Vibration control mechanism

Abstract

To provide a vibration control mechanism capable of suppressing a resonance phenomenon at a natural frequency of a structure to be vibration-controlled.SOLUTION: A vibration control device D is installed in a structure S to be vibration-controlled with a predetermined natural frequency (f), can vibrate in a direction crossing a vibration direction of the structure S to be vibration-controlled, and has a natural frequency (f / 2) that is half the natural frequency (f) of the structure S to be vibration-controlled. The vibration control device D comprises: a vibration unit D1 that is provided with a shaft part 11 that is rotatably supported by the structure S to be vibration-controlled and whose rotational axis is arranged parallel to a structural surface of the structure S to be vibration-controlled, and an arm part 12 to which a weight part 13 is attached and that vibrates so as to rotate the shaft part 11; and an adjustment unit that is provided with a torsion bar 21 of which one end is attached to the shaft part 11 and the other end is fixed to the structure S to be vibration-controlled, and that is twisted by the rotation of the shaft part 11, where the adjustment unit adjusts the vibration of arm part 12.SELECTED DRAWING: Figure 4

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, in recent years, in tower-like structures such as high-rise buildings that experience lateral sway (horizontal vibration), vibration control devices called tuned mass dampers (TMDs) have been installed on the top floors where the amplitude of vibration is greatest. This device adds an auxiliary mass (auxiliary mass) to the structure to be damped via a spring or other means, and the auxiliary mass vibrates in a way that takes over the vibration of the structure, thereby suppressing resonance around the natural frequency of the structure.

[0004] As a document relating to vibration damping devices, for example, Japanese Patent Application Laid-Open No. 10-082208 is known. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-082208 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in structures that extend horizontally, such as bridges, the structures tend to sway vertically (vibrate up and down), making it difficult to install the tuned mass dampers described above.

[0007] The present invention has been made in view of the above-mentioned technical background, and has as its object to provide a vibration control mechanism capable of suppressing the resonance phenomenon at the natural frequency of a structure to be vibration-controlled. [Means for solving the problem]

[0008] In order to solve the above problem, the vibration control mechanism of the present invention described in claim 1 comprises a target structure to be damped, which has a predetermined natural frequency (f), and vibration control means installed on the target structure to be damped, which 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 axle section that is rotatably supported on the target structure to be damped and whose rotation axis is arranged parallel to the structural surface of the target structure to be damped, an arm section that is attached to the axle section so as to be perpendicular to the rotation axis and vibrates to rotate the axle section, and a vibrating section that has a weight section attached to the arm section, and an adjustment section that has one end attached to the axle section and the other end fixed to the target structure to be damped, which is provided with a torsion member that twists when the axle section rotates, and which adjusts the vibration of the arm section.

[0009] The vibration control mechanism of the present invention described in claim 2 is characterized in that, in the invention described in claim 1, the vibration direction of the arm portion constituting the vibration control means is perpendicular to the vibration direction of the structure to be controlled.

[0010] A vibration damping mechanism of the present invention as set forth in claim 3 is the invention as set forth in claim 1 or 2, characterized in that the torsion members are provided on both sides or one side of the shaft portion.

[0011] The vibration damping mechanism of the present invention described in claim 4 is characterized in that, in the invention described in claim 1 or 2, the torsional rigidity of the torsion member is set from the effective length of the arm portion, which is the length between the center of gravity of the weight portion and the axis of the shaft portion, and the mass of the weight portion, so that the swing angle of the arm portion can be guaranteed to be isochronous and the frequency is f / 2.

[0012] The vibration damping mechanism of the present invention described in claim 5 is characterized in that, in the invention described in claim 3, the torsional rigidity of the torsion member is set from the effective length of the arm portion, which is the length between the center of gravity of the weight portion and the axis of the shaft portion, and the mass of the weight portion, so that the swing angle of the arm portion can be ensured to be isochronous and the frequency is f / 2.

[0013] A vibration damping mechanism of the present invention as set forth in claim 6 is the invention as set forth in claim 1 or 2, characterized in that the torsion member is a torsion bar.

[0014] A vibration damping mechanism of the present invention as set forth in claim 7 is the invention as set forth in claim 3, characterized in that the torsion member is a torsion bar.

[0015] The vibration damping mechanism of the present invention described in claim 8 is characterized in that, in the invention described in claim 6, a support part is movably provided at an intermediate position of the torsion bar to set the twistable length of the torsion bar, which is the length from the connection position with the shaft part, and the twistable length of the torsion bar is changed by moving the support part, thereby adjusting the vibration frequency of the arm part to f / 2.

[0016] The vibration damping mechanism of the present invention described in claim 9 is characterized in that, in the invention described in claim 7, a support part is movably provided at an intermediate position of the torsion bar to set the twistable length of the torsion bar, which is the length from the connection position with the shaft part, and the twistable length of the torsion bar is changed by moving the support part, thereby adjusting the vibration frequency of the arm part to f / 2.

[0017] A vibration damping mechanism of the present invention described in claim 10 is the invention described in claim 1 or 2, characterized in that the torsion member is a torsion coil spring.

[0018] The vibration damping mechanism of the present invention described in claim 11 is the invention described in claim 3, characterized in that the torsion member is a torsion coil spring.

[0019] The vibration damping mechanism of the present invention described in claim 12 is characterized in that, in the invention described in claim 1, the weight portion is movable in the length direction of the arm portion, and the effective length of the arm portion is changed by moving the weight portion, thereby adjusting the vibration frequency of the arm portion to f / 2.

[0020] The vibration control mechanism of the present invention described in claim 13 is characterized in that, in the invention described in claim 1 above, the structure to be damped is a beam-like or plate-like structure extending horizontally, and the vibration control means is installed on the underside of the structure to be damped to damp up and down vibrations of the structure to be damped.

[0021] The vibration control mechanism of the present invention described in claim 14 is characterized in that, in the invention described in claim 1 above, the structure to be damped is a beam-like or plate-like structure extending horizontally, and the vibration control means is installed on the upper surface side of the structure to be damped to damp the vertical vibrations of the structure to be damped.

[0022] The vibration control mechanism of the present invention described in claim 15 is characterized in that, in the invention described in claim 13 or 14, the structure to be damped has a doubly supported structure supported at both ends, and the vibration control means has the arm portion installed at a center position between the support positions at both ends of the structure to be damped.

[0023] The vibration control mechanism of the present invention described in claim 16 is characterized in that, in the invention described in claim 13 or 14, the structure to be controlled has a cantilever structure supported at only one end, and the vibration control means is installed at the free end opposite to the one end of the structure to be controlled.

[0024] The vibration control mechanism of the present invention described in claim 17 is characterized in that, in the invention described in claim 1, 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 damp horizontal vibrations of the structure to be damped.

[0025] The vibration control mechanism of the present invention as set forth in claim 18 is characterized in that, in the invention as set forth in claim 17, the vibration control means is installed at the upper end of the structure to be vibration-controlled. [Effects of the Invention]

[0026] According to the present invention, by setting the natural frequency of a vibration control means having an arm portion that vibrates to rotate an axis portion whose rotation axis is arranged parallel to the structural surface of the vibration-control target structure to half the natural frequency of the vibration-control target structure, it becomes possible to suppress resonance phenomena at the natural frequency of the vibration-control target structure. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic diagram showing a vibration damping mechanism according to an embodiment of the present invention. [Figure 2] 2A and 2B are schematic diagrams illustrating the vibration of the arm of the vibration damping device in the vibration damping mechanism of FIG. 1, where FIG. 2A shows the arm swinging toward the front of the drawing, and FIG. 2B shows the arm swinging toward the back of the drawing. [Figure 3] 2 is a schematic diagram showing a test specimen prepared for verifying vibration damping by the vibration damping device in the vibration damping mechanism of FIG. 1. FIG. [Figure 4] 4A is a graph showing the acceleration generated in the beam when the arm constituting the vibration damping device of FIG. 3 is allowed to vibrate freely, and FIG. 4B is a graph showing the swing angle of the arm. [Figure 5](a) is the Fourier spectrum of the acceleration of the beam in Figure 4(a), and (b) is the Fourier spectrum of the vibration of the arm in Figure 4(b). [Figure 6] 4A is a graph showing a resonance curve obtained from the maximum value of the time series of response acceleration, and FIG. 4B is a graph showing a phase curve, when the arm portion constituting the vibration damping device of FIG. 3 is in operation and when it is not in operation. [Figure 7] 4A is a graph showing the response acceleration of the beam, and FIG. 4B is a graph showing the swing angle of the arm when the input acceleration of the piezoelectric actuator that constitutes the vibration damping device of FIG. 3 is 0.29 m / s 2 . [Figure 8] 4A is a graph showing the response acceleration of the beam, and FIG. 4B is a graph showing the deflection angle of the arm when the input acceleration of the piezoelectric actuator that constitutes the vibration damping device of FIG. 3 is 0.37 m / s 2 . [Figure 9] 4 is a graph showing the relationship between the input acceleration of the arm and the response acceleration of the beam at the natural frequency of the beam in the vibration damping device of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0028] 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.

[0029] As shown in Figure 1, the vibration control device (vibration control means) D that constitutes the vibration control mechanism of this embodiment is installed on the underside of the target structure S to be vibration controlled, which is a beam-like or plate-like structure that extends horizontally, such as a bridge, which is an aerial structure built to allow roads, railways, etc. to pass over land obstacles, rivers, valleys, seas, etc., and has the function of damping the up and down vibrations of the target structure S to be vibration controlled.

[0030] 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.

[0031] The vibration damping device D of this embodiment for suppressing the vertical vibration of such a target structure S for vibration damping is composed of a vibration section D1 and an adjustment section D2.

[0032] The vibrating part D1 is provided with a shaft part 11 that is rotatably supported by a pair of bearings Sa attached to the target structure S to be damped and whose rotation axis is arranged parallel to the structural surface of the target structure S to be damped, an arm part 12 (see FIG. 2) that is attached to the shaft part 11 so as to be perpendicular to the rotation axis of the shaft part 11 and vibrates to rotate the shaft part 11, and a weight part 13 attached to the arm part 12. Note that in this embodiment, the arm part 12 is attached to the shaft part 11 via a connecting block 12a, but it may also be attached directly without the connecting block 12a.

[0033] The adjustment unit D2 is provided with a torsion bar (torsion member) 21, one end of which is attached to the shaft 11 and the other end of which is fixed to the vibration-damping target structure S (more specifically, a support plate Sb attached to the vibration-damping target structure S), which is twisted by the rotation of the shaft 11, and the vibration of the arm unit 12 is adjusted by the torsion bar 21.

[0034] In this embodiment, weight 13 is movable in the length direction of arm 12, and can be fixed to a desired position on arm 12 by a fixing member such as a fixing pin (not shown). However, as will be described later, if there is no need to move weight 13 in adjusting the natural frequency of vibration damping device D, weight 13 may be immovable. Also, although torsion bar 21 is provided on only one side of shaft 11, it may be provided on both sides of shaft 11.

[0035] Here, the torsion bar 21 constituting the adjustment part D2 is a type of spring that utilizes a repulsive force when the torsion bar 21 is twisted, and the repulsive force depends on the torsional rigidity of the torsion bar 21. In this embodiment, the torsion bar 21 is made of a solid steel rod, but it may also be hollow (steel pipe).

[0036] 2(a), when the arm portion 12 swings toward the front of the drawing, the torsion bar 21 is twisted in the circumferential direction by the shaft portion 11 that is rotated by the arm portion 12. Also, as shown in FIG. 2(b), when the arm portion 12 swings toward the back of the drawing, the torsion bar 21 is twisted in the circumferential direction opposite to that described above by the shaft portion 11 that is rotated by the arm portion 12.

[0037] In the vibration control device D, the natural frequency generated by the vibration of the arm portion 12 is set as described below, thereby damping the vibration of the target structure S in the vertical direction.

[0038] Here, in order to damp the vertical vibrations of the vibration-damping target structure S, which is constructed to extend horizontally, the aforementioned vibration-damping device D is installed so that the vibration direction of the arm portion 12 that constitutes the vibration-damping device D is perpendicular to the vibration direction of the vibration-damping target structure S.

[0039] It should be noted that the vibration direction of the arm portion 12 and the vibration direction of the vibration-damping target structure S need only intersect, and are not limited to being perpendicular as in this embodiment. However, as will be described later, if they are perpendicular, the vibration damping effect of the vibration-damping target structure S will be extremely large, so it is desirable that the vibration direction of the arm portion 12 and the vibration direction of the vibration-damping target structure S be perpendicular.

[0040] The vibration control device D is installed at 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 arm portion 12 is located at the center of the support positions F (FIG. 1) at both ends of the target structure S, and if the target structure S 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, the target structure S is assumed to be doubly supported, and the vibration control device D is attached so that the arm portion 12 is located at the center of the two support positions F of the target structure S.

[0041] Furthermore, the target structure S has a predetermined natural frequency (f), but 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. The natural frequency of the vibration control device D can be set to f / 2 by applying either or both of the setting of the torsional rigidity of the torsion bar 21 (the repulsive force against torsion of the torsion bar 21) and the setting of the effective length of the arm portion 12 (the length between the center of gravity of the weight portion 13 and the axis of the shaft portion 11).

[0042] That is, setting the torsional rigidity of the torsion bar 21 means setting the torsional rigidity of the torsion bar 21 from the effective length of the arm 12 and the mass of the weight 13 so that the oscillation angle of the vibrating part D1 (i.e., the oscillation angle of the arm 12) can be ensured to be isochronous and the frequency of the vibrating part D1 is f / 2. Also, setting the effective length of the arm 12 means changing the effective length of the arm 12 by moving the weight 13 to a predetermined position, thereby setting the frequency of the arm 12 to f / 2. Note that in this embodiment where the torsion member is the torsion bar 21, a support part (not shown) that sets the torsional length of the torsion bar 21 (i.e., the length from the connection position with the shaft 11) may be provided movably at a midpoint of the torsion bar 21, and the torsional length of the torsion bar 21 may be changed by moving the support part, thereby adjusting the frequency of the arm 12 to f / 2.

[0043] 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.

[0044] Next, we will explain how, in the vibration control mechanism of this embodiment, the vibration of the target structure S is suppressed by the vibration control device D, which has a natural frequency (f / 2) that is half the natural frequency (f) of the target structure S, which vibrates in the vertical direction. Here, we created a test specimen T of the vibration control mechanism as shown in Figure 3 and performed verification.

[0045] In Figure 3, beam B corresponds to the target structure S to be damped. Support bases Fa are provided on both ends of beam B to rotatably support a pair of support arms 14. A vibrator consisting of a piezoelectric actuator P to which a load mass M is attached is fixed to beam B in order to vibrate beam B up and down. The other components are the same as those in Figure 1.

[0046] In the specimen T shown in Figure 3, beam B was made of an iron plate with a length (length between both supported ends) of 853 mm, a width of 100 mm, a thickness of 6 mm, and a weight of 3.978 kg. The arm 12 located at the center of beam B is 70 mm long and weighs 45 g. The weight 13 is 30 mm long and weighs 48 g, and the total weight of the shaft 11 and support arm 14 is 195 g. The weight of the load mass M is 394 g, and the weight of the piezoelectric actuator P is 206 g, so the total weight of the vibrator, including both, is 600 g. The vibrator was installed 70 mm away from the center of beam B. In order to synchronize the arm 12 with the natural frequency of the beam B, the position of the weight 13 (the length from the radial lower end of the shaft 11 to the center of the weight 13 when the weight 13 is at the top or bottom) can be changed from 25 mm to 60 mm, and the natural period of the arm 12 can be adjusted in the range of 6.9 Hz to 12.3 Hz. The piezoelectric actuator P generates a displacement of 8.0 x 10 with an input voltage of 5 V. -5 It is manufactured in m.

[0047] Now, Fig. 4(a) shows the acceleration generated in beam B when a forced displacement is applied to arm 12 of test specimen T shown in Fig. 3, causing arm 12 to vibrate freely, and Fig. 4(b) shows the swing angle of arm 12. In Fig. 4, the vibration of beam B continues for 15.5 seconds, and the vibration of arm 12 continues for 4.58 seconds. It can also be seen that the vibration of arm 12 excites the vibration of beam B, so that the vibration of beam B and the vibration of arm 12 are synchronized.

[0048] The acceleration Fourier spectrum of beam B in Figure 4(a) is shown in Figure 5(a), and the Fourier spectrum of the vibration of arm section 12 in Figure 4(b) is shown in Figure 5(b). The natural frequency of beam B is 16.2 Hz, and the natural frequency of arm section 12 is 8.06 Hz, so the natural frequency of beam B and the natural frequency of arm section 12 are tuned at a ratio of 1:2.

[0049] Here, in order to understand the vibration damping effect of the arm portion 12, a resonance experiment was carried out when the arm portion 12 was in operation and when it was not in operation. The input acceleration of the piezo actuator P was 0.29 m / s 2Measurements were taken for 100 seconds from the time when the vibration of Beam B was determined to be in a steady state. The excitation frequency range was set to 16.05 Hz to 16.3 Hz based on Beam B's natural frequency. Because Beam B's damping constant is very small, the frequency was increased in 0.01 Hz increments. Figure 6(a) shows the resonance curve obtained from the maximum value of the time series of response acceleration. In Figure 6(a), the arm 12 does not vibrate at frequencies below 16.05 Hz and above 16.30 Hz, so the response acceleration of Beam B is constant. When Arm 12 does not vibrate, the natural frequency is 16.16 Hz, which is 0.04 Hz lower than the natural frequency obtained from the free vibration experiment. Furthermore, the phase curve shown in Figure 6(b) indicates that at 16.16 Hz, the phase of Beam B lags approximately 90° behind the phase of Piezoelectric Actuator P, confirming that the natural frequency (f) of Beam B is 16.16 Hz.

[0050] As shown in the resonance curve in Figure 6(a), when the arm section 12 vibrates between 16.13 Hz and 16.23 Hz, the response acceleration is smaller than when the arm section 12 does not vibrate. At the natural frequency, the amplitude ratio when the arm section 12 does not vibrate is 30 times, and when it vibrates it is 15 times, which shows that the response acceleration of beam B is reduced to about half.

[0051] Next, the input acceleration of the piezo actuator P is 0.29 m / s 2 7(a) shows the response acceleration of beam B, and Fig. 7(b) shows the deflection angle of arm section 12. In Fig. 7(a) and (b), the excitation frequency of piezo actuator P is 16.16 Hz, and in Fig. 7(b), the time when arm section 12 starts vibrating (manual vibration start) is 22.4 seconds after the start of voltage application to piezo actuator P.

[0052] In FIG. 7, the acceleration of beam B when arm 12 does not vibrate is 9.08 m / s 2The amplitude ratio to the input is 31.3 times. Also, when the arm 12 is vibrated 22.4 seconds after the start of voltage application to the piezo actuator P, the deflection angle of the arm 12 gradually increases, reaching a maximum value at 26.2 seconds, then gradually decreases, reaching a minimum at 38 seconds, and the deflection angle also shows a tendency to gradually increase. In this way, when the acceleration of the beam B is 3.98 m / s 2 When the arm portion 12 approaches this point, the vibration of the arm portion 12 decreases.

[0053] In this way, near the limit acceleration at which arm portion 12 vibrates, as the swing angle of arm portion 12 increases, the acceleration of beam B decreases, and as the acceleration of beam B decreases, the swing angle of arm portion 12 decreases again and the acceleration of beam B increases.

[0054] The input acceleration of the piezo actuator P is 0.37 m / s 2 8(a) shows the response acceleration of beam B, and Fig. 8(b) shows the deflection angle of arm section 12. In Fig. 8(a) and (b), the excitation frequency of piezo actuator P is 16.16 Hz, and in Fig. 8(b), the time when arm section 12 starts vibrating (manual vibration start) is 22.3 seconds after the start of voltage application to piezo actuator P.

[0055] In FIG. 8, when the arm portion 12 does not vibrate, the acceleration of the beam B is 10.4 m / s 2 The amplitude ratio is 28.1 times. When a stimulus is applied to arm 12 at 22.3 seconds, arm 12 reaches its maximum amplitude in about 1 second, gradually decreases until about 37 seconds, and then vibrates steadily. The acceleration of beam B also decreases at the same time as arm 12 starts vibrating, reaching 4.28 m / s at about 37 seconds. 2 and then oscillates steadily.

[0056] Thus, the acceleration of beam B is 3.98 m / s 2 In this case, the vibration of the arm 12 and the beam B shows a beat-like phenomenon (Fig. 7), and the vibration is 4.28 m / s 2In this case, the vibration of the arm 12 is steady (Fig. 8). Therefore, the limit acceleration of the beam B that causes the arm 12 to vibrate is 4 m / s 2 It is thought that this is the case.

[0057] Figure 9 shows the relationship between the input acceleration of arm section 12 and the response acceleration of beam B at the natural frequency of beam B (f = 16.16 Hz: resonance point). As shown in the figure, the acceleration of beam B when arm section 12 vibrates is reduced to about half compared to when arm section 12 does not vibrate. Furthermore, the rate of reduction tends to increase as the input acceleration of arm section 12 increases.

[0058] From the above, by vibrating the arm portion 12 which is tuned to a frequency which is half the natural frequency (f) of the beam vibrating in the vertical direction (f=16.16 Hz in this embodiment), that is, by using the vibration control device D which has a natural frequency (f / 2) which is half the natural frequency (f) of the vibration control target structure S which vibrates in the vertical direction, it becomes possible to suppress the vibration of the vibration control target structure S.

[0059] 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.

[0060] For example, vibration control effects can be achieved by setting the natural frequency of the vibration control device D to half (f / 2) of the natural frequency (f) of the structure S to be controlled, but the "half of the natural frequency" here does not necessarily have to be half in the strict sense.

[0061] Furthermore, although the present embodiment uses a torsion bar 21 as the torsion member, a torsion coil spring (a coil spring that receives a torsional moment around the central axis of the coil) may also be used. Note that when a torsion coil spring is used, it is considered structurally difficult to set the torsional length by providing a movable support portion as in the case of the torsion bar 21, and to adjust the vibration frequency of the arm portion 12 to f / 2 by changing the torsional length.

[0062] In addition, in this embodiment, the vibration control device D is installed on the underside of the structure S to be vibration controlled, but it does not have to be on the underside and may be installed on the upper side of the structure S to be vibration controlled.

[0063] In addition, in this embodiment, the vibration control device D is arranged so that the rotation axis of the shaft portion 11 faces the support position F of the structure S to be vibration-controlled, but the arrangement direction of the vibration control device D is not particularly limited.

[0064] Furthermore, the vibration-damping target structure S is not limited to structures that experience vertical sway (up-and-down vibration), but can also be applied to tower-shaped vibration-damping target structures S, such as high-rise buildings, that experience lateral sway (horizontal vibration). In other words, if the vibration-damping device D is installed on the side of the vibration-damping target structure S, it is possible to attenuate the horizontal vibration of the vibration-damping target structure S. In this case, it is desirable to install the vibration-damping device D on the upper end of the side of the tower-shaped vibration-damping target structure S, where the sway (vibration) is greatest. [Industrial Applicability]

[0065] In the vibration control mechanism of the present invention, the structures to be controlled are not limited to structures that experience vertical sway (up and down vibration), but can also be applied to tower-like structures such as high-rise buildings that experience lateral sway (horizontal vibration). [Explanation of symbols]

[0066] 11 Shaft 12 Arm section 13 Weight 14 Support arm 21 Torsion bar (torsion member) B beam D. Vibration control device (vibration control means) D1 Vibrating part D2 adjustment section M Load mass F Support position Fa support stand P Piezo Actuator S Structure to be controlled Sa bearing Sb support plate T test specimen

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 shaft portion that is rotatably supported on the target structure and has a rotation axis that is arranged parallel to the structural surface of the target structure, an arm portion that is attached to the shaft portion so as to be perpendicular to the rotation axis and that vibrates to rotate the shaft portion, and a vibration portion that is provided with a weight portion attached to the arm portion; an adjustment unit having a torsion member attached to the shaft portion at one end and fixed to the target vibration-damping structure at the other end, the torsion member being twisted by the rotation of the shaft portion, and adjusting the vibration of the arm portion; A vibration damping mechanism characterized by:

2. The vibration direction of the arm portion constituting the vibration damping means is perpendicular to the vibration direction of the target structure.

2. The vibration damping mechanism according to claim 1.

3. The torsion member is Provided on both sides or one side of the shaft portion, 3. The vibration damping mechanism according to claim 1 or 2.

4. The torsional rigidity of the torsion member is set based on the effective length of the arm portion, which is the length between the center of gravity of the weight portion and the axis of the shaft portion, and the mass of the weight portion, so that the swing angle of the arm portion can be isochronous and the frequency is f / 2.

3. The vibration damping mechanism according to claim 1 or 2.

5. The torsional rigidity of the torsion member is set based on the effective length of the arm portion, which is the length between the center of gravity of the weight portion and the axis of the shaft portion, and the mass of the weight portion, so that the swing angle of the arm portion can be isochronous and the frequency is f / 2.

4. The vibration damping mechanism according to claim 3.

6. The torsion member is a torsion bar.

3. The vibration damping mechanism according to claim 1 or 2.

7. The torsion member is a torsion bar.

4. The vibration damping mechanism according to claim 3.

8. a support portion that sets the length of the torsion bar from the connection position with the shaft portion, which is the length of the torsion bar that can be twisted, is movably provided at an intermediate position of the torsion bar; The length of twisting of the torsion bar is changed by moving the support portion, and the vibration frequency of the arm portion is adjusted to f / 2.

7. The vibration damping mechanism according to claim 6.

9. a support portion that sets the length of the torsion bar from the connection position with the shaft portion, which is the length of the torsion bar that can be twisted, is movably provided at an intermediate position of the torsion bar; The length of twisting of the torsion bar is changed by moving the support portion, and the vibration frequency of the arm portion is adjusted to f / 2.

8. The vibration damping mechanism according to claim 7.

10. The torsion member is a torsion coil spring.

3. The vibration damping mechanism according to claim 1 or 2.

11. The torsion member is a torsion coil spring.

4. The vibration damping mechanism according to claim 3.

12. The weight portion is movable in the length direction of the arm portion, The effective length of the arm portion is changed by moving the weight portion, and the vibration frequency of the arm portion is adjusted to be f / 2.

2. The vibration damping mechanism according to claim 1.

13. The target structure to be damped is a beam-like or board-like structure extending horizontally, the vibration damping means is installed on the underside of the target structure to be damped and damps vertical vibrations of the target structure to be damped; 2. The vibration damping mechanism according to claim 1.

14. The target structure to be damped is a beam-like or board-like structure extending horizontally, the vibration damping means is installed on the upper surface side of the vibration-damping target structure to damp vertical vibrations of the vibration-damping target structure; 2. The vibration damping mechanism according to claim 1.

15. The target structure to be damped has a double-supported structure supported at both ends, The vibration damping means is arranged such that the arm portion is installed at a center position between support positions at both ends of the target structure.

15. The vibration damping mechanism according to claim 13 or 14.

16. The target structure to be damped has a cantilever structure supported only at one end, The vibration damping means is installed at a free end opposite to the one end of the vibration damping target structure.

15. The vibration damping mechanism according to claim 13 or 14.

17. 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 damps horizontal vibrations of the target structure to be damped; 2. The vibration damping mechanism according to claim 1.

18. The vibration control means is installed at the upper end of the vibration control target structure.

18. The vibration damping mechanism according to claim 17.

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