CN117889184A - Multistage vibration isolation device - Google Patents
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- CN117889184A CN117889184A CN202311555914.XA CN202311555914A CN117889184A CN 117889184 A CN117889184 A CN 117889184A CN 202311555914 A CN202311555914 A CN 202311555914A CN 117889184 A CN117889184 A CN 117889184A
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Abstract
The scheme belongs to the technical field of low-frequency vibration isolation, and discloses a multistage vibration isolation device, including first platform and the second platform that are parallel to each other, and positive stiffness spring and the negative stiffness spring of setting between first platform and second platform, positive stiffness spring perpendicular to first/second platform, the negative stiffness spring is on a parallel with first/second platform, positive stiffness spring and negative stiffness spring are parallelly connected with second rack and pinion mechanism through the first rack and pinion mechanism that the symmetry set up, when the rack moves the distance of half circumference of gear reference circle down, vibration isolation device's quasi zero stiffness region will appear in circulation, can carry out effective vibration isolation to multiple different loads. The magnitude of the effective load of the vibration isolation device can be easily regulated and controlled by adjusting the relative positions of the first support and the second support without replacing any parts, the dimensionless bearing capacity-displacement multi-platform curve of the vibration isolation device can be customized at will, and effective vibration isolation of any load in a bearing range can be realized.
Description
Technical Field
The scheme belongs to the technical field of low-frequency vibration isolation, and particularly relates to a multistage vibration isolation device.
Background
The quazi-zero vibration isolator (QZS) has the advantages of high bearing capacity, wider vibration isolation frequency band, low natural frequency and the like, has almost zero overall dynamic stiffness in an effective working range under the condition of not sacrificing the bearing capacity, has wide application prospect in the ultralow frequency vibration isolation field, can overcome the defect that the linear vibration isolator is difficult to meet the low frequency vibration isolation requirement, and is a vibration control collarOne of the hot spots of domain research. By quasi-zero stiffness vibration damper, i.e. vibration isolation platform with high static stiffness, meaning high load carrying capacity or less static load deflection, and low dynamic stiffness, meaning a lower or near 0 natural frequency. The damper having such characteristics mainly solves the following problems occurring in the conventional linear damper composed of a mass m and a stiffness k: the effective vibration isolation frequency of the linear vibration damper is larger thanThe natural frequency is multiplied, and therefore, if a wide vibration isolation band range is to be obtained, the stiffness k of the linear damper needs to be infinitely small (the natural frequency is closer to 0), but this causes a great static deformation. Thus, quasi-zero stiffness vibration dampers with high static stiffness and low dynamic stiffness have been developed.
When the QZS vibration isolator is designed, the main idea is to introduce a negative stiffness mechanism to offset the positive stiffness of the elastic element so as to ensure that the dynamic stiffness is zero, and meanwhile, the static bearing capacity is kept high, so that the design of the negative stiffness mechanism is one of the most important links in the research of the quasi-zero stiffness vibration isolator. The passive negative stiffness mechanism is designed by students at home and abroad, and is summarized and can be divided into three types, namely springs, geometric nonlinearity and magnetic structures, and further divided into seven types, namely a negative stiffness mechanism consisting of linear springs, a buckling beam structure serving as the negative stiffness mechanism, an air spring serving as the negative stiffness mechanism, a geometric nonlinearity serving as the negative stiffness mechanism, a disc spring serving as the negative stiffness mechanism, a magnetic spring serving as the negative stiffness mechanism and other novel mixed mechanisms.
A plateau was observed from the force-displacement curve of the QZS isolator, indicating that the force was nearly constant over an effective displacement range with zero dynamic stiffness. The force corresponding to the platform is referred to herein as the payload of QZS. When the vibration isolator is loaded with effective load, the vibration isolator can be just compressed to the platform section, the dynamic rigidity of the vibration isolator becomes zero, and the vibration isolator has excellent low-frequency and even ultra-low-frequency vibration isolation effect. Currently, most QZS isolators are generally implemented by connecting positive and negative stiffness elements in parallel, and the QZS isolator based on such a mechanism generally has only a single effective working area, so that the mass of an isolated object (i.e., the QZS payload) is uniquely determined, and when the QZS isolator is in an underload or overload state, the vibration isolation effect of the QZS isolator is greatly reduced.
Disclosure of Invention
Aiming at the problems that the existing quasi-zero stiffness vibration isolator generally only has a single effective load and the vibration isolation effect on non-effective loads is greatly weakened, the scheme utilizes the transmission characteristic of a gear-rack, provides a multistage vibration isolation device based on the gear-rack transmission principle, and solves the problems that a single quasi-zero stiffness system is poor in vibration isolation and vibration absorption characteristics on different masses.
In order to solve the technical problems, the following technical scheme is adopted:
a multistage vibration isolation device comprising a first platform and a second platform which are parallel to each other, and a positive stiffness spring and a negative stiffness spring which are arranged between the first platform and the second platform, wherein the positive stiffness spring is perpendicular to the first platform/the second platform, and the negative stiffness spring is parallel to the first platform/the second platform; the positive stiffness spring and the negative stiffness spring are connected in parallel with the second gear rack mechanism through the first gear rack mechanism which is symmetrically arranged; the first gear and rack mechanism comprises a first gear and a first rack which are meshed with each other, and the second gear and rack mechanism comprises a second gear and a second rack which are meshed with each other; the tooth surfaces of the first rack and the second rack are opposite or opposite, one end of the first rack is connected with the first platform, the other end of the first rack is connected with one end of the positive stiffness spring, and the other end of the positive stiffness spring is connected with the second platform; the shafts of the first gear and the second gear are arranged on the second platform, the shaft transmission of the first gear is connected with a first transmission shaft parallel to the first transmission shaft, the shaft transmission of the second gear is connected with a second transmission shaft parallel to the second transmission shaft, and two ends of the negative stiffness spring are respectively connected with the first transmission shaft and the second transmission shaft in a transmission mode.
The device uses the rack and the gear to be meshed for transmission, and uses the negative stiffness spring as the negative stiffness elastic element, the gear can rotate along with the downward movement of the rack, when the gear rotates by 180 degrees by integer times, a new quasi-zero stiffness region can be formed, the loaded mass and the downward movement amount of the rack can be completely converted with each other, which means that the quasi-zero stiffness region of the vibration isolation device can be circularly formed when the rack moves downwards by a distance of half a circumference of a gear reference circle, the platform section can be continuously circularly formed by observing a dimensionless bearing capacity-displacement curve of the device, and the quasi-zero stiffness region can be continuously circularly formed by observing the dimensionless stiffness-displacement curve of the device, so that the device can effectively isolate vibration aiming at various different loads. And secondly, the size of the effective load of the vibration isolation device can be easily regulated and controlled by adjusting the relative positions of the first support and the second support without replacing any parts, the dimensionless bearing capacity-displacement multi-platform curve of the vibration isolation device can be arbitrarily customized, the dimensionless bearing capacity-displacement curve before and after adjustment of the vibration isolation device can be observed to enable the height of the platform to continuously change in the bearing range through adjustment, and the device can realize effective vibration isolation of any load in the bearing range through adjustment.
At least one end of the negative stiffness spring is in transmission connection with the first transmission shaft and/or the second transmission shaft through a spring fixing component which can be telescopically adjusted in the axial direction of the negative stiffness spring so as to adjust the precompression amount or the pretension amount of the negative stiffness spring. Preferably, the spring fixing assembly comprises a first connecting piece and a second connecting piece, one end of the first connecting piece is fixedly connected with a negative stiffness spring, the other end of the first connecting piece is provided with internal threads, one end of the second connecting piece is provided with external threads, the other end of the second connecting piece is in transmission connection with a first transmission shaft and/or a second transmission shaft, and the internal threads of the first connecting piece are matched with the external threads of the second connecting piece; or the spring fixing assembly comprises a first connecting piece and a second connecting piece, one end of the first connecting piece is fixedly connected with the negative stiffness spring, the other end of the first connecting piece is provided with external threads, one end of the second connecting piece is provided with internal threads, the other end of the second connecting piece is in transmission connection with the first transmission shaft and/or the second transmission shaft, and the external threads of the first connecting piece are matched with the internal threads of the second connecting piece; the expansion and contraction amount of the spring fixing assembly can be adjusted by adjusting the matching length of the external threads and the internal threads, so that the precompression amount or the prestretching amount of the negative stiffness spring can be adjusted.
The first transmission shaft is in transmission connection with the shaft of the first gear through an eccentric disc, or the second transmission shaft is in transmission connection with the shaft of the second gear through an eccentric disc, or the first transmission shaft and the second transmission shaft are respectively in transmission connection with the shaft of the first gear through eccentric discs. The eccentric disc is provided with a central hole and an eccentric hole, the center Kong Chuandong is connected with the shafts of the first gear and/or the second gear, the eccentric hole is provided with a long hole, the central line of the long hole in the length direction passes through the center of the central hole, the first transmission shaft and/or the second transmission shaft is fixedly connected with the long hole through a fastener, and the relative positions of the first transmission shaft and/or the second transmission shaft and the long hole can be adjusted, so that the relative positions of the first transmission shaft and the shafts of the first gear can be adjusted. The central hole is a spline hole, and the shaft of the first gear and/or the shaft of the second gear are/is provided with a spline matched with the spline hole so as to realize the circumferential positioning of the shaft of the first gear and the eccentric disc.
The shafts of the first gear and the second gear are arranged on the second platform through gear fixing brackets with telescopic height, so that the relative heights between the first gear and the second platform and between the first gear and the second platform can be adjusted according to the device requirement before fastening connection. Preferably, the gear fixing seat comprises a rod-shaped first support and a cylindrical second support, the second support is sleeved outside the first support, a threaded hole is formed in the side wall of the second support, and the threaded hole is connected with a fastener which abuts against the side face of the first support so as to adjust the relative height between the gear and the second platform by adjusting the relative positions of the first support and the second support. The shaft brackets of the first gear and the second gear are arranged at the free ends of the first support, and the free ends of the second support are fixed on the second platform.
The first platform is provided with a guide hole, and the second platform is fixed with a guide rod matched with the guide hole so as to realize the guiding function of the device in the direction vertical to the first platform/second platform. Preferably, one end of the first rack and one end of the second rack are fixed on the first platform through a first rack fixing piece, the other end of the first rack and the second rack are fixedly connected with a positive stiffness spring through a second rack fixing piece, and the first rack fixing piece and the second rack fixing piece are respectively provided with a guide hole matched with the guide rod, so that the guiding effect of each component in the device in the direction vertical to the first platform/the second platform is better realized. More preferably, the guides Kong Zhongan of the first and second rack fixtures are provided with linear bearings that mate with the guide rods.
Compared with the prior art, the scheme has the following beneficial effects: the device uses the rack and the gear to realize meshing transmission, and uses the negative stiffness spring as the negative stiffness elastic element, so that the gear can rotate along with the downward movement of the rack, a new quasi-zero stiffness region can be formed when the gear rotates by 180 degrees by integer multiple, the loaded mass and the downward movement amount of the rack can be completely converted with each other, and the fact that the quasi-zero stiffness region of the vibration isolation device can be cyclically formed when the rack moves downwards by a distance of half of the circumference of the gear reference circle, and effective vibration isolation can be performed for various different loads. And secondly, the size of the effective load of the vibration isolation device can be easily regulated and controlled by adjusting the relative positions of the first support and the second support without replacing any parts, the dimensionless bearing capacity-displacement multi-platform curve of the vibration isolation device can be customized at will, and effective vibration isolation of any load in a bearing range can be realized.
Drawings
The drawings are for illustrative purposes only and are not to be construed as limiting the present solution; for better illustration of the present solution, some parts of the figures may be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
Figure 1 is an isometric view of a multi-stage vibration isolation apparatus;
figure 2 is a two-dimensional front view of the multi-stage vibration isolation apparatus;
figure 3 is a two-dimensional left side view of the multi-stage vibration isolation apparatus;
figure 4 is a two-dimensional top view of a multi-stage vibration isolation apparatus;
fig. 5 is a dimensionless load-bearing force-displacement curve of a multi-stage vibration isolation device;
figure 6 is a dimensionless stiffness-displacement curve of a multi-stage vibration isolation device;
fig. 7 is a dimensionless load-bearing force versus displacement curve of the multi-stage vibration isolation device before and after adjustment.
Reference numerals illustrate: the first platform 100, the second platform 200, the positive stiffness spring 300, the first spring fixing piece 310, the second spring fixing piece 320, the negative stiffness spring 400, the third spring fixing piece 410, the fourth spring fixing piece 420, the first connecting piece 421, the second connecting piece 422, the first rack and pinion mechanism 510, the first gear 511, the first rack 512, the second rack and pinion mechanism 520, the second gear 521, the second rack 522, the gear shaft 530, the first support 541, the second support 542, the bearing base 551, the bearing upper cover 552, the bearing end cover 553, the second support 554, the first sleeve 555, the second sleeve 556, the first rack fixing piece 561, the second rack fixing piece 562, the first transmission shaft 610, the second transmission shaft 620, the eccentric disc 630, the central hole 631, the eccentric hole 632, and the guide bar 700.
Detailed Description
In order to better understand the present solution, a further detailed description of the present solution will be provided below in conjunction with specific embodiments.
Figures 1-4 illustrate one embodiment of a multi-stage vibration isolation apparatus. In this embodiment, the multistage vibration isolation apparatus includes first and second stages 100 and 200 parallel to each other, and positive and negative springs 300 and 400 disposed between first and second stages 100 and 200, positive springs 300 being perpendicular to first and second stages 100 and 200, and negative springs 400 being parallel to first and second stages 100 and 200.
The positive rate spring 300 and the negative rate spring 400 are connected in parallel with the second gear 521 and the rack mechanism 520 through the first gear 511 and the rack mechanism 510 which are symmetrically arranged. The first gear 511 rack mechanism 510 includes a first gear 511 and a first rack 512 that are meshed with each other, and the second gear 521 rack mechanism 520 includes a second gear 521 and a second rack 522 that are meshed with each other; the tooth surfaces of the first rack 512 and the second rack 522 are opposite or opposite, one end of the first rack is connected with the first platform 100, the other end of the first rack is connected with one end of the positive stiffness spring 300, and the other end of the positive stiffness spring 300 is connected with the second platform 200; the shafts of the first gear 511 and the second gear 521 are both arranged on the second platform 200, the shaft transmission of the first gear 511 is connected with a first transmission shaft 610 parallel to the first transmission shaft, the shaft transmission of the second gear 521 is connected with a second transmission shaft 620 parallel to the second transmission shaft 620, and the two ends of the negative stiffness spring 400 are respectively connected with the first transmission shaft 610 and the second transmission shaft 620 in a transmission manner.
The positive rate spring 300 is provided at both ends thereof with a first spring fixing member 310 and a second spring fixing member 320, respectively. The first spring fixing member 310 and the second spring fixing member 320 are provided with a clamping groove on one surface facing the positive stiffness spring 300, and two ends of the positive stiffness spring 300 are respectively fixed in the clamping grooves, so that the positive stiffness spring 300 can be compressed or pulled during operation of the device. The first spring fixing member 310 connects the first rack 512 and the second rack 522, and the second spring fixing member 320 is fixed to the second platform 200, so that one end of the positive stiffness spring 300 is connected with the first rack 512 and the second rack 522, and the other end is fixed to the second platform 200. The second spring fixing member 320 may be fastened to the threaded hole at the center of the second platform 200 by external threads, or may be fixed to the second platform 200 by other fixing means.
The first rack 512 and the second rack 522 are provided with a first rack 512 fixing member and a second rack 522 fixing member at both ends thereof, respectively. The first rack 512 mount is fixed to the first platform 100 and the second rack 522 mount is connected to the first spring mount 310, thereby enabling the two ends of the first rack 512 and the second rack 522 to be connected to the first platform 100 and the positive rate spring 300, respectively. The second rack 522 fixing member may be fixedly connected to the first spring fixing member 310 by fastening, welding, or the like, or may be integrally formed on the first spring fixing member 310.
The second platform 200 is secured with a guide bar 700 that passes through the positive rate spring 300, the first spring mount 310, the second rack 522 mount, the first rack 512 mount, and the first platform 100 in that order. The corresponding positions of the first spring fixing member 310, the second rack 522 fixing member, the first rack 512 fixing member and the first platform 100 are respectively provided with a guide hole, and the guide Kong Zhongan of the first rack 512 fixing member and the second rack 522 fixing member is provided with a linear bearing matched with the guide rod 700 so as to realize the guiding function of the first platform 100, the positive stiffness spring 300, the first spring fixing member 310, the second rack 522 fixing member, the first rack 512 fixing member and the first platform 100 in the direction vertical to the first platform 100/the second platform 200. The guide 700 may be fixed to the second platform 200 by the second spring fixing member 320, and a blind hole is formed in a surface of the second spring fixing member 320 facing away from the second platform 200, and the fixed end of the guide 700 is mounted in the blind hole.
The negative rate spring 400 is provided at both ends thereof with a third spring fixing member 410 and a fourth spring fixing member 420, respectively. An end surface of one end of the third spring fixing member 410 is fixedly connected with the negative stiffness spring 400, a through hole is formed in a side surface of the other end, and a first bearing matched with the first transmission shaft 610 is installed in the through hole. The fourth spring fixing member 420 is a spring fixing assembly that is telescopically adjustable in the axial direction of the negative stiffness spring 400, and the spring fixing assembly includes a first connecting member 421 and a second connecting member 422, wherein one end of the first connecting member 421 is fixedly connected with the negative stiffness spring 400, the other end of the first connecting member is provided with internal threads, one end of the second connecting member 422 is provided with external threads, the other end of the second connecting member is provided with a through hole, and a first bearing matched with the second transmission shaft 620 is installed in the through hole. The internal thread of the first connecting member 421 is engaged with the external thread of the second connecting member 422, and the amount of expansion and contraction of the spring fixing member can be adjusted by adjusting the engagement length thereof, thereby adjusting the pre-compression amount or pre-tension amount of the negative stiffness spring 400. In addition, the third spring mount 410 may also be provided as a spring mount assembly telescopically adjustable in the axial direction of the negative rate spring 400.
The first drive shaft 610 is in driving connection with the shaft of the first gear 511 via an eccentric disc 630. The eccentric disc 630 is provided with a central hole 631 and an eccentric hole 632, the shaft of the first gear 511 is in transmission connection with the central hole 631, and the first transmission shaft 610 is fixedly connected with the eccentric hole 632. The central hole 631 is configured as a splined hole, and the shaft of the first gear 511 is provided with a spline matching with the central hole, so as to realize circumferential positioning of the shaft of the first gear 511 and the eccentric disc 630. The eccentric hole 632 is provided as a long hole, a center line of which in a length direction passes through a center of the central hole 631, and the first transmission shaft 610 is adjustably coupled to the eccentric disc 630 by engagement of a fastener with the long hole, so as to adjust a relative position of the first transmission shaft 610 and the shaft of the first gear 511. Accordingly, the second transmission shaft 620 is in driving connection with the shaft of the second gear 521 via another eccentric disk 630.
The shafts of the first gear 511 and the second gear 521 (collectively, gear shafts 530) are provided to the second stage 200 by gear fixing mounts having a height telescopically adjustable so as to adjust the relative heights between the first gear 511 and the second gear 521 (collectively, gears) and the second stage 200 according to the device requirements before fastening connection. The gear fixing seat comprises a rod-shaped first support 541 and a cylindrical second support 542, the second support 542 is sleeved outside the first support 541, a threaded hole is formed in the side wall of the second support 542, and a fastener abutting against the side face of the first support 541 is connected with the threaded hole; the relative height between the gear and the second platform 200 may be adjusted by adjusting the relative positions of the first and second brackets 541, 542 prior to tightening the fasteners. The gear shaft 530 is mounted on a free end (an end far from the second support 542) of the first support 541, and the free end (an end far from the first support 541) of the second support 542 is fixed to the second platform 200.
The free end of the first support 541 is provided with a bearing seat, which comprises a bearing base 551 fixed on the free end of the first support 541, a bearing upper cover 552 covering the top of the bearing base 551, and bearing end caps 553 covering both sides of the bearing base 551 and the bearing upper cover 552. Two second bearings 554 matched with the gear shaft 530 and a first sleeve 555 coaxially arranged between the two second bearings 554 are arranged in the bearing seat, the first sleeve 555, the two second bearings 554 and the two bearing end caps 553 are sleeved outside the gear shaft 530, and the outer sides of the second bearings 554 are abutted against the bearing end caps 553 and the inner sides are abutted against the first sleeve 555, so that axial positioning is realized. The gear sleeve is arranged outside the part of the gear shaft 530 extending out of the bearing seat, one surface of the gear facing the second bearing 554 can be abutted against the second sleeve 556 which is sleeved outside the gear shaft 530 and is positioned between the gear and the second bearing 554, the gear sleeve can also be abutted against a shaft shoulder arranged on the gear shaft 530, the tail end of the gear shaft 530 is provided with external threads for connecting a fastener, and one surface of the gear facing away from the second bearing 554 can be abutted against the fastener, so that the axial positioning of the gear is realized, and the circumferential positioning is realized between the gear and the gear shaft 530 through key connection.
In the multi-stage vibration isolation apparatus described above, the vibration generated from the vibration source is transferred to the first stage 100 through the second stage 200, and an object to be isolated is placed on the first stage 100, and the apparatus aims to isolate the vibration inputted to the second stage 200 and reduce the vibration of the first stage 100. After the device passes the debugging, the first platform 100 has a good vibration isolation effect after placing a proper mass (payload), and the number of payloads which can be supported by the device can be N. Secondly, the dimensionless bearing capacity-displacement multi-platform curve of the vibration isolation device can be customized at will by adjusting the relative positions of the first support 541 and the second support 542, so that effective vibration isolation of any load in a bearing range can be realized.
After loading one of the payloads on the first platform 100, the positive rate spring 300 will be compressed and produce a compression as the payload is applied, with the device in a static equilibrium state. With the application of the effective load, the rack moves downwards, the rack moves to drive the gear to rotate due to the meshing relationship between the rack and the gear, the gear rotates to cause the gear shaft 530 to rotate, the rotating motion of the gear shaft 530 drives the eccentric disc 630 to rotate, at this time, the first transmission shaft 610 and the second transmission shaft 620 rotate around the gear shaft 530, so that the center distance between the two first transmission shafts 610 and the second transmission shaft 620 on the same side of the device changes, the length of the negative stiffness spring 400 changes due to the change of the center distance, and because a certain effective load supported by the device is applied to the first platform 100, when the device is in a static balance state, four axis connecting lines of the first transmission shaft 610, the second transmission shaft 620 and the two gear shafts 530 are horizontal, and by design, the device can normally work and has a certain stretching amount or compression amount when the device is in the static balance state, so that the device has vibration isolation capability. The vibration isolation principle is mainly that a positive stiffness element (a positive stiffness spring 300) and a negative stiffness mechanism (assembled by parts such as a rack, a gear and a negative stiffness spring 400) are connected in parallel, so that the dynamic stiffness of a working area is zero, and meanwhile, the higher static bearing capacity is maintained.
The negative stiffness mechanism in the device has more component parts, and the core parts mainly comprise racks, gears, a negative stiffness spring 400 and the like. When the rack moves downwards, the two gears on the same side of the device can generate reverse passive rotation movement, at the moment, the four axes of the first transmission shaft 610, the second transmission shaft 620 and the two gear shafts 530 are not collinear, so that the axes of the first transmission shaft 610 and the gear shafts 530 on the same side are connected with the horizontal line to generate a non-zero included angle, the axes of the second transmission shaft 620 and the gear shafts 530 on the same side are connected with the horizontal line to generate the same non-zero included angle, the center distance between the first transmission shaft 610 and the second transmission shaft 620 is determined when the rack moves downwards, and because the negative stiffness spring 400 has a certain stretching amount or compression amount when the rack moves downwards in the balanced state, the negative stiffness spring 400 can drive the two gears on the same side to further generate reverse rotation movement when the angles between the axes of the first transmission shaft 610 and the second transmission shaft 620 and the horizontal line are not zero, at the moment, the reverse rotation movement of the two gears on the same side is changed into active movement, the second transmission shaft 620 and the same non-zero included angle with the horizontal line can further drive the rack to move downwards, so that the whole negative stiffness can not return to the original state.
After the device is debugged, a certain effective load is loaded on the first platform 100, when the second platform 200 is affected by a vibration source to generate vibration, the first platform 100 and the second platform 200 can generate relative motion, when the first platform 100 moves downwards relative to the second platform 200, the racks can also generate downward relative motion, the positive stiffness spring 300 is further compressed to provide an upward force for the racks, at the moment, two gears on the same side of the device can generate reverse rotation motion, the balance state of the negative stiffness mechanism is broken, the negative stiffness spring 400 can further drive the gears to rotate, the moment applied to the gears by the negative stiffness spring 400 can be converted into a downward force for the racks through the meshing of the gears and the racks, the resultant force (restoring force) of the racks in an effective interval is stable and approaches zero, so that the dynamic stiffness of the device in the effective interval tends to zero, the vibration of the second platform 200 can be effectively isolated, and the influence of the object on the first platform 100 by the vibration of the second platform 200 is reduced.
After the device is debugged, any load in the bearing range is loaded on the first platform 100, if the loaded any load is the payload supported by the device after the device is debugged, at this time, the axes of the first transmission shaft 610, the second transmission shaft 620 and the two gear shafts 530 are collinear, the included angle between the axis connecting line of the first transmission shaft 610 and the gear shaft 530 on the same side and the horizontal line is zero, the included angle between the axis connecting line of the second transmission shaft 620 and the gear shaft 530 on the same side and the horizontal line is also zero, and the vibration isolation effect is better as in the embodiment above under the condition that no adjustment is required. If any load to be loaded is not the payload supported by the device after debugging, at this time, the axes of the first transmission shaft 610 and the second transmission shaft 620 and the axes of the two gear shafts 530 are not collinear, the axes of the first transmission shaft 610 and the gear shafts 530 on the same side are connected to form a non-zero included angle with the horizontal line, the axes of the second transmission shaft 620 and the gear shafts 530 on the same side are connected to form the same non-zero included angle with the horizontal line, the state corresponds to a black dot a on a dimensionless bearing capacity-displacement curve before and after the device is adjusted as shown in fig. 7, obviously, the dynamic stiffness at this time is larger, the relative positions of the first support 541 and the second support 542 can be adjusted to ensure that the axes of the first transmission shaft 610, the second transmission shaft 620 and the two gear shafts 530 are collinear, the adjusted state corresponds to a red dot B on a dimensionless bearing capacity-displacement curve before and after the device is adjusted as shown in fig. 7, and the dynamic stiffness at the point B is obviously observed to be even near zero from the figure, and the vibration isolation effect is better as in the embodiment described above after one adjustment.
The conventional quasi-zero stiffness vibration isolation mechanism usually has only one effective working interval, the device uses a rack and a gear to be meshed for transmission, and uses a negative stiffness spring 400 as a negative stiffness elastic element, so that a gear can rotate along with the downward movement of the rack, a new quasi-zero stiffness region can be formed when the gear rotates by an integral multiple of 180 degrees, the loaded mass and the downward movement amount of the rack can be completely converted with each other, that is, when the rack moves downwards by a distance of half a circumference of a gear reference circle, the quasi-zero stiffness region of the vibration isolation device can be circularly formed, as shown in fig. 5, the dimensionless bearing capacity-displacement curve of the device can be observed, the platform section can be continuously circularly formed from the dimensionless bearing capacity-displacement curve of the device, as shown in fig. 6, the quasi-zero stiffness region can be continuously circularly formed from the dimensionless stiffness-displacement curve of the device, and the device can be effectively isolated for various loads. Secondly, after the vibration isolation device is assembled and debugged, the size of the effective load of the vibration isolation device can be easily regulated and controlled by adjusting the relative positions of the first support 541 and the second support 542 without replacing any parts, the dimensionless bearing capacity-displacement multi-platform curve of the vibration isolation device can be arbitrarily customized, as shown in fig. 7, the dimensionless bearing capacity-displacement curve of the vibration isolation device before and after adjustment can be observed, the height of the platform can be continuously changed in the bearing range through adjustment, and effective vibration isolation of any load in the bearing range can be realized.
It is apparent that the above examples of the present solution are merely examples for clearly illustrating the present solution and are not limiting of the embodiments of the present solution. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present solution should be included in the protection scope of the present solution claims.
Claims (10)
1. A multistage vibration isolation device comprising a first platform and a second platform which are parallel to each other, and a positive stiffness spring and a negative stiffness spring which are arranged between the first platform and the second platform, wherein the positive stiffness spring is perpendicular to the first platform/the second platform, and the negative stiffness spring is parallel to the first platform/the second platform; it is characterized in that the method comprises the steps of,
the positive stiffness spring and the negative stiffness spring are connected in parallel with the second gear rack mechanism through the first gear rack mechanism which is symmetrically arranged; the first gear and rack mechanism comprises a first gear and a first rack which are meshed with each other, and the second gear and rack mechanism comprises a second gear and a second rack which are meshed with each other; the tooth surfaces of the first rack and the second rack are opposite or opposite, one end of the first rack is connected with the first platform, the other end of the first rack is connected with one end of the positive stiffness spring, and the other end of the positive stiffness spring is connected with the second platform; the shafts of the first gear and the second gear are arranged on the second platform, the shaft transmission of the first gear is connected with a first transmission shaft parallel to the first transmission shaft, the shaft transmission of the second gear is connected with a second transmission shaft parallel to the second transmission shaft, and two ends of the negative stiffness spring are respectively connected with the first transmission shaft and the second transmission shaft in a transmission mode.
2. The multi-stage vibration isolation apparatus of claim 1, wherein,
at least one end of the negative stiffness spring is in transmission connection with the first transmission shaft and/or the second transmission shaft through a spring fixing component which can be telescopically adjusted in the axial direction of the negative stiffness spring.
3. The multi-stage vibration isolation apparatus of claim 2, wherein,
the spring fixing assembly comprises a first connecting piece and a second connecting piece, one end of the first connecting piece is fixedly connected with a negative stiffness spring, the other end of the first connecting piece is provided with internal threads, one end of the second connecting piece is provided with external threads, the other end of the second connecting piece is in transmission connection with a first transmission shaft and/or a second transmission shaft, and the internal threads of the first connecting piece are matched with the external threads of the second connecting piece; or alternatively
The spring fixing assembly comprises a first connecting piece and a second connecting piece, one end of the first connecting piece is fixedly connected with a negative stiffness spring, the other end of the first connecting piece is provided with external threads, one end of the second connecting piece is provided with internal threads, the other end of the second connecting piece is in transmission connection with a first transmission shaft and/or a second transmission shaft, and the external threads of the first connecting piece are matched with the internal threads of the second connecting piece.
4. The multi-stage vibration isolation apparatus of claim 1, wherein,
the first transmission shaft is in transmission connection with the shaft of the first gear through an eccentric disc, and/or the second transmission shaft is in transmission connection with the shaft of the second gear through an eccentric disc; the eccentric disc is provided with a central hole and an eccentric hole, the center Kong Chuandong is connected with the shafts of the first gear and/or the second gear, the eccentric hole is provided with a long hole, the center line of the long hole in the length direction passes through the center of the central hole, and the first transmission shaft and/or the second transmission shaft are fixedly connected with the long hole through a fastener.
5. The multi-stage vibration isolator according to claim 4, wherein,
the central hole is a spline hole, and the shaft of the first gear and/or the second gear is provided with a spline matched with the central hole.
6. The multi-stage vibration isolation apparatus of claim 1, wherein,
the shafts of the first gear and the second gear are arranged on the second platform through gear fixing brackets with telescopic height.
7. The multi-stage vibration isolation apparatus according to claim 6, wherein,
the gear fixing seat comprises a rod-shaped first support and a cylindrical second support, the second support is sleeved outside the first support, a threaded hole is formed in the side wall of the second support, and the threaded hole is connected with a fastener which abuts against the side face of the first support; the shaft brackets of the first gear and the second gear are arranged at the free ends of the first support, and the free ends of the second support are fixed on the second platform.
8. The multistage vibration isolation device according to any one of claims 1 to 7, characterized in that,
the first platform is provided with a guide hole, and the second platform is fixed with a guide rod matched with the guide hole.
9. The multi-stage vibration isolation apparatus of claim 8, wherein,
one end of the first rack and one end of the second rack are fixed on the first platform through a first rack fixing piece, the other end of the first rack and the second rack are fixedly connected with a positive stiffness spring through a second rack fixing piece, and the first rack fixing piece and the second rack fixing piece are respectively provided with a guide hole matched with the guide rod.
10. The multi-stage vibration isolation apparatus of claim 9, wherein,
the guides Kong Zhongan of the first and second rack fixtures are provided with linear bearings that mate with the guide rods.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311555914.XA CN117889184A (en) | 2023-11-20 | 2023-11-20 | Multistage vibration isolation device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311555914.XA CN117889184A (en) | 2023-11-20 | 2023-11-20 | Multistage vibration isolation device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117889184A true CN117889184A (en) | 2024-04-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311555914.XA Pending CN117889184A (en) | 2023-11-20 | 2023-11-20 | Multistage vibration isolation device |
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| Country | Link |
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| CN (1) | CN117889184A (en) |
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