Vibration control device

Abstract

To provide a vibration control device in which a natural period of an additional mass body is set longer than a natural period of a structure and achieves large vibration control effect even if a mass ratio of the additional mass body to the structure is small.SOLUTION: A vibration control device includes: an additional mass body 12; a support member 13 which is installed at a structure 11 and supports the additional mass body 12 in a manner that allows the additional mass body 12 to be displaced in a horizontal direction; and a damping mechanism 14 which is installed between the structure 11 and the additional mass body 12, absorbs vibrational energy acting on the structure 11, and limits displacement of the additional mass body 12. The damping mechanism 14 includes: a rotational inertia mass damper 14 which generates a rotational inertia mass by displacement of the additional mass body 12; a spring member 18 which is expanded or contracted by the displacement of the additional mass body 12; and a damping member 19 which damps the displacement of the additional mass body 12. A natural period of the additional mass body 12 is set larger than a natural period of the structure 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vibration damping device, and more particularly to a vibration damping device that is mounted on a structure such as a building to reduce vibrations. [Background technology]

[0002] Tuned mass dampers (TMDs), which are added mass dampers that are connected to the building via springs or other mechanisms, are well known as response control technologies for buildings due to wind, earthquakes, etc.

[0003] However, this TMD has some problems, such as the difficulty of adjusting the natural period of the TMD because it requires adjusting springs, etc. to synchronize the natural period of the TMD with the natural period of the building; while it is an effective method for response control to steady waves (floor vibration, etc.), it is not effective for non-steady waves such as earthquake motion; and the need to adjust the TMD period as part of maintenance to prevent deterioration of the building over time (cracks in the structure, etc.).

[0004] To solve these problems, Patent Document 1 discloses a system in which the natural period of an added-mass type vibration damping device is set to 2 to 10 times the natural period of the building, thereby eliminating the need to synchronize the natural period of the added mass with the natural period of the building and thereby achieving vibration damping effects.

[0005] However, this system has the problem that unless the mass of the added mass is more than 10% of the mass of the building, the vibration control effect cannot be expected to be very good. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-107290 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made based on the above technical background and has the following objectives. An object of the present invention is to provide a vibration damping device in which the natural period of an additional mass is set to be greater than the natural period of a structure, and which exhibits a large vibration damping effect even when the mass ratio of the additional mass to the structure is small. [Means for solving the problem]

[0008] The inventors of the present invention conducted extensive research to solve the above-mentioned problems and found that, in a vibration control device in which the natural period of an additional mass is set to be greater than the natural period of a structure, the damping mechanism connected to the additional mass includes a rotational inertia mass damper that generates rotational inertia mass due to displacement of the additional mass, a spring member that expands and contracts due to displacement of the additional mass, and a damping member that damps the displacement of the additional mass, and that this makes it possible to obtain great damping performance even if the mass ratio of the additional mass to the structure is small.

[0009] The present invention is based on the above findings and is specified as follows. That is, the present invention is Single A vibration damping device that is mounted on a structure and reduces vibrations of the structure, an additional mass; a support member that is installed on the structure and supports the additional mass so that the additional mass can be displaced in a horizontal direction; and a damping mechanism that is installed between the structure and the additional mass and absorbs vibration energy acting on the structure and limits displacement of the additional mass, the damping mechanism includes a rotary inertia mass damper that generates a rotary inertia mass by displacement of the additional mass body; a rotational inertia mass damper; a spring member that expands and contracts in response to displacement of the additional mass body, and a damping member that damps the displacement of the additional mass body, The vibration damping device is characterized in that the natural period of the additional mass body is set to be greater than the natural period of the structure. Here, as disclosed in Patent Document 1, for example, the natural period of the additional mass body is set to be 2 to 10 times the natural period of the structure.

[0010] The inventors of this invention further investigated the relationship between the mass ratio μ of the additional mass body to the structure and the damping performance by using the rotational inertia mass The ratio γ, the ratio of the damper's rotational inertia mass to the mass of the added mass, was varied and investigated. As a result, it was found that the larger γ, the better the damping performance, but even if γ is increased beyond 10, no improvement in damping performance can be expected.

[0011] Based on this finding, it is preferable to set the mass of the additional mass body and the rotational inertia mass of the rotational inertia mass damper in consideration of the ratio μ of the mass of the structure to the mass of the additional mass body and the ratio γ of the mass of the additional mass body to the rotational inertia mass of the rotational inertia mass damper.

[0012] Specifically, it is preferable that the ratio γ of the mass of the additional mass body to the rotational inertia mass of the rotational inertia mass damper is 10 or less.

[0013] Furthermore, it is preferable that the support member be of a pendulum type from the viewpoint of ease of adjusting the natural period. [Effects of the Invention]

[0014] According to this invention, in a vibration damping device in which the natural period of the additional mass is set to be greater than the natural period of the structure, a large vibration damping effect can be expected even if the mass ratio of the additional mass to the structure is small. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a front view showing an embodiment of the present invention. [Figure 2] FIG. 1 is a front view showing an example of a damping mechanism incorporated in a vibration damping device. [Figure 3]FIG. 10 is a front view showing another example of a damping mechanism incorporated in a vibration damping device. [Figure 4] FIG. 1 is a diagram showing a model of a structure and a vibration damping device mounted thereon. [Figure 5] 10 is a graph showing the optimum viscous damping constant versus mass ratio for a vibration control device incorporating a first type of damping mechanism. [Figure 6] 10 is a graph showing the optimum viscous damping constant versus mass ratio for a vibration control device incorporating a second type of damping mechanism. [Figure 7] 10 is a graph showing the optimum viscous damping constant versus mass ratio for a vibration control device incorporating a third type of damping mechanism. [Figure 8] FIG. 10 is a front view showing another example of the support member. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a schematic overall view of an embodiment of the present invention. In this embodiment, a vibration damping device 10 is mounted on the top of a building 11, which is usually called the rooftop, in the same manner as a conventional TMD. The building 11 on which the vibration damping device 10 is to be installed may be made of steel, reinforced concrete, steel reinforced concrete, wood, or the like, and may be either an existing or new building. Furthermore, the structure on which the vibration damping device 10 is mounted is not limited to a building, and may be a tower-like structure, a tank structure, or other structures.

[0017] The vibration control device 10 comprises an added mass 12, a support member 13 that is installed on the top of the building and supports the added mass 12 so that it can be displaced horizontally, and a damping mechanism 14 that absorbs the vibration energy of the building 11 and limits the displacement of the added mass 12.

[0018] 2 is a front view specifically showing the configuration of the vibration damping device 10. The additional mass 12 is made of, for example, steel and has a rectangular shape with an appropriate thickness. A plurality of support members 13 that support the additional mass 12 are installed on the building 11.

[0019] In the illustrated embodiment, a pendulum-type spherical sliding bearing is used as the bearing member 13. As is well known, the spherical sliding bearing 13 is a bearing that is fixed to the added mass 12 side and the building 11 side, respectively, and includes members 13a and 13b with opposing concave spherical surfaces 15, and a slider 16 that is sandwiched between the concave spherical surfaces 15. The added mass 12 is supported by this bearing member 13, and can be displaced in the horizontal direction. By using a pendulum-type bearing member 13, the natural period of the added mass 12 can be calculated from the radius of curvature of the concave spherical surface 15, making it easy to set the natural period.

[0020] The damping mechanism 14 includes a rotational inertia mass damper 17 that generates a rotational inertia mass in response to the displacement of the additional mass body 12, a spring member 18 that expands and contracts in response to the displacement of the additional mass body 12, and a damping member 19 made of an oil damper that damps the displacement of the additional mass body 12. The rotational inertia mass damper 17 includes a rotary weight 20 and a rotational force transmission mechanism 21 that transmits the displacement of the additional mass body 12 to the rotary weight 20 as a rotational force.

[0021] The oscillating weight 20 is supported on a shaft so as to be rotatable horizontally relative to the building 11. The rotational force transmission mechanism 21 includes a rack 22 that is provided so as to be movable horizontally relative to the building 11, and a gear train 23 that includes a pinion that rotates in mesh with the rack 22. The rack 22 has teeth on both sides in the longitudinal direction, and therefore the gear train 23 and oscillating weight 20 are provided on both sides of the rack 22.

[0022] Displacement of additional mass 12 causes rack 22 to move horizontally, and this horizontal movement is transmitted as a rotational force to oscillating weight 20 by gear train 23. This causes oscillating weight 20 to rotate, generating a rotational inertia mass. The rotational inertia mass generated by rotational inertia mass damper 17 is calculated from the moment of inertia of each gear that makes up gear train 23, the moment of inertia of oscillating weight 20, etc.

[0023] There are three types of configurations for the damping mechanism 14 equipped with the rotary inertia mass damper 17, spring member 18, and damping member 19 as described above. In the first type, as shown in Fig. 2(a), the spring member 18 and damping member 19 are arranged in parallel in the path that transmits the displacement of the added mass 12 to the rotary inertia mass damper 17; hereinafter, this type will be referred to as an M-CK type system.

[0024] As shown in Figure 2(b), the second type, in addition to the configuration of the first type M-CK type system, further includes an additional damping member 27 that expands and contracts in response to the movement of the rack 22, arranged in parallel with the rotary inertia mass damper 17; hereinafter, this type will be referred to as the MC-CK type system.

[0025] In the third type, as shown in FIG. 2(c), only spring members 18 are arranged in series in the path that transmits the displacement of the added mass 12 to the rotational inertia mass damper 17, and damping members 19 are arranged in parallel to the rotational inertia mass damper 17 and spring members 18. Hereinafter, this type will be referred to as the C_MK type system.

[0026] In FIG. 2, a gear train 23 (excluding pinions) made up of spur gears is shown as a component of the torque transmission mechanism 21, but a speed reducer can be used instead of such a gear train made up of spur gears. of It is preferable to use a device incorporating the planetary gear mechanism used (for example, "IB Series P2 Type" manufactured by Sumitomo Heavy Industries, Ltd.).

[0027] In this case, by connecting the shaft of the pinion that meshes with the rack to the output shaft of the reducer and connecting the shaft of the oscillating weight 20 to the input shaft, it is possible to increase the rotation speed of the oscillating weight 20. The helical gear used in the reducer is stronger than a spur gear, and furthermore, by using the reducer, it is possible to make the rotational force transmission mechanism 21 more compact.

[0028] 3 shows another embodiment of the rotary inertia mass damper 17. In this embodiment, a horizontally disposed ball screw 24 is used as the rotational force transmission mechanism 21. An end of the ball screw 24 is connected to a housing 25 that is provided so as to be horizontally movable relative to the building 11.

[0029] Oscillating weight 20 is provided on the outer periphery of ball screw 24. A nut threaded onto ball screw 24 is housed in housing 26 fixed to building 11, and oscillating weight 20 is fixed to this nut. When ball screw 24 moves horizontally due to the displacement of additional mass body 12, the nut rotates, causing oscillating weight 20 to rotate, thereby generating a rotational inertial mass.

[0030] When a ball screw 24 is used as this rotational force transmission mechanism 21, there are three types of damping mechanism 14, as in the case of the rack 22 and gear train 23 shown in Figure 2, and Figures 3(a), (b), and (c) show the M-CK type system, MC-CK type system, and C_MK type system, respectively.

[0031] Figure 4 shows a model of a vibration control device including each type of damping mechanism 14 described above. The models shown in (a), (b), and (c) correspond to the M-CK type system, the MC-CK type system, and the C_MK type system, respectively, and assume that the structure (building) in which the vibration control device is installed has eight stories (eight floors). M1 to M8 are the mass of each story, K1 to K8 are the rigidity of each story, m is the mass of the additional mass body 12, m d is the rotational inertia mass of the rotational inertia mass damper 17, c d is the damping coefficient of the damping member 19, k d and indicate the stiffness of the spring member 18.

[0032] In the model shown in Fig. 4, it is assumed that the bearing member supporting the added mass 12 is a laminated rubber bearing or the like having spring rigidity, and k indicates the spring rigidity. Also, Fig. 4(d) shows a model of the conventional vibration damping device disclosed in Patent Document 1 (hereinafter, this conventional type will be referred to as a C-type system).

[0033] For each model shown in Figure 4, the natural period (primary mode) of the structure (building) was set to 1.1 seconds, and the natural period of the added mass was set to 4 seconds, which is longer than the natural period of the structure, and an optimum design study was conducted using complex eigenvalue analysis. The results are shown in Figure 5 (M-CK type system), Figure 6 (MC-CK type system), and Figure 7 (C_MK type system). In each figure, the horizontal axis shows the mass ratio (mass of added mass / mass of building) μ, and the vertical axis shows the optimum viscous damping constant hopt.

[0034] Also, the rotational inertia mass m of the rotational inertia mass damper d The ratio of the mass m of the additional mass to the rotational inertia mass m of the rotary inertia mass damper d The mass ratio μ of the additional mass m was varied between 0.5 and 100, and the change in the optimum viscous damping constant hopt with respect to the mass ratio μ at each γ value was investigated.

[0035] According to the results of the study, it was found that the optimal viscous damping constant hopt increases as the mass ratio μ increases, and this is true for both the conventional C-type system and the M-CK-type system according to the present invention. However, it was found that the M-CK-type system according to the present invention can obtain a large optimal viscous damping constant hopt at a small mass ratio μ.

[0036] For example, as shown in Figure 5, when the mass ratio μ is 0.01 (1%), the damping added by a vibration control device using the conventional C-type system is 0.005 (0.5%), while the damping added by a vibration control device using the M-CK system is 0.03 to 0.05 (3 to 5%), meaning that the vibration control device using the M-CK system provides viscous damping that is approximately 6 to 10 times that of a vibration control device using the conventional C-type system.Furthermore, as shown in Figures 6 and 7, the MC-CK and C_MK type vibration control devices also provide viscous damping similar to that described above.

[0037] Therefore, according to this invention, in a vibration control device in which the natural period of the additional mass is set longer than the natural period of the structure, a large vibration control effect against earthquakes can be expected even if the mass ratio of the additional mass to the structure is small.

[0038] Furthermore, according to the results of the study, as shown in Figs. 5, 6 and 7, the rotational inertia mass m d The ratio of the mass m of the additional mass to the rotational inertia mass m of the rotary inertia mass damper d When the mass ratio μ (m) of the additional mass body is changed, the optimal viscous damping constant hopt increases with increasing γ value up to a value of 10, but when the γ value exceeds 10, no increase in the optimal viscous damping constant hopt is observed.

[0039] Therefore, when designing a vibration damping device, it is preferable to set the mass of the additional mass body and the rotational inertia mass of the rotational inertia mass damper taking into consideration the mass ratio μ and the ratio γ of the mass of the additional mass body to the rotational inertia mass of the rotational inertia mass damper, and it is particularly preferable to set the γ value to 10 or less.

[0040] 8 shows another embodiment of the support member. The support member 13 includes a support column 30 provided on the underside of the additional mass body 12, a guide rail 31 provided on the building 11 to support the support column 30 so that it can move (slide) horizontally, and a spring 32 provided between the additional mass body 12 and the building 11 to restore the additional mass body 12 to its original position if it is displaced horizontally. One or more springs 32 may be provided, and in this embodiment, the natural period of the additional mass body 12 is calculated from the stiffness of the spring 32.

[0041] In the above embodiment, an example was shown in which the vibration damping device according to the present invention was mounted on the top of a building, but this is not limiting and the vibration damping device can also be installed on the middle floors of a building, in which case multiple floors may be used. Furthermore, the bearing members are not limited to pendulum-type bearings such as spherical sliding bearings or those shown in FIG. 8, but laminated rubber bearings can also be used. Furthermore, the number of bearing members can be either single or multiple, depending on the shape of the structure in which the vibration damping device is to be installed. [Explanation of symbols]

[0042] 10: Vibration control device 11: Buildings (structures) 12: Additional mass 13: Support member 14: Damping mechanism 17: Rotating inertial mass damper 18: Spring material 19: Damping member 20: Oscillating weight 21: Rotational force transmission mechanism

Claims

1. A vibration control device mounted on a single structure to reduce vibration of the structure, comprising: an additional mass; a support member that is installed on the structure and supports the additional mass so that the additional mass can be displaced in a horizontal direction; and a damping mechanism that is installed between the structure and the additional mass and absorbs vibration energy acting on the structure and limits displacement of the additional mass, the damping mechanism comprises: a rotational inertia mass damper that generates a rotational inertia mass in response to a displacement of the additional mass body; a spring member that is provided in a path that transmits the displacement of the additional mass body to the rotational inertia mass damper and expands and contracts in response to the displacement of the additional mass body; and a damping member that damps the displacement of the additional mass body; A vibration damping device, characterized in that the natural period of the additional mass is set to be greater than the natural period of the structure.

2. 2. The vibration damping device according to claim 1, wherein a ratio γ of the mass of said additional mass body to the rotational inertia mass of said rotational inertia mass damper is set to 10 or less.

3. 2. The vibration damping device according to claim 1, wherein said support member is of a pendulum type.

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