Quasi-zero stiffness isolator

Abstract

The present invention relates to a quasi-zero stiffness vibration isolator, belonging to the field of vibration control, which includes a bottom plate and a top plate arranged parallel to the bottom plate, a positive stiffness mechanism and a negative stiffness mechanism connecting the bottom plate and the top plate are arranged between the bottom plate and the top plate, the negative stiffness mechanism includes two cross-arranged elastic arms, a first base and a second base are respectively arranged at both ends of the elastic arm, the first base and the second base are respectively pivotally connected to the upper surface of the bottom plate and the lower surface of the top plate through a rotating shaft, the elastic arm includes a sleeve and a sliding rod slidably inserted in the sleeve, the first base and the second base are respectively pivotally connected to the upper surface of the bottom plate and the lower surface of the top plate through a rotating shaft, the elastic arm includes a sleeve and a sliding rod slidably inserted in the sleeve, a first cylindrical spring is sleeved on the elastic arm, and the two ends of the first cylindrical spring are respectively fixedly connected to the first base and the second base. The present invention exhibits good vibration isolation performance when the vibration amplitude is very small, and can be used to isolate micro-amplitude low-frequency vibrations.

Description

Technical Field

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

[0002] Vibration and shock phenomena are widely present in daily life, industrial technology and national defense. Most of these vibrations have a negative effect on the performance of equipment and the comfort requirements of personnel. Therefore, it is necessary to effectively isolate these vibrations. At the same time, people's requirements for vibration environment, product and structural vibration characteristics have been further improved. In particular, operating tables, high-precision instruments and meters, high-precision mechanical equipment, etc. all need to establish ultra-precision vibration isolation platforms to achieve low-frequency / ultra-low-frequency vibration isolation, so that there is a large attenuation at higher frequencies. In daily life, people are also most sensitive to low-frequency vibrations. Long-term exposure to low-frequency vibration environments will cause people to have adverse reactions such as fatigue and anxiety; however, traditional linear vibration isolators can only have vibration isolation effects when the external disturbance frequency is greater than 1.4 times the natural frequency of the vibration isolator. When dealing with low-frequency / ultra-low-frequency external disturbances, the vibration control effect is limited by structural space and stability. Therefore, it is particularly important to effectively reduce the natural frequency of the vibration isolator without destroying the original performance of the entire system, so that people and other mechanical equipment are not affected by low-frequency / ultra-low-frequency vibrations. However, existing vibration isolators cannot effectively isolate low-frequency vibrations between equipment and equipment foundations. Based on the principle of a nonlinear vibration isolator with high static stiffness and low dynamic stiffness, the present invention proposes a nonlinear ultra-low frequency vibration isolator composed of a vibration reduction rod and a spring to meet the needs of practical use. Summary of the invention

[0003] Based on this, it is necessary to provide a quasi-zero stiffness vibration isolator, comprising a bottom plate and a top plate arranged parallel to the bottom plate, a positive stiffness mechanism and a negative stiffness mechanism connecting the bottom plate and the top plate are arranged between the bottom plate and the top plate, the negative stiffness mechanism comprises two cross-arranged elastic arms, a first base and a second base are respectively arranged at both ends of the elastic arm, the first base and the second base are respectively pivoted to the upper surface of the bottom plate and the lower surface of the top plate through a rotating shaft, the elastic arm comprises a sleeve and a sliding rod slidably inserted in the sleeve, the first base and the second base are respectively pivoted to the upper surface of the bottom plate and the lower surface of the top plate through a rotating shaft, the elastic arm comprises a sleeve and a sliding rod slidably inserted in the sleeve, a first cylindrical spring is sleeved on the elastic arm, and the two ends of the first cylindrical spring are respectively fixedly connected to the first base and the second base.

[0004] Among them, the outer wall of the sliding rod is in close fit and slidable cooperation with the inner wall of the sleeve, the sliding rod can only move back and forth along the center line of the sleeve, the end of the sleeve away from the sliding rod is connected to the first base, and the end of the sliding rod away from the sleeve is connected to the second base; or the end of the sleeve away from the sliding rod is connected to the second base, and the end of the sliding rod away from the sleeve is connected to the first base.

[0005] In the present invention, the bottom plate is used to fix the vibration isolator on a bearing structure such as a foundation, the top plate is used to bear the object to be isolated, the bottom plate and the top plate, and the positive stiffness mechanism and the negative stiffness mechanism located between the bottom plate and the top plate form a quasi-zero stiffness system, and the dynamic stiffness of the quasi-zero stiffness system at the static equilibrium position is zero, so that the stiffness of the vibration isolator can be close to zero while ensuring the bearing capacity, thereby exhibiting excellent low-frequency vibration isolation performance.

[0006] Among them, the number of positive stiffness mechanisms is one or more, which are used to support the top plate and make the top plate stable; the number of negative stiffness mechanisms is one or more, and the specific number is determined according to the number and specifications of the positive stiffness mechanisms to ensure that the present invention can become a quasi-zero stiffness system after placing the vibration-isolated object.

[0007] In the present invention, the two ends of the elastic arm are pivotally connected to the lower surface of the top plate and the upper surface of the bottom plate respectively. When the top plate moves downward due to carrying the object to be isolated, the elastic arm will tend to be parallel to the bottom plate. At this time, the elastic arm will be compressed, and the first cylindrical spring on the elastic arm will be compressed, and the sliding rod will be inserted deeper into the sleeve, that is, the elastic arm is deformed to produce negative stiffness. At this time, the negative stiffness mechanism and the positive stiffness mechanism form a quasi-zero stiffness system, and the object to be isolated in the present invention is mainly supported by the positive stiffness mechanism, and the elastic arm in the negative stiffness mechanism is tilted. When the top plate moves downward, the compression of the first cylindrical spring is greater than the moving distance of the top plate. Therefore, the elastic arm in the present invention is more sensitive to stiffness. Therefore, the negative stiffness mechanism in the present invention can make the vibration isolator show good vibration isolation performance when the vibration amplitude is very small, and can be suitable for isolating small low-frequency vibrations; at the same time, compared with the spring as a negative stiffness structure in the existing vibration isolator, the negative stiffness mechanism in the present invention occupies a smaller installation space, thereby realizing the miniaturization of the vibration isolator.

[0008] In addition, the two elastic arms in the negative stiffness mechanism of the present invention are arranged crosswise with each other, which can avoid the generation of torsional torque of the vibration isolator and also make it difficult for the vibration isolator to deform when subjected to external force in the horizontal direction.

[0009] The first base and the second base are adjustably disposed at two ends of the elastic arm.

[0010] By adjusting the positions of the first base and the second base at both ends of the elastic arm on the elastic arm, the pre-compression amount of the first cylindrical spring between the first base and the second base can be adjusted, thereby realizing the adjustment of the parameters of the negative stiffness mechanism, and further realizing the adjustment of the parameters of the quasi-zero stiffness isolator.

[0011] The adjustable structure is as follows: an external thread is provided on the outer surface of the sleeve, and the first base is provided with a threaded hole corresponding to the external thread, and the sleeve is installed in the threaded hole, and the position of the first base relative to the sleeve, that is, the position of the first base relative to the elastic arm, can be adjusted by rotating the sleeve, and the outer surface of the sliding rod on the side away from the sleeve is provided with an external thread, and the second base is provided with a threaded hole corresponding to the external thread, and the sliding rod is installed in the threaded hole, and the position of the second base on the sliding rod can be adjusted by rotating the sliding rod, that is, the position of the second base relative to the elastic arm is adjusted; or the outer surface of the sleeve is provided with an external thread, and the second base is provided with a threaded hole corresponding to the external thread, and the sleeve is installed in the threaded hole, and the position of the second base relative to the sleeve, that is, the position of the second base relative to the elastic arm can be adjusted by rotating the sleeve, and the outer surface of the side of the sliding rod away from the sleeve is provided with an external thread, and the first base is provided with a threaded hole corresponding to the external thread, and the sliding rod is installed in the threaded hole, and the position of the first base on the sliding rod can be adjusted by rotating the sliding rod, that is, the position of the first base relative to the elastic arm is adjusted.

[0012] Furthermore, the positive stiffness mechanism includes a first mounting seat fixedly arranged on the upper surface of the base plate and a second mounting seat fixedly arranged on the lower surface of the top plate, a second cylindrical spring is arranged between the first mounting seat and the second mounting seat, and the upper end and the lower end of the second cylindrical spring are fixedly connected to the second mounting seat and the first mounting seat respectively.

[0013] The first mounting seat and the second mounting seat can be respectively arranged on the bottom plate and the top plate by means of a fixed connection structure such as a bolt connection structure and a welding connection structure, and the two ends of the second cylindrical spring can be connected to the first mounting seat and the second mounting seat by means of a fixed connection structure such as a bolt connection structure and a welding connection structure.

[0014] Furthermore, the bottom plate and the top plate are provided with a first mounting hole for installing a first mounting seat and a second mounting seat, the first mounting hole is set through the bottom plate or the top plate, the first base and the second base are provided with a first threaded hole corresponding to the first mounting hole, and the first mounting seat and the second mounting seat are installed in the first mounting hole through a bolt connection structure.

[0015] The first mounting hole can be a threaded hole, and the first mounting seat and the second mounting seat are respectively fixed to the bottom plate and the top plate by bolts installed in the first threaded hole and the first mounting hole at the same time; or the first mounting hole is a through hole, and the first mounting seat and the second mounting seat are respectively installed on the bottom plate and the top plate by a bolt and nut connection structure, wherein an expanded hole for accommodating a nut is provided at the upper end or the lower end of the first mounting hole to keep the lower surface of the bottom plate and the upper surface of the top plate flush; in addition, the first mounting seat and the second mounting seat can also be respectively fixed to the bottom plate and the top plate by a welding connection structure.

[0016] Furthermore, the upper surface of the bottom plate and the lower surface of the top plate are respectively provided with brackets corresponding to the first base and the second base, the rotating shaft is fixedly provided on the brackets, the first base and the second base are provided with mounting rings corresponding to the rotating shaft, the mounting rings are sleeved on the rotating shaft, and a rubber ring is fixedly provided on the inner side of the mounting ring, and the inner side of the rubber ring is against the surface of the rotating shaft.

[0017] Among them, a blocking structure, such as a block, can be set at the end of the rotating shaft to prevent the mounting ring from detaching from the rotating shaft; a rubber ring is set between the rotating shaft and the mounting ring, so that the rotating shaft and the mounting ring can be relatively displaced within a certain range to offset the installation error of the elastic arm.

[0018] Furthermore, a second mounting hole for installing the bracket is opened on the bottom plate and the top plate, the second mounting hole is set through the bottom plate or the top plate, the bracket is provided with a second threaded hole corresponding to the second mounting hole, and the bracket is installed in the second mounting hole through a bolt connection structure.

[0019] The second mounting hole can be a threaded hole, and the bracket is fixed to the base plate and the top plate by bolts installed in the second threaded hole and the second mounting hole at the same time; or the second mounting hole is a through hole, and the bracket is installed on the base plate and the top plate by a bolt and nut connection structure, wherein an expanded hole for accommodating a nut is provided at the upper end or the lower end of the first mounting hole to keep the lower surface of the base plate and the upper surface of the top plate flush.

[0020] Furthermore, the second mounting hole includes a circular hole and an elongated hole, and the center of the circular hole is located on the center line of the elongated hole in the length direction.

[0021] Among them, the circular holes and the elongated holes on the top plate are arranged corresponding to the circular holes and the elongated holes on the bottom plate, and the bracket is installed on the top plate and the circular holes and the elongated holes on the bottom plate through a bolt structure. The bracket installed in the elongated hole can move in the elongated hole along the length direction of the elongated hole to adjust the position of the bracket. The two ends of one of the elastic arms in the negative stiffness mechanism are respectively pivoted to the bracket in the circular hole on the top plate and the bracket in the elongated hole on the bottom plate, and the two ends of the other elastic arm are respectively pivoted to the bracket in the elongated hole on the top plate and the bracket in the circular hole on the bottom plate. At this time, the two elastic arms are cross-arranged without contacting each other, and then the length of the elastic arm can be adjusted by adjusting the position of the bracket in the elongated hole to adjust the compression amount of the spring, thereby achieving the purpose of adjusting the parameters of the negative stiffness mechanism so that the vibration isolator can provide good vibration isolation performance under different loads.

[0022] Furthermore, a limiting mechanism is provided between the bottom plate and the top plate for limiting the movement travel of the top plate relative to the bottom plate.

[0023] The limiting mechanism is used to limit the maximum stroke of the top plate relative to the bottom plate to prevent the negative stiffness mechanism from being damaged due to excessive formation of the top plate.

[0024] Furthermore, the limiting mechanism includes a limiting bracket fixedly arranged on the bottom plate and a limiting rod fixedly arranged on the top plate, a ring is arranged at the bottom end of the limiting bracket, the upper end of the limiting rod passes through the ring, and a blocking part is arranged at the top of the limit, the width of the blocking part is greater than the inner diameter of the ring, and a vibration-damping rubber is also arranged on the side of the ring facing the blocking part.

[0025] The limit rod and the limit bracket are fixedly connected to the top plate and the bottom plate respectively by a bolt connection structure or a welding structure, wherein the retaining ring limits the upward movement of the blocking part, thereby limiting the upward movement of the top plate relative to the bottom plate, and the top of the limit rod can limit the downward movement of the top plate, and the vibration-damping rubber is used to buffer the impact of the ring and the blocking part.

[0026] Furthermore, the blocking portion is adjustably arranged on the limiting rod.

[0027] Among them, the upper part of the limit rod is provided with an external thread, and the blocking part is a nut, which is installed on the upper part of the limit rod to realize that the position of the position blocking part is adjustably set on the limit rod. By adjusting the position of the blocking part on the limit rod, the maximum stroke of the top plate relative to the bottom plate can be adjusted.

[0028] The principle and effect of the present invention are further described below in combination with the above technical solutions and the accompanying drawings:

[0029] The object to be isolated in the present invention is mainly supported by the positive stiffness mechanism, and the elastic arm in the negative stiffness mechanism is inclined. When the top plate moves downward, the compression of the first cylindrical spring is greater than the moving distance of the top plate, that is, the elastic arm in the present invention is more sensitive to stiffness. Therefore, the negative stiffness mechanism in the present invention can make the vibration isolator show good vibration isolation performance when the vibration amplitude is very small, and can be suitable for isolating slight low-frequency vibrations. At the same time, compared with the spring as a negative stiffness structure in the existing vibration isolator, the negative stiffness mechanism in the present invention occupies a smaller installation space, thereby realizing the miniaturization of the vibration isolator. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic cross-sectional structure diagram of the quasi-zero stiffness vibration isolator according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the bottom plate according to an embodiment of the present invention;

[0032] Figure 3 It is a schematic structural diagram of the elastic arm described in an embodiment of the present invention.

[0033] Description of reference numerals:

[0034] 1-bottom plate, 11-first mounting hole, 121-round hole, 122-long hole, 13-third mounting hole, 2-top plate, 31-first mounting seat, 32-second mounting seat, 33-second cylindrical spring, 41-elastic arm, 411-sleeve, 412-slide rod, 42-first cylindrical spring, 43-second base, 44-first base, 45-bracket, 46-mounting ring, 461-rubber ring, 51-limiting rod, 511-blocking part, 52-limiting bracket, 521-ring. DETAILED DESCRIPTION

[0035] In order to facilitate understanding by those skilled in the art, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0036] like Figure 1-3A quasi-zero stiffness vibration isolator, comprising a bottom plate 1 and a top plate 2 arranged parallel to the bottom plate 1, wherein a positive stiffness mechanism and a negative stiffness mechanism connecting the bottom plate 1 and the top plate 2 are arranged between the bottom plate 1 and the top plate 2, wherein the negative stiffness mechanism comprises two cross-arranged elastic arms 41, wherein two ends of the elastic arm 41 are respectively provided with a first base 44 and a second base 43, wherein the first base 44 and the second base 43 are respectively pivotally connected to the upper surface of the bottom plate 1 and the lower surface of the top plate 2 through a rotating shaft, wherein the elastic arm 41 is ... The arm 41 includes a sleeve 411 and a slide rod 412 slidably inserted in the sleeve 411. The first base 44 and the second base 43 are respectively pivoted to the upper surface of the bottom plate 1 and the lower surface of the top plate 2 through a rotating shaft. The elastic arm 41 includes a sleeve 411 and a slide rod 412 slidably inserted in the sleeve 411. A first cylindrical spring 42 is sleeved on the elastic arm 41. The two ends of the first cylindrical spring 42 are respectively fixedly connected to the first base 44 and the second base 43.

[0037] The outer wall of the slide bar 412 fits and slidably cooperates with the inner wall of the sleeve 411, and the slide bar 412 can only reciprocate along the center line of the sleeve 411. The end of the sleeve 411 away from the slide bar 412 is connected to the first base 44, and the end of the slide bar 412 away from the sleeve 411 is connected to the second base 43. In another embodiment, the end of the sleeve 411 away from the slide bar 412 is connected to the second base 43, and the end of the slide bar 412 away from the sleeve 411 is connected to the first base 44.

[0038] The bottom plate 1 is used to fix the vibration isolator on a bearing structure such as a foundation, and the top plate 2 is used to bear the object to be isolated. The bottom plate 1 and the top plate 2 as well as the positive stiffness mechanism and the negative stiffness mechanism located between the bottom plate 1 and the top plate 2 form a quasi-zero stiffness system. The dynamic stiffness of the quasi-zero stiffness system at the static equilibrium position is zero, which can make the stiffness of the vibration isolator close to zero while ensuring the bearing capacity, thereby exhibiting excellent low-frequency vibration isolation performance.

[0039] There are four positive stiffness mechanisms, which are distributed at the four sharp corners of the square bottom plate 1 and are symmetrically distributed about the center line in the vertical direction of the bottom plate 1, for supporting the top plate 2 and making the top plate 2 stable; there are two negative stiffness mechanisms, which are symmetrically distributed about the center line in the vertical direction of the bottom plate 1. In another embodiment, there are three positive stiffness mechanisms, which are symmetrically distributed about the center line in the vertical direction of the bottom plate 1, and there are two negative stiffness mechanisms, which are symmetrically distributed about the center line in the vertical direction of the bottom plate 1.

[0040] The two ends of the elastic arm 41 are respectively pivoted to the lower surface of the top plate 2 and the upper surface of the bottom plate 1. When the top plate 2 moves downward due to carrying the vibration-isolating object, the elastic arm 41 tends to be parallel to the bottom plate 1. At this time, the elastic arm 41 is compressed, and the first cylindrical spring 42 on the elastic arm 41 is compressed, and the slide bar 412 is inserted deeper into the sleeve 411, that is, the elastic arm 41 is deformed to generate negative stiffness. At this time, the negative stiffness mechanism and the positive stiffness mechanism form a quasi-zero stiffness system, and the vibration-isolating object in the present invention is mainly supported by the positive stiffness mechanism, while the negative stiffness mechanism is not. The elastic arm 41 in the stiffness mechanism is arranged at an angle. When the top plate 2 moves downward, the compression of the first cylindrical spring 42 is greater than the moving distance of the top plate 2. Therefore, the elastic arm 41 in the present invention is more sensitive to stiffness. Therefore, the negative stiffness mechanism in the present invention can make the vibration isolator show good vibration isolation performance when the vibration amplitude is very small, and can be suitable for isolating slight low-frequency vibrations. At the same time, compared with the spring as a negative stiffness structure in the existing vibration isolator, the negative stiffness mechanism in the present invention occupies a smaller installation space, thereby realizing the miniaturization of the vibration isolator.

[0041] In addition, the two elastic arms 41 in the negative stiffness mechanism of the present invention are arranged crosswise to avoid the generation of torsional torque of the vibration isolator and also make it difficult for the vibration isolator to deform when subjected to horizontal external force.

[0042] The first base 44 and the second base 43 are adjustably disposed at two ends of the elastic arm 41 .

[0043] By adjusting the positions of the first base 44 and the second base 43 at both ends of the elastic arm 41 on the elastic arm 41, the pre-compression amount of the first cylindrical spring 42 between the first base 44 and the second base 43 can be adjusted, thereby realizing the adjustment of the parameters of the negative stiffness mechanism, and further realizing the adjustment of the parameters of the quasi-zero stiffness isolator.

[0044] The adjustable structure is as follows: an external thread is provided on the outer surface of the sleeve 411, a threaded hole is provided on the first base 44 corresponding to the external thread, and the sleeve 411 is installed in the threaded hole. By rotating the sleeve 411, the position of the first base 44 relative to the sleeve 411, that is, the position of the first base 44 relative to the elastic arm 41 can be adjusted. The outer surface of the sliding rod 412 on the side away from the sleeve 411 is provided with an external thread, and the second base 43 is provided with a threaded hole corresponding to the external thread. The sliding rod 412 is installed in the threaded hole. By rotating the sliding rod 412, the position of the second base 43 on the sliding rod 412 can be adjusted, that is, the position of the second base 43 relative to the elastic arm 41 can be adjusted. In another embodiment, the adjustable structure is: an external thread is provided on the outer surface of the sleeve 411, and a threaded hole is provided on the second base 43 corresponding to the external thread. The sleeve 411 is installed in the threaded hole. The position of the second base 43 relative to the sleeve 411, that is, the position of the second base 43 relative to the elastic arm 41, can be adjusted by rotating the sleeve 411. The outer surface of the sliding rod 412 on the side away from the sleeve 411 is provided with an external thread, and the first base 44 is provided with a threaded hole corresponding to the external thread. The sliding rod 412 is installed in the threaded hole. The position of the first base 44 on the sliding rod 412 can be adjusted by rotating the sliding rod 412, that is, the position of the first base 44 relative to the elastic arm 41 is adjusted.

[0045] The positive stiffness mechanism includes a first mounting seat 31 fixedly arranged on the upper surface of the base plate 1 and a second mounting seat 32 fixedly arranged on the lower surface of the top plate 2, a second cylindrical spring 33 is arranged between the first mounting seat 31 and the second mounting seat 32, and the upper end and the lower end of the second cylindrical spring 33 are fixedly connected to the second mounting seat 32 and the first mounting seat 31 respectively.

[0046] The first mounting seat 31 and the second mounting seat 32 are respectively arranged on the bottom plate 1 and the top plate 2 by a bolt connection structure, and the two ends of the second cylindrical spring 33 are connected to the first mounting seat 31 and the second mounting seat 32 by a bolt connection structure. In another embodiment, the first mounting seat 31 and the second mounting seat 32 are respectively arranged on the bottom plate 1 and the top plate 2 by a welding connection structure, and the two ends of the second cylindrical spring 33 are connected to the first mounting seat 31 and the second mounting seat 32 by a welding connection structure.

[0047] The bottom plate 1 and the top plate 2 are provided with a first mounting hole 11 for installing a first mounting seat 31 and a second mounting seat 32. The first mounting hole 11 is set through the bottom plate 1 or the top plate 2. The first base 44 and the second base 43 are provided with a first threaded hole corresponding to the first mounting hole 11. The first mounting seat 31 and the second mounting seat 32 are installed in the first mounting hole 11 through a bolt connection structure.

[0048] The first mounting hole 11 is a threaded hole, and the first mounting seat 31 and the second mounting seat 32 are respectively fixed to the bottom plate 1 and the top plate 2 by bolts installed in the first threaded hole and the first mounting hole 11. In another embodiment, the first mounting hole 11 is a through hole, and the first mounting seat 31 and the second mounting seat 32 are respectively installed on the bottom plate 1 and the top plate 2 by a bolt and nut connection structure, wherein the upper end or the lower end of the first mounting hole 11 is provided with a widened hole for accommodating a nut to keep the lower surface of the bottom plate 1 and the upper surface of the top plate 2 flush. In another embodiment, the first mounting seat 31 and the second mounting seat 32 are respectively fixed to the bottom plate 1 and the top plate 2 by a welding connection structure.

[0049] The upper surface of the bottom plate 1 and the lower surface of the top plate 2 are respectively provided with brackets 45 corresponding to the first base 44 and the second base 43, the rotating shaft is fixedly provided on the brackets 45, the first base 44 and the second base 43 are provided with mounting rings 46 corresponding to the rotating shaft, the mounting ring 46 is sleeved on the rotating shaft, and a rubber ring 461 is fixedly provided on the inner side of the mounting ring 46, and the inner side of the rubber ring 461 is against the surface of the rotating shaft.

[0050] Among them, a blocking structure, such as a block, is provided at the end of the rotating shaft to prevent the mounting ring 46 from detaching from the rotating shaft; a rubber ring 461 is provided between the rotating shaft and the mounting ring 46, so that the rotating shaft and the mounting ring 46 can be relatively displaced within a certain range to offset the installation error of the elastic arm 41.

[0051] The bottom plate 1 and the top plate 2 are provided with a second mounting hole for mounting the bracket 45. The second mounting hole passes through the bottom plate 1 or the top plate 2. The bracket 45 is provided with a second threaded hole corresponding to the second mounting hole. The bracket 45 is mounted on the second mounting hole through a bolt connection structure.

[0052] The second mounting hole is a threaded hole, and the bracket 45 is fixed to the bottom plate 1 and the top plate 2 by bolts installed in the second threaded hole and the second mounting hole at the same time. In another embodiment, the second mounting hole is a through hole, and the bracket 45 is installed on the bottom plate 1 and the top plate 2 by a bolt and nut connection structure, wherein the upper end or the lower end of the first mounting hole 11 is provided with a widened hole for accommodating a nut to keep the lower surface of the bottom plate 1 and the upper surface of the top plate 2 flush.

[0053] The second mounting hole includes a circular hole 121 and an elongated hole 122 , and the center of the circular hole 121 is located on the center line of the elongated hole 122 in the length direction.

[0054] The circular hole 121 and the long hole 122 on the top plate 2 are arranged corresponding to the circular hole 121 and the long hole 122 on the bottom plate 1. The bracket 45 is installed on the top plate 2 and the circular hole 121 and the long hole 122 on the bottom plate 1 through a bolt structure. The bracket 45 installed in the long hole 122 can move in the long hole 122 along the length direction of the long hole 122 to adjust the position of the bracket 45. The two ends of one of the elastic arms 41 in the negative stiffness mechanism are respectively pivotally connected to the bracket 45 in the circular hole 121 on the top plate 2. and the bracket 45 in the long hole 122 on the bottom plate 1, and the two ends of the other elastic arm 41 are respectively pivotally connected to the bracket 45 in the long hole 122 on the top plate 2 and the bracket 45 in the round hole 121 on the bottom plate 1. At this time, the two elastic arms 41 are cross-arranged without contacting each other, and then the length of the elastic arm 41 can be adjusted by adjusting the position of the bracket 45 in the long hole 122 to adjust the compression amount of the spring, thereby achieving the purpose of adjusting the parameters of the negative stiffness mechanism so that the vibration isolator can provide good vibration isolation performance under different loads.

[0055] A limiting mechanism is also provided between the bottom plate 1 and the top plate 2 for limiting the movement of the top plate 2 relative to the bottom plate 1 .

[0056] The limiting mechanism is used to limit the maximum travel of the top plate 2 relative to the bottom plate 1 to prevent the negative stiffness mechanism from being damaged due to excessive formation of the top plate 2.

[0057] The limiting mechanism includes a limiting bracket 52 fixedly arranged on the bottom plate 1 and a limiting rod 51 fixedly arranged on the top plate 2, a collar 521 is arranged at the bottom end of the limiting bracket 52, the upper end of the limiting rod 51 passes through the collar 521, and a blocking portion 511 is arranged at the top of the limiting portion, the width of the blocking portion 511 is greater than the inner diameter of the collar 521, and a vibration-damping rubber is also arranged on the side of the collar 521 facing the blocking portion 511.

[0058] A third mounting hole 13 penetrating the bottom plate 1 is provided on the bottom plate 1, and the third mounting hole 13 is a threaded hole. The lower end of the limiting rod 51 is provided with a thread corresponding to the third mounting hole 13, and is installed in the third mounting hole 13 through the thread. A fourth mounting hole penetrating the bottom plate 1 is provided on the top plate 2, and the upper end of the limiting rod 51 is provided with a thread corresponding to the fourth mounting hole, and is installed in the fourth mounting hole through the thread. The retaining ring limits the upward movement of the blocking part 511, thereby limiting the upward movement of the top plate 2 relative to the bottom plate 1. The top of the limiting rod 51 can limit the downward movement of the top plate 2, and the vibration-damping rubber is used to buffer the impact of the ring 521 and the blocking part 511.

[0059] The blocking portion 511 is adjustably disposed on the limiting rod 51 .

[0060] Among them, the upper part of the limiting rod 51 is provided with an external thread, the blocking part 511 is a nut, and the blocking part 511 is installed on the upper part of the limiting rod 51 to realize that the position of the position blocking part 511 is adjustably set on the limiting rod 51, and the maximum stroke of the top plate 2 relative to the bottom plate 1 can be adjusted by adjusting the position of the blocking part 511 on the limiting rod 51.

[0061] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A quasi-zero stiffness vibration isolator, comprising a bottom plate and a top plate arranged parallel to the bottom plate, wherein a positive stiffness mechanism and a negative stiffness mechanism connecting the bottom plate and the top plate are arranged between the bottom plate and the top plate, characterized in that: The negative stiffness mechanism comprises two cross-arranged elastic arms, the two ends of the elastic arms are respectively provided with a first base and a second base, the first base and the second base are respectively pivotally connected to the upper surface of the bottom plate and the lower surface of the top plate through a rotating shaft, the elastic arm comprises a sleeve and a sliding rod slidably inserted in the sleeve, a first cylindrical spring is sleeved on the elastic arm, and the two ends of the first cylindrical spring are respectively fixedly connected to the first base and the second base; The first base and the second base are adjustably arranged at two ends of the elastic arm; The number of the positive stiffness mechanisms is several, and the several positive stiffness mechanisms are symmetrically distributed about the center line in the vertical direction of the base plate.

2. The quasi-zero stiffness isolator according to claim 1, characterized in that: The positive stiffness mechanism includes a first mounting seat fixedly arranged on the upper surface of the base plate and a second mounting seat fixedly arranged on the lower surface of the top plate, a second cylindrical spring is arranged between the first mounting seat and the second mounting seat, and the upper end and the lower end of the second cylindrical spring are fixedly connected to the second mounting seat and the first mounting seat respectively.

3. The quasi-zero stiffness vibration isolator according to claim 2, characterized in that: The bottom plate and the top plate are provided with first mounting holes for installing the first mounting seat and the second mounting seat, the first mounting hole is set through the bottom plate or the top plate, the first mounting seat and the second mounting seat are provided with first threaded holes corresponding to the first mounting holes, and the first mounting seat and the second mounting seat are installed in the first mounting hole through a bolt connection structure.

4. The quasi-zero stiffness isolator according to claim 1, characterized in that: The upper surface of the bottom plate and the lower surface of the top plate are respectively provided with brackets corresponding to the first base and the second base, the rotating shaft is fixedly provided on the brackets, the first base and the second base are provided with mounting rings corresponding to the rotating shaft, the mounting rings are sleeved on the rotating shaft, and a rubber ring is fixedly provided on the inner side of the mounting ring, and the inner side of the rubber ring is against the surface of the rotating shaft.

5. The quasi-zero stiffness vibration isolator according to claim 4, characterized in that: The bottom plate and the top plate are provided with a second mounting hole for mounting the bracket, the second mounting hole is set through the bottom plate or the top plate, the bracket is provided with a second threaded hole corresponding to the second mounting hole, and the bracket is mounted on the second mounting hole through a bolt connection structure.

6. The quasi-zero stiffness vibration isolator according to claim 5, characterized in that: The second mounting hole includes a circular hole and an elongated hole, and the center of the circular hole is located on the center line of the elongated hole in the length direction.

7. The quasi-zero stiffness vibration isolator according to claim 1, characterized in that: A limiting mechanism is also provided between the bottom plate and the top plate for limiting the moving stroke of the top plate relative to the bottom plate.

8. The quasi-zero stiffness vibration isolator according to claim 7, characterized in that: The limiting mechanism includes a limiting bracket fixedly arranged on the bottom plate and a limiting rod fixedly arranged on the top plate, a ring is arranged on the top end of the limiting bracket, the lower end of the limiting rod is arranged through the ring, and a blocking part is arranged on the bottom of the limiting rod, the width of the blocking part is greater than the inner diameter of the ring, and a vibration-damping rubber is also arranged on the side of the ring facing the blocking part.

9. The quasi-zero stiffness vibration isolator according to claim 8, characterized in that: The blocking portion is adjustably arranged on the limiting rod.

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