A low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range

Abstract

The present invention discloses a low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range, comprising a bottom frame and a top cover, wherein the top cover is horizontally arranged on the top of the bottom frame, a first support ring is arranged at the inner bottom center of the bottom frame, a second support ring corresponding to the first support ring is fixedly connected to the bottom of the top cover, and a negative stiffness mechanism mounting sleeve corresponding to the second support ring is fixedly connected to the bottom of the top cover; the edges of the first support ring and the second support ring are connected by a plurality of arc-shaped steel wire ropes, a guide rod is fixedly connected to the bottom center of the second support ring, and a through opening corresponding to the guide rod is fixedly connected to the top of the first support ring. The present invention enables the negative stiffness mechanism to produce quasi-zero stiffness characteristics within a large displacement range through the setting of a magnet ring-type negative stiffness mechanism, so that the vibration isolation range of the vibration isolator can be infinitely changed with the change of load, thereby effectively improving the application range of the quasi-zero stiffness vibration isolator.

Description

Technical Field

[0001] The invention relates to the technical field of vibration isolators, and in particular to a low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range. Background Art

[0002] Vibration isolators reduce the adverse effects of vibration by reducing the dynamic coupling between the object being isolated and the vibration source. They are widely used in aerospace, vehicle transportation, precision instruments and other fields. According to vibration theory, the vibration isolation frequency band of the vibration isolator is determined by its natural frequency. When the disturbance frequency of the vibration source is greater than the natural frequency of the vibration isolator, the vibration isolator will times to effectively isolate vibration.

[0003] There are two important indicators for vibration isolators: vibration isolation bandwidth and load-bearing capacity. Expanding the vibration isolation bandwidth requires reducing the natural frequency of the vibration isolator, which is generally achieved by reducing the system stiffness or increasing the system mass. However, reducing the system stiffness and increasing the system mass will increase the static deformation of the system. In a limited space, its load-bearing capacity is low and the engineering feasibility is poor, especially for low frequency and ultra-low frequency. In order to increase the load-bearing capacity in a limited space, it is necessary to increase the system stiffness, which will increase the natural frequency of the vibration isolator and reduce the vibration isolation frequency band. Therefore, the vibration isolation bandwidth and load-bearing capacity are a pair of natural contradictions.

[0004] By connecting positive and negative stiffness in parallel, the quasi-zero stiffness isolator can achieve high static stiffness and low dynamic stiffness. The bearing capacity of the system is determined by the positive stiffness spring, and the negative stiffness element is used to reduce the dynamic stiffness of the system, effectively solving the contradiction between the vibration isolation bandwidth and the bearing capacity.

[0005] However, the existing quasi-zero stiffness isolators have a narrow low stiffness displacement range, and the stiffness increases significantly with the increase of displacement, the nonlinearity is significantly enhanced, the initial vibration isolation frequency of the isolator increases, the vibration isolation frequency band becomes narrower, and the low-frequency vibration isolation performance decreases, thus affecting the application scope of the quasi-zero stiffness isolator. Summary of the invention

[0006] 1. Technical problems to be solved

[0007] The purpose of the present invention is to solve the problem that the low-stiffness displacement range of the quasi-zero stiffness isolator in the prior art is narrow and the low-frequency vibration isolation performance is poor, and to propose a low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range.

[0008] 2. Technical solution

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range comprises a bottom frame and a top cover, wherein the top cover is horizontally arranged on the top of the bottom frame, a first support ring is arranged at the center of the inner bottom of the bottom frame, a second support ring arranged parallel to the first support ring is fixedly connected to the bottom of the top cover, and a negative stiffness mechanism mounting sleeve corresponding to the second support ring is fixedly connected to the bottom of the top cover;

[0011] The edges of the first support ring and the second support ring are connected by a plurality of arc-shaped steel wire ropes, a guide rod is fixedly connected to the bottom center of the second support ring, and a through hole corresponding to the guide rod is fixedly connected to the top of the first support ring;

[0012] A plurality of negative stiffness rods are disposed around the inner side wall of the bottom frame, and two ends of the negative stiffness rods are rotatably connected to the negative stiffness mechanism mounting sleeve and the bottom frame through a first connecting assembly and a second connecting assembly respectively;

[0013] The negative stiffness rod includes a connecting rod, a first connecting sleeve and a second connecting sleeve, the first connecting sleeve is fixedly connected to one end of the second connecting sleeve, a connecting rod is slidably inserted in the first connecting sleeve, a circular hole is provided at the ends of the connecting rod and the second connecting sleeve that are away from each other, a bearing is installed in the circular hole, a linear coil spring is installed between the connecting rod and the second connecting sleeve, one end of the connecting rod located in the linear coil spring is fixedly connected to the middle magnet ring by a locking screw, the outside of the linear coil spring is surrounded by a first magnet ring, a second magnet ring and a third magnet ring, the inner wall of the second connecting sleeve is provided with step holes corresponding to the first magnet ring, the second magnet ring and the third magnet ring, and the first magnet ring, the second magnet ring and the third magnet ring are separated by a magnet ring partition ring.

[0014] Preferably, the first connecting assembly includes a first connecting head, and a first mounting seat corresponding to the first connecting head is fixedly connected to the inner wall of the bottom frame, and the first connecting head is rotatably connected to the inner wall of the first mounting seat.

[0015] Preferably, the second connecting assembly includes a second connecting head, a second mounting seat corresponding to the second connecting head is fixedly connected to the outer wall of the negative stiffness mechanism mounting sleeve, and the second connecting head is rotatably 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, and the locking blocks are provided with locking openings.

[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, and a guide sleeve corresponding to the guide rod is fixedly connected to the top of the support seat.

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

[0020] Preferably, a flexible dust cover is disposed around the top outer wall of the bottom frame.

[0021] 3. Beneficial effects

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

[0023] (1) In the present invention, by setting up a magnet ring type negative stiffness mechanism, the negative stiffness mechanism can produce a quasi-zero stiffness characteristic within a large displacement range, so that the vibration isolation range of the vibration isolator can be infinitely changed with the change of load, thereby effectively improving the application range of the quasi-zero stiffness vibration isolator.

[0024] (2) In the present invention, when the top load of the top cover changes, the top cover drives the second support ring to move downward, and at the same time, multiple negative stiffness rods can be used as negative stiffness mechanisms to offset the stiffness value of the arc-shaped steel wire rope, thereby achieving zero stiffness characteristics.

[0025] (3) In the present invention, the setting of the locking block can facilitate the fixation of the bottom frame, and the setting of multiple fixing holes can facilitate the connection of the counterweight and the top cover. The setting of the vibration isolation strip can provide a certain support for the second gear ring, and the setting of the guide rod and the guide sleeve can prevent the second support ring from shaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the structure of a low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range proposed by the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the top cover of a low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range proposed by the present invention;

[0028] Figure 3 This is a schematic structural diagram of the bottom frame of a low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range proposed by the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of a low-frequency vibration isolator support seat with an ultra-wide quasi-zero stiffness range proposed by the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the arc-shaped steel wire rope of a low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range proposed by the present invention.

[0031] Figure 6 The present invention is a schematic diagram of the internal structure of a negative stiffness rod of a low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range.

[0032] In the figure: 1 bottom frame, 2 top cover, 3 first support ring, 4 second support ring, 5 negative stiffness mechanism mounting sleeve, 6 arc-shaped steel wire rope, 7 guide rod, 8 guide sleeve, 9 negative stiffness rod, 91 bearing, 92 connecting rod, 93 first connecting sleeve, 94 magnet ring partition ring, 95 locking screw, 96 second connecting sleeve, 97 linear coil spring, 98 first magnet ring, 99 second magnet ring, 910 third magnet ring, 911 middle magnet ring, 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

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

[0034] Embodiment 1:

[0035] Reference Figure 1-6 A low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range comprises a bottom frame 1 and a top cover 2. A flexible dust cover 16 is arranged around the top outer wall of the bottom frame 1 to prevent dust or splashing water from entering the inside of the vibration isolator. A plurality of locking blocks 14 are fixedly connected to the outer wall of the bottom frame 1. The locking blocks 14 are provided with locking openings to facilitate the installation and fixing of the bottom frame 1. The top cover 2 is horizontally arranged on the top of the bottom frame 1. A plurality of fixing holes are arranged on the top of the top cover 2.

[0036] In the present invention, a first support ring 3 is provided at the center of the inner bottom of the bottom frame 1, a second support ring 4 arranged parallel to the first support ring 3 is fixedly connected to the bottom of the top cover 2 for supporting an arc-shaped steel wire rope 6, and a negative stiffness mechanism mounting sleeve 5 corresponding to the second support ring 4 is fixedly connected to the bottom of the top cover 2 for distributing the load of the top cover 2 to the negative stiffness rod 9;

[0037] In the present invention, the edges of the first support ring 3 and the second support ring 4 are connected by a plurality of arc-shaped steel wire ropes 6, which play a certain supporting role on the second support ring 4. The plurality of arc-shaped steel wire ropes 6 are staggered. The bottom center of the second support ring 4 is fixedly connected with a guide rod 7. The top of the first support ring 3 is fixedly connected with a through opening corresponding to the guide rod 7. The inner bottom of the bottom frame 1 is fixedly connected with a support seat 15. The top of the support seat 15 is fixedly connected with a guide sleeve 8 corresponding to the guide rod 7 to prevent the second support ring 4 from shaking.

[0038] In the present invention, a plurality of negative stiffness rods 9 are arranged around the inner side wall of the bottom frame 1, which serve as a negative stiffness mechanism to offset the stiffness value of the arc-shaped steel wire rope 6, thereby realizing a zero stiffness characteristic. The two ends of the negative stiffness rod 9 are rotatably connected to the negative stiffness mechanism mounting sleeve 5 and the bottom frame 1 through a first connecting component and a second connecting component respectively.

[0039] The negative stiffness rod 9 includes a connecting rod 92, a first connecting sleeve 93 and a second connecting sleeve 96. The first connecting sleeve 93 is fixedly connected to one end of the second connecting sleeve 96. The connecting rod 92 is slidably inserted in the first connecting sleeve 93. The ends of the connecting rod 92 and the second connecting sleeve 96 that are away from each other are both provided with a circular hole, in which a bearing 91 is installed. A linear coil spring 97 is installed between the connecting rod 92 and the second connecting sleeve 96. One end of the connecting rod 92 located in the linear coil spring 97 is fixedly connected to an intermediate magnet ring 911 through a locking screw 95. The outside of the linear coil spring 97 is surrounded by a first magnet ring 98, a second magnet ring 99 and a third magnet ring 910. The inner wall of the second connecting sleeve 96 is provided with a stepped hole corresponding to the first magnet ring 98, the second magnet ring 99 and the third magnet ring 910. The first magnet ring 98, the second magnet ring 99 and the third magnet ring 910 are separated by a magnet ring partition ring 94.

[0040] In the present invention, the first connecting assembly includes a first connecting head 10, and a first mounting seat 11 corresponding to the first connecting head 10 is fixedly connected to the inner wall of the bottom frame 1. The first connecting head 10 is rotatably connected to the inner wall of the first mounting seat 11, so as to facilitate the fixed installation of the negative stiffness rod 9;

[0041] In the present invention, the second connecting assembly includes a second connecting head 12, and a second mounting seat 13 corresponding to the second connecting head 12 is fixedly connected to the outer wall of the negative stiffness mechanism mounting sleeve 5. The second connecting head 12 is rotatably connected to the inner wall of the second mounting seat 13 to facilitate the fixed installation of the negative stiffness rod 9.

[0042] In the present invention, when the top load of the top cover 2 changes, the top cover 2 drives the second support circle 4 to move downward, and the multiple negative stiffness rods 9 can be used as a negative stiffness mechanism to offset the stiffness value of the arc-shaped steel wire rope 6, thereby realizing a zero stiffness characteristic; the setting of the locking block 14 can facilitate the fixation of the bottom frame 1, and the setting of the multiple fixing holes can facilitate the connection of the counterweight to the top cover 2, and the setting of the negative stiffness mechanism mounting sleeve 5 can provide a certain supporting effect on the second support circle 4, and the setting of the guide rod 7 and the guide sleeve 8 can prevent the second support circle 4 from shaking.

[0043] In the present invention, when the mass of the vibration-isolated equipment is equal to the rated mass, the arc-shaped steel wire rope 6 is compressed and the amount of compression is equal to the rated compression. At this time, the negative stiffness rod 9 is just in a horizontal position, the linear coil spring 97 in the negative stiffness rod 9 is compressed, and the middle magnet ring 911 and the third magnet ring 910 are flush. The middle magnet ring 911 and the third magnet ring 910 have the same polarity and produce the maximum repulsive force when they are flush with each other. At this time, the permanent magnet group and the linear coil spring 97 together form a negative stiffness mechanism, which offsets the stiffness value of the positive stiffness mechanism composed of the arc-shaped steel wire rope 6 and realizes low-frequency vibration isolation. Because the middle magnet ring 911 and the third magnet ring 910 group are introduced into the negative stiffness mechanism, the negative stiffness mechanism can produce a quasi-zero stiffness characteristic within a large displacement range, so that the vibration isolator has an ultra-wide quasi-zero stiffness range.

[0044] In the present invention, when the amplitude of the external excitation acting on the vibration isolator increases, the dynamic response of the vibration-isolated device increases, the rotation angle of the negative stiffness rod 9 around the first mounting seat 11 increases, the compression amount of the linear coil spring 97 decreases, and the middle magnet ring 911 deviates from the third magnet ring 910 and approaches the second magnet ring 99. At this time, the negative stiffness is mainly provided by the middle magnet ring 911 and the second magnet ring 99, and the linear coil spring 97, realizing the quasi-zero stiffness characteristic under the condition of large dynamic response amplitude.

[0045] In the present invention, when the external excitation amplitude acting on the vibration isolator is further increased, the dynamic response of the vibration-isolated device is further increased, the rotation angle of the negative stiffness rod 9 around the first mounting seat 11 is increased, the compression amount of the linear coil spring 97 is reduced, and the middle magnet ring 911 deviates from the second magnet ring 99 and approaches the first magnet ring 98. At this time, the negative stiffness is mainly provided by the middle magnet ring 911 and the first magnet ring 98, and the linear coil spring 97, realizing the quasi-zero stiffness characteristic under the condition of ultra-large dynamic response amplitude.

[0046] In the present invention, by setting up a magnet ring type negative stiffness mechanism, the negative stiffness mechanism can produce a quasi-zero stiffness characteristic in a large displacement range, so that the vibration isolation range of the vibration isolator can be infinitely changed with the change of load, thereby effectively improving the application range of the quasi-zero stiffness vibration isolator.

[0047] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range, comprising a bottom frame (1) and a top cover (2), characterized in that: The top cover (2) is horizontally arranged on the top of the bottom frame (1); a first support ring (3) is provided at the center of the inner bottom of the bottom frame (1); a second support ring (4) arranged parallel to the first support ring (3) is fixedly connected to the bottom of the top cover (2); and a negative stiffness mechanism mounting sleeve (5) corresponding to the second support ring (4) is fixedly connected to the bottom of the top cover (2); The edges of the first support ring (3) and the second support ring (4) are connected by a plurality of arc-shaped steel wire ropes (6); a guide rod (7) is fixedly connected to the bottom center of the second support ring (4); and a through opening corresponding to the guide rod (7) is fixedly connected to the top of the first support ring (3); A plurality of negative stiffness rods (9) are disposed around the inner side wall of the bottom frame (1), and two ends of the negative stiffness rods (9) are rotatably connected to the negative stiffness mechanism mounting sleeve (5) and the bottom frame (1) through a first connecting assembly and a second connecting assembly, respectively; The negative stiffness rod (9) comprises a connecting rod (92), a first connecting sleeve (93) and a second connecting sleeve (96); the first connecting sleeve (93) is fixedly connected to one end of the second connecting sleeve (96); a connecting rod (92) is slidably inserted in the first connecting sleeve (93); a circular hole is provided at the ends of the connecting rod (92) and the second connecting sleeve (96) that are away from each other; a bearing (91) is installed in the circular hole; a linear coil spring (97) is installed between the connecting rod (92) and the second connecting sleeve (96); the connecting rod (92) is located at the linear coil spring One end of the spring (97) is fixedly connected to an intermediate magnet ring (911) via a locking screw (95); a first magnet ring (98), a second magnet ring (99) and a third magnet ring (910) are arranged around the outside of the linear coil spring (97); a stepped hole corresponding to the first magnet ring (98), the second magnet ring (99) and the third magnet ring (910) is arranged on the inner wall of the second connecting sleeve (96); the first magnet ring (98), the second magnet ring (99) and the third magnet ring (910) are separated by a magnet ring partition ring (94); The inner bottom of the bottom frame (1) is fixedly connected to a support seat (15), the top of the support seat (15) is fixedly connected to a guide sleeve (8) corresponding to the guide rod (7), and a plurality of arc-shaped steel wire ropes (6) are arranged in a staggered manner.

2. A low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range according to claim 1, characterized in that: The first connection assembly comprises 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 (1), and the first connection head (10) is rotatably connected to the inner wall of the first mounting seat (11).

3. The low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range according to claim 1, characterized in that: The second connection assembly comprises 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 sleeve (5); and the second connection head (12) is rotatably connected to the inner wall of the second mounting seat (13).

4. The low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range according to claim 1, characterized in that: A plurality of locking blocks (14) are fixedly connected to the outer wall of the bottom frame (1), and the locking blocks (14) are provided with locking openings.

5. The low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range according to claim 1, characterized in that: The top of the top cover (2) is provided with a plurality of fixing holes.

6. The low-frequency vibration isolator with an ultra-wide quasi-zero stiffness range according to claim 1, characterized in that: A flexible dust cover (16) is disposed around the top outer wall of the bottom frame (1).

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