Single flywheel resettable inertial damper

Abstract

This invention belongs to the field of structural energy dissipation and vibration reduction technology, and relates to a single-flywheel repositionable inertial damper. It is a passive vibration reduction device applicable to small structures or cable-stayed bridge structures, used to suppress structural vibration under seismic or wind loads. The device is implemented using a rack and pinion drive and bevel gear reversing system, and a flywheel and eddy current damping system. This invention ensures that during the reciprocating motion of the structure, the damper provides inertial and damping forces when the structure's speed exceeds the flywheel's speed; in other phases, it does not provide control forces. Simultaneously, the flywheel decelerates and brakes during this period, allowing the structure to continuously obtain inertial and damping forces during the acceleration phase of its reciprocating motion, thus passively approximating the performance of Bang-Bang control.

Description

Technical Field

[0001] This invention belongs to the field of structural energy dissipation and vibration reduction technology, and relates to a single flywheel repositionable inertial damper, which is a passive energy dissipation and vibration reduction device that can be applied to small structures or bridge cable structures to suppress structural vibration under earthquakes or wind vibrations. Background Technology

[0002] Improving the service performance of civil structures and infrastructure, and significantly enhancing their wind and earthquake resistance, is of great strategic importance. Passive control technology, which does not rely on external energy input, is a stable and reliable vibration control strategy and is widely used in the vibration control of civil structures.

[0003] In recent years, inertial dampers have become a research hotspot in the field of civil engineering. An inertial damper is an acceleration-type vibration damper. Its theoretical model is a two-node element, and the element's output force is an inertial force proportional to the relative acceleration between the two nodes. The magnitude of the proportionality coefficient characterizes the output performance of the inertial damper. Inertial dampers can significantly reduce the load intensity on the input structure, thereby reducing the structural response. Moreover, inertial dampers have a more significant vibration damping effect on long-period structures.

[0004] Studies have shown that inertial containers provide unfavorable thrust during the structural deceleration phase, thus prolonging the deceleration process and ultimately leading to excessive structural displacement response. Introducing a ratchet mechanism between the flywheel and transmission system of the inertial container ensures that the flywheel rotates only in one direction and is only driven during the acceleration phase. Furthermore, the flywheel does not transfer loads back to the structure, thus addressing the issue of unfavorable thrust from the flywheel. However, due to the lack of an energy dissipation mechanism, the kinetic energy gained from the structure cannot be consumed or transferred. Therefore, the flywheel maintains a certain speed while idling until the start of the next vibration cycle, preventing the energy dissipation and vibration damping effect of the device from being continuously and efficiently utilized. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a single flywheel resettable inertial damper. This damper exerts force only during a specific acceleration phase in each vibration cycle of the structure, and utilizes eddy current damping to decelerate or brake the flywheel during a specific deceleration phase, ensuring that the flywheel is in a low-speed or stationary state before the acceleration phase. The structure receives inertial force and damping force only during a specific acceleration phase in reciprocating vibration. This damper passively approximates Bang-Bang control.

[0006] The technical solution of this invention is:

[0007] A single-flywheel reconfigurable inertial damper includes a rack and pinion drive and bevel gear reversing system, a flywheel and an eddy current damping system.

[0008] The aforementioned gear and rack transmission and bevel gear reversing system includes a housing 1, a rack guide rail 2, a rack 3, a cylindrical gear 4, a large bevel gear 5, a small bevel gear 6, a gearbox 7, a transmission rod 11, and a one-way bearing 12. The housing 1 is a cylindrical structure, sealed at one end with an external ring for mounting a damper, and open at the other end. There are two rack guide rails 2, two racks 3, two cylindrical gears 4, two large bevel gears 5, and two one-way bearings 12. The rack guide rail 2 is fixed parallel to the inner wall of the housing 1. The rack 3 is mounted on the rack guide rail 2 and reciprocates along it. One end of the rack 3 is inside the housing 1, and the other end is outside the housing 1. The ends outside the housing 1 are connected as one unit by a connecting plate with an external ring for mounting a damper. The cylindrical gear 4 is fixed to the transmission rod 1. 1. The two ends of the transmission rod 11 are fixed to the inner wall of the device housing 1. Two cylindrical gears 4 mesh with two racks 3 respectively. The racks 3 drive the cylindrical gears 4 to rotate, which is connected to and drives the one-way bearing 12 to rotate through the transmission rod 11. The large bevel gear 5 is mounted on the transmission rod 11 through the one-way bearing 12 and is located between the two cylindrical gears 4. The small bevel gear 6 is mounted between the two large bevel gears 5 and meshes with them. When the locking direction of the one-way bearing 12 is consistent with the movement direction of the large bevel gear 5 on the same side, the large bevel gear 5 drives the small bevel gear 6 to rotate. The small bevel gear 6 meshes with and drives the large bevel gear 5 on the other side to rotate freely. The gearbox 7 is installed inside the device housing 1. Its output shaft is connected to the small bevel gear 6. The transmission is transmitted to the flywheel and the eddy current damping system through the gearbox 7. The gearbox 7 amplifies the rotational speed of the small bevel gear 6.

[0009] The flywheel and eddy current damping system includes a flywheel 8, a magnet plate 9, a copper ring 10, and a magnet fixing bolt 13. The flywheel 8 is connected to the input shaft of the transmission 7. A set of tile-shaped magnet plates 9 are fixed to the surface of the flywheel 8 by the magnet fixing bolt 13, and the copper ring 10 is fixed to the inner surface of the device housing 1. The flywheel 8 drives the magnet plate 9 to rotate. The radial magnetic field generated by the magnet plate 9 rotates and generates eddy currents in the copper ring 10, which dissipate energy.

[0010] The beneficial effects of this invention are as follows: This invention ensures that during the reciprocating motion of the structure, the damper provides inertial and damping forces when the structure's speed exceeds the flywheel's speed, and does not provide control forces during other stages. Simultaneously, the flywheel decelerates and brakes during this time period, allowing the structure to continuously obtain inertial and damping forces during the acceleration phase of its reciprocating motion. The device of this invention implements a segmented control model of inertial capacitance and damping, approximating the Bang-Bang control strategy in the form of a passive device, combining the stability and reliability of passive control with the high performance of active control. Attached Figure Description

[0011] Figure 1 This is a side cross-sectional view of a single-flywheel resettable inertial damper;

[0012] Figure 2 This is a top cross-sectional view of a single-flywheel resettable inertial damper;

[0013] Figure 3 This is a schematic diagram of the structure of a large bevel gear and a one-way bearing;

[0014] Figure 4 This is an isometric drawing of a single-flywheel resettable inertial damper;

[0015] Figure 5 This is a cross-sectional view of the design of the eddy current damping mechanism.

[0016] In the diagram: 1. Device housing; 2. Rack and pinion guide; 3. Rack; 4. Cylindrical gear; 5. Large bevel gear; 6. Small bevel gear; 7. Gearbox; 8. Flywheel; 9. Magnet plate; 10. Copper ring; 11. Transmission rod; 12. One-way bearing; 13. Magnet fixing bolt. Detailed Implementation

[0017] The specific embodiments of the present invention are described below in conjunction with the technical solutions and accompanying drawings.

[0018] like Figure 1 , Figure 2 and Figure 3 As shown, a single flywheel repositionable inertial damper of the present invention includes a rack and pinion drive and bevel gear reversing system, and a flywheel and eddy current damping system. The rack and pinion drive and bevel gear reversing system includes a housing 1, a rack guide rail 2, a rack 3, a cylindrical gear 4, a large bevel gear 5, a small bevel gear 6, a gearbox 7, a transmission rod 11, and a one-way bearing 12; as shown... Figure 4 As shown, the flywheel and eddy current damping system includes a flywheel 8, a magnet plate 9, a copper ring 10, and a magnet fixing bolt 13.

[0019] The single-flywheel resettable inertial damper can be applied to cable structures in small structures or bridges. The following is a specific implementation description using cable structures as an example: The damper device housing 1 is fixed to the cable structure by a ring, and fixed to the bridge pier or a fixed position by a ring on the rack 3.

[0020] like Figure 1 and 2As shown, when the device moves along direction 1 or direction 2 due to the movement of the structure, the rack 3 drives the cylindrical gear 4 to rotate, which in turn drives the one-way bearing 12 to move by relying on the fixed transmission rod 11. Regardless of whether the device moves along direction 1 or direction 2, there will always be a one-way bearing 12 moving in the same direction as a large bevel gear 5. The large bevel gear 5 then drives the small bevel gear 6 to rotate, which in turn transmits the motion to the transmission 7. The transmission 7 adjusts the speed of the flywheel 8 so that the flywheel speed is less than the structural speed in the next structural acceleration phase, so that the device can provide inertial force in a reciprocating manner. When the flywheel speed is greater than the structural speed, the inertial force applied to the structure by the device is 0. In addition, the magnitude of the inertial force is related to the mass, radius, and damping of the flywheel. The transmission 7 drives the flywheel 8 to rotate, and the magnet 9 on the flywheel 8 rotates at the same time, causing the copper ring 10 to cut the magnetic field lines and generate eddy currents in the copper ring 10, which generate heat that is eventually dissipated.

[0021] Working principle:

[0022] (1) Starting from a stationary state, when the rack 3 of the device is driven by the structure to move along direction 1 or direction 2, the one-way bearing 12 on one side locks the rotation direction and rotates coaxially with the large bevel gear 5 on that side, further driving the transmission 7 and the flywheel 8 to rotate, so that the structure obtains the inertial force generated by the rotation of the flywheel 8 and the damping force of the eddy current damping system.

[0023] (2) In the flywheel system, the rotation of flywheel 8 can be divided into two stages: acceleration and deceleration. After flywheel 8 accelerates to its maximum speed for the first time, the large bevel gear 6, which rotates with flywheel 8, also reaches its maximum speed. The one-way bearing 12, which was previously meshed with the large bevel gear 6 on one side, will have a disengagement effect. The structure and flywheel do not affect each other, and no control force is generated. The flywheel begins to decelerate under eddy current damping, and the structure also begins to decelerate during this period. After the structure changes direction, it continues to accelerate, driving the one-way bearing 12 on the other side to rotate. When the rotation speed of the inner ring of the one-way bearing 12 exceeds the speed of the large bevel gear 6 on that side again, the one-way bearing 12 locks its rotation direction, and flywheel 8 is driven by the structure again. This process repeats, and the inertial force can be repeatedly applied to the structure.

[0024] (3) The control force F ultimately provided to the structure by the single flywheel resettable inertial damper is: in, The endpoint speed of the device or the speed response of the structure; Angular velocity of the flywheel; r: radius of flywheel 8; b: maximum design inertia coefficient of the device; c fThe maximum damping coefficient of the device is the damping force generated by the eddy current, which is similar to the damping force generated by the viscous liquid. Theoretically, both belong to the velocity-type linear damping force. This damping coefficient is related to the magnetic induction intensity, the thickness and surface area of ​​the conductor, etc.

Claims

1. A single-flywheel resettable inertial damper, characterized in that, The single flywheel resettable inertial damper includes a rack and pinion drive and bevel gear reversing system, a flywheel and an eddy current damping system; The aforementioned gear and rack transmission and bevel gear reversing system includes a device housing (1), a rack guide rail (2), a rack (3), a cylindrical gear (4), a large bevel gear (5), a small bevel gear (6), a gearbox (7), a transmission rod (11), and a one-way bearing (12). The device housing (1) has a cylindrical structure, with one end sealed and an external ring for installing a damper, and the other end is open. The rack guide rail (2), rack (3), cylindrical gear (4), and large bevel gear (5) are also included. Two one-way bearings (12) are provided; the rack guide rail (2) is fixed parallel to the inner wall of the device housing (1), the rack (3) is installed on the rack guide rail (2), and the rack (3) reciprocates along the rack guide rail (2); one end of the rack (3) is located inside the device housing (1), and the other end is located outside the device housing (1), and the end located outside the device housing (1) is connected as one unit by a connecting plate, and the connecting plate is provided with a ring for the installation of the damper; the cylindrical gear (4) is fixed on the transmission rod (11). On the transmission rod (11), both ends are fixed to the inner wall of the outer casing (1). Two cylindrical gears (4) mesh with two racks (3) respectively. The racks (3) drive the cylindrical gears (4) to rotate, which is connected to and drives the one-way bearing (12) to rotate through the transmission rod (11). The large bevel gear (5) is mounted on the transmission rod (11) through the one-way bearing (12) and is located between the two cylindrical gears (4). The small bevel gear (6) is mounted between the two large bevel gears (5) and is connected to the two large bevel gears. (5) Meshing; When the locking direction of the one-way bearing (12) is consistent with the movement direction of the large bevel gear (5) on the same side, the large bevel gear (5) drives the small bevel gear (6) to rotate, and the small bevel gear (6) drives the large bevel gear (5) on the other side to rotate freely through meshing; The gearbox (7) is installed in the housing (1) of the device, and its output shaft is connected to the small bevel gear (6). The transmission is transmitted to the flywheel and the eddy current damping system through the gearbox (7). The gearbox (7) amplifies the rotational speed of the small bevel gear (6); The flywheel and eddy current damping system includes a flywheel (8), a magnet (9), a copper ring (10), and a magnet fixing bolt (13). The flywheel (8) is connected to the input shaft of the transmission (7). A set of tile-shaped magnets (9) are fixed to the surface of the flywheel (8) by the magnet fixing bolt (13). The copper ring (10) is fixed to the inner surface of the device housing (1). The flywheel (8) drives the magnets (9) to rotate. The radial magnetic field generated by the magnets (9) rotates and generates eddy currents in the copper ring (10) to dissipate energy.

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