickly attenuate vibration energy and shorten the system stabilization time. This is the second innovation point of the present invention from the prior art.
(3) According to the technical scheme, the magnetic rings magnetized in the radial direction are coaxially nested to form the negative-stiffness magnetic spring, so that the characteristics of high stability and no influence of the floating height of the air spring vibration isolator can be realized. The magnetic rings magnetized in the radial direction are coaxially nested to form the negative-stiffness magnetic spring, the gap of the magnetic rings is perpendicular to the rising and falling movement direction of the air spring vibration isolator, and the influence of the floating height of the air spring vibration isolator on the stiffness value of the negative-stiffness magnetic spring is eliminated; the mode of increasing the negative stiffness value of the radial array magnetic ring can effectively avoid the problems of gravity center height lifting and stability reduction of the negative stiffness magnetic spring caused by the axial array mode of the magnetic ring. This is the third innovation point of the present invention from the prior art.
(4) The invention can effectively avoid rigid collision under the excitation of impact disturbance. According to the invention, the rubber pad is arranged at the bottom of the main air chamber of the air spring vibration isolator as a protection measure of the negative stiffness magnetic spring, so that the phenomenon that the moving magnetic ring is rigidly collided with the bottom of the main air chamber under the excitation of impact disturbance to cause damage to the magnetic ring can be effectively avoided. This is the fourth innovation point of the present invention from the prior art.
Drawings
FIG. 1 is a schematic three-dimensional cross-sectional view of an ultra-low frequency air spring vibration isolator based on a radial magnetized magnetic ring negative stiffness structure;
FIG. 2 is a schematic cross-sectional view of an ultra-low frequency air spring vibration isolator based on a radial magnetized magnetic ring negative stiffness structure;
FIG. 3 is a force analysis diagram at the equilibrium position of a negative rate magnetic spring;
FIG. 4 is a force analysis graph of a negative rate magnetic spring moving upward away from equilibrium;
FIG. 5 is a force analysis graph of a negative rate magnetic spring moving downward away from equilibrium.
Description of part numbers in the figures: 1 air inlet, 2 rubber pads, 3 main air chambers, 4 additional air chambers, 5 elastic films, 6 internal pressure rings, 7 external pressure rings, 8a internal fixed magnetic ring, 8b external fixed magnetic ring, 9 fixed magnetic ring fixing pieces, 10 movable magnetic rings, 11 movable magnetic ring mounting pieces and 12 throttling holes.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings.
An ultralow frequency air spring vibration isolator based on a radial magnetization magnetic ring negative stiffness structure comprises an air spring vibration isolator and a negative stiffness magnetic spring, wherein the negative stiffness magnetic spring is coaxially nested in the air spring vibration isolator, the overall structure is in axial symmetry, the air spring vibration isolator comprises a main air chamber 3, an elastic membrane 5, an inner compression ring 6 and an outer compression ring 7, the outer compression ring 7 compresses and fixes the outer end of the annular elastic membrane 5 on the main air chamber 3, and the top end of the inner compression ring 6 supports a vibration isolation load; the air spring vibration isolator further comprises an additional air chamber 4, the additional air chamber 4 is fixedly installed right below the main air chamber 3, an air inlet 1 is formed in the side wall of the additional air chamber 4, 2-10 throttling holes 12 are uniformly formed between the main air chamber 3 and the additional air chamber 4, the main air chamber 3 is made of aluminum alloy, titanium alloy or austenitic stainless steel which is not magnetic conductive or weak magnetic conductive, and an annular rubber pad 2 is arranged at the bottom of the main air chamber 3; the negative-stiffness magnetic spring comprises a fixed magnetic ring fixing piece 9, an inner fixed magnetic ring 8a, a moving magnetic ring mounting piece 11, a moving magnetic ring 10 and an outer fixed magnetic ring 8b which are coaxially nested outwards along the radius from the axis, the fixed magnetic ring fixing piece 9 and the moving magnetic ring mounting piece 11 are made of non-magnetic or weakly-magnetic aluminum alloy, titanium alloy or austenitic stainless steel, the axial height centers of the inner fixed magnetic ring 8a, the moving magnetic ring 10 and the outer fixed magnetic ring 8b are positioned on the same horizontal line, and a gap is formed between the bottom of the inner fixed magnetic ring and the bottom of the main air chamber 3; the inner fixed magnetic ring 8a, the movable magnetic ring 10 and the outer fixed magnetic ring 8b are magnetized along the radial direction, and the magnetization directions of the inner fixed magnetic ring 8a and the outer fixed magnetic ring 8b are the same and are opposite to the magnetization direction of the movable magnetic ring 10; the inner fixed magnetic ring 8a is fixedly arranged on the outer wall of the fixed magnetic ring fixing piece 9, the bottom of the fixed magnetic ring fixing piece 9 is fixedly connected with the bottom of the main air chamber 3, a gap is arranged between the inner fixed magnetic ring 8a and the movable magnetic ring mounting piece 11 along the radial direction, the movable magnetic ring 10 is fixedly arranged on the outer wall of the movable magnetic ring mounting piece 11, the inner end of the annular elastic film 5 is pressed and fixed on the top end of the movable magnetic ring mounting piece 11 by the inner pressing ring 6, a gap is arranged between the movable magnetic ring 10 and the outer fixed magnetic ring 8b along the radial direction, and the outer fixed magnetic.
In a specific embodiment, the orifice 12 has a circular, elliptical, or polygonal shape.
In a specific embodiment, the diameter of the circumcircle of the orifice 12 is 1mm to 10 mm.
As a specific implementation manner, the inner fixed magnetic ring 8a, the outer fixed magnetic ring 8b and the moving magnetic ring 10 are permanent magnets or electromagnets.
In a particular embodiment, the volume of the additional air chamber 4 is not greater than 3 times the volume of the main air chamber 3.
In a specific embodiment, the elastic membrane 5 is formed by vulcanizing a rubber material and a nylon cord or a polyester cord.
In a specific embodiment, the rubber pad 2 is formed by vulcanizing a rubber material and a nylon cord or a polyester cord.
An embodiment of the present invention is given below with reference to fig. 1 to 2.
Fig. 1 and fig. 2 are a three-dimensional cross-sectional schematic view and a front cross-sectional view of an ultra-low frequency air spring vibration isolator based on a radial magnetized magnetic ring negative stiffness structure according to the present invention. As shown in fig. 1 and 2, the invention comprises an air spring vibration isolator and a negative stiffness magnetic spring, wherein the air spring vibration isolator and the negative stiffness magnetic spring are coaxially installed and are arranged in parallel, and the whole body is in axial symmetry. The air spring vibration isolator comprises a main air chamber 3, an additional air chamber 4, an elastic membrane 5, an internal compression ring 6 and an external compression ring 7, wherein the main air chamber 3 and the additional air chamber 4 are made of 304 stainless steel materials, the volume of the additional air chamber 4 is 3 times of that of the main air chamber 3, the positive stiffness generated by the air spring vibration isolator is reduced by 75%, the inherent frequency is reduced by 50%, and the bearing capacity of the air spring vibration isolator is not changed. Elastic membrane 5 is the loop configuration with outer clamping ring 7, and interior clamping ring 6 is cylindrical structure, and elastic membrane 5 is vulcanized by rubber and nylon cord and forms, and the material of interior clamping ring 6 and outer clamping ring 7 is light aluminum alloy. The top end of the inner compression ring 6 supports vibration isolation load, the bottom of the inner compression ring 6 compresses and fixes the inner end of the elastic membrane 5 to the top end of the movable magnetic ring mounting part 11, and the outer compression ring 7 compresses and fixes the outer end of the elastic membrane 5 to the side wall of the main air chamber 3. The rubber pad 2 which is 2mm thick and is formed by vulcanizing rubber and nylon cords is arranged at the bottom of the main air chamber 3 and is used for preventing the movable magnetic ring 10 of the negative-stiffness magnetic spring 1 from colliding with the main air chamber 3 due to large vibration displacement. The bottom of the main air chamber 3 and the top end of the chamber of the additional air chamber 4 are uniformly provided with 6 round holes with the diameter of phi 5mm along the circumference with the diameter of 40mm, the top end of the additional air chamber 4 is provided with a round hole with the diameter equal to the outer diameter of the chamber of the main air chamber 3, the depth is a round groove with the diameter of 1mm, the main air chamber 3 is coaxially and fixedly arranged in the round groove on the top end of the chamber of the additional air chamber 4, the bottom of the main air chamber 3 is opposite to the round hole on the top end of the chamber of the additional air chamber 4, and the main air. The side wall of the additional air chamber 4 is provided with a circular air inlet 1, clean compressed air is introduced into the air inlet 1 through an air supply system to support vibration isolation load, the working air pressure of the air spring vibration isolator is 0.3MPa, and the floating height is 10 mm.
The negative stiffness magnetic spring comprises a fixed magnetic ring fixing piece 9, an inner fixed magnetic ring 8a, a moving magnetic ring mounting piece 11, a moving magnetic ring 10 and an outer fixed magnetic ring 8b, the fixed magnetic ring fixing piece 9 and the moving magnetic ring mounting piece 11 are made of 304 stainless steel, the inner fixed magnetic ring 8a and the outer fixed magnetic ring 8b are magnetized along the radial direction axis, the moving magnetic ring 10 is magnetized outwards along the radius from the axis, and the magnetization direction of the magnetic rings is shown as an arrow in figure 2; the inner fixed magnetic ring 8a is fixedly arranged on the outer wall of the fixed magnetic ring fixing piece 9, the bottom of the fixed magnetic ring fixing piece 9 is fixedly connected with the bottom of the main air chamber 3, a gap is arranged between the inner fixed magnetic ring 8a and the movable magnetic ring mounting piece 11 along the radial direction and is not contacted with the inner fixed magnetic ring 10, the outer fixed magnetic ring 8b is fixedly arranged on the inner wall of the main air chamber 3, the inner end of the annular elastic film 5 is pressed and fixed on the top end of the movable magnetic ring mounting piece 11 by the inner pressing ring 6, a gap is arranged between the movable magnetic ring 10 and the outer fixed magnetic ring 8b along the radial; the magnetic ring is made of N50 grade neodymium iron boron, the residual magnetic induction intensity is 1.43T, and the relative magnetic conductivity is 1.03. When the air spring vibration isolator is not inflated, the axial height center of the movable magnetic ring 10 is 10mm lower than the axial height centers of the inner fixed magnetic ring 8a and the outer fixed magnetic ring 8b, when the air spring vibration isolator is inflated to 0.3MPa, the elastic membrane 5 expands under the action of compressed air, so that the inner pressure ring 6 drives the movable magnetic ring 10 to move 10mm in the axial positive direction through the movable magnetic ring mounting part 11, and the axial height centers of the movable magnetic ring 10 and the inner fixed magnetic ring 8a and the outer fixed magnetic ring 8b are equal in height. Under the interference of external vibration, the movable magnetic ring 10 moves relative to the inner fixed magnetic ring 8a and the outer fixed magnetic ring 8b, magnetic induction lines generated by the movable magnetic ring 10 cut the main air chamber 3 and the fixed magnetic ring fixing piece 9, so that eddy currents are generated in the main air chamber 3 and the fixed magnetic ring fixing piece 9, eddy current damping hinders the movable magnetic ring 10 from moving relative to the inner fixed magnetic ring 8a and the outer fixed magnetic ring 8b, vibration attenuation is accelerated, and the stable adjustment time of the vibration isolation system is shortened.
FIG. 3 is a force analysis diagram of the balance position of the negative-stiffness magnetic spring, in which the moving magnetic ring 10 is located at the inner fixed magnetic ringIn the magnetic field excited by 8a and the outer fixed magnetic ring 8b, the magnetic force borne by the negative stiffness spring 2 is the repulsion force f of the movable magnetic ring 10 from the inner fixed magnetic ring 8a1Repulsive force f from the outer stationary magnetic ring 8b2At the position of sum and balance, the axial height center of the magnetic ring is on the same horizontal line, so the magnetic force f1The inner fixed magnetic ring 8a points to the moving magnetic ring 10 along the horizontal direction, the magnetic force f2The outer fixed magnetic ring 8b points to the moving magnetic ring 10 along the horizontal direction, and the magnetic force borne by the negative stiffness magnetic spring at the balance position is 0 because the negative stiffness magnetic spring is in a central symmetrical structure.
FIG. 4 is a force analysis diagram of the negative rate magnetic spring when moving upward away from the equilibrium position, the axial height center of the moving magnetic ring 10 is higher than the axial height centers of the inner fixed magnetic ring 8a and the outer fixed magnetic ring 8b, f1Pointing to the axis along the central connecting line of the inner fixed magnetic ring 8a and the moving magnetic ring 10, f2The central connecting line of the outer fixed magnetic ring 8b and the movable magnetic ring 10 points to the axis, and the negative stiffness magnetic spring is in a central symmetrical structure, so f1、f2The components in the radial direction cancel each other out, while the components in the axial direction add each other. Therefore, the magnetic force direction borne by the negative stiffness magnetic spring is upward along the axis, and the negative stiffness magnetic spring is forced to deviate from the balance position and move upward along the axis.
FIG. 5 is a force analysis diagram of the negative rate magnetic spring moving downward from the equilibrium position, where the axial height center of the moving magnetic ring 10 is lower than the axial height centers of the inner fixed magnetic ring 8a and the outer fixed magnetic ring 8b, and f1Away from the axis along the central connecting line of the inner fixed magnetic ring 8a and the movable magnetic ring 10, f2The central connecting line of the outer fixed magnetic ring 8b and the movable magnetic ring 10 is far away from the axis, and f is caused by the structural symmetry of the negative stiffness magnetic spring1、f2The components in the radial direction cancel each other out, while the components in the axial direction add each other. Therefore, the magnetic force applied to the negative stiffness magnetic spring is downward along the axis, and the negative stiffness magnetic spring is forced to deviate from the balance position and move downward along the axis.
Claims (7)
1. An ultralow frequency air spring vibration isolator based on a radial magnetization magnetic ring negative stiffness structure comprises an air spring vibration isolator and a negative stiffness magnetic spring, wherein the negative stiffness magnetic spring is coaxially nested in the air spring vibration isolator, the overall structure is in axial symmetry, the air spring vibration isolator comprises a main air chamber (3), an elastic membrane (5), an inner compression ring (6) and an outer compression ring (7), the outer end of the annular elastic membrane (5) is tightly pressed and fixed on the main air chamber (3) by the outer compression ring (7), and the top end of the inner compression ring (6) supports vibration isolation load; the method is characterized in that: the air spring vibration isolator further comprises an additional air chamber (4), the additional air chamber (4) is fixedly installed right below the main air chamber (3), an air inlet hole (1) is formed in the side wall of the additional air chamber (4), 2-10 throttle holes (12) are uniformly formed between the main air chamber (3) and the additional air chamber (4), the main air chamber (3) is made of non-magnetic or weak-magnetic aluminum alloy, titanium alloy or austenitic stainless steel, and an annular rubber pad (2) is arranged at the bottom of the main air chamber (3); the negative-stiffness magnetic spring comprises a fixed magnetic ring fixing piece (9), an inner fixed magnetic ring (8a), a moving magnetic ring mounting piece (11), a moving magnetic ring (10) and an outer fixed magnetic ring (8b) which are coaxially nested outwards along a radius from an axis, the fixed magnetic ring fixing piece (9) and the moving magnetic ring mounting piece (11) are made of non-magnetic or weakly magnetic aluminum alloy, titanium alloy or austenitic stainless steel, the axial height centers of the inner fixed magnetic ring (8a), the moving magnetic ring (10) and the outer fixed magnetic ring (8b) are positioned on the same horizontal line, and a gap is formed between the bottom of the inner fixed magnetic ring (8a) and the bottom of the main air chamber (3); the inner fixed magnetic ring (8a), the movable magnetic ring (10) and the outer fixed magnetic ring (8b) are magnetized along the radial direction, and the magnetization directions of the inner fixed magnetic ring (8a) and the outer fixed magnetic ring (8b) are the same and are opposite to the magnetization direction of the movable magnetic ring (10); the inner fixed magnetic ring (8a) is fixedly arranged on the outer wall of the fixed magnetic ring fixing piece (9), the bottom of the fixed magnetic ring fixing piece (9) is fixedly connected with the bottom of the main air chamber (3), a gap is arranged between the inner fixed magnetic ring (8a) and the movable magnetic ring mounting piece (11) along the radial direction, the movable magnetic ring (10) is fixedly arranged on the outer wall of the movable magnetic ring mounting piece (11), the inner end of the annular elastic film (5) is tightly pressed and fixed at the top end of the movable magnetic ring mounting piece (11) by the inner pressing ring (6), a gap is arranged between the movable magnetic ring (10) and the outer fixed magnetic ring (8b) along the radial direction, and the outer fixed magnetic ring (8 b.
2. The ultralow frequency air spring vibration isolator based on the radial magnetization magnetic ring negative stiffness structure as claimed in claim 1, is characterized in that: the orifice (12) is circular, elliptical or polygonal in shape.
3. The ultralow frequency air spring vibration isolator based on the radial magnetization magnetic ring negative stiffness structure as claimed in claim 1, is characterized in that: the diameter of the circumcircle of the throttle hole (12) is 1 mm-10 mm.
4. The ultralow frequency air spring vibration isolator based on the radial magnetization magnetic ring negative stiffness structure as claimed in claim 1, is characterized in that: the inner fixed magnetic ring (8a), the outer fixed magnetic ring (8b) and the movable magnetic ring (10) are permanent magnets or electromagnets.
5. The ultralow frequency air spring vibration isolator based on the radial magnetization magnetic ring negative stiffness structure as claimed in claim 1, is characterized in that: the volume of the additional air chamber (4) is not more than 3 times of the volume of the main air chamber (3).
6. The ultralow frequency air spring vibration isolator based on the radial magnetization magnetic ring negative stiffness structure as claimed in claim 1, is characterized in that: the elastic membrane (5) is formed by vulcanizing a rubber material and a nylon cord or a polyester cord.
7. The ultralow frequency air spring vibration isolator based on the radial magnetization magnetic ring negative stiffness structure as claimed in claim 1, is characterized in that: the rubber pad (2) is formed by vulcanizing a rubber material and a nylon cord or a polyester cord.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114161890A (en) * | 2021-11-30 | 2022-03-11 | 江苏大学 | Air suspension based on quasi-zero stiffness principle and structural design and optimization method thereof |
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