阅读说明：本技术 一种两自由度准零刚度低频隔振装置 (Two-degree-of-freedom quasi-zero-rigidity low-frequency vibration isolation device ) 是由 宋春芳 嵇雯 刘彦琦 于 2021-02-02 设计创作，主要内容包括：本发明涉及低频隔振技术领域,尤其是一种两自由度准零刚度低频隔振装置,其中支撑平板用来放置被隔振体,上层准零刚度隔振器中上层垂向平面弹簧的上下两端分别垂直固定在支撑平板和中间质量块上,上层非线性弹簧的一端和支撑平板的侧面相连,上层非线性弹簧的另一端和上层水平移动机构相连实现水平可移动调节,垂向移动机构带动支撑平板实现上下移动调节,下层准零刚度隔振器中下层垂向平面弹簧的上下两端分别垂直固定在中间质量块和基座上,下层非线性弹簧的一端和中间质量块相连,下层非线性弹簧的另一端和下层水平移动机构相连实现水平调节,本申请能减小系统的起始隔振频率,在特定的频率区域内,隔振性能优于单自由度准零刚度隔振系统。(The invention relates to the technical field of low-frequency vibration isolation, in particular to a two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device, wherein a support flat plate is used for placing a body to be isolated, the upper end and the lower end of an upper vertical plane spring in an upper quasi-zero stiffness vibration isolator are respectively and vertically fixed on the support flat plate and a middle mass block, one end of an upper nonlinear spring is connected with the side surface of the support flat plate, the other end of the upper nonlinear spring is connected with an upper horizontal moving mechanism to realize horizontal movable adjustment, a vertical moving mechanism drives the support flat plate to realize up-and-down movement adjustment, the upper end and the lower end of a lower vertical plane spring in a lower quasi-zero stiffness vibration isolator are respectively and vertically fixed on a middle mass block and a base, one end of a lower nonlinear spring is connected with the middle mass block, the other end of the lower nonlinear spring is connected with the, in a specific frequency region, the vibration isolation performance is superior to that of a single-degree-of-freedom quasi-zero-stiffness vibration isolation system.)

1. The utility model provides a two degree of freedom quasi-zero rigidity low frequency vibration isolation devices which characterized in that: the vibration isolator comprises a base (1), an upper-layer quasi-zero stiffness vibration isolator, a lower-layer quasi-zero stiffness vibration isolator, a supporting flat plate (20), a middle mass block (9), two upper-layer horizontal moving mechanisms, two lower-layer horizontal moving mechanisms and a vertical moving mechanism (21), wherein the supporting flat plate (20) is horizontally arranged above the middle mass block (9), and the supporting flat plate (20) is used for placing a vibration isolator (22);

the upper-layer quasi-zero stiffness vibration isolator comprises an upper-layer nonlinear spring (15), an upper-layer nonlinear spring outer guide sleeve (14) and an upper-layer vertical plane spring (11), wherein the upper end and the lower end of the upper-layer vertical plane spring (11) are respectively and vertically fixed on a support flat plate (20) and a middle gauge block (9), the upper-layer nonlinear spring (15) is limited in the upper-layer nonlinear spring outer guide sleeve (14) and can do limited telescopic movement along the sleeve length direction of the upper-layer nonlinear spring outer guide sleeve (14), the upper-layer nonlinear springs (15) are two and are symmetrically distributed on two sides of the support flat plate (20), one end of the upper-layer nonlinear spring (15) is connected with the side surface of the support flat plate (20), the other end of the upper-layer nonlinear spring (15) is connected with an upper-layer horizontal moving mechanism to achieve horizontal movable adjustment, the upper-layer horizontal moving mechanism is installed on a base (1), and the vertical moving mechanism (21) is installed on the base (1), the vertical moving mechanism (21) drives the supporting flat plate (20) to realize up-and-down movement adjustment;

the lower-layer quasi-zero stiffness vibration isolator comprises a lower-layer nonlinear spring (5), a lower-layer nonlinear spring outer guide sleeve (8) and a lower-layer vertical plane spring (2), the upper end and the lower end of the lower-layer vertical plane spring (2) are respectively and vertically fixed on a middle mass block (9) and a base (1), the lower-layer nonlinear spring (5) is limited in the lower-layer nonlinear spring outer guide sleeve (8) and can move in a limiting and telescopic mode along the sleeve length direction of the lower-layer nonlinear spring outer guide sleeve (8), the lower-layer nonlinear spring (5) is two and symmetrically distributed on two sides of the middle mass block (9), one end of the lower-layer nonlinear spring (5) is connected with the middle mass block (9), the other end of the lower-layer nonlinear spring (5) is connected with a lower-layer horizontal movement mechanism to achieve horizontal movable adjustment, and the lower-layer horizontal movement mechanism is.

2. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 1, wherein: the upper-layer quasi-zero stiffness vibration isolator comprises an upper-layer vertical damper (12), and the upper end and the lower end of the upper-layer vertical damper (12) are respectively and vertically fixed on a support flat plate (20) and a middle mass block (9).

3. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 2, wherein: the upper-layer quasi-zero stiffness vibration isolator comprises upper-layer transverse damping (17), the upper-layer transverse damping (17) is two and is symmetrically distributed on two sides of a supporting flat plate (20), one end of the upper-layer transverse damping (17) is connected with the side face of the supporting flat plate (20), and the other end of the upper-layer transverse damping (17) is connected with an upper-layer horizontal moving mechanism.

4. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 3, wherein: the lower-layer quasi-zero stiffness vibration isolator comprises a lower-layer vertical damper (3), and the upper end and the lower end of the lower-layer vertical damper (3) are respectively and vertically fixed on a middle mass block (9) and a base (1).

5. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 4, wherein: the quasi-zero stiffness vibration isolator comprises lower-layer transverse damping (10), the lower-layer transverse damping (10) is two and symmetrically distributed on two sides of a supporting flat plate (20), one end of the lower-layer transverse damping (10) is connected with the side face of a medium mass block (9), and the other end of the lower-layer transverse damping (10) is connected with a lower-layer horizontal moving mechanism.

6. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 5, wherein: base (1) includes that base and vertical two parallel relative curb plates of fixing on the base, the upper end of two curb plates inwards overhang respectively has fixed plate (19) that the level was arranged, the lower extreme of vertical planar spring (2) of lower floor and vertical damping (3) of lower floor is fixed respectively on the base, vertical moving mechanism (21) are screw one, vertical moving mechanism (21) are two and install respectively on two fixed plates (19), vertical moving mechanism (21) vertical the arranging, the lower extreme symmetry of two vertical moving mechanism (21) supports the both edges that lean on at the last face that supports dull and stereotyped (20).

7. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 6, wherein: the upper horizontal moving mechanism comprises a second screw (13), an upper vertical sliding plate (16) and an upper horizontal guide rail (18), the upper horizontal guide rail (18) is installed on the lower plate surface of the fixing plate (19), the upper end of the upper vertical sliding plate (16) and the upper horizontal guide rail (18) form a transverse sliding fit, the other end of the upper transverse damper (17) and the other end of the upper nonlinear spring (15) are respectively fixed on one side plate surface of the upper vertical sliding plate (16), the second screw (13) is installed on a side plate of the base (1), and the end part of the second screw (13) abuts against the other side plate surface of the upper vertical sliding plate (16).

8. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 7, wherein: lower floor's horizontal migration mechanism includes three (7) of screw, perpendicular slide (6) of lower floor and lower floor transverse guide (4), install on the base of base (1) lower floor transverse guide (4), the lower extreme and lower floor transverse guide (4) of the perpendicular slide (6) of lower floor constitute horizontal sliding fit, the other end of lower floor's horizontal damping (10), the other end of lower floor's nonlinear spring (5) is fixed respectively on one side face of the perpendicular slide (6) of lower floor, install on the curb plate of base (1) three (7) of screw, the tip of three (7) of screw supports and leans on the opposite side face of the perpendicular slide (6) of lower floor.

9. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 1, wherein: the upper nonlinear spring outer guide sleeve (14) is in a circular tube shape, end covers are arranged at two ends of the circular tube, and two ends of the upper nonlinear spring (15) freely penetrate through the end covers at two ends of the circular tube respectively.

10. The two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device according to claim 9, wherein: the structure of the lower nonlinear spring outer guide sleeve (8) is the same as that of the upper nonlinear spring outer guide sleeve (14).

Technical Field

The invention relates to the technical field of low-frequency vibration isolation, in particular to a two-degree-of-freedom quasi-zero-stiffness low-frequency vibration isolation device.

Background

Vibration is a physical phenomenon commonly existing in nature, and is ubiquitous particularly in daily life and industrial production. In some cases, vibration can be detrimental to our scientific research and production activities. The traditional linear vibration isolator faces the contradiction between the bearing capacity and the vibration isolation effect, and the quasi-zero stiffness vibration isolation system is used as a novel nonlinear low-frequency vibration isolation technology, so that the traditional concept of vibration isolation of the linear system is changed. The quasi-zero stiffness vibration isolation system is formed by connecting positive and negative stiffness structures in parallel, not only has enough static stiffness to support the vibration isolation equipment and good stability, but also has smaller dynamic stiffness near a balance position, reduced natural frequency of the system and good low-frequency vibration isolation performance. Therefore, the quasi-zero stiffness vibration isolation system gives consideration to the contradiction between stability and vibration isolation performance.

The single-degree-of-freedom quasi-zero stiffness vibration isolation system can realize good vibration isolation in a low-frequency stage, and the vibration isolation performance of the single-degree-of-freedom quasi-zero stiffness vibration isolation system is equivalent to that of a linear vibration isolation system in a medium-frequency stage and a high-frequency stage. Scientific and technical development is rapid, the performance requirements of precision machinery, ship-based equipment, high-speed vehicles and the like on the vibration isolation system are higher and higher, and the traditional linear vibration isolation system and the single-degree-of-freedom quasi-zero-stiffness vibration isolation system are difficult to meet the increasing requirements of various industries.

Disclosure of Invention

The applicant aims at the defects in the prior art and provides a two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device, which can reduce the initial vibration isolation frequency of a system and widen the vibration isolation frequency band, and in a specific frequency region, the vibration isolation performance is superior to that of a single-degree-of-freedom quasi-zero stiffness vibration isolation system.

The technical scheme adopted by the invention is as follows: a two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device comprises a base, an upper-layer quasi-zero stiffness vibration isolator, a lower-layer quasi-zero stiffness vibration isolator, a supporting flat plate, a middle mass block, two upper-layer horizontal moving mechanisms, two lower-layer horizontal moving mechanisms and a vertical moving mechanism, wherein the supporting flat plate is horizontally arranged above the middle mass block and used for placing a to-be-isolated body;

the upper quasi-zero stiffness vibration isolator comprises upper nonlinear springs, upper nonlinear spring outer guide sleeves and upper vertical plane springs, the upper and lower ends of each upper vertical plane spring are vertically fixed on a support flat plate and a middle gauge block respectively, the upper nonlinear springs are limited in the upper nonlinear spring outer guide sleeves and can do limited telescopic movement along the sleeve length direction of the upper nonlinear spring outer guide sleeves, the upper nonlinear springs are two and are symmetrically distributed on two sides of the support flat plate, one ends of the upper nonlinear springs are connected with the side surfaces of the support flat plate, the other ends of the upper nonlinear springs are connected with an upper horizontal moving mechanism to achieve horizontal movable adjustment, the upper horizontal moving mechanism is installed on a base, a vertical moving mechanism is installed on the base, and the vertical moving mechanism drives the support flat plate to achieve up-down movement adjustment;

the quasi-zero stiffness vibration isolator of lower floor includes lower floor's non-linear spring, lower floor's non-linear spring outer guide pin bushing and the vertical planar spring of lower floor, the upper and lower both ends of the vertical planar spring of lower floor are the vertical fixation respectively on middle quality piece and base, lower floor's non-linear spring is spacing in lower floor's non-linear spring outer guide pin bushing and can be followed the cover length direction of lower floor's non-linear spring outer guide pin bushing and do spacing flexible removal, lower floor's non-linear spring is two and symmetric distribution in the both sides of middle quality piece, lower floor's non-linear spring's one end and middle quality piece link to each other, lower floor's non-linear spring's the other end.

As a further improvement of the above technical solution:

the upper quasi-zero stiffness vibration isolator comprises an upper vertical damping, and the upper end and the lower end of the upper vertical damping are respectively and vertically fixed on a support flat plate and a middle mass block.

The upper-layer quasi-zero stiffness vibration isolator comprises upper-layer transverse damping, the upper-layer transverse damping is two and is symmetrically distributed on two sides of a supporting flat plate, one end of the upper-layer transverse damping is connected with the side face of the supporting flat plate, and the other end of the upper-layer transverse damping is connected with an upper-layer horizontal moving mechanism.

The lower-layer quasi-zero stiffness vibration isolator comprises a lower-layer vertical damping, and the upper end and the lower end of the lower-layer vertical damping are respectively and vertically fixed on the middle mass block and the base.

The lower-layer quasi-zero stiffness vibration isolator comprises lower-layer transverse damping, the lower-layer transverse damping is two and symmetrically distributed on two sides of the supporting flat plate, one end of the lower-layer transverse damping is connected with the side face of the medium mass block, and the other end of the lower-layer transverse damping is connected with the lower-layer horizontal moving mechanism.

The base includes that base and vertical two parallel relative curb plates of fixing on the base, the upper end of two curb plates inwards overhang respectively has the fixed plate of horizontal arrangement, and the vertical planar spring of lower floor and the vertical damped lower extreme of lower floor are fixed respectively on the base, and vertical moving mechanism is screw one, and vertical moving mechanism is two and installs respectively on two fixed plates, and vertical moving mechanism is vertical to be arranged, and the lower extreme symmetry of two vertical moving mechanism supports and leans on the both sides edge at the dull and stereotyped last face of support.

The upper horizontal moving mechanism comprises a second screw, an upper vertical sliding plate and an upper transverse guide rail, the upper transverse guide rail is installed on the lower plate surface of the fixing plate, the upper end of the upper vertical sliding plate and the upper transverse guide rail form transverse sliding fit, the other end of the upper transverse damping and the other end of the upper nonlinear spring are fixed on one side plate surface of the upper vertical sliding plate respectively, the second screw is installed on a side plate of the base, and the end portion of the second screw abuts against the other side plate surface of the upper vertical sliding plate.

The lower-layer horizontal moving mechanism comprises a third screw, a lower-layer vertical sliding plate and a lower-layer transverse guide rail, the lower-layer transverse guide rail is installed on the base of the base, the lower end of the lower-layer vertical sliding plate and the lower-layer transverse guide rail form transverse sliding fit, the other end of the lower-layer transverse damping and the other end of the lower-layer nonlinear spring are fixed on the plate surface on one side of the lower-layer vertical sliding plate respectively, the third screw is installed on the side plate of the base, and the end portion of the third screw abuts against the plate surface.

The upper nonlinear spring outer guide sleeve is in a circular tube shape, end covers are arranged at two ends of the circular tube, and two ends of the upper nonlinear spring freely penetrate through the end covers at two ends of the circular tube respectively.

The structure of the lower nonlinear spring outer guide sleeve is the same as that of the upper nonlinear spring outer guide sleeve.

The invention has the following beneficial effects: when the vibration isolator is placed on the upper surface of the supporting flat plate, the upper vertical plane spring and the lower vertical plane spring are compressed, and the upper nonlinear spring and the lower nonlinear spring can be positioned at horizontal positions by screwing the second screw and the third screw. If the mass of the vibration-isolated body changes, the whole vibration-isolating system returns to the balance state again by adjusting the vertical moving mechanism. By selecting proper structural parameters and mechanical parameters of the system and combining the horizontal moving mechanism and the vertical moving mechanism, the rigidity of the system is zero. When the vibration-isolated body vibrates near the balance position, the natural frequency of the system is low, and the bearing capacity is high. Therefore, the vibration isolation system can realize the aim of low-frequency vibration reduction, not only can reduce the initial vibration isolation frequency of the system and widen the vibration isolation frequency band, but also has the vibration isolation performance superior to that of a single-degree-of-freedom quasi-zero-rigidity vibration isolation system in a specific frequency region.

Drawings

Fig. 1 is a schematic structural view of the present invention when no vibration insulator is added.

FIG. 2 is a schematic view of the present invention in use;

FIG. 3 is a cross-sectional view of the upper vertical planar spring of the present invention;

FIG. 4 is a force transfer rate curve comparison diagram of a two-degree-of-freedom system and a single-degree-of-freedom system under the working conditions that the vertical damping ratios of the upper-layer quasi-zero stiffness vibration isolator are different;

FIG. 5 is a force transfer rate curve comparison diagram of a two-degree-of-freedom system and a single-degree-of-freedom system under different working conditions of stiffness ratios of a lower vertical planar spring and an upper vertical planar spring;

FIG. 6 is a comparison graph of force transfer rate curves of a two-degree-of-freedom system and a single-degree-of-freedom system under different working conditions of mass ratios of the intermediate mass block and the vibration isolator.

Wherein: 1. a base; 2. a lower vertical planar spring; 3. the lower layer is vertically damped; 4. a lower layer transverse guide rail; 5. a lower non-linear spring; 6. a lower vertical sliding plate; 7. a third screw; 8. a lower nonlinear spring outer guide sleeve; 9. a middle mass block; 10. the lower layer is transversely damped; 11. an upper vertical planar spring; 12. upper layer vertical damping; 13. a second screw; 14. an upper nonlinear spring outer guide sleeve; 15. an upper non-linear spring; 16. an upper vertical sliding plate; 17. upper layer lateral damping; 18. an upper layer transverse guide rail; 19. a fixing plate; 20. supporting the flat plate; 21. a vertical moving mechanism; 22. an object to be vibration-isolated.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

As shown in fig. 1-6, the two-degree-of-freedom quasi-zero stiffness low-frequency vibration isolation device of the present embodiment includes a base 1, an upper quasi-zero stiffness vibration isolator, a lower quasi-zero stiffness vibration isolator, a support flat plate 20, a middle mass block 9, two upper horizontal moving mechanisms, two lower horizontal moving mechanisms, and a vertical moving mechanism 21, wherein the support flat plate 20 is horizontally disposed above the middle mass block 9, and the support flat plate 20 is used for placing a to-be-isolated body 22;

the upper quasi-zero stiffness vibration isolator includes an upper non-linear spring 15, the upper-layer nonlinear spring outer guide sleeve 14 and the upper-layer vertical plane spring 11, the upper end and the lower end of the upper-layer vertical plane spring 11 are respectively and vertically fixed on a support flat plate 20 and a middle gauge block 9, the upper-layer nonlinear spring 15 is limited in the upper-layer nonlinear spring outer guide sleeve 14 and can do limited telescopic movement along the sleeve length direction of the upper-layer nonlinear spring outer guide sleeve 14, the two upper-layer nonlinear springs 15 are symmetrically distributed on two sides of the support flat plate 20, one end of the upper-layer nonlinear spring 15 is connected with the side surface of the support flat plate 20, the other end of the upper-layer nonlinear spring 15 is connected with an upper-layer horizontal moving mechanism to realize horizontal movable adjustment, the upper-layer horizontal moving mechanism is installed on a base 1, a vertical moving mechanism 21 is installed on the base 1, and the vertical moving mechanism 21 drives the support flat plate 20 to realize up-;

the quasi-zero stiffness vibration isolator of lower floor includes lower floor's non-linear spring 5, lower floor's non-linear spring outer guide pin bushing 8 and lower floor's vertical plane spring 2, the upper and lower both ends of the vertical plane spring 2 of lower floor are vertical fixation respectively on middle quality piece 9 and base 1, lower floor's non-linear spring 5 is spacing in lower floor's non-linear spring outer guide pin bushing 8 and can be followed lower floor's non-linear spring outer guide pin bushing 8 cover length direction and do spacing flexible removal, lower floor's non-linear spring 5 is two and symmetric distribution in the both sides of middle quality piece 9, lower floor's non-linear spring 5's one end and middle quality piece 9 link to each other, lower floor's non-linear spring 5's the other end and lower floor.

The upper-layer quasi-zero stiffness vibration isolator comprises an upper-layer vertical damper 12, wherein the upper end and the lower end of the upper-layer vertical damper 12 are respectively and vertically fixed on a support flat plate 20 and a middle mass block 9.

The upper-layer quasi-zero stiffness vibration isolator comprises two upper-layer transverse damping 17, the two upper-layer transverse damping 17 are symmetrically distributed on two sides of a supporting flat plate 20, one end of the upper-layer transverse damping 17 is connected with the side face of the supporting flat plate 20, and the other end of the upper-layer transverse damping 17 is connected with an upper-layer horizontal moving mechanism.

The lower quasi-zero stiffness vibration isolator comprises a lower vertical damper 3, and the upper end and the lower end of the lower vertical damper 3 are respectively and vertically fixed on the middle mass block 9 and the base 1.

The lower-layer quasi-zero stiffness vibration isolator comprises lower-layer transverse damping 10, the lower-layer transverse damping 10 is two and is symmetrically distributed on two sides of a supporting flat plate 20, one end of the lower-layer transverse damping 10 is connected with the side face of a middle mass block 9, and the other end of the lower-layer transverse damping 10 is connected with a lower-layer horizontal moving mechanism.

The base 1 comprises a base and two parallel opposite side plates vertically fixed on the base, the upper ends of the two side plates are respectively and inwardly suspended to form a horizontally-arranged fixing plate 19, the lower ends of a lower-layer vertical planar spring 2 and a lower-layer vertical damping 3 are respectively fixed on the base, a vertical moving mechanism 21 is a screw I, the vertical moving mechanisms 21 are two and are respectively installed on the two fixing plates 19, the vertical moving mechanism 21 is vertically arranged, and the lower ends of the two vertical moving mechanisms 21 are symmetrically supported at two edges of an upper plate surface of a supporting flat plate 20.

The upper horizontal moving mechanism comprises a second screw 13, an upper vertical sliding plate 16 and an upper transverse guide 18, the upper transverse guide 18 is installed on the lower plate surface of the fixing plate 19, the upper end of the upper vertical sliding plate 16 and the upper transverse guide 18 form transverse sliding fit, the other end of the upper transverse damping 17 and the other end of the upper nonlinear spring 15 are respectively fixed on one side plate surface of the upper vertical sliding plate 16, the second screw 13 is installed on a side plate of the base 1, and the end part of the second screw 13 abuts against the other side plate surface of the upper vertical sliding plate 16.

The lower horizontal moving mechanism comprises a third screw 7, a lower vertical sliding plate 6 and a lower transverse guide rail 4, the lower transverse guide rail 4 is installed on the base of the base 1, the lower end of the lower vertical sliding plate 6 and the lower transverse guide rail 4 form transverse sliding fit, the other end of the lower transverse damping 10 and the other end of the lower nonlinear spring 5 are respectively fixed on one side plate surface of the lower vertical sliding plate 6, the third screw 7 is installed on a side plate of the base 1, and the end part of the third screw 7 is abutted against the other side plate surface of the lower vertical sliding plate 6.

The upper nonlinear spring outer guide sleeve 14 is in a circular tube shape, end covers are arranged at two ends of the circular tube, and two ends of the upper nonlinear spring 15 freely penetrate through the end covers at two ends of the circular tube respectively.

The structure of the lower non-linear spring jacket 8 is the same as the structure of the upper non-linear spring jacket 14.

The main working principle of the application is as follows: as shown in fig. 1, when the vibration receiver 22 is not placed, both the upper nonlinear spring 15 and the lower nonlinear spring 5 are in an inclined state. When the vibration-isolated body 22 is placed on the upper surface of the support plate 20, the upper vertical planar spring 11 and the lower vertical planar spring 2 are compressed, and the upper nonlinear spring 15 and the lower nonlinear spring 5 can be in a horizontal position by screwing the second screw 13 and the third screw 7. The cross-sectional view of the upper vertical planar spring 11 is shown in FIG. 3, where b₁Is the thickness of the outer plane, b₂For the thickness of the inner plane, the required rigidity of the upper layer vertical plane spring 11 can be obtained by only reasonably designing the thickness of the outer plane and the thickness of the inner plane. If the mass of the vibration-isolated body 22 changes, the whole vibration-isolating system is balanced again by adjusting the vertical moving mechanism 21State. By selecting proper structural parameters and mechanical parameters of the system and combining the horizontal moving mechanism and the vertical moving mechanism 21, the rigidity of the system is enabled to be zero. When the body 22 vibrates near the equilibrium position, the natural frequency of the system is low and the load-bearing capacity is large. Therefore, the vibration isolation system can achieve the aim of low-frequency vibration reduction.

The transverse damping ratio of the upper-layer quasi-zero stiffness vibration isolator is set to beThe vertical damping ratio of the upper-layer quasi-zero stiffness vibration isolator isThe stiffness ratio of the lower vertical flat spring 2 to the upper vertical flat spring 11 isThe mass ratio of the intermediate mass 9 to the vibration-isolated body 22 isWherein the content of the first and second substances,c_h1the transverse damping coefficient of the upper vibration isolator, c₁And the vertical damping coefficient of the upper-layer vibration isolator.

The force transmission rate is an important index for evaluating the vibration isolation performance of the vibration isolation system, and is defined as follows: the vibration isolation system is subjected to the action of exciting force and then transmits the ratio of the force amplitude to the exciting force amplitude to the foundation. The smaller the force transmission rate of the system, the better the vibration isolation of the system. When simple harmonic excitation force acts on the vibration-isolated body 22 in the vibration isolation system, reasonable transverse damping ratio, vertical damping ratio, rigidity ratio and mass ratio are selected, and the vibration isolation performance of the two-degree-of-freedom quasi-zero rigidity vibration isolation system and the single-degree-of-freedom system is contrastively researched by using a numerical analysis method.

Under the working conditions that the vertical damping ratios of the upper-layer quasi-zero stiffness vibration isolator are different, the force transmission of the two-degree-of-freedom system and the single-degree-of-freedom systemThe gradient curve is compared with a graph shown in fig. 4, the influence of the change of the vertical damping ratio of the upper-layer quasi-zero stiffness vibration isolator on the first peak value of the force transmission rate is small, the larger the damping ratio is, the peak valley of the force transmission rate is increased, and the second peak value is reduced; when the damping ratio increases to a larger value (ζ)₁0.5), both the valley and the second peak gradually disappear.

Fig. 5 is a graph comparing force transfer rate curves of a two-degree-of-freedom system and a single-degree-of-freedom system under the working conditions that the stiffness ratios of a lower vertical planar spring 2 and an upper vertical planar spring 11 are different, and according to the graph, a first peak value of the force transfer rate is reduced along with the reduction of the stiffness ratio, and deviates to a low frequency region, the initial vibration isolation frequency is reduced, and the vibration isolation frequency bandwidth is increased; whereas the peak-valley and the second peak increase with decreasing stiffness ratio, the peak-valley increases relatively much.

As shown in fig. 6, under the working conditions that the mass ratio of the intermediate mass block 9 to the vibration-isolated body 22 is different, the force transfer rate curve of the two-degree-of-freedom system and the force transfer rate curve of the single-degree-of-freedom system are compared, and the larger the mass ratio is, the first peak value of the force transfer rate is slightly increased, and the tendency of shifting to the low frequency region appears; both the peak-to-valley and the second peak increase significantly with increasing mass ratio.

Comparative analysis of fig. 4, 5 and 6 can yield: compared with a single-degree-of-freedom quasi-zero stiffness vibration isolation system, the force transfer rate curve of the two-degree-of-freedom quasi-zero stiffness vibration isolation system has two peak values and one peak valley; although the vibration isolation effect in the local area of the second peak value is relatively weak, the vibration isolation performance in the frequency domain near the peak valley is obviously enhanced; reasonable parameters can be selected, the force transfer rate peak value and the initial vibration isolation frequency of the system are reduced, and the vibration isolation interval is enlarged. When the frequency ratio omega is more than 1.96, the attenuation rate of the system force transfer rate is obviously improved, the vibration isolation performance in the frequency band is obviously superior to that of a single-degree-of-freedom quasi-zero-stiffness vibration isolation system, and the low-frequency vibration isolation performance is further improved.

The above description is intended to be illustrative and not restrictive, and the scope of the invention is defined by the appended claims, which may be modified in any manner within the scope of the invention.