CN112160438B - Magnetic screw type eddy current damper with negative-stiffness nonlinear energy trap - Google Patents
Magnetic screw type eddy current damper with negative-stiffness nonlinear energy trap Download PDFInfo
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- CN112160438B CN112160438B CN202011014713.5A CN202011014713A CN112160438B CN 112160438 B CN112160438 B CN 112160438B CN 202011014713 A CN202011014713 A CN 202011014713A CN 112160438 B CN112160438 B CN 112160438B
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- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H9/00—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate
- E04H9/02—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate withstanding earthquake or sinking of ground
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Abstract
The invention relates to a magnetic lead screw type eddy current damper with a negative stiffness nonlinear energy trap, which comprises a spring mass system, an inertial mass system, an eddy current damping system, a negative stiffness system and a supporting system. The spring mass system comprises a spring and a balancing weight, the inertia mass system comprises a flywheel, a magnetic lead screw nut pair and a magnetic suspension thrust bearing, the eddy current damping system comprises a straight permanent magnet, a conductor plate and a back iron, the supporting system comprises a guide rod, a supporting bracket and an outer frame, and the negative stiffness system comprises a different-name permanent magnet group and/or a same-name permanent magnet group. The damper introduces an inertial capacitance principle, lightens a physical counterweight, improves the mass ratio of the device, and reduces the net elongation of the spring of a device control low-frequency structure. The invention introduces the negative-stiffness nonlinear energy trap element, and can capture resonance energy in a wider frequency range. The invention adopts the magnetic screw and nut pair, eliminates the friction between the screw and the nut and improves the working efficiency. Meanwhile, the magnetic suspension thrust bearing is used in a matched mode, and the normal work of the flywheel suspended in the flywheel chamber is guaranteed.
Description
Technical Field
The invention belongs to the field of vibration control devices of engineering structures, and particularly relates to a magnetic lead screw type eddy current damper with a negative-stiffness nonlinear energy trap.
Background
The Tuned Mass Damper (TMD) is used for structural vibration reduction, belongs to one of structural vibration passive control technologies, is widely applied to the field of engineering structures, is installed in a vibrating bridge structure or a high-rise building structure, and has a very obvious inhibiting effect on structural vibration.
However, when the stiffness of the spring element of the TMD vibrates at low frequency, the theoretical stiffness higher frequency band is significantly reduced, and the spring static elongation is very large, so that the use requirement cannot be met. In order to solve the problem of static extension of a TMD spring, an inertial container is combined with the TMD spring, one mode of the inertial container is that a ball screw is utilized to convert linear motion of a balancing weight into rotary motion of a flywheel, and the device can use smaller physical mass to generate larger inertia force, so that the physical mass of the balancing weight can be reduced, and the problem of overlarge static extension of the spring is solved.
For example, patent application CN202010086393 provides a low-frequency vertical tuned mass damper with negative stiffness nonlinear energy trap, which belongs to the technical field of structural vibration control, and the tuned mass damper comprises a bottom plate, a thrust bearing, a helical spring, a ball screw, a ball nut, a balancing weight, a moving permanent magnet group, a stationary steel plate, a fixed permanent magnet group, a sliding bearing and a copper flywheel; the device has the characteristics of negative-rigidity nonlinear energy traps by utilizing the nonlinearity of attraction force between the moving permanent magnet group and the fixed permanent magnet group; the ball screw type inerter-damper mechanism is adopted to amplify the equivalent vibration mass of the tuned mass damper, so that the vibration attenuation effect of the tuned mass damper is improved, and the problem of overlarge net extension of a spring of the ultra-low frequency vertical tuned mass damper is solved; the device integrates the advantages of the nonlinear energy trap and the tuned mass damper, and widens the control frequency band of the tuned mass damper; meanwhile, the electric eddy current damping technology is adopted, so that the durability of the device is improved.
However, the damping force generated by the eddy current in the device changes constantly, and the damping force is very small when the distance is large. The device does not solve the problem of magnetic flux leakage of the eddy current damper. In addition, because the copper flywheel rotates and produces damping force, the damping force has the moment of torsion effect to the device, thereby can increase the pressure between balancing weight and the smooth guide shaft and produce frictional force. Furthermore, friction force still exists between the nut and the screw rod of the traditional ball screw type inerter, so that the efficiency of the damper is reduced, the problem of abrasion and damage can occur in the long-term use process, and the durability of the damper is reduced.
Therefore, there is a need in the art to provide a damper with stable damping force, higher energy consumption efficiency, smooth movement and better durability.
Disclosure of Invention
The invention aims to improve the light weight and durability level of the traditional TMD, improve the robustness of a system, solve the problems of overlarge physical mass, overlarge static elongation of a spring, narrower vibration reduction frequency band, friction of a ball screw type inerter and the like of the traditional TMD, and provide a vertical tuned mass magnetic force screw type inerter eddy current damper with a negative-stiffness nonlinear energy trap.
The invention provides a magnetic lead screw type eddy current damper with a negative stiffness nonlinear energy trap, which comprises a spring mass system, an inertial mass system, an eddy current damping system, a negative stiffness system and a supporting system, wherein the spring mass system is connected with the inertial mass system through a magnetic coupling; the spring mass system comprises a spring (3) and a balancing weight (5); the inertial mass system comprises a flywheel (6) capable of rotating in a horizontal plane, a magnetic lead screw nut pair (7) comprising a magnetic nut (71) and a magnetic lead screw (72), and a magnetic suspension thrust bearing (8) comprising a rotor (81) and a stator (82); the eddy current damping system comprises a straight permanent magnet (9), a conductor plate (10) and a back iron (11); the supporting system comprises an outer frame (1), a guide rod (2) and a supporting bracket (4);
the guide rod (2) is vertically arranged, the support bracket (4) is horizontally arranged, the support bracket (4) divides the outer frame (1) into an upper layer and a lower layer, the guide rod (2) is arranged on the upper layer or the lower layer, and two ends of the guide rod are respectively fixedly arranged on the support bracket (4) and the top wall or the bottom plate of the outer frame (1);
the spring (3) is sleeved on the guide rod (2), the balancing weight (5) is sleeved on the guide rod (2) in a sliding manner, the fixed end of the spring (3) is fixedly connected with the outer frame (1) or the support bracket (4), and the free end of the spring is fixedly connected with the balancing weight (5);
the straight permanent magnet (9) is fixedly arranged on the vertical side wall of the balancing weight (5) and can move up and down along with the balancing weight (5), the back iron (11) is attached to the vertical inner side wall of the outer frame, and the back iron (11), the straight permanent magnet (9) and the balancing weight (5) are positioned in the upper layer or the lower layer of the outer frame; the conductor plate (10) is attached to the surface of the back iron (11), and a set gap is reserved between the straight permanent magnet (9) and the conductor plate (10);
the magnetic screw (72) is vertically arranged, and the fixed end of the magnetic screw is fixedly connected with the geometric center of the balancing weight (5) in the horizontal plane of the balancing weight (5); the free end of the magnetic lead screw (72) passes through a hole reserved on the support bracket (4) and extends into the lower layer or the upper layer without the counterweight (5); the flywheel (6) is coaxially and fixedly connected to the radial outer side of the magnetic nut (71), the flywheel (6) and the magnetic nut (71) are sleeved on the magnetic lead screw (72), and the flywheel (6) and the magnetic nut (71) are arranged in the lower layer or the upper layer where the free end of the magnetic lead screw (72) is located; the rotor (81) of the magnetic suspension thrust bearing (8) is fixed on the flywheel (6) and can rotate along with the flywheel, and the stator (82) is fixed on the outer frame (1) and the support bracket (4); the magnetic suspension thrust bearings (8) are coaxially arranged with the flywheel (6) and the magnetic lead screw nut pair (7); in the vertical direction, one magnetic suspension thrust bearing (8) is arranged between the flywheel (6) and the support bracket (4), and the other magnetic suspension thrust bearing (8) is arranged between the flywheel (6) and a bottom plate or a top plate of the outer frame (1);
the negative stiffness system comprises a different name permanent magnet group (14) and/or a same name permanent magnet group (13), the different name permanent magnet group (14) comprises a first different name permanent magnet arranged on the top surface and the bottom surface of the balancing weight (5) and a second different name permanent magnet arranged on the outer frame (1) and the supporting bracket (4), the magnetizing directions of the first different name permanent magnet and the second different name permanent magnet, namely the connecting line directions of the N pole and the S pole of the first different name permanent magnet are both vertical to the upper plate surface and the lower plate surface of the balancing weight (5), the first different name permanent magnet arranged on the top surface of the balancing weight is opposite to the different name of the magnetic pole of the second different name permanent magnet correspondingly arranged on the lower surface of the supporting bracket (4) or on the lower bottom surface of the top plate of the outer frame (1), and the first different name permanent magnet arranged on the bottom surface of the balancing weight is opposite to the magnetic pole of the second different name permanent magnet correspondingly arranged on the upper surface of the supporting bracket (4) or on the upper surface of the bottom plate of the outer frame (1); when straight permanent magnet (9) set up on a pair of lateral wall in the lateral wall all around of balancing weight (5), the homonymy permanent magnet group (13) is including fixed setting up first homonymy permanent magnet on another pair of lateral wall in the lateral wall all around of balancing weight (5) to and including setting up the second homonymy permanent magnet on outer frame (1) inside wall with first homonymy permanent magnet relative position, the direction of magnetizing of first homonymy permanent magnet and second homonymy permanent magnet namely the line direction of its N utmost point and S utmost point all is perpendicular with the lateral wall face of outer frame (1), and sets up the magnetic pole homonymy relative setting of first homonymy permanent magnet on balancing weight (5) and the second homonymy permanent magnet of setting on the outer frame inside wall.
In a specific embodiment, the outer frame (1) is a cuboid framework, and the outer frame (1) is fixedly connected with the support bracket (4); the balancing weight (5) is a cuboid; the straight permanent magnets (9) are symmetrically distributed on the front side surface, the rear side surface and/or the left side surface and the right side surface of the balancing weight (5); preferably, the permanent magnets are distributed on the front, back, left and right sides of the balancing weight (5).
In the invention, when the damper has a large requirement on the damping force of the eddy current, the straight permanent magnets can be arranged on the front, the back, the left and the right side surfaces of the balancing weight, and at the moment, different-name permanent magnet groups are correspondingly arranged, but only different-name permanent magnet groups are arranged.
When the damper has low requirement on the damping force of the eddy current, the straight permanent magnets can be arranged on the front side and the rear side or the left side and the right side of the balancing weight, the permanent magnet groups with the same name can be arranged on the other two opposite sides of the balancing weight, and the permanent magnet groups with different names can be arranged on the top surface and the bottom surface of the balancing weight.
In the invention, because the different-name permanent magnet group and/or the same-name permanent magnet group are arranged, when the counterweight block moves to deviate from a balance position, and particularly when the counterweight block moves for a period of displacement in the vertical direction, the different-name permanent magnet group and/or the same-name permanent magnet group provide a nonlinear magnetic force consistent with the original movement direction for the counterweight block, thereby promoting the movement of the counterweight block. Specifically, when the counterweight block moves up and down along the guide rod due to an external action, the vertical component force of the repulsive force between the permanent magnets of the same name can further urge the counterweight block to move; when the balancing weight moves up and down along the guide rod due to external action, the attraction difference between the upper and lower two different-name permanent magnet groups can further promote the balancing weight to move. Therefore, the eddy current damper has the negative-rigidity nonlinear energy trap effect by arranging the different-name permanent magnet group and/or the same-name permanent magnet group.
In a specific embodiment, a round hole with the diameter larger than that of the magnetic lead screw (72) is reserved at the central position of the support bracket (4); preferably, the number of the guide rods (2) is not less than three, and the intersection points of the guide rods and the clump weight (5) are not totally collinear.
In a specific embodiment, the rotor (81) and the stator (82) both comprise permanent magnets, the magnetizing directions of the rotor (81) and the stator (82), namely the connecting line directions of the N pole and the S pole, are both in the vertical direction, and the magnetic poles of the rotor (81) and the stator (82) in the same magnetic suspension thrust bearing (8) are arranged to be opposite in the same pole; preferably, the width of the rotor (81) in the horizontal direction is smaller than the width of the stator (82) in the horizontal direction, so that the flywheel can be kept in a magnetic field range when lateral shaking occurs, and the flywheel can be rapidly stabilized and restored.
In a specific embodiment, the outer frame (1) has enough space or holes on the motion track of the free end of the magnetic lead screw (72), and preferably a raised platform with a certain height is arranged on the top surface of the outer frame bottom plate or the bottom surface of the outer frame top plate.
In a specific embodiment, a guide bearing for reducing friction between the balancing weight (5) and the guide rod (2) is further arranged at the joint of the balancing weight and the guide rod.
In a specific embodiment, the straight permanent magnet (9) is a straight magnet horizontally arranged in the length direction, the magnetizing direction of the permanent magnet, namely the connecting line direction of the N pole and the S pole of the permanent magnet, is perpendicular to the plate surface of the corresponding conductor plate (10), and the polarities of the upper permanent magnet and the lower permanent magnet which are adjacent to each other are opposite, that is, when the side of the upper permanent magnet close to the conductor plate is the N pole and the side far away from the conductor plate is the S pole, the side of the lower permanent magnet close to the conductor plate adjacent to the upper permanent magnet is the S pole, and the side far away from the conductor plate is the N pole; preferably, the distance between two vertical permanent magnets (9) adjacent to each other is 2-5 cm.
In the invention, each straight strip permanent magnet can be a full-length one, or a plurality of straight strip permanent magnets are connected in series or a distance is arranged between the front and the back of the plurality of straight strip permanent magnets. The length, width and height of the permanent magnets and the distance between the permanent magnets can be designed according to the required size of the damping coefficient. The straight bar permanent magnets, the homonymous permanent magnet groups and the synonymous permanent magnet groups may be, for example, customized neodymium-iron-boron magnets.
In a specific embodiment, during the up-and-down movement of the balancing weight (5), the gap between the permanent magnet and the conductor plate is kept unchanged, and the gap can be adjusted according to the required magnitude of the damping coefficient, such as 0.2-20 mm, preferably 1-5 mm; preferably, the fixed end of the spring is fixedly connected with the top surface of the support bracket (4) or the top surface of the bottom plate of the outer frame (1).
In a specific embodiment, the magnetic nut (71) comprises a permanent magnet having an N pole and an S pole both in a spiral shape and arranged at intervals between the N pole and the S pole, and the magnetic screw (72) also comprises a permanent magnet having an N pole and an S pole both in a spiral shape and arranged at intervals between the N pole and the S pole.
In a specific embodiment, the inertial mass system may further include a modulation ring (12) for improving the transmission efficiency of the magnetic screw-nut pair (7), two ends of the modulation ring (12) in the vertical direction are respectively fixed on the outer frame (1) and the support bracket (4), a middle section of the modulation ring (12) in the vertical direction is disposed between the magnetic nut (71) and the magnetic screw (72) in the radial direction, and the modulation ring (12) includes a magnetic conductive block and a non-magnetic conductive block, both of which are spirally arranged at intervals.
According to the invention, the outer frame (1), the guide rod (2) and the support bracket (4) are all made of steel structures, the counterweight block (5) and the flywheel (6) are made of steel structures, and the conductor plate (10) is a copper plate or an aluminum plate.
According to the invention, the straight permanent magnet (9), the homonymous permanent magnet group (13), the synonymous permanent magnet group (14), the magnetic screw nut pair (7) comprising the magnetic nut (71) and the magnetic screw (72), the magnetic suspension thrust bearing (8) comprising the rotor (81) and the stator (82), and the modulation ring (12) can be directly purchased commercially or the permanent magnet which meets the requirements and is customized by a magnet manufacturer can be found, and the permanent magnet is, for example, a neodymium iron boron magnet. In addition, in the present invention, the rotor and the stator are both arranged in a circular shape having a certain width in a plan view.
In the invention, a certain gap is arranged among the magnetic nut (71), the magnetic screw rod (72) and the modulation ring (12) in the radial direction.
In the invention, the balancing weight and the flywheel are positioned on different layers, so that the replacement of parts in the later period is facilitated, the structural space can be fully utilized, and the enough large size of the flywheel is ensured; the spring deforms along with the movement of the balancing weight and is coaxially arranged with the guide rod so as to ensure that the spring does not skew.
According to the invention, according to the electromagnetic induction principle, under the condition that the balancing weight moves, damping acting force can be generated between the straight permanent magnet and the conductor plate, and the damping can be adjusted by adjusting the gap between the straight permanent magnet and the conductor plate.
As preferred scheme, the straight permanent magnet fixed mounting be in on the lateral wall of balancing weight, the back iron is fixed on the inside wall of outer frame, the conductor board is fixed on the back iron, and the existence of back iron can guarantee that the magnetic field is closed, reduces the magnetic leakage.
Preferably, the plates of the outer frame are hollowed out as necessary, so that the structural mass can be reduced and the replacement of elements is facilitated, and a hole with a sufficient size needs to be reserved on the top plate or the support bracket of the outer frame for the magnetic lead screw to freely pass through.
As the preferred scheme, the balancing weight is in the shape of a cuboid, a hole for the guide rod to penetrate through is reserved, the diameter of the hole is larger than that of the guide rod, a guide bearing can be further arranged between the balancing weight and the guide rod, and the balancing weight can move along the guide rod conveniently without generating large friction.
As a preferred scheme, the guide rods are arranged in parallel at least three, and at least three connecting lines among the guide rods are not in the same straight line, so that the balancing weight can be limited to only do vertical movement.
Preferably, the permanent magnet poles of the magnetic nut fixedly mounted on the inner wall of the center of the flywheel and the permanent magnet poles of the lead screw are alternately arranged, so that the lead screw can pass through the center of the flywheel without contact and drive the flywheel to rotate.
Preferably, the conductor plate and the straight permanent magnet are arranged in parallel with a gap left therebetween, and the damping magnitude can be adjusted by adjusting the gap.
The beneficial effects of the invention include:
1. the invention introduces the inertial capacitance principle, lightens the physical counter weight, realizes the improvement of the mass ratio of the device and simultaneously reduces the net elongation of the spring of the device control low-frequency structure.
2. The magnetic screw-nut pair or the magnetic field modulation type magnetic screw-nut pair is adopted to replace a ball screw, so that friction between the screw and the nut is eliminated, and the working efficiency is improved. Meanwhile, the magnetic suspension thrust bearing is used in a matched mode, and the normal work of the flywheel suspended in the flywheel chamber is guaranteed. The friction of the whole structure is greatly reduced, and the service life is prolonged.
3. By adopting linear eddy current damping, the application of the back iron reduces magnetic leakage, the eddy current damping energy consumption efficiency is obviously improved, and the durability of the device is improved by non-contact damping.
4. The upper and lower layered frame structure is adopted, so that the modular assembly is facilitated, certain parts can be replaced and still used, and the cost is reduced. The damper is a single-node damper, and is applied without connecting two points which generate relative motion, so that the application range is wide.
5. The gap between the permanent magnet and the conductor plate is kept unchanged in the movement process of the parts such as the balancing weight and the like, so that the distance between the permanent magnet and the conductor plate can be set to be very small, and a very large damping force can be generated; in the invention, the balancing weight and other parts do linear relative motion, the damping force has no torque to the balancing weight, the pressure between the balancing weight and the guide rod cannot be increased, and the motion is very smooth. In the patent application CN202010086393, the gap between the magnet and the conductor plate changes during the movement, the damping force also changes accordingly, and the damping force is small when the gap is large; and the permanent magnet and the conductor plate generate relative rotation movement, and the balancing weight generates pressure on the guide rod under the action of the torque of the damping force, so that the friction between the balancing weight and the guide rod is increased.
6. The negative stiffness nonlinear energy trap is applied to the tuned mass damper, so that the tuned mass damper has the effect of widening the control frequency band, has better robustness, and can solve the problem that the tuned mass damper can only have better vibration damping effect in a very small neighborhood of specific frequency. That is to say, the invention adopts the nonlinear energy trap of negative stiffness of permanent magnetism type, through its characteristic of negative stiffness, nonlinearity, make the damper have wider control frequency band, and can absorb more vibrational energy from the controlled structure.
Drawings
Fig. 1 is a schematic structural diagram of a magnetic screw type eddy current damper with a counterweight block located on an upper layer and having a negative-stiffness nonlinear energy trap, wherein the scheme includes a permanent magnet group and a modulation ring of the same name.
Fig. 2 is a schematic structural diagram of a magnetic screw type eddy current damper with a counterweight block located on the upper layer and having a negative-stiffness nonlinear energy trap, wherein the magnetic screw type eddy current damper includes a permanent magnet group of the same name.
Fig. 3 is a schematic structural diagram of a magnetic screw type eddy current damper with a balancing weight located at a lower layer and having a negative-stiffness nonlinear energy trap, wherein the scheme includes a permanent magnet group and a modulation ring of the same name.
Fig. 4 is a schematic structural diagram of a magnetic screw type eddy current damper with a balancing weight located at a lower layer and having a negative-stiffness nonlinear energy trap, wherein the scheme includes a permanent magnet group of the same name.
Fig. 5 is a schematic structural diagram of a magnetic screw type eddy current damper with a counterweight block on the upper layer and a negative-stiffness nonlinear energy trap, wherein the magnetic screw type eddy current damper comprises a synonym permanent magnet group and a modulation ring.
Fig. 6 is a schematic structural diagram of a magnetic screw type eddy current damper with a counterweight block on the upper layer and a negative-stiffness nonlinear energy trap, wherein the magnetic screw type eddy current damper comprises a synonym permanent magnet group.
Fig. 7 is a schematic structural diagram of a magnetic screw type eddy current damper with a weight block located at a lower layer and having a negative-stiffness nonlinear energy trap, wherein the scheme includes a synonym permanent magnet group and a modulation ring.
Fig. 8 is a schematic structural diagram of a magnetic screw type eddy current damper with a weight block located at a lower layer and having a negative-stiffness nonlinear energy trap, wherein the scheme includes a synonym permanent magnet group.
Fig. 9 is a cross-sectional view a-a of fig. 1, 2, 5 and 6.
Fig. 10 is a B-B sectional view of fig. 3, 4, 7 and 8.
Fig. 11 is a schematic structural view of a magnetic screw-nut pair.
Fig. 12 is a schematic structural diagram of a magnetic field modulation type magnetic screw nut pair.
Fig. 13 is a schematic structural diagram of a magnetic suspension thrust bearing.
In the figure:
1-an outer frame; 2-a guide rod; 3-a spring; 4-a support bracket; 5-a balancing weight; 6-a flywheel; 7-magnetic screw and nut pair; 71-a magnetic nut; 72-magnetic lead screw; 8-magnetic suspension thrust bearing; 81-rotor; 82-a stator; 9-straight bar permanent magnet; 10-a conductor plate; 11-back iron; 12-a modulation loop; 13-group of homonymous permanent magnets; 14-group of synonyms permanent magnets.
Detailed Description
The technical scheme of the invention is explained in detail in the following by combining the drawings and two specific embodiments.
Example 1
As shown in fig. 2, 4, 6 and 8, a vertical tuned mass magnetic screw inerter eddy current damper with a negative stiffness nonlinear energy trap comprises a spring mass system, an inertial mass system, an eddy current damping system, a negative stiffness system and a support system.
The spring quality system comprises a spring (3) and a balancing weight (5), wherein the balancing weight (5) is in a cuboid shape, and a hole with the diameter larger than that of the guide rod (2) is reserved on the balancing weight (5), so that the balancing weight (5) is sleeved on the guide rod (2) and can linearly move along the guide rod; the spring (3) is sleeved on the guide rod (2), one end of the spring is fixedly connected with the balancing weight (5), and the other end of the spring is fixedly connected with the outer frame (1) or the support bracket (4).
The inertial mass system comprises a flywheel (6), a magnetic lead screw nut pair (7) and a magnetic suspension thrust bearing (8). The flywheel (6) is sleeved on a magnetic screw (72) and a magnetic nut (71) of the magnetic screw-nut pair (7), the magnetic nut (71) is fixedly installed on the inner wall of the center of the flywheel (6), and magnetic poles of the magnetic nut and magnetic poles of a permanent magnet on the magnetic screw (72) are alternately arranged; the magnetic suspension thrust bearing (8) is formed by a rotor (81) fixed on the flywheel (6) and a stator (82) fixed on the outer frame (1) and the support bracket (4), and the transverse width of the rotor (81) is smaller than that of the stator (82).
The eddy current damping system comprises a straight bar permanent magnet (9), a conductor plate (10) and a back iron (11). The straight permanent magnets (9) are uniformly and fixedly arranged on the side wall of the balancing weight (5), a fixed interval is reserved between the straight permanent magnets (9), the magnetizing direction of the straight permanent magnets is perpendicular to the side wall of the balancing weight (5) where the straight permanent magnets are located, and the magnetizing directions of the straight permanent magnets (9) which are adjacent up and down are opposite; the conductor plate (10) is fixed on the back iron (11), and is arranged in parallel with the straight bar permanent magnet (9) with a gap; the back iron (11) is fixed on the inner side wall of the outer frame (1).
The supporting system comprises an outer frame (1), a guide rod (2) and a supporting bracket (4), plates of the outer frame (1) are hollowed out as necessary, and a hole with enough size is reserved on a top plate of the outer frame (1) or the supporting bracket (4) for a lead screw (72) of the magnetic lead screw-nut pair (7) to freely pass through; two ends of the guide rod (2) are respectively fixedly connected to the outer frame (1) and the support bracket (4), at least three guide rods (2) are arranged in parallel, and at least three points of intersection points of the guide rods (2) on the same horizontal plane are not on the same straight line; the spring (3) is sleeved on the guide rod (2), and two ends of the spring (3) are fixedly connected with the balancing weight (5) and the outer frame (1) or the supporting bracket (4) respectively.
The negative stiffness system comprises a different name permanent magnet group (14) and/or a same name permanent magnet group (13), the different name permanent magnet group (14) comprises a first different name permanent magnet arranged on the top surface and the bottom surface of the balancing weight (5) and a second different name permanent magnet arranged on the outer frame (1) and the supporting bracket (4), the magnetizing directions of the first different name permanent magnet and the second different name permanent magnet, namely the connecting line directions of the N pole and the S pole of the first different name permanent magnet are both vertical to the upper plate surface and the lower plate surface of the balancing weight (5), the first different name permanent magnet arranged on the top surface of the balancing weight is opposite to the different name of the magnetic pole of the second different name permanent magnet correspondingly arranged on the lower surface of the supporting bracket (4) or on the lower bottom surface of the top plate of the outer frame (1), and the first different name permanent magnet arranged on the bottom surface of the balancing weight is opposite to the magnetic pole of the second different name permanent magnet correspondingly arranged on the upper surface of the supporting bracket (4) or on the upper surface of the bottom plate of the outer frame (1); when straight permanent magnet (9) set up on a pair of lateral wall in the lateral wall all around of balancing weight (5), the homonymy permanent magnet group (13) is including fixed setting up first homonymy permanent magnet on another pair of lateral wall in the lateral wall all around of balancing weight (5) to and including setting up the second homonymy permanent magnet on outer frame (1) inside wall with first homonymy permanent magnet relative position, the direction of magnetizing of first homonymy permanent magnet and second homonymy permanent magnet namely the line direction of its N utmost point and S utmost point all is perpendicular with the lateral wall face of outer frame (1), and sets up the magnetic pole homonymy relative setting of first homonymy permanent magnet on balancing weight (5) and the second homonymy permanent magnet of setting on the outer frame inside wall.
Example 2
As shown in fig. 1, 3, 5 and 7, a vertical tuned mass magnetic field modulation type magnetic screw inerter eddy current damper with a negative stiffness nonlinear energy trap includes a spring mass system, an inertial mass system, an eddy current damping system, a negative stiffness system and a support system.
The spring quality system comprises a spring (3) and a balancing weight (5), wherein the balancing weight (5) is in a cuboid shape, and a hole with the diameter larger than that of the guide rod (2) is reserved on the balancing weight (5), so that the balancing weight (5) is sleeved on the guide rod (2) and can linearly move along the guide rod; the spring (3) is sleeved on the guide rod (2), one end of the spring is fixedly connected with the balancing weight (5), and the other end of the spring is fixedly connected with the outer frame (1) or the support bracket (4).
The inertial mass system comprises a flywheel (6), a magnetic lead screw nut pair (7), a modulation ring (12) and a magnetic suspension thrust bearing (8). The flywheel (6) is sleeved on a magnetic screw (72) and a magnetic nut (71) of the magnetic screw-nut pair (7), the magnetic nut (71) is fixedly installed on the inner wall of the center of the flywheel (6), and magnetic poles of the magnetic nut and magnetic poles of a permanent magnet on the magnetic screw (72) are alternately arranged; a modulation ring (12) is arranged between the magnetic screw rod (72) and the magnetic nut (71) in the radial direction, and the two ends of the modulation ring in the length direction are fixed on the outer frame (1) and the support bracket (4); the magnetic suspension thrust bearing (8) is formed by a rotor (81) fixed on the flywheel (6) and a stator (82) fixed on the outer frame (1) and the support bracket (4), and the transverse width of the rotor (81) is smaller than that of the stator (82).
The eddy current damping system comprises a straight bar permanent magnet (9), a conductor plate (10) and a back iron (11). The straight permanent magnets (9) are uniformly and fixedly arranged on the side wall of the balancing weight (5), a fixed interval is reserved between the straight permanent magnets (9), the magnetizing direction of the straight permanent magnets is perpendicular to the side wall of the balancing weight (5) where the straight permanent magnets are located, and the magnetizing directions of the straight permanent magnets (9) which are adjacent up and down are opposite; the conductor plate (10) is fixed on the back iron (11), and is arranged in parallel with the straight bar permanent magnet (9) with a gap; the back iron (11) is fixed on the inner side wall of the outer frame (1).
The supporting system comprises an outer frame (1), a guide rod (2) and a supporting bracket (4), plates of the outer frame (1) are hollowed out as necessary, and a hole with enough size is reserved on a top plate of the outer frame (1) or the supporting bracket (4) for a lead screw (72) of the magnetic lead screw-nut pair (7) to freely pass through; two ends of the guide rod (2) are respectively fixedly connected to the outer frame (1) and the support bracket (4), at least three guide rods (2) are arranged in parallel, and at least three points of intersection points of the guide rods (2) on the same horizontal plane are not on the same straight line; the spring (3) is sleeved on the guide rod (2), and two ends of the spring (3) are fixedly connected with the balancing weight (5) and the outer frame (1) or the supporting bracket (4) respectively.
The negative stiffness system comprises a different name permanent magnet group (14) and/or a same name permanent magnet group (13), and the arrangement is the same as that of embodiment 1.
In addition, in the invention, when the damper comprises the different-name permanent magnet groups and the counterweight block is in a balance position, the distance between the first different-name permanent magnet and the second different-name permanent magnet of the upper different-name permanent magnet group and the lower different-name permanent magnet group needs to be kept the same; when the damper comprises the same-name permanent magnet group, when the balancing weight is in a balance position, the first same-name permanent magnet and the second same-name permanent magnet need to be located at the same height.
The working principle of the invention is as follows: the device is fixed with a controlled vibration structure through a bottom plate of an outer frame, when the controlled structure vibrates vertically and the main vibration frequency of a damper is adjusted to be close to the vibration frequency of the controlled structure, the vibration energy of the controlled structure is transmitted to the damper, a balancing weight moves up and down along a guide rod, permanent magnets uniformly distributed on four side walls of the balancing weight generate magnetic fields, and a conductor plate cuts magnetic induction lines to generate eddy current damping force; meanwhile, the up-and-down movement of the balancing weight can drive the magnetic lead screw to move up and down together, the magnetic coupling force generated by the magnetic lead screw and the magnetic nut drives the flywheel to rotate, so that an inertial mass effect which is far greater than the physical mass of the flywheel is generated, and the magnetic bearing utilizes the repulsive force of two permanent magnets with the same name (namely the same polarity), so that the flywheel is kept in a non-collision and non-friction suspension state in the movement process; the whole inertia volume mass system greatly lightens the physical mass, improves the mass ratio of the device and simultaneously reduces the net elongation of the spring of the device control low-frequency structure. Finally, the energy of the controlled structure vibration is dissipated in the form of heat energy, so that the aim of vibration reduction is fulfilled. When the balancing weight moves to deviate from the balance position, the different-name permanent magnet group and/or the same-name permanent magnet group provide nonlinear magnetic force consistent with the original movement direction for the balancing weight, and the movement of the balancing weight is promoted. Therefore, the eddy current damper has the negative-rigidity nonlinear energy trap effect by arranging the different-name permanent magnet group and/or the same-name permanent magnet group.
The invention adopts the inertial capacity principle and the magnetic transmission principle, and converts the linear motion of the balancing weight into the rotary motion of the flywheel through the magnetic lead screw nut pair, so that smaller physical mass generates larger inertial mass, the mass of the balancing weight can be relatively reduced, and the problem of overlarge static extension of the spring of the existing vertical tuned mass damper is solved; the application of the magnetic lead screw nut pair and the magnetic suspension thrust bearing eliminates the friction force between the flywheel and the lead screw and between the flywheel and the supporting system, improves the working efficiency of the damper and prolongs the service life of elements.
The above examples are only for clearly illustrating the technical solutions of the present invention, and are not intended to limit the embodiments of the present invention. Any other changes or modifications of the equivalent technical features without changing the basic idea and essence of the present invention shall fall within the protection scope of the claims of the present invention.
Claims (10)
1. A magnetic screw rod type eddy current damper with a negative stiffness nonlinear energy trap is characterized by comprising a spring mass system, an inertial mass system, an eddy current damping system, a negative stiffness system and a supporting system; the spring mass system comprises a spring (3) and a balancing weight (5); the inertial mass system comprises a flywheel (6) capable of rotating in a horizontal plane, a magnetic lead screw nut pair (7) comprising a magnetic nut (71) and a magnetic lead screw (72), and a magnetic suspension thrust bearing (8) comprising a rotor (81) and a stator (82); the eddy current damping system comprises a straight permanent magnet (9), a conductor plate (10) and a back iron (11); the supporting system comprises an outer frame (1), a guide rod (2) and a supporting bracket (4);
the guide rod (2) is vertically arranged, the support bracket (4) is horizontally arranged, the support bracket (4) divides the outer frame (1) into an upper layer and a lower layer, the upper layer and the lower layer are used for accommodating the flywheel (6) and the balancing weight (5), the balancing weight (5) is positioned at the lower layer when the flywheel (6) is positioned at the upper layer, and the balancing weight (5) is positioned at the upper layer when the flywheel (6) is positioned at the lower layer; the outer frame (1) is a cuboid framework, and the outer frame (1) is fixedly connected with the support bracket (4); the guide rod (2) is arranged on the upper layer or the lower layer, and two ends of the guide rod are respectively fixedly arranged on the support bracket (4) and the top wall or the bottom plate of the outer frame (1);
the spring (3) is sleeved on the guide rod (2), the balancing weight (5) is sleeved on the guide rod (2) in a sliding manner, the fixed end of the spring (3) is fixedly connected with the outer frame (1) or the support bracket (4), and the free end of the spring is fixedly connected with the balancing weight (5); the number of the guide rods (2) is not less than three, and more than three fixing points of the guide rods and the balancing weight (5) are not completely collinear;
the straight permanent magnet (9) is fixedly arranged on the vertical side wall of the balancing weight (5) and can move up and down along with the balancing weight (5), the back iron (11) is attached to the vertical inner side wall of the outer frame, and the back iron (11), the straight permanent magnet (9) and the balancing weight (5) are positioned in the upper layer or the lower layer of the outer frame; the conductor plate (10) is attached to the surface of the back iron (11), and a set gap is reserved between the straight permanent magnet (9) and the conductor plate (10); in the up-and-down movement process of the balancing weight (5), the gap between the permanent magnet and the conductor plate is kept unchanged, and the gap is 0.2-20 mm;
the magnetic screw (72) is vertically arranged, and the fixed end of the magnetic screw is fixedly connected with the geometric center of the balancing weight (5) in the horizontal plane of the balancing weight (5); the free end of the magnetic lead screw (72) passes through a hole reserved on the support bracket (4) and extends into the lower layer or the upper layer without the counterweight (5); the flywheel (6) is coaxially and fixedly connected to the radial outer side of the magnetic nut (71), the flywheel (6) and the magnetic nut (71) are sleeved on the magnetic lead screw (72), and the flywheel (6) and the magnetic nut (71) are arranged in the lower layer or the upper layer where the free end of the magnetic lead screw (72) is located; the rotor (81) of the magnetic suspension thrust bearing (8) is fixed on the flywheel (6) and can rotate along with the flywheel, and the stator (82) is fixed on the outer frame (1) and the support bracket (4); the magnetic suspension thrust bearings (8) are coaxially arranged with the flywheel (6) and the magnetic lead screw nut pair (7); in the vertical direction, one magnetic suspension thrust bearing (8) is arranged between the flywheel (6) and the support bracket (4), and the other magnetic suspension thrust bearing (8) is arranged between the flywheel (6) and a bottom plate or a top plate of the outer frame (1);
the negative stiffness system comprises a different name permanent magnet group (14) and/or a same name permanent magnet group (13), the different name permanent magnet group (14) comprises a first different name permanent magnet arranged on the top surface and the bottom surface of the balancing weight (5) and a second different name permanent magnet arranged on the outer frame (1) and the supporting bracket (4), the magnetizing directions of the first different name permanent magnet and the second different name permanent magnet, namely the connecting line directions of the N pole and the S pole of the first different name permanent magnet are both vertical to the upper plate surface and the lower plate surface of the balancing weight (5), the first different name permanent magnet arranged on the top surface of the balancing weight is opposite to the different name of the magnetic pole of the second different name permanent magnet correspondingly arranged on the lower surface of the supporting bracket (4) or on the lower bottom surface of the top plate of the outer frame (1), and the first different name permanent magnet arranged on the bottom surface of the balancing weight is opposite to the magnetic pole of the second different name permanent magnet correspondingly arranged on the upper surface of the supporting bracket (4) or on the upper surface of the bottom plate of the outer frame (1); when straight permanent magnet (9) set up on a pair of lateral wall in the lateral wall all around of balancing weight (5), the homonymy permanent magnet group (13) is including fixed setting up first homonymy permanent magnet on another pair of lateral wall in the lateral wall all around of balancing weight (5) to and including setting up the second homonymy permanent magnet on outer frame (1) inside wall with first homonymy permanent magnet relative position, the direction of magnetizing of first homonymy permanent magnet and second homonymy permanent magnet namely the line direction of its N utmost point and S utmost point all is perpendicular with the lateral wall face of outer frame (1), and sets up the magnetic pole homonymy relative setting of first homonymy permanent magnet on balancing weight (5) and the second homonymy permanent magnet of setting on the outer frame inside wall.
2. The damper of claim 1, wherein: the balancing weight (5) is a cuboid; the straight permanent magnets (9) are symmetrically distributed on the front side surface, the rear side surface and/or the left side surface and the right side surface of the balancing weight (5).
3. The damper of claim 1, wherein: and a round hole with the diameter larger than that of the magnetic lead screw (72) is reserved at the center of the support bracket (4).
4. The damper of claim 1, wherein: the rotor (81) and the stator (82) both comprise permanent magnets, the magnetizing directions of the rotor (81) and the stator (82), namely the connecting line directions of the N pole and the S pole, are both in the vertical direction, and the magnetic poles of the rotor (81) and the stator (82) in the same magnetic suspension thrust bearing (8) are arranged to be opposite in the same pole; the width of the rotor (81) in the horizontal direction is smaller than that of the stator (82) in the horizontal direction, so that the flywheel can be kept in a magnetic field range when lateral shaking occurs, and the flywheel can be rapidly stabilized and restored.
5. The damper of claim 1, wherein: the outer frame (1) is provided with enough space or a hole on the motion trail of the free end of the magnetic lead screw (72).
6. The damper of claim 1, wherein: and a guide bearing used for reducing friction between the balancing weight (5) and the guide rod (2) is further arranged at the joint of the balancing weight and the guide rod.
7. The damper of claim 1, wherein: the straight bar permanent magnets (9) are straight bar permanent magnets horizontally arranged in the length direction, the magnetizing direction of the straight bar permanent magnets, namely the connecting line direction of the N pole and the S pole of the straight bar permanent magnets, is vertical to the plate surface of the corresponding conductor plate (10), and the polarities of the upper and lower adjacent straight bar permanent magnets are opposite, namely when the side, close to the conductor plate, of the upper straight bar permanent magnet is the N pole, and the side, far away from the conductor plate, of the upper straight bar permanent magnet is the S pole, the side, close to the conductor plate, of the lower straight bar permanent magnet adjacent to the upper straight bar permanent magnet is the S pole, and the side, far away from the conductor plate, of the lower straight bar permanent magnet is the N pole; and the distance between two vertical adjacent straight permanent magnets (9) is 2-5 cm.
8. The damper according to any one of claims 1 to 7, wherein: in the up-and-down movement process of the balancing weight (5), the gap between the straight permanent magnet and the conductor plate is 1-5 mm; and the fixed end of the spring is fixedly connected with the top surface of the support bracket (4) or the top surface of the bottom plate of the outer frame (1).
9. The damper according to any one of claims 1 to 7, wherein: the magnetic nut (71) comprises permanent magnets of which the N poles and the S poles are both spiral and are arranged at intervals between the N poles and the S poles, and the magnetic lead screw (72) also comprises permanent magnets of which the N poles and the S poles are both spiral and are arranged at intervals between the N poles and the S poles.
10. The damper of claim 9, wherein: the inertial mass system can further comprise a modulation ring (12) used for improving the transmission efficiency of the magnetic screw-nut pair (7), two ends of the modulation ring (12) in the vertical direction are respectively fixed on the outer frame (1) and the support bracket (4), the middle section of the modulation ring (12) in the vertical direction is arranged between the magnetic nut (71) and the magnetic screw (72) in the radial direction, the modulation ring (12) comprises a magnetic conduction block and a non-magnetic conduction block, and the magnetic conduction block and the non-magnetic conduction block are both spirally arranged at intervals.
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| CN102082483B (en) * | 2011-02-16 | 2012-07-25 | 东南大学 | Flywheel energy storing device with permanent magnet bearing and thrust bearing |
| CN202926894U (en) * | 2012-11-23 | 2013-05-08 | 北京奇峰聚能科技有限公司 | Composite magnetic levitation protective bearing system |
| CN107228147B (en) * | 2017-06-09 | 2019-05-14 | 浙江大学 | A kind of vertical tuned mass damper of magneto ultralow frequency |
| CN108797311B (en) * | 2018-07-18 | 2020-06-19 | 武汉理工大学 | Eddy current tuned mass damper for ropeway bridge and design method |
| CN110034658A (en) * | 2019-04-19 | 2019-07-19 | 哈尔滨工业大学 | Novel magnetic field modulation system magnetic Screw |
| CN111139730B (en) * | 2020-02-11 | 2021-06-15 | 东南大学 | Low-frequency vertical tuned mass damper with negative-stiffness nonlinear energy trap |
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Effective date of registration: 20220610 Address after: Room 107, 1st floor, East District, incubation building, science and Technology Park, Hunan University, 186 Guyuan Road, high tech Development Zone, Changsha City, Hunan Province Patentee after: HUNAN XIAOZHEN ENGINEERING TECHNOLOGY CO.,LTD. Address before: 410082 Yuelu District Lushan South Road Lushan Gate, Changsha City, Hunan Province Patentee before: HUNAN University |