Vibration damping mechanism

Abstract

To suppress occurrence of a nonlinear mechanical component in restoring force of a tension coil spring.SOLUTION: A damping device D installed on a damping target structure S includes: a vibrating body D1 having an arm part 11 that vibrates with the damping target structure S as a fulcrum, and a mass body 12 attached to the arm part 11; first and second tension coil springs D2a and D2b, each having the same spring constant, with one ends thereof locked to the arm part 11 at positions located on mutually opposite sides of the arm part 11 in a direction aligned with a vibration surface of the arm part 11; and first and second locking members D3a and D3b respectively lock the other ends of the first and second tension coil springs D2a and D2b. A distance L1 between two locking positions of the first tension coil spring D2a and a distance L2 between two locking positions of the second tension coil spring D2b are equal, and the mounting angles of the first and second tension coil springs D2a and D2b are set to 15° to 45°.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vibration control mechanism for suppressing vibrations occurring in a target structure. [Background technology]

[0002] For example, in beam- or plate-like structures that extend horizontally, such as bridges that allow roads and railways to pass over land obstacles, rivers, valleys, or the sea, and in tower-like structures such as high-rise buildings (structures to be controlled), the period of shaking during earthquakes or strong winds is long, and the shaking continues for some time even after the earthquake or strong winds have subsided.

[0003] Therefore, vibrations are controlled by installing vibration control means on the target structure. This device installs a vibrating body, which has an auxiliary mass attached via an arm that can vibrate with the target structure as a fulcrum, on the target structure, so that the vibrating body vibrates in a way that takes over the vibrations of the structure, thereby suppressing the resonance phenomenon around the natural frequency of the target structure.

[0004] Specifically, by installing vibration control means in which the direction of vibration of the vibrating body is perpendicular to the direction of vibration of the structure to be vibration-controlled and the vibration period of the vibrating body is half the natural period of the structure to be vibration-controlled, it becomes possible to reduce the vibration of the structure to be vibration-controlled.

[0005] In addition, technology for reducing vibrations of a structure to be damped using a vibration damping means that halves the vibration period of the vibrating body relative to the natural period of the structure to be damped is described in detail, for example, in Patent Publication No. 2020-148339. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2020-148339 Summary of the Invention [Problem to be solved by the invention]

[0007] Here, as a vibration control means, a structure in which tension coil springs are attached to both sides of the arm portion of the vibrating body in a direction coinciding with the vibration plane of the arm portion, and the vibrating body is vibrated by the restoring force of the tension coil springs, can be considered.

[0008] In such a structure using a tension coil spring, as the vibration angle of the vibrating body increases, a nonlinear mechanical component occurs in the restoring force of the tension coil spring, causing the linearity of the vibration to be lost and the period of the vibrating body to become longer or shorter. As a result, when the vibrating body vibrates significantly, the vibration control means is unable to control the vibration of the target structure.

[0009] The present invention has been made in view of the above-mentioned technical background, and an object of the present invention is to provide a vibration damping mechanism that can suppress the occurrence of nonlinear mechanical components in the restoring force of a tension coil spring used in a vibration damping means. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the vibration control mechanism of the present invention as set forth in claim 1 comprises a target structure to be damped, which has a predetermined natural frequency (f), and vibration control means that is installed on the target structure to be damped and is capable of vibrating in a direction intersecting the vibration direction of the target structure to be damped, and which has a natural frequency (f / 2) that is half the natural frequency (f) of the target structure to be damped, wherein the vibration control means comprises an arm portion that is installed on the target structure to be damped and is capable of vibrating around a rotation axis provided on the target structure to be damped as a fulcrum, a vibrating body that has a mass body attached to the arm portion, a first tension coil spring and a second tension coil spring that have the same spring constant and one end of which is engaged with the arm portion in a direction that coincides with the vibration plane of the arm portion and at positions opposite to each other across the arm portion, and a vibration damping mechanism that is connected to the first tension coil spring and the second tension coil spring. The vibration damping device has a first locking member and a second locking member that lock the other end of the coil spring, respectively; the distance between the locking position of the arm portion of the first tension coil spring and the locking position of the first locking member is equidistant from the distance between the locking position of the arm portion of the second tension coil spring and the locking position of the second locking member; and the angle formed by the axis of the first tension coil spring and a perpendicular line drawn from the locking point of the first locking member of the first tension coil spring toward the axis of the arm portion in a state perpendicular to the installation surface of the vibration damping target structure, and the angle formed by the axis of the second tension coil spring and a perpendicular line drawn from the locking point of the second locking member of the second tension coil spring toward the axis of the arm portion in a state perpendicular to the installation surface of the vibration damping target structure, are 15° to 45°.

[0011] In order to solve the above problems, the vibration control mechanism of the present invention as set forth in claim 2 comprises a target structure to be damped, which has a predetermined natural frequency (f), and vibration control means that is installed on the target structure to be damped and is capable of vibrating in a direction intersecting the vibration direction of the target structure to be damped, and which has a natural frequency (f / 2) that is half the natural frequency (f) of the target structure to be damped, wherein the vibration control means comprises an arm portion that is installed on the target structure to be damped and is capable of vibrating around a rotation axis provided on the target structure to be damped as a fulcrum, a vibrating body that includes a mass body attached to the arm portion, a first tension coil spring and a second tension coil spring that have the same spring constant and one end of which is engaged with the arm portion in a direction that coincides with the vibration plane of the arm portion and at positions opposite to each other across the arm portion, and a vibration damping mechanism that is configured to damp the first tension coil spring and the second tension coil spring. the distance between the locking position of the arm portion of the first tension coil spring and the locking position of the first locking member is equal to the distance between the locking position of the arm portion of the second tension coil spring and the locking position of the second locking member; and the angle formed by the axis of the first tension coil spring and a perpendicular line drawn from the locking point of the first locking member of the first tension coil spring toward the axis of the arm portion in a state perpendicular to the installation surface of the target structure, and the angle formed by the axis of the second tension coil spring and a perpendicular line drawn from the locking point of the second locking member of the second tension coil spring toward the axis of the arm portion in a state perpendicular to the installation surface of the target structure, are 30°±5°.

[0012] The vibration control mechanism of the present invention described in claim 3 is characterized in that, in the invention described in claim 1 or 2 above, the structure to be controlled is a beam-like or plate-like structure that extends horizontally and is supported at both ends, and the vibration control means is installed on the top or bottom surface of the structure to be controlled at a center position between the support positions at both ends, thereby suppressing vertical vibrations of the structure to be controlled.

[0013] The vibration control mechanism of the present invention described in claim 4 is characterized in that, in the invention described in claim 1 or 2 above, the structure to be damped is a beam-like or plate-like structure with a cantilever structure constructed extending horizontally and supported at only one end, and the vibration control means is installed on the upper or lower surface of the free end opposite the one end of the structure to be damped, thereby suppressing vertical vibrations of the structure to be damped.

[0014] The vibration control mechanism of the present invention described in claim 5 is characterized in that, in the invention described in claim 1 or 2 above, the structure to be damped is a tower-shaped structure, and the vibration control means is installed facing upward on the horizontal surface of the structure to be damped to suppress horizontal vibration of the structure to be damped.

[0015] The vibration control mechanism of the present invention as set forth in claim 6 is the invention as set forth in claim 5, characterized in that the vibration control means is installed at the top of the structure to be vibration-controlled.

[0016] The vibration control mechanism of the present invention described in claim 7 is characterized in that, in the invention described in claim 1 or 2 above, the structure to be damped is a tower-shaped structure, and the vibration control means is installed on the side of the structure to be damped to suppress horizontal or vertical vibrations of the structure to be damped.

[0017] The vibration damping mechanism of the present invention as set forth in claim 8 is characterized in that, in the invention as set forth in claim 7, the vibration damping means is installed on the upper side surface of the structure to be damped. [Effects of the Invention]

[0018] According to the present invention, it is possible to suppress the occurrence of nonlinear mechanical components in the restoring force of the tension coil spring used in the vibration damping means. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram showing a vibration damping mechanism according to an embodiment of the present invention. [Figure 2]10 is a graph showing the relationship between the tension coil spring and the deflection angle of the vibrating body. [Figure 3] 10A and 10B are diagrams illustrating the movements of a vibrating body and a tension coil spring when the inventor simulated the relationship between the mounting angle of the tension coil spring and the restoring force. [Figure 4] FIG. 1 is a diagram showing the relationship between the spring deflection angle and the spring force when the mounting angle of the tension coil spring is 0°, 15°, 30°, and 45°. [Figure 5] FIG. 1 is a diagram showing the relationship between the spring deflection angle and the arm length when the mounting angle of the tension coil spring is 0°, 15°, 30°, and 45°. [Figure 6] FIG. 1 is a diagram showing the relationship between the spring deflection angle and torque when the mounting angle of the tension coil spring is 0°, 15°, 30°, and 45°. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings for explaining the embodiment, the same components are generally designated by the same reference numerals, and repeated description thereof will be omitted.

[0021] Fig. 1 is a schematic diagram showing a vibration control mechanism according to one embodiment of the present invention. As shown in Fig. 1, a vibration control device (vibration control means) D constituting the vibration control mechanism of this embodiment is installed on the underside of a target structure S to be controlled, which is a beam-like or board-like structure extending horizontally, such as a bridge, which is an aerial structure built to allow roads, railways, etc. to pass over land obstacles, rivers, valleys, the sea, etc., and has the function of suppressing vertical vibrations of the target structure S to be controlled.

[0022] The vertical vibration of the target structure S is caused by strong winds due to earthquakes or typhoons, and in the case of bridges, by vehicles or trains passing over the bridge. These vertical vibrations have a long period of time, and continue for some time even after the earthquake or strong winds have subsided or the vehicle has passed.

[0023] A vibration damping device D for suppressing the vertical vibration of such a target structure S for vibration damping has a vibrating body D1, a tension coil spring D2, and a locking member D3.

[0024] In Fig. 1, vibrating body D1 comprises an arm 11 that is installed on the underside of a target structure S to be damped and vibrates around the target structure S as a fulcrum, and a mass 12 attached to arm 11. Because mass 12 is attached to arm 11 at its center of gravity, vibrating body D1 hangs down vertically in a free state (a state in which it is not constrained by the spring force of a tension coil spring D2, which will be described later). Arm 11 is attached to a mounting base 13 that is fixed to the target structure S to be damped by a pivot 14 so that it can rotate. This allows arm 11 to oscillate like a pendulum, with pivot 14 as a fulcrum.

[0025] The tension coil spring D2 is made up of a first tension coil spring D2a and a second tension coil spring D2b, each of which has one end engaged with the arm portion 11 in a direction that coincides with the vibration plane of the arm portion 11 and at positions opposite each other across the arm portion 11. The first tension coil spring D2a and the second tension coil spring D2b have the same spring constant, and are engaged by having one end hooked onto hooks 11a-1 provided on both sides of a large diameter portion 11a that constitutes part of the arm portion 11.

[0026] The locking members D3 are a first locking member D3a and a second locking member D3b provided on the first tension coil spring D2a and the second tension coil spring D2b, respectively, on the opposite side of the arm portion 11. The other end of the first tension coil spring D2a is locked to the first locking member D3a, and the other end of the second tension coil spring D2b is locked to the second locking member D3b.

[0027] As shown in the figure, the locking member D3 is composed of a bracket 31 fixed to the target structure S to be damped, a bolt 32 attached by passing through the bracket 31, a nut 33 screwed onto the bolt 32 so as to sandwich the bracket 31 from both sides, and a locking tool 34 attached to the end of the arm portion 11 of the bolt 32 and provided with a hook 34-1 on which the other end of the tension coil spring D2 is hooked. Then, the bolt 32 is fixed to the bracket 31 by the nut 33 sandwiching the bracket 31 from both sides.

[0028] 1, the length by which the bolt 32 of the first locking member D3a protrudes toward the arm portion 11 is the same as the length by which the bolt 32 of the second locking member D3b protrudes toward the arm portion 11. In other words, the distance L1 between the locking position of the first tension coil spring D2a with respect to the arm portion 11 (the position of the hook 11a-1 on which the first tension coil spring D2a is hooked) and the locking position of the first locking member D3a (the position of the hook 34-1 on which the first tension coil spring D2a is hooked) is the same as the distance L2 between the locking position of the second tension coil spring D2b with respect to the arm portion 11 (the position of the hook 11a-1 on which the second tension coil spring D2b is hooked) and the locking position of the second locking member D3b (the position of the hook 34-1 on which the second tension coil spring D2b is hooked). As described above, the first tension coil spring D2a and the second tension coil spring D2b have the same spring constant, and therefore the first tension coil spring D2a and the second tension coil spring D2b are pulled with the same strength.

[0029] As a result, the first tension coil spring D2a and the second tension coil spring D2b attempt to maintain balance, causing the vibrating body D1 to hang down vertically, and the restoring forces of the first tension coil spring D2a and the second tension coil spring D2b cause the vibrating body D1 to vibrate.

[0030] 2, in a structure using a tension coil spring D2, when the vibration body D1 does not vibrate greatly, linearity is maintained in the relationship between the vibration angle of the vibration body D1 and the tension coil spring D2. However, as the vibration angle of the vibration body D1 increases, a nonlinear mechanical component is generated in the restoring force of the tension coil spring D2, losing linearity and causing the period of the vibration body to become longer or shorter.

[0031] Specifically, as the mounting angle θ of the tension coil spring D2 (the angle between the axis A2 of the tension coil spring D2 and a perpendicular line P drawn from the locking point of the locking member D3 of the tension coil spring D2 toward the axis A1 of the arm section 11 when the arm section 11 is perpendicular to the installation surface of the target vibration-damping structure S) becomes smaller (as the mounting angle θ approaches 0°), the restoring force of the tension coil spring D2 weakens when the oscillation angle of the vibrating body D1 increases, the linearity of the vibration is lost, and the period of the vibrating body D1 becomes longer (the part shown by the dashed line in Figure 2). On the other hand, as the mounting angle θ of the tension coil spring D2 becomes larger (as the mounting angle θ approaches 90°), the restoring force of the tension coil spring D2 becomes stronger when the oscillation angle of the vibrating body D1 increases, the linearity of the vibration is lost, and the period of the vibrating body D1 becomes shorter (the part shown by the dashed line in Figure 2).

[0032] Therefore, the present inventors conducted a simulation of the relationship between the mounting angle θ of the tension coil spring D2 and the restoring force, and considered the optimal mounting angle θ. Here, Fig. 3 is a diagram illustrating the movements of the vibrating body and the tension coil spring when the present inventors conducted a simulation of the relationship between the mounting angle θ of the tension coil spring and the restoring force.

[0033] In FIG. 3, the part indicated by the thick line shows the positions of the vibrating body and the tension coil spring when the vibrating body is at the origin (a position perpendicular to the installation surface of the target vibration-damping structure), and the part indicated by the thin line shows the positions of the vibrating body and the tension coil spring when the vibrating body vibrates. Furthermore, point O is the pivot point of the vibrating body, point C is the center of gravity of the vibrating body at the origin, point C' is the center of gravity of the vibrating body during vibration, points P and Q are the attachment positions of the tension coil spring on the vibrating body side at the origin, points P' and Q' are the attachment positions of the tension coil spring on the vibrating body side during vibration, points S and R are the attachment positions (locking points) of the tension coil spring on the locking member side, line segment OA is the length component of line segment OC' on the extension side of the tension coil spring, line segment OB is the length component of the arm of line segment OC' on the compression side of the tension coil spring, line segment SP is the tension coil spring at the origin, line segment SP' is the tension coil spring in an extended state, line segment QR is the tension coil spring at the origin, and line segment G'R is the tension coil spring in a compressed state.

[0034] In Figure 3, torque is "arm length component x tension coil spring force," so the torque of the tension coil spring on the extension side is "SP' x OA," and the torque of the tension coil spring on the compression side is "Q'R x OB." Also, because the magnitude of OB is very small compared to OA, the torque of the tension coil spring on the compression side can be ignored, and the nonlinearity of the tension coil spring can be considered using only the parameters of the tension coil spring on the extension side.

[0035] The inventors performed simulations for tension coil spring mounting angles θ of 0°, 15°, 30°, and 45°, and calculated the tension coil spring force (OA), arm length (SP'), and torque (SP' x OA) for each angle. The results are shown in Figures 4, 5, and 6. The "Spring Force" graph in Figure 4 shows the relationship between the spring deflection angle and spring force for each mounting angle θ, the "Arm Length" graph in Figure 5 shows the relationship between the spring deflection angle and arm length for each mounting angle θ, and the "Torque" graph in Figure 6 shows the relationship between the spring deflection angle and torque for each mounting angle θ.

[0036] In the "torque" graph in Figure 6, when the graph approaches a straight line, the linearity of the spring is maintained. In other words, the linearity is maintained in the relationship between the deflection angle of the vibrating body D1 and the tension coil spring D2. When the mounting angle θ of the tension coil spring is 0°, the characteristic of the spring's restoring force weakening and the period of the vibrating body becoming longer is clearly observed. When the mounting angle θ of the tension coil spring is 15°, the characteristic of the spring's restoring force weakening and the period of the vibrating body becoming longer is slightly observed. When the mounting angle θ of the tension coil spring is 45°, the characteristic of the spring's restoring force strengthening and the period of the vibrating body becoming shorter is slightly observed. On the other hand, when the mounting angle θ of the tension coil spring is 30°, the graph is almost a straight line, and the spring's restoring force hardly changes, and the period of the vibrating body is stable.

[0037] Therefore, the mounting angle θ of the tension coil spring D2 (the angle formed by the perpendicular line P drawn from the locking point of the locking member D3 of the tension coil spring D2 toward the axis A1 of the arm section 11 when the tension coil spring D2 is perpendicular to the installation surface of the target vibration-damping structure S, and the axis A2 of the tension coil spring D2) should be set to 15° to 45°, which is the range in which nonlinearity does not become large in the graph of Fig. 6. Also, as mentioned above, the graph becomes almost linear when the mounting angle θ is 30°, but considering that it is difficult to set the mounting angle θ to 30° in the strict sense, it is preferable to set the mounting angle θ to 30°±5°.

[0038] From the above, by setting the mounting angle θ of the tension coil spring D2 (first tension coil spring D2a and second tension coil spring D2b) to 15° to 45°, preferably 30°±5°, it is possible to suppress the occurrence of nonlinear mechanical components in the restoring force of the tension coil spring D2 even when the vibrating body D1 vibrates greatly.

[0039] In the vibration control device D of this embodiment, the natural frequency generated by the vibration of the arm portion 11 is set to half the natural frequency of the vibration-control target structure S, as described below, thereby suppressing the vertical vibration of the vibration-control target structure S.

[0040] It is desirable to install the vibration control device D in a location where the vibration of the target structure S is at its maximum. In other words, if the target structure S has a doubly supported structure (a structure supported at both ends), the vibration control device D is installed so that the vibrating body D1 is located at the center of the support positions at both ends of the target structure S, and if it has a cantilevered structure (a structure supported at only one end), the vibration control device D is installed at the free end opposite the supported end. In this embodiment, it is assumed that the target structure S is doubly supported, and the vibration control device D is attached so that the vibrating body D1 is located at the center of the two support positions of the target structure S.

[0041] Here, the target structure S to be damped has a predetermined natural frequency (f), and the vibration control device D installed on this target structure S has a natural frequency (f / 2) that is half the natural frequency (f) of the target structure S. By adjusting the effective length of the arm portion 11 (the distance between the center of the mass body 12 and the rotation axis 14), the natural frequency of the vibration control device D can be set to f / 2. In other words, by moving the mass body 12 to a predetermined position on the arm portion 11, the effective length of the arm portion 11 can be changed, and the frequency of the vibration control device D can be set to f / 2.

[0042] In this application, the natural frequency (f / 2) of the vibration control device D does not mean a natural frequency that is exactly half the natural frequency of the vibration-control target structure S (i.e., a natural frequency that is the natural frequency f of the vibration-control target structure S multiplied by 0.5), but means a natural frequency that is approximately half the natural frequency of the vibration-control target structure S. This is because, although the vibration control effect of the vibration-control target structure S becomes extremely large when the natural frequency of the vibration control device D is exactly half the natural frequency of the vibration-control target structure S, an effective vibration control effect can be obtained even if it is not exactly half.

[0043] The invention made by the inventor has been specifically described above based on the embodiments, but the embodiments disclosed in this specification are illustrative in all respects and are not limited to the disclosed technology. In other words, the technical scope of the present invention should not be interpreted restrictively based on the description of the above embodiments, but should be interpreted solely in accordance with the claims, and includes technologies equivalent to the technologies described in the claims and all modifications that do not deviate from the gist of the claims.

[0044] For example, in this embodiment, a vibration control device D is installed on the underside of the structure S, which is a beam-like or plate-like structure constructed horizontally, to suppress vertical shaking (up and down vibration), but the vibration control device D may also be installed on the top surface of the structure S, which is the target of vibration control.

[0045] Furthermore, the vibration control target structure S may be a tower-like structure such as a mid- to high-rise building or a mid- to high-rise apartment building, and the vibration control device D may be installed facing upward on the horizontal surface of the vibration control target structure S to suppress lateral shaking (horizontal vibration). Note that, since tower-like structures tend to shake more greatly at higher points, it is desirable to install the vibration control device D at the top of the vibration control target structure S.

[0046] Furthermore, when the target structure S is a tower-like structure, the vibrating body D1 of the vibration control device D may be installed horizontally on the side of the target structure S. When installed in this manner, the vibrating body D1 is pulled from both sides by the first tension coil spring D2a and the second tension coil spring D2b and held horizontally. When installing the vibrating body D1 on the side of the target structure S, two possible installation modes are available: one in which the arm portion 11 is installed so that it can vibrate vertically, and one in which the arm portion 11 is installed so that it can vibrate horizontally. The former installation mode can suppress lateral vibration (horizontal vibration) of the tower-like structure, which is the target structure S, while the latter installation mode can suppress lateral vibration (horizontal vibration) and vertical vibration (up-down vibration) of the tower-like structure, which is the target structure S. When the target structure S is a tower-like structure, as mentioned above, higher parts tend to vibrate more significantly, so it is desirable to install the vibration control device D on the upper side of the target structure S. [Industrial Applicability]

[0047] In the vibration control mechanism of the present invention, the target structure to be controlled may be various structures other than buildings, such as elevators and plants that involve vibration, where vibration needs to be suppressed. [Explanation of symbols]

[0048] 11 Arm section 11a Large diameter part 11a-1 hook 12 mass body 13 Mounting base 14 Rotating shaft 31 Bracket 32 volts 33 Nut 34 Locking device 34-1 Hook A1 Axis of arm A2 Axis of tension coil spring D. Vibration control device (vibration control means) D1 vibrating body D2 tension coil spring D2a First tension coil spring D2b Second tension coil spring D3 Locking member D3a First locking member D3b Second locking member L1,L2 interval P is the perpendicular line drawn from the locking point of the locking member in the tension coil spring S Structure to be controlled

Claims

1. A vibration-damping target structure having a predetermined natural frequency (f); a vibration control means that is installed in the target structure and is capable of vibrating in a direction intersecting the vibration direction of the target structure and has a natural frequency (f / 2) that is half the natural frequency (f) of the target structure; The vibration damping means is a vibrating body including an arm portion that is installed on the target structure and can vibrate around a pivot shaft provided on the target structure side as a fulcrum, and a mass body attached to the arm portion; a first tension coil spring and a second tension coil spring, one ends of which are engaged with the arm portion in a direction coinciding with the vibration plane of the arm portion and at positions opposite to each other across the arm portion, the first tension coil spring and the second tension coil spring having the same spring constant; a first locking member and a second locking member that lock the other ends of the first tension coil spring and the second tension coil spring, respectively; a distance between a locking position of the arm portion of the first tension coil spring and a locking position of the first locking member is equal to a distance between a locking position of the arm portion of the second tension coil spring and a locking position of the second locking member, an angle formed by a perpendicular line drawn from the locking point of the first locking member of the first tension coil spring toward the axis of the arm portion in a state perpendicular to the installation surface of the vibration-damping target structure and the axis of the first tension coil spring, and an angle formed by a perpendicular line drawn from the locking point of the second locking member of the second tension coil spring toward the axis of the arm portion in a state perpendicular to the installation surface of the vibration-damping target structure and the axis of the second tension coil spring are 15° to 45°; A vibration damping mechanism characterized by:

2. A vibration-damping target structure having a predetermined natural frequency (f); a vibration control means that is installed in the target structure and is capable of vibrating in a direction intersecting the vibration direction of the target structure and has a natural frequency (f / 2) that is half the natural frequency (f) of the target structure; The vibration damping means is a vibrating body including an arm portion that is installed on the target structure and can vibrate around a pivot shaft provided on the target structure side as a fulcrum, and a mass body attached to the arm portion; a first tension coil spring and a second tension coil spring, one ends of which are engaged with the arm portion in a direction coinciding with the vibration plane of the arm portion and at positions opposite to each other across the arm portion, the first tension coil spring and the second tension coil spring having the same spring constant; a first locking member and a second locking member that lock the other ends of the first tension coil spring and the second tension coil spring, respectively; a distance between a locking position of the arm portion of the first tension coil spring and a locking position of the first locking member is equal to a distance between a locking position of the arm portion of the second tension coil spring and a locking position of the second locking member, an angle formed by a perpendicular line drawn from the locking point of the first locking member of the first tension coil spring toward the axis of the arm portion in a state perpendicular to the installation surface of the target vibration-damping structure and the axis of the first tension coil spring, and an angle formed by a perpendicular line drawn from the locking point of the second locking member of the second tension coil spring toward the axis of the arm portion in a state perpendicular to the installation surface of the target vibration-damping structure and the axis of the second tension coil spring are 30°±5°; A vibration damping mechanism characterized by:

3. The target vibration-damping structure is a beam-like or board-like structure that is constructed to extend horizontally and is supported at both ends, the vibration damping means is installed on the upper or lower surface of the target structure at a center position between support positions at both ends thereof to suppress vertical vibration of the target structure; 3. The vibration damping mechanism according to claim 1 or 2.

4. The target vibration-damping structure is a beam-like or plate-like structure that is constructed to extend horizontally and has a cantilever structure supported at only one end, the vibration damping means is installed on the upper or lower surface of the free end opposite to the one end of the vibration damping target structure to suppress vertical vibration of the vibration damping target structure; 3. The vibration damping mechanism according to claim 1 or 2.

5. the vibration-damping target structure is a tower-like structure, the vibration control means is installed facing upward on the horizontal surface of the vibration control target structure to suppress horizontal vibration of the vibration control target structure; 3. The vibration damping mechanism according to claim 1 or 2.

6. The vibration control means is installed on the top of the target structure.

6. The vibration damping mechanism according to claim 5.

7. the vibration-damping target structure is a tower-like structure, the vibration damping means is installed on a side surface of the target structure to be damped and suppresses horizontal vibration or vertical vibration of the target structure; 3. The vibration damping mechanism according to claim 1 or 2.

8. The vibration control means is installed on the upper side surface of the vibration control target structure.

8. The vibration damping mechanism according to claim 7.

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