A multi-stage quasi-zero stiffness vibration isolator

Abstract

The present invention discloses a multi-stage quasi-zero stiffness vibration isolator, which includes a bottom frame body and a top cover. The top cover is horizontally arranged at the top of the bottom frame body. A first mounting plate is provided at the center of the inner bottom of the bottom frame body. The bottom of the top cover is fixedly connected with a second mounting plate corresponding to the first mounting plate, and a negative stiffness mechanism mounting rod corresponding to the second mounting plate is fixedly connected to the bottom of the top cover. The edges of the first mounting plate and the second mounting plate are connected by a plurality of arc-shaped steel wires. In the present invention, the arc-shaped steel wires are combined in parallel with a negative stiffness mechanism composed of permanent magnets. The arc-shaped steel wires support the mass of the equipment to be vibration-isolated, and the negative stiffness mechanism offsets the stiffness value of the arc-shaped steel wires, realizing the quasi-zero stiffness characteristic. At the same time, through the setting of multiple groups of negative stiffness basic modules in the vibration isolator, the quasi-zero stiffness position of the vibration isolator can change synchronously with the change of the load, thereby effectively improving the vibration isolation effect of the quasi-zero stiffness vibration isolator under variable load conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration isolators, and in particular, to a multi-stage quasi-zero stiffness vibration isolator. Background Art

[0002] A vibration isolator is an elastic element connecting equipment and a foundation, used to reduce and eliminate the vibration force transmitted from the equipment to the foundation and the vibration transmitted from the foundation to the equipment. A traditional linear vibration isolator has vibration isolation ability when the external excitation frequency is higher than the square root of two times its natural frequency. Since the mass of a general load cannot be changed, reducing the stiffness is an effective method to expand the vibration isolation frequency band. However, too low stiffness will lead to excessive static deformation, resulting in the problem that the effective vibration isolation frequency band of the traditional vibration isolator is limited by the bearing capacity.

[0003] To solve this problem, a quasi-zero stiffness vibration isolator is generally designed by paralleling positive and negative stiffness springs. The negative stiffness is opposite to the common positive stiffness characteristic, that is, the direction of the load increment is opposite to the direction of the deformation increment. The quasi-zero stiffness vibration isolator has the characteristics of high static stiffness to ensure large bearing capacity and low dynamic stiffness to broaden the vibration isolation frequency band, and can achieve vibration isolation at low frequencies or even ultra-low frequencies.

[0004] However, the existing quasi-zero stiffness vibration isolator has a relatively simple composition structure. With the change of the load, the quasi-zero stiffness interval of the vibration isolator cannot change synchronously, resulting in a significant increase in the stiffness of the vibration isolator and a non-linear enhancement of the stiffness, thereby affecting the low-frequency vibration isolation effect of the quasi-zero stiffness vibration isolator. Summary of the Invention

[0005] 1. Technical Problem to be Solved

[0006] The purpose of the present invention is to solve the problem in the prior art that the composition structure of the quasi-zero stiffness vibration isolator is relatively simple. With the change of the load, the quasi-zero stiffness interval of the vibration isolator cannot change synchronously, resulting in a significant increase in the stiffness of the vibration isolator and a non-linear enhancement of the stiffness, and to propose a multi-stage quasi-zero stiffness vibration isolator.

[0007] 2. Technical Solution

[0008] To achieve the above purpose, the present invention adopts the following technical solution:

[0009] A multi-stage quasi-zero stiffness vibration isolator includes a bottom frame body and a top cover. The top cover is horizontally arranged on the top of the bottom frame body. A first mounting plate is provided at the center of the inner bottom of the bottom frame body. A second mounting plate corresponding to the first mounting plate is fixedly connected to the bottom of the top cover. A negative stiffness mechanism mounting rod corresponding to the second mounting plate is fixedly connected to the bottom of the top cover.

[0010] The edges of the first mounting plate and the second mounting plate are connected by a plurality of arc-shaped steel wire ropes. A guide rod is fixedly connected to the center of the bottom of the second mounting plate, and a through hole corresponding to the guide rod is fixedly connected to the top of the first mounting plate.

[0011] On the inner side wall of the bottom frame body, a plurality of negative stiffness basic modules corresponding to the negative stiffness mechanism mounting rods are arranged in a ring. The two ends of the negative stiffness basic module are respectively rotationally connected to the negative stiffness mechanism mounting rod and the bottom frame body through a first connection assembly and a second connection assembly.

[0012] The negative stiffness basic module includes a top rod sleeve and a top rod. The top rod is slidably connected to one end of the top rod sleeve. A second magnet is fixedly connected to the end of the top rod located inside the top rod sleeve. The second magnet is connected to the top rod through a locking screw. A first magnet that repels the second magnet is fixedly connected to the inner wall of the top rod sleeve. Round holes are provided at the ends of the top rod and the top rod sleeve that are away from each other, and bearings are installed in the round holes.

[0013] Preferably, there are five groups of the negative stiffness basic modules, with a difference of 72 degrees between each group. The number of the negative stiffness basic modules in each group is three, and the negative stiffness basic modules at the top and bottom are inclined inward.

[0014] Preferably, the first connection assembly includes a first connection head. A first mounting seat corresponding to the first connection head is fixedly connected to the inner wall of the bottom frame body. The first connection head is rotationally connected to the inner wall of the first mounting seat.

[0015] Preferably, the second connection assembly includes a second connection head. A second mounting seat corresponding to the second connection head is fixedly connected to the outer wall of the negative stiffness mechanism mounting rod. The second connection head is rotationally connected to the inner wall of the second mounting seat.

[0016] Preferably, a plurality of locking blocks are fixedly connected to the outer wall of the bottom frame body, and locking ports are provided on the locking blocks.

[0017] Preferably, a plurality of fixing holes are provided on the top of the top cover.

[0018] Preferably, a support seat is fixedly connected to the inner bottom of the bottom frame body, and a linear bearing corresponding to the guide rod is fixedly connected to the top of the support seat.

[0019] Preferably, the plurality of arc-shaped steel wire ropes are arranged in a staggered manner.

[0020] Preferably, a flexible dust cover is arranged in a ring on the top outer wall of the bottom frame body.

[0021] 3. Beneficial effects

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] (1) In the present invention, through the setting of multiple groups of negative stiffness basic modules, the vibration isolator can change synchronously with the change of the load, thereby effectively improving the vibration isolation effect of the quasi-zero stiffness vibration isolator under variable load conditions.

[0024] (2) In the present invention, when the top load of the top cover changes, the top cover drives the second mounting plate to move downward. At the same time, multiple negative stiffness basic modules can act as negative stiffness mechanisms to offset the stiffness value of the arc-shaped wire rope, thereby achieving the zero stiffness characteristic.

[0025] (3) In the present invention, the setting of the locking block can facilitate the fixation of the bottom frame body. At the same time, the setting of multiple fixing holes can facilitate the connection of the counterweight and the top cover. The setting of the arc-shaped wire rope provides positive stiffness for the vibration isolator to support the load mass. At the same time, the setting of the guide rod and the linear bearing can prevent the shaking of the second mounting plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of a multi-stage quasi-zero stiffness vibration isolator proposed by the present invention;

[0027] Figure 2 is a schematic structural diagram of the top cover of a multi-stage quasi-zero stiffness vibration isolator proposed by the present invention;

[0028] Figure 3 is a schematic structural diagram of the bottom frame body of a multi-stage quasi-zero stiffness vibration isolator proposed by the present invention;

[0029] Figure 4 is a schematic structural diagram of the support seat of a multi-stage quasi-zero stiffness vibration isolator proposed by the present invention;

[0030] Figure 5 is a schematic structural diagram of the arc-shaped wire rope of a multi-stage quasi-zero stiffness vibration isolator proposed by the present invention;

[0031] Figure 6 is a schematic internal structural diagram of the negative stiffness basic module of a multi-stage quasi-zero stiffness vibration isolator proposed by the present invention.

[0032] In the figure: 1 bottom frame body, 2 top cover, 3 first mounting plate, 4 second mounting plate, 5 negative stiffness mechanism mounting rod, 6 arc-shaped wire rope, 7 guide rod, 8 linear bearing, 9 negative stiffness basic module, 91 locking screw, 92 bearing, 93 ejector sleeve, 94 first magnet, 95 second magnet, 96 ejector rod, 10 first connector, 11 first mounting seat, 12 second connector, 13 second mounting seat, 14 locking block, 15 support seat, 16 flexible dust cover. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0034] Embodiment 1:

[0035] Referring to Figure 1-6 , a multi-stage quasi-zero stiffness isolator includes a bottom frame body 1 and a top cover 2. A flexible dust-proof sleeve is provided around the outer wall of the top of the bottom frame body 1, which can prevent dust or splashed water stains from invading the interior of a multi-stage quasi-zero stiffness isolator while not affecting the up and down movement of the top cover 2. A plurality of locking blocks 14 are fixedly connected to the outer wall of the bottom frame body 1, and locking ports are provided on the locking blocks 14 to facilitate the installation and fixation of the bottom frame body 1. The top cover 2 is horizontally arranged on the top of the bottom frame body 1, and a plurality of fixing holes are provided on the top of the top cover 2 to facilitate connection with a counterweight;

[0036] In the present invention, a first mounting plate 3 is provided at the center of the inner bottom of the bottom frame body 1. A second mounting plate 4 corresponding to the first mounting plate 3 is fixedly connected to the bottom of the top cover 2. A negative stiffness mechanism mounting rod 5 corresponding to the second mounting plate 4 is fixedly connected to the bottom of the top cover 2, which is used to mount a negative stiffness basic module to offset the positive stiffness value of the arc-shaped wire rope, so as to achieve the quasi-zero stiffness characteristic. In the present invention, the edges of the first mounting plate 3 and the second mounting plate 4 are connected by a plurality of arc-shaped wire ropes 6 to support the second mounting plate 4 and the load mass of the isolator. The plurality of arc-shaped wire ropes 6 are arranged in a staggered manner. A guide rod 7 is fixedly connected to the center of the bottom of the second mounting plate 4, and a through hole corresponding to the guide rod 7 is fixedly connected to the top of the first mounting plate 3. A support seat 15 is fixedly connected to the inner bottom of the bottom frame body 1, and a linear bearing 8 corresponding to the guide rod 7 is fixedly connected to the top of the support seat 15 to prevent the second mounting plate 4 from shaking;

[0037] In the present invention, a plurality of groups of negative stiffness basic modules 9 corresponding to the negative stiffness mechanism mounting rods 5 are provided around the inner side wall of the bottom frame body 1. The negative stiffness basic module 9 includes a top rod sleeve 93 and a top rod 96. The top rod 96 is slidably connected to one end of the top rod sleeve 93. A second magnet 95 is fixedly connected to the end of the top rod 96 located inside the top rod sleeve 93. The second magnet 95 and the top rod 96 are connected by a locking screw 91. A first magnet 94 that repels the second magnet 95 is fixedly connected to the inner wall of the top rod sleeve 93. Round holes are provided at the ends of the top rod 96 and the top rod sleeve 93 away from each other, and bearings 92 are installed in the round holes;

[0038] There are five groups of negative stiffness basic modules 9, with a difference of 72 degrees between each group. The number of negative stiffness basic modules 9 in each group is three. When the load mass of the vibration isolator is equal to the rated load mass, the negative stiffness basic module 9 in the middle of each group of negative stiffness basic modules 9 is in a horizontal position. The distance between the second magnet 95 and the first magnet 94 is the shortest, the repulsive force is the largest, and the negative stiffness value just offsets the stiffness value of the positive stiffness mechanism composed of the arc-shaped steel wire rope 6. The negative stiffness basic modules 9 at the top and bottom are inclined inward, the distance between the second magnet 95 and the first magnet 94 increases, and the negative stiffness effect is weak or has no negative stiffness effect. The two ends of the negative stiffness basic module 9 are respectively rotatably connected to the negative stiffness mechanism mounting rod 5 and the bottom frame body 1 through the first connection assembly and the second connection assembly; in the present invention, the first connection assembly includes a first connection head 10, and a first mounting seat 11 corresponding to the first connection head 10 is fixedly connected to the inner wall of the bottom frame body 1. The first connection head 10 is rotatably connected to the inner wall of the first mounting seat 11, which is convenient for fixedly installing the negative stiffness basic module 9;

[0039] In the present invention, the second connection assembly includes a second connection head 12, and a second mounting seat 13 corresponding to the second connection head 12 is fixedly connected to the outer wall of the negative stiffness mechanism mounting rod 5. The second connection head 12 is rotatably connected to the inner wall of the second mounting seat 13, which is convenient for fixedly installing the negative stiffness basic module 9.

[0040] In the present invention, when the top load of the top cover 2 changes, the top cover 2 drives the second mounting plate 4 to move downward. At the same time, multiple negative stiffness basic modules 9 can be used as a negative stiffness mechanism to offset the stiffness value of the arc-shaped steel wire rope 6, so as to achieve the zero stiffness characteristic; the setting of the locking block 14 can facilitate the fixation of the bottom frame body 1. At the same time, the setting of multiple fixing holes can facilitate the connection of the counterweight to the top cover 2. The setting of the vibration isolation strip 5 can play a certain supporting role for the second gear ring 4. At the same time, the setting of the guide rod 7 and the linear bearing 8 can prevent the second mounting plate 4 from shaking.

[0041] In the present invention, when the mass of the equipment to be vibration isolated is equal to the rated load of a multi-stage quasi-zero stiffness vibration isolator, the positive stiffness mechanism is compressed, and the negative stiffness basic module 9 in the middle of each group of negative stiffness basic modules 9 is in a horizontal position. The distance between the first magnet 94 and the second magnet 95 in the negative stiffness basic module 9 is the smallest, and the two magnets generate a repulsive force, providing negative stiffness for a multi-stage quasi-zero stiffness vibration isolator and offsetting the stiffness value of the positive stiffness mechanism, so as to achieve low-frequency vibration isolation.

[0042] In the present invention, when the mass of the equipment to be vibration-isolated is less than the rated load of a multi-stage quasi-zero stiffness vibration isolator, the compression amount of the positive stiffness mechanism is less than the compression amount under the rated load. The negative stiffness basic module 9 at the top of each group of negative stiffness basic modules 9 is in a horizontal position, and the distance between its first magnet 94 and second magnet 95 is the smallest. At this time, the negative stiffness basic module 9 at the uppermost provides negative stiffness for the vibration isolator to offset the stiffness value of the positive stiffness mechanism. And each negative stiffness basic module 9 except the uppermost negative stiffness basic module 9 in each negative stiffness basic module 9 rotates around the mounting seat, the length of the negative stiffness basic module 9 increases, the distance between the first magnet 94 and the second magnet 95 increases, the repulsive force decreases, and the negative stiffness effect decreases or disappears.

[0043] In the present invention, when the mass of the equipment to be vibration-isolated is greater than the rated load of a multi-stage quasi-zero stiffness vibration isolator, the compression amount of the positive stiffness mechanism is greater than the compression amount under the rated load. The negative stiffness basic module 9 at the lowermost side of each group of negative stiffness basic modules 9 is in a horizontal position, and the distance between its first magnet 94 and second magnet 95 is the smallest. At this time, the negative stiffness basic module 9 at the lowermost provides negative stiffness for the vibration isolator to offset the stiffness value of the positive stiffness mechanism. And each negative stiffness basic module 9 except the lowermost negative stiffness basic module 9 in each negative stiffness basic module 9 rotates around the mounting seat, the length of the negative stiffness basic module 9 increases, the distance between the first magnet 94 and the second magnet 95 increases, the repulsive force decreases, and the negative stiffness effect decreases or disappears.

[0044] In the present invention, by arranging multiple groups of negative stiffness basic modules 9, the quasi-zero stiffness position of the vibration isolator can vary steplessly with the change of the load, thereby effectively improving the vibration isolation effect of the quasi-zero stiffness vibration isolator under variable load conditions.

[0045] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered by the protection scope of the present invention.

Claims

1. A multi-stage quasi-zero stiffness vibration isolator, comprising a bottom frame body (1) and a top cover (2), characterized in that, The top cover (2) is horizontally arranged on the top of the bottom frame body (1). A first mounting plate (3) is provided at the center of the inner bottom of the bottom frame body (1). The bottom of the top cover (2) is fixedly connected with a second mounting plate (4) corresponding to the first mounting plate (3). The bottom of the top cover (2) is fixedly connected with a plurality of negative stiffness mechanism mounting rods (5) corresponding to the second mounting plate (4). The edges of the first mounting plate (3) and the second mounting plate (4) are connected by a plurality of arc-shaped steel wires (6). A guide rod (7) is fixedly connected to the center of the bottom of the second mounting plate (4). A through hole corresponding to the guide rod (7) is fixedly connected to the top of the first mounting plate (3). A plurality of groups of negative stiffness basic modules (9) corresponding to the negative stiffness mechanism mounting rods (5) are arranged in a ring on the inner side wall of the bottom frame body (1). The two ends of the negative stiffness basic module (9) are respectively rotatably connected to the negative stiffness mechanism mounting rod (5) and the bottom frame body (1) through a first connection component and a second connection component. The negative stiffness basic module (9) includes a top rod sleeve (93) and a top rod (96). The top rod (96) is slidably connected to one end of the top rod sleeve (93). A second magnet (95) is fixedly connected to the end of the top rod (96) located inside the top rod sleeve (93). The second magnet (95) is connected to the top rod (96) through a locking screw (91). A first magnet (94) that repels the second magnet (95) is fixedly connected to the inner wall of the top rod sleeve (93). Circular holes are provided at the ends of the top rod (96) and the top rod sleeve (93) away from each other, and bearings (92) are installed in the circular holes. The number of each group of negative stiffness basic modules (9) is three. When the vibration isolator load is placed on the top cover (2) and its value is equal to the rated load value, the middle negative stiffness basic module (9) is in a horizontal position, and the negative stiffness basic modules (9) at the top and bottom are inclined inward. The first connection component includes a first connection head (10). A first mounting seat (11) corresponding to the first connection head (10) is fixedly connected to the inner wall of the bottom frame body (1). The first connection head (10) is rotatably connected to the inner wall of the first mounting seat (11). The second connection component includes a second connection head (12). A second mounting seat (13) corresponding to the second connection head (12) is fixedly connected to the outer wall of the negative stiffness mechanism mounting rod (5). The second connection head (12) is rotatably connected to the inner wall of the second mounting seat (13). A plurality of locking blocks (14) are fixedly connected to the outer wall of the bottom frame body (1), and locking openings are provided on the locking blocks (14).

2. The multi-stage quasi-zero stiffness vibration isolator according to claim 1, wherein A plurality of fixing holes are provided on the top of the top cover (2).

3. The multi-stage quasi-zero stiffness vibration isolator according to claim 1, characterized in that, A support seat (15) is fixedly connected to the inner bottom of the bottom frame body (1). A linear bearing (8) corresponding to the guide rod (7) is fixedly connected to the top of the support seat (15).

4. A multi-stage quasi-zero stiffness vibration isolator according to claim 1, wherein, The plurality of arc-shaped steel wires (6) are arranged in a staggered manner.

5. A multi-stage quasi-zero stiffness vibration isolator according to claim 1, characterized in that, A flexible dust cover (16) is arranged in a ring on the top outer wall of the bottom frame body (1).

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