A low frequency vibration isolator

Abstract

This invention discloses a low-frequency vibration isolator, belonging to the field of vibration isolator technology, possessing quasi-zero stiffness characteristics. It includes an upper end cover, a lower end cover, a negative stiffness vibration isolator assembly, and a positive stiffness vibration isolator assembly. The negative stiffness vibration isolator assembly includes a first spring vertically placed in the central region, which is connected to both the upper and lower end covers and is initially in an extended state. The positive stiffness vibration isolator assembly includes vibration isolation units located around the first spring and spaced circumferentially. Each vibration isolation unit includes a deformable connecting rod structure and a second spring initially in an extended state. The upper and lower ends of the connecting rod structure are connected to the upper and lower end covers, respectively. The connecting rod structure has a left and right half arranged opposite to each other. The second spring is fixedly connected between the left and right half to pull the left and right half inwards to deform. This low-frequency vibration isolator has small size, high load-bearing capacity, and quasi-zero stiffness characteristics, making it suitable for high-end manufacturing platform equipment.

Description

Technical Field

[0001] The invention relates to the technical field of vibration isolators, in particular to a low-frequency vibration isolator. Background Art

[0002] With the rapid development of high-end manufacturing technology, precision machining, aerospace, semiconductors, medical devices and other fields have put forward higher requirements for manufacturing accuracy and system stability. These manufacturing platforms usually integrate a large number of precision equipment, such as sensors, electronic control systems and high-precision processing equipment, which are particularly sensitive to vibrations in the external environment. In particular, low-frequency vibrations, because their frequencies are close to the natural frequencies of the equipment, are very likely to cause resonance, which will have an adverse effect on the normal operation of the equipment and the manufacturing accuracy of the product. In high-end manufacturing platforms, the accuracy of the equipment is crucial to the quality of the final product. However, low-frequency vibrations are likely to cause equipment resonance, resulting in inaccurate data collection, errors in the processing process, and ultimately affecting product quality. Especially in extremely demanding production environments, such as nanometer-level precision in semiconductor manufacturing, the impact of low-frequency vibrations is more obvious. Continuous low-frequency vibrations will not only affect the immediate performance of the equipment, but also cause long-term fatigue of the internal components of the equipment, shortening the service life of the equipment. This is particularly unfavorable for expensive precision equipment in high-end manufacturing platforms, and frequent replacement and maintenance of equipment will greatly increase operating costs. Therefore, effectively isolating low-frequency vibrations is the key to extending equipment life and reducing the frequency of equipment maintenance.

[0003] Traditional vibration isolation devices are mainly aimed at medium and high frequency vibrations. Low-frequency vibration isolation devices often have large strokes and sizes, or insufficient load-bearing capacity, and are not suitable for high-end manufacturing platform equipment. In addition, the three types of vibration isolators commonly used in high-end manufacturing platforms, namely rubber, spring and hydraulic, are used alone or in combination. They are too dependent on the performance of the material, and inevitably have defects and limitations in the material properties. It is difficult to achieve a good vibration isolation effect in the low-frequency and ultra-low-frequency domains.

[0004] Therefore, how to design a low-frequency vibration isolator that can be used to reduce and absorb the energy and low-frequency vibration of unstable operation of high-end manufacturing platform equipment is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The purpose of the present invention is to provide a low-frequency vibration isolator to address the defects and shortcomings in the prior art, which improves the load-bearing capacity without increasing the size and has a quasi-zero stiffness characteristic, and can be suitable for high-end manufacturing platform equipment.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The present invention provides a low-frequency vibration isolator, comprising an upper end cover, a lower end cover, and a negative stiffness vibration isolation component and a positive stiffness vibration isolation component that enable the low-frequency vibration isolator to have a quasi-zero stiffness characteristic;

[0008] The negative stiffness vibration isolation assembly comprises a first spring vertically arranged in the central area of ​​the low-frequency vibration isolator, the first spring is respectively connected to the upper end cover and the lower end cover, and is initially in an extended state;

[0009] The positive stiffness vibration isolation assembly includes at least two vibration isolation units located around the first spring and spaced apart along the circumferential direction, the vibration isolation unit includes a deformable connecting rod structure and a second spring that is initially in an extended state, the upper and lower ends of the connecting rod structure are respectively connected to the upper end cover and the lower end cover, the connecting rod structure has a left half and a right half that are relatively arranged, the second spring is horizontally placed between the left half and the right half and is fixedly connected to the left half and the right half, respectively, so as to pull the left half and the right half to shrink and deform inward.

[0010] Preferably, n second springs are connected in parallel between the left half and the right half, where n is an integer ≥1.

[0011] Preferably, the positive stiffness vibration isolation assembly also includes an upper vibration isolation assembly and a lower vibration isolation assembly, a middle plate is provided between the upper end cover and the lower end cover, the upper vibration isolation assembly is respectively connected to the upper end cover and the middle plate, and the lower vibration isolation assembly is respectively connected to the middle plate and the lower end cover.

[0012] Preferably, the upper vibration isolation assembly and the lower vibration isolation assembly have the same structure, and the corresponding vibration isolation units in the upper vibration isolation assembly and the lower vibration isolation assembly are aligned.

[0013] Preferably, a single vibration isolation unit is arranged along the radial direction of the middle plate or the lower end cover, and all vibration isolation units in the upper vibration isolation assembly and all vibration isolation units in the lower vibration isolation assembly are arranged to form a radial shape with internal concentration and external dispersion.

[0014] Preferably, the number of vibration isolation units in the upper vibration isolation assembly and the number of vibration isolation units in the lower vibration isolation assembly are both even numbers greater than zero, and the vibration isolation units in the upper vibration isolation assembly and the vibration isolation units in the lower vibration isolation assembly are both symmetrically arranged along the first spring axis.

[0015] Preferably, the connecting rod structure is a frame-like structure with a closed outer contour and bilateral symmetry, and the connecting rod structure is connected to the upper end cover or the middle plate or the lower end cover through a surface.

[0016] Preferably, the connecting rod structure includes a first frame and a second frame symmetrically arranged front and back, the first frame and the second frame each include a connecting rod, an upper base and a lower base, the connecting rods are hingedly connected to each other, the connecting rods and the upper base, and the connecting rods and the lower base, a rotating shaft is provided between the hinge point in the first frame and the corresponding hinge point in the second frame, and the first frame and the second frame are connected via the rotating shaft.

[0017] Preferably, both the first frame and the second frame are regular hexagonal structures.

[0018] Preferably, a positioning rod is further provided in the middle of the low-frequency vibration isolator, and the first spring is sleeved on the outside of the positioning rod.

[0019] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0020] The present invention adopts a method of arranging a first spring providing negative stiffness in the middle area of ​​the low-frequency vibration isolator. Compared with arranging a positive stiffness spring in the central area, the present invention can reduce the size of the first spring; multiple vibration isolation units for providing positive stiffness are arranged around the first spring, and the multiple vibration isolation units are arranged in parallel to produce a larger equivalent stiffness coefficient, thereby improving the positive stiffness bearing effect without increasing the size of the low-frequency vibration isolation device; and according to different loads, the stiffness coefficient ratio of the first spring and the second spring is changed, so that the effect of close to zero stiffness within a certain displacement range can be achieved, that is, the low-frequency vibration isolator has the characteristics of small size, high load-bearing capacity, and quasi-zero stiffness characteristics, and can be suitable for high-end manufacturing platform equipment.

[0021] In addition, since the vibration isolation unit is a structure composed of a connecting rod structure and a second spring, that is, the connecting rod structure and the second spring jointly bear the load, compared with rubber, spring and hydraulic vibration isolators used alone or in combination, it will not overly rely on the performance of the material and can achieve better low-frequency vibration isolation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 It is a front view structural schematic diagram of a low-frequency vibration isolator disclosed in a specific embodiment of the present invention;

[0024] Figure 2 for Figure 1 A schematic cross-sectional structure diagram of;

[0025] Figure 3 It is a schematic diagram of the axial structure of a low-frequency vibration isolator disclosed in a specific embodiment of the present invention;

[0026] Figure 4 It is a front view structural schematic diagram of a vibration isolation unit disclosed in a specific embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of the axial structure of a vibration isolation unit disclosed in a specific embodiment of the present invention.

[0028] Among them, 1. positioning rod; 2. upper end cover; 3. vibration isolation unit; 4. first spring; 5. middle plate; 6. lower end cover; 7. lower vibration isolation assembly; 8. upper vibration isolation assembly; 9. upper base; 10. connecting rod; 11. lower base; 12. rotating shaft; 13. second spring; 14. first frame; 15. second frame. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] like Figures 1 to 5 As shown, the present invention provides a low-frequency vibration isolator, comprising an upper end cover 2, a lower end cover 6, a negative stiffness vibration isolation component and a positive stiffness vibration isolation component, the negative stiffness vibration isolation component and the positive stiffness vibration isolation component can make the low-frequency vibration isolator have the characteristic of quasi-zero stiffness; the negative stiffness vibration isolation component comprises a first spring 4 vertically arranged in the central area of ​​the low-frequency vibration isolator, the first spring 4 is respectively connected to the upper end cover 2 and the lower end cover 6, and is initially in an extended state; the positive stiffness vibration isolation component comprises at least two vibration isolation units 3 located around the first spring 4 and distributed at intervals along the circumferential direction, the vibration isolation unit 3 comprises a deformable connecting rod structure and a second spring 13 initially in an extended state, the upper and lower ends of the connecting rod structure are respectively connected to the upper end cover 2 and the lower end cover 6, the connecting rod structure has a left half and a right half arranged oppositely, the second spring 13 is horizontally arranged between the left half and the right half and is respectively fixedly connected to the left half and the right half to pull the left half and the right half to shrink and deform inward to provide an upward supporting force.

[0032] The traditional quasi-zero stiffness vibration isolation device provides positive stiffness support through the first spring 4 located in the central area. Therefore, under the action of static heavy load, the stiffness coefficient of the first spring 4 needs to be particularly large. Due to material limitations, this will cause the size of the first spring 4 to be larger. If the size of the first spring 4 is limited, the bearing capacity must be sacrificed, resulting in insufficient bearing capacity of the first spring 4. Therefore, the low-frequency vibration isolator of the existing structure is not suitable for high-end manufacturing platform equipment. The present application sets the first spring 4 located in the central area to provide negative stiffness, and sets at least two vibration isolation units 3 arranged in parallel around the first spring 4, so that the at least two vibration isolation units 3 can produce a larger equivalent stiffness coefficient, thereby improving the positive stiffness and bearing capacity of the low-frequency vibration isolator without increasing the size; and according to the different loads, changing the stiffness coefficient ratio of the first spring 4 and the second spring 13 can achieve an effect close to zero stiffness within a certain displacement range, so that the low-frequency vibration isolator can be suitable for high-end manufacturing platform equipment with high precision requirements. In addition, as the vibration frequency increases, the relative displacement between the upper end cover 2 and the lower end cover 6 decreases, the overall equivalent of the low-frequency vibration isolation device is closer to zero, the vibration isolation effect is better, and it can play an effective vibration isolation effect in the range of 10Hz~1000Hz, with a wide-band vibration isolation effect.

[0033] Furthermore, n second springs 13 are connected in parallel between the left and right halves of the connecting rod structure, where n is an integer ≥ 1. By connecting multiple second springs 13 in parallel in the vibration isolation unit 3, the positive stiffness coefficient and bearing capacity of the vibration isolation unit 3 and the positive stiffness vibration isolation assembly are improved.

[0034] The positive stiffness vibration isolation assembly also includes an upper vibration isolation assembly 8 and a lower vibration isolation assembly 7. A middle plate 5 is provided between the upper end cover 2 and the lower end cover 6. The upper vibration isolation assembly 8 is respectively connected to the upper end cover 2 and the middle plate 5, and the upper vibration isolation assembly 8 includes all vibration isolation units 3 located between the upper end cover 2 and the middle plate 5. The lower vibration isolation assembly 7 is respectively connected to the middle plate 5 and the lower end cover 6, and the lower vibration isolation assembly 7 includes all vibration isolation units 3 located between the middle plate 5 and the lower end cover 6. By setting up upper and lower layers of vibration isolation assemblies, the vibration isolation effect of the positive stiffness vibration isolation assembly can be further improved. In order to ensure that the forces between the upper and lower vibration isolation assemblies are the same, the present application sets the upper vibration isolation assembly 8 and the lower vibration isolation assembly 7 to have the same structure, and the corresponding vibration isolation units 3 in the upper vibration isolation assembly 8 and the lower vibration isolation assembly 7 are aligned.

[0035] A single vibration isolation unit 3 is arranged along the radial direction of the middle plate 5 or the lower end cover 6 (that is, the length direction of the vibration isolation unit 3 extends along the radial direction of the middle plate 5 or the lower end cover 6), and all the vibration isolation units 3 in the upper vibration isolation assembly 8 and all the vibration isolation units 3 in the lower vibration isolation assembly 7 are arranged to form a radial shape with internal concentration and external dispersion; compared with the arrangement form in which the length direction of a single vibration isolation unit 3 is perpendicular to or intersecting with the radial direction of the middle plate 5 or the upper end cover 2, the arrangement method of the present application can improve the load-bearing uniformity and stability of the low-frequency vibration isolator.

[0036] Compared with an odd number of vibration isolation units 3, an even number of vibration isolation units 3 symmetrically arranged along the axis of the first spring 4 can better improve the stability of the low-frequency vibration isolator. In addition, in order to further reduce the size of the low-frequency vibration isolator, the more vibration isolation units 3 the better if permitted. In one embodiment, the upper vibration isolation assembly 8 and the lower vibration isolation assembly 7 are each provided with 6 vibration isolation units 3 symmetrically arranged relative to the axis of the first spring 4.

[0037] There are many forms of setting the connecting rod structure, such as V-shape, W-shape, quadrilateral, pentagon, hexagon, octagon, etc. Since the stability of structures such as V-shape, W-shape, pentagon, etc. is worse than that of left-right symmetrical structures such as quadrilateral, hexagon, octagon, etc., the present application prefers that the connecting rod structure is a frame-like structure with a closed outer contour and left-right symmetry, and the connecting rod structure is connected to the upper end cover 2 or the middle plate 5 or the lower end cover 6 through a surface.

[0038] The specific connecting rod structure includes a first frame 14 and a second frame 15 that are symmetrical in front and back. The first frame 14 and the second frame 15 both have a closed outer contour, left-right symmetry, and are connected to the upper end cover 2 or the middle plate 5 or the lower end cover 6 through a surface. The first frame 14 and the second frame 15 both include a connecting rod 10, an upper base 9 and a lower base 11. The connecting rods 10 and the connecting rods 10, the connecting rods 10 and the upper base 9, and the connecting rods 10 and the lower base 11 are all hingedly connected. A rotation axis 12 is provided between the hinge points in the first frame 14 and the corresponding hinge points in the second frame 15, and the first frame 14 and the second frame 15 are connected through the rotation axis 12. Specifically, a rotation axis 12 is provided between all the hinge points in the first frame 14 and the corresponding hinge points in the second frame 15. In one embodiment, the first frame 14 and the second frame 15 are both regular hexagonal structures. In another embodiment, the first frame 14 and the second frame 15 share the upper base 9 and the lower base 11 , and the connecting rod structure is connected to the upper end cover 2 or the middle plate 5 through the upper base 9 , and is connected to the middle plate 5 or the lower end cover 6 through the lower base 11 .

[0039] A positioning rod 1 is also provided in the middle of the low-frequency vibration isolator of the present application, and a first spring 4 is sleeved on the outside of the positioning rod 1. Furthermore, the ends of the positioning rod 1 extend out of the upper end cover 2 and the lower end cover 6, and the positioning rod 1 is connected to the upper end cover 2, the middle plate 5 and the lower end cover 6 through a coupling, so that the low-frequency vibration isolator can be used in a vibration isolation environment with rotation requirements to improve the scope of application.

[0040] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A low frequency vibration isolator, characterized in that: It comprises an upper end cover, a lower end cover, and a negative stiffness vibration isolation component and a positive stiffness vibration isolation component which enable the low-frequency vibration isolator to have a quasi-zero stiffness characteristic; The negative stiffness vibration isolation assembly comprises a first spring vertically arranged in the central area of ​​the low-frequency vibration isolator, the first spring is respectively connected to the upper end cover and the lower end cover, and is initially in an extended state; The positive stiffness vibration isolation assembly comprises at least two vibration isolation units located around the first spring and spaced apart in the circumferential direction, the vibration isolation unit comprises a deformable connecting rod structure and a second spring initially in an extended state, the upper and lower ends of the connecting rod structure are respectively connected to the upper end cover and the lower end cover, the connecting rod structure has a left half and a right half that are arranged oppositely, the second spring is transversely placed between the left half and the right half and is respectively fixedly connected to the left half and the right half to pull the left half and the right half to shrink and deform inwardly; A first spring located in the central area is arranged to provide negative stiffness, and at least two vibration isolation units arranged in parallel are arranged around the first spring, so that the at least two vibration isolation units can produce a larger equivalent stiffness coefficient, thereby improving the positive stiffness and load-bearing capacity of the low-frequency vibration isolator without increasing the size.

2. The low frequency vibration isolator according to claim 1, characterized in that: N second springs are connected in parallel between the left half and the right half, where n is an integer ≥1.

3. The low frequency vibration isolator according to claim 2, characterized in that: The positive stiffness vibration isolation assembly also includes an upper vibration isolation assembly and a lower vibration isolation assembly. A middle plate is provided between the upper end cover and the lower end cover. The upper vibration isolation assembly is respectively connected to the upper end cover and the middle plate, and the lower vibration isolation assembly is respectively connected to the middle plate and the lower end cover.

4. The low frequency vibration isolator according to claim 3, characterized in that: The upper vibration isolation assembly and the lower vibration isolation assembly have the same structure, and the corresponding vibration isolation units in the upper vibration isolation assembly and the lower vibration isolation assembly are aligned.

5. The low frequency vibration isolator according to claim 4, characterized in that: The single vibration isolation unit is arranged along the radial direction of the middle plate or the lower end cover, and all the vibration isolation units in the upper vibration isolation assembly and all the vibration isolation units in the lower vibration isolation assembly are arranged to form a radial shape with internal concentration and external dispersion.

6. The low frequency vibration isolator according to claim 5, characterized in that: The number of vibration isolation units in the upper vibration isolation assembly and the number of vibration isolation units in the lower vibration isolation assembly are both even numbers greater than zero, and the vibration isolation units in the upper vibration isolation assembly and the vibration isolation units in the lower vibration isolation assembly are both symmetrically arranged along the first spring axis.

7. The low frequency vibration isolator according to any one of claims 3 to 6, characterized in that: The connecting rod structure is a frame-like structure with a closed outer contour and bilateral symmetry, and the connecting rod structure is connected to the upper end cover or the middle plate or the lower end cover through a surface.

8. The low frequency vibration isolator according to claim 7, characterized in that: The connecting rod structure includes a first frame and a second frame symmetrically arranged front and back, the first frame and the second frame each include a connecting rod, an upper base and a lower base, the connecting rods are hingedly connected to each other, the connecting rods and the upper base, and the connecting rods and the lower base, a rotating shaft is provided between the hinge point in the first frame and the corresponding hinge point in the second frame, and the first frame and the second frame are connected via the rotating shaft.

9. The low frequency vibration isolator according to claim 8, characterized in that: The first frame and the second frame are both regular hexagonal structures.

10. The low frequency vibration isolator according to claim 1, characterized in that: A positioning rod is also provided in the middle of the low-frequency vibration isolator, and the first spring is sleeved on the outside of the positioning rod.

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