Cantilever type synchronization mass damper

Abstract

To provide a cantilever type synchronization mass damper that does not require any change in components when adjusting a natural frequency and does not involve a risk of the overall dimensions becoming large.SOLUTION: A cantilever type synchronization mass damper 50 comprises a frame 10 that is installed on a component of a building, a coupling member 20 whose one end 22 is cantilever-fixed directly or indirectly to the frame 10, and a mass 30 that is fixed to the other end 24 of the coupling member 20, where a cross-sectional shape perpendicular to a longitudinal direction of the coupling member 20 is a multiple-rotationally symmetric cross-section, and by rotating the coupling member 20 around a rotation axis L1 along the longitudinal direction, the moment of inertia of area with respect to a reference line L2 perpendicular to a vibration direction passing through a centroid P1 of the cross-sectional shape of the coupling member 20 is changed, thereby adjusting a vibration frequency of the synchronization mass damper 50.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cantilever type tuned mass damper.

Background Art

[0002] On the floor of a building (or a structure), there are always minute vibrations caused by the so-called environmental vibrations, such as the minute vibrations of the earth itself, traffic vibrations caused by the running of vehicles including trains, vibrations during the operation of factory equipment, vibrations caused by wind loads, and further vibrations caused by walking indoors. In order to reduce the minute vibrations (acceleration) of such a floor, a tuned mass damper (TMD) may be installed on the floor or the beams supporting the floor.

[0003] The tuned mass damper needs to be adjusted to a natural frequency effective for vibration reduction in accordance with the natural frequency of the building, which is the object of vibration reduction, or the floor, which is a component thereof. The natural frequency of this tuned mass damper is inversely proportional to the square root of the mass of the mass, which is a component thereof, and is proportional to the square root of the rigidity of the connecting member that connects the gantry and the mass and vibrates. Therefore, as a general method for adjusting the natural frequency, there are adjustment of the mass of the mass, adjustment of the rigidity of the connecting member, and further adjustment of both.

[0004] Among these, as a method for adjusting the mass of the mass, for example, a method of preparing a plurality of masses and adjusting by increasing or decreasing the number of masses can be mentioned. On the other hand, as a method for adjusting the rigidity of the connecting member, for example, a method of preparing a plurality of connecting members having different lengths and cross-sectional areas and selecting a connecting member having a rigidity that gives a desired natural frequency, or a method of changing the effective length of the connecting member by changing the attachment position of the mass to the connecting member can be mentioned.

[0005] Thus, the conventional method for adjusting the natural frequency of a tuned mass damper requires an increase or decrease in the number of components or a change in components, such as an increase or decrease in mass or a change in connecting members with different stiffness. Therefore, every time the natural frequency is adjusted, the arrangement of the components needs to be adjusted, which poses a problem. In addition, when changing the attachment position of the mass to the connecting member, it is necessary to set the attachment position in various ways, which naturally increases the length (space) of the connecting member, resulting in an increase in the overall dimensions of the tuned mass damper.

[0006] Here, Patent Document 1 also proposes a vibration damping device that aims to solve the same problem as above, that is, to adjust the natural frequency without replacing the mass (here, the weight) and the connecting member (here, the spring). This vibration damping device includes a frame fixed to a building, a weight attached to the frame via an elastic body, and an adjustment means for adjusting the stiffness of the elastic body. The elastic body is a spring, and the adjustment means adjusts the effective length of the spring by adjusting the gripping position of the spring by gripping means provided on the frame side or the weight side.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] According to the floor vibration damping device described in Patent Document 1, for example, by adjusting the gripping position of the spring by the gripping means provided on the frame side to adjust the effective length of the spring, although the replacement of the spring can be made unnecessary, in order to set the gripping position of the spring in various ways, the length of the spring and the gripping means naturally increases, resulting in an increase in the overall dimensions of the vibration damping device, including the above problems.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a cantilever type tuned mass damper that does not require a change in components when adjusting the natural frequency and has no fear of increasing the overall dimensions.

Means for Solving the Problems

[0010] In order to achieve the above object, one aspect of the cantilever type tuned mass damper according to the present invention is a pedestal installed on a building component, a connecting member directly or indirectly connected to the pedestal and having one end fixed in a cantilever manner, and a mass fixed to the other end of the connecting member, wherein a cross-sectional shape perpendicular to the longitudinal direction of the connecting member is a rotationally symmetric cross-section a plurality of times, and by rotating the connecting member about a rotation axis along the longitudinal direction, the second moment of inertia of the cross-section with respect to a reference line perpendicular to the vibration direction passing through the centroid of the cross-sectional shape of the connecting member is changed, and the vibration frequency of the tuned mass damper is adjusted.

[0011] According to this aspect, one end of the connecting member fixed to the pedestal in a cantilever manner and the other end fixed with a mass has a cross-sectional shape perpendicular to the longitudinal direction that is a rotationally symmetric cross-section a plurality of times. By rotating the connecting member about a rotation axis along the longitudinal direction, the second moment of inertia of the cross-section with respect to a reference line perpendicular to the vibration direction passing through the centroid of the cross-sectional shape of the connecting member is changed, and the vibration frequency of the tuned mass damper is adjusted. Therefore, when adjusting the natural frequency of the tuned mass damper, it is not necessary to change the components such as the mass and the connecting member, and there is no fear of increasing the overall dimensions.

[0012] Here, "one end of the connecting member is directly or indirectly fixed to the pedestal" includes both a form in which one end of the connecting member is directly fixed to the pedestal and a form in which one end of the connecting member is indirectly fixed to the pedestal via, for example, a rotating means for rotating the connecting member. In the form in which the connecting member is directly fixed to the pedestal, the connecting member is rotatably attached to the pedestal, and the connecting member is manually rotated.

[0013] When the object to be vibration-reduced is the floor of a building, the pedestal may be directly installed on the floor, or the pedestal may be installed on a beam supporting the floor. At this time, when the floor is a double floor, by installing the tuned mass damper on the floor slab of the double floor, it is possible to effectively reduce the sway of the floor caused by environmental vibration while effectively using the space under the double floor, such as a free access floor, as the installation space for the tuned mass damper. Further, when the object to be vibration-reduced is the entire building, the pedestal is installed on, for example, the roof floor of the building.

[0014] Regarding "the cross-sectional shape of the connecting member is a rotationally symmetric cross-section of multiple rotations", when the cross-sectional shape is rectangular or elliptical, it is a two-fold rotationally symmetric cross-section, when the cross-sectional shape is an equilateral triangle, it is a three-fold rotationally symmetric cross-section, when the cross-sectional shape is a square, it is a four-fold rotationally symmetric cross-section, and when the cross-sectional shape is a regular hexagon, it is a six-fold rotationally symmetric cross-section. A suitable connecting member with a rotationally symmetric cross-section of multiple rotations may be applied.

[0015] Another aspect of the cantilever type tuned mass damper according to the present invention is characterized in that the rotation axis is set at the centroid position of the cross-sectional shape.

[0016] According to this aspect, since the rotation axis along the longitudinal direction of the connecting member is set at the centroid position of the cross-sectional shape of the connecting member, it becomes easy to set (specify) the second moment of area with respect to the reference line orthogonal to the vibration direction, which changes due to the rotation of the connecting member.

[0017] Another aspect of the cantilever type tuned mass damper according to the present invention is The rotating shaft is set at an eccentric position different from the centroid position in the cross-sectional shape.

[0018] According to this aspect, since the rotating shaft along the longitudinal direction of the connecting member is set at an eccentric position different from the centroid position of the connecting member, the second moment of area with respect to the reference line orthogonal to the vibration direction of the connecting member can be changed not only by the cross-sectional shape of the connecting member but also by its eccentric position. Therefore, the variation in the rigidity of the connecting member can be further increased.

[0019] Another aspect of the cantilever type tuned mass damper according to the present invention is One end at the rotating shaft of the connecting member is attached to the drive shaft of a motor, and the motor is fixed to the gantry. The connecting member is rotated about the rotating shaft by the motor.

[0020] According to this aspect, since the connecting member is rotated about the rotating shaft by the motor, the rigidity of the connecting member can be accurately and automatically adjusted, and remote operation becomes possible.

[0021] Another aspect of the cantilever type tuned mass damper according to the present invention is A plurality of the connecting members are provided side by side.

[0022] According to this aspect, since a plurality of connecting members are provided side by side, it is possible to vibrate the mass in a desired vibration direction while suppressing the torsion of the connecting members. Here, the plurality of connecting members are preferably adjusted so that, for example, all the connecting members have the same second moment of area with respect to the reference line orthogonal to the common vibration direction.

[0023] Another aspect of the cantilever type tuned mass damper according to the present invention is A pair of regulating guides for regulating the vibration direction of the mass are provided on both sides of the mass in a direction orthogonal to the vibration direction of the mass.

[0024] According to this aspect, by providing a pair of regulating guides for regulating the vibration direction of the mass on both sides in a direction orthogonal to the vibration direction of the mass, the mass can be stably vibrated in a desired vibration direction while suppressing the torsion of the connecting member.

[0025] Also, another aspect of the cantilever type tuned mass damper according to the present invention is the gantry is installed on the constituent member of the building with the connecting member extending in the horizontal direction, characterized in that the vertical vibration of the building or the constituent member of the building is reduced by the vibration of the mass.

[0026] According to this aspect, the gantry is installed on the constituent member of the building with the connecting member extending in the horizontal direction, and by reducing the vertical vibration of the building or the constituent member of the building due to the vibration of the mass, for example, the natural frequencies of various minute vibrations caused by the environmental vibration of the floor of the building can be effectively reduced, and the natural frequency of the tuned mass damper can be quickly set by the rotation of the connecting member.

[0027] Also, another aspect of the cantilever type tuned mass damper according to the present invention is the gantry is installed on the constituent member of the building with the connecting member extending in the vertical direction, characterized in that the horizontal vibration of the building or the constituent member of the building is reduced by the vibration of the mass.

[0028] According to this aspect, the gantry is installed on the constituent member of the building with the connecting member extending in the vertical direction, and by reducing the horizontal vibration of the building or the constituent member of the building due to the vibration of the mass, for example, the natural frequency of the building caused by the vibration of the building during an earthquake can be effectively reduced, and the natural frequency of the tuned mass damper can be quickly set by the rotation of the connecting member.

Advantages of the Invention

[0029] As can be understood from the above description, according to the cantilever type tuned mass damper of the present invention, it is possible to provide a cantilever type tuned mass damper that does not require a change in components when adjusting the natural frequency and has no risk of increasing the overall dimensions.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0031] Hereinafter, a cantilever type tuned mass damper according to an embodiment will be described with reference to the accompanying drawings. In the present specification and the drawings, substantially the same components may be denoted by the same reference numerals, and redundant descriptions may be omitted.

[0032] [Cantilever type tuned mass damper according to an embodiment] With reference to FIGS. 1 to 9, an example of a cantilever type tuned mass damper according to an embodiment will be described. Here, FIG. 1 is a longitudinal sectional view showing an example of a cantilever type tuned mass damper according to an embodiment. Further, FIG. 2 is a view taken along the arrow II-II of FIG. 1, and is a view for explaining the second moment of area of the connecting member having a rectangular cross-sectional shape with respect to the reference line in a state where the width of the connecting member is parallel to the reference line. FIG. 3 is a view taken along the arrow III-III of FIG. 1, and is a longitudinal sectional view cut at an intermediate position of the vertical wall of the gantry. Further, FIG. 4 is a view for explaining the second moment of area of the connecting member with respect to the reference line in a state where the connecting member is rotated by an angle θ about the rotation axis. FIG. 5 is a view showing the relationship between the rotation angle and the ratio of the second moment of area (I ratio) of the connecting member having a rectangular cross-sectional shape. Furthermore, FIG. 6 is a view corresponding to FIG. 4, and is a view for explaining the second moment of area of the connecting member with respect to the reference line in a state where the connecting member is rotated by an angle θ about the rotation axis in a form in which the rotation axis is set at an eccentric position different from the centroid position of the cross-sectional shape.

[0033] The cantilever type tuned mass damper 50 shown in FIG. 1 includes an L-shaped gantry 10 having a bottom plate 11 and a vertical plate 12 in a side view, a connecting member 20 having one end 22 rotatably attached to the vertical plate 12, and a mass 30 fixed to the other end 24 of the connecting member 20.

[0034] All components of the gantry 10, the connecting member 20, and the mass 30 are all formed of, for example, steel material.

[0035] A through hole 13 is provided at an intermediate position of the vertical plate 12. On the other hand, as shown in Fig. 2, the connecting member 20 is a continuum of a general portion 21 having a rectangular cross-sectional shape perpendicular to its longitudinal direction, a rotating portion 22 having a circular cross-sectional shape inserted into the through hole 13, and a locking portion 23 locked to the outer surface of the vertical plate 12.

[0036] Since the cross-sectional shape of the general portion 21 is rectangular, when the general portion 21 is rotated about a rotation axis L1 passing through the centroid P1 of the general portion 21 shown in Fig. 2, the general portion 21 has a two-fold rotational symmetry cross-section.

[0037] As shown in Fig. 2, the general portion 21 has a width b and a height h. In the posture of the general portion 21 shown in Fig. 2, the second moment of inertia I of the cross-section with respect to a reference line L2 perpendicular to the X1 direction (vertical direction), which is the vibration direction passing through the centroid P1 of the rectangular cross-sectional shape 1 is I 1 = 1 / 12 × bh 3 is obtained.

[0038] As shown in Figs. 1 and 3, a bearing mechanism 14 with a number of bearings arranged is provided on the inner wall of the through hole 13 of the vertical plate 12, and the rotating portion 22 of the connecting member 20 is rotatably inserted through the inside of the bearing mechanism 14. Here, although not shown, a bearing mechanism is provided in which a mass has a hollow and a number of bearings are arranged on the inner wall surface of the hollow, and the tip of the general portion of the connecting member also has a rotating portion with a circular cross-sectional shape, and this rotating portion is inserted into the hollow of the mass, so that the mass may be rotatably attached to the connecting member.

[0039] Furthermore, as shown in Fig. 3, a plurality of pin holes 17 are provided around the through hole 13 in the vertical plate 12, and a pin hole 27 aligned with any of the pin holes 17 is also provided in the locking portion 23 of the connecting member 20. After the connecting member 20 is rotated in the Y1 direction by a predetermined angle about the rotation axis L1, a locking pin 28 is inserted into the mutually aligned pin holes 17 and 27, so that the posture of the connecting member 20 rotated by the predetermined angle is maintained.

[0040] For example, as shown in FIG. 4, when the connecting member 20 is rotated counterclockwise by an angle θ from the posture shown in FIG. 2 and this rotated posture is maintained, the sectional second moment I with respect to the reference line L2 orthogonal to the vibration direction X1 passing through the centroid P1 of the cross-sectional shape of the connecting member 20 2 is, I 2 = 1 / 12 cosθ × (b 2 h sin 3 θ cosθ + h 3 cos 3 θ).

[0041] That is, due to the rotation of the connecting member 20, the sectional second moment (rigidity) with respect to the reference line L2 orthogonal to the vibration direction passing through the centroid P1 of the cross-sectional shape of the general portion 21 of the connecting member 20 is changed, and the vibration frequency of the tuned mass damper 50 can be adjusted by the rotation of the connecting member 20.

[0042] Thus, in the tuned mass damper 50, by rotating the connecting member 20 that vibrates the mass 30 about its rotation axis L1, the sectional second moment (rigidity) with respect to the vibration direction of the connecting member 20 is changed. Therefore, not only is it unnecessary to change its components when adjusting the natural vibration frequency of the tuned mass damper 50, but also there is no risk that the overall dimensions of the tuned mass damper 50 including the connecting member 20 will increase.

[0043] The ratio (I ratio on the vertical axis) of the sectional second moment of the connecting member 20 at each rotation angle when the connecting member 20 having a rectangular cross-sectional shape is rotated about the rotation axis L1 to the sectional second moment of the connecting member 20 in the posture shown in FIG. 2 can be adjusted in the range of 0.1 to 1.0, for example, as shown in FIG. 5.

[0044] Although not shown, the sectional second moment of the connecting member with respect to the reference line orthogonal to the vibration direction corresponding to the rotation angle of the connecting member 20 is specified in advance, and the vibration frequency of the tuned mass damper 50 corresponding to each sectional second moment is also specified. The rotation angle is set so that it becomes the vibration frequency of the tuned mass damper 50 that can effectively reduce the vibration of the object to be vibration-reduced.

[0045] Further, as shown in FIG. 6, a form may be adopted in which the rotation axis L3 is set at an eccentric position P3 (a position eccentric by a distance z from the reference line L2) different from the centroid position P1 of the cross-sectional shape of the general portion 21.

[0046] In this form, when the connecting member 20 is rotated by an angle θ about the rotation axis L3, the second moment of inertia I of the cross-section with respect to the reference line L4 orthogonal to the X1 direction, which is the vibration direction passing through the eccentric position P1 of the cross-sectional shape of the connecting member 20 3 is 3 =I 2 +bhz 2 (I 2 has been described above)

[0047] Thus, since the rotation axis L3 along the longitudinal direction of the connecting member 20 is set at an eccentric position P3 different from the centroid position P1 of the connecting member 20, the second moment of inertia of the cross-section with respect to the reference line L4 orthogonal to the X1 direction, which is the vibration direction of the connecting member 20, can be changed not only by the cross-sectional shape of the connecting member 20 but also by its eccentric position. Therefore, the variation in the rigidity of the connecting member 20 can be further increased.

[0048] Next, with reference to FIG. 7, an example of the installation mode of the tuned mass damper for the building component will be described. Here, FIG. 7 is a view showing a state in which an example of the cantilever type tuned mass damper according to the embodiment is installed on a pair of beams supporting the floor.

[0049] The object whose vibration is reduced by the tuned mass damper 50 shown in FIG. 7 is the floor 60 (an example of a component) forming the building. The floor 60 in the illustrated example is, for example, a concrete floor slab with a span of about 15 m between a pair of large beams (not shown). There is a pair of small beams 70 (an example of a beam) supporting the floor 60 in the same manner between the pair of large beams (not shown).

[0050] The girders 70 are formed of H-shaped steel (including I-shaped steel), an installation base 75 is bridged over the lower flanges 71 of a pair of girders 70, and the bottom plate 11 of the base 10 forming the tuned mass damper 50 is installed on the installation base 75. Therefore, the tuned mass damper 50 in the illustrated example is indirectly installed on the floor 60 via the girders 70.

[0051] In this way, since the tuned mass damper 50 is installed between the two girders 70 that support the floor 60 below the floor 60, the underfloor space can be effectively utilized as the installation space for the tuned mass damper 50. Although not shown in the drawings, in addition to the illustrated example, there is also a form in which the underfloor space of a double floor such as a raised floor is effectively utilized as the installation space for the tuned mass damper.

[0052] In the installation mode of the cantilever type tuned mass damper 50 shown in FIG. 7, the connecting member 20 is installed with the base 10 in a horizontally extending posture, and the vibration in the X2 direction, which is the vertical direction of the floor 60, is reduced by the vibration in the X1 direction, which is the vertical direction of the mass 30.

[0053] At this time, the connecting member 20 is rotated about its rotation axis, and the second moment of area with respect to the reference line orthogonal to the X1 direction, which is the vibration direction passing through the centroid in the cross-sectional shape of the general part 21, is adjusted as desired, so that the vibration frequency of the tuned mass damper 50 is adjusted to the vibration frequency that can effectively reduce the vibration of the floor 60.

[0054] Here, although not shown in the drawings, when reducing the horizontal vibration of a building or a building component, for example, by installing the vertical plate 12 of the base 10 shown in FIG. 1 as the bottom plate on the component, the connecting member 20 is in a vertically extending posture, and the horizontal vibration of the building or the building component can be reduced by the vibration of the mass 30. For example, when reducing the horizontal vibration during an earthquake of the entire building, it is preferable to install the tuned mass damper 50 with the vertical plate 12 of the base 10 as the bottom plate on the floor of the roof or the like.

[0055] Next, with reference to FIGS. 8 and 9, another example of the cantilever type tuned mass damper according to the embodiment will be described. Here, FIG. 8 is a longitudinal sectional view showing another example of the cantilever type tuned mass damper according to the embodiment. Further, FIG. 9 is a view showing still another example of the cantilever type tuned mass damper according to the embodiment, where (a) is a longitudinal sectional view and (b) is a view taken in the direction of arrow b of (a).

[0056] The tuned mass damper 50A shown in FIG. 8 is different from the tuned mass damper 50 in that a part of the motor 40 is embedded in the vertical plate 12 of the gantry 10, and one end 22A of the connecting member 20A is connected to a drive shaft 41 (rotor) that rotates in the Y2 direction inside the stator 42 constituting the motor 40.

[0057] According to the tuned mass damper 50A, for example, by remotely driving the motor 40 to rotate in the Y2 direction by a controller or the like and rotating the connecting member 20A in the Y1 direction, the second moment of inertia of the cross section of the connecting member 20A can be automatically adjusted.

[0058] On the other hand, the tuned mass damper 50B shown in FIG. 9 is different from the tuned mass dampers 50 and 50A in that a mass 30 is fixed to the ends of a plurality (two in the illustrated example) of connecting members 20 provided, and a pair of regulating guides 45 for regulating the vibration direction of the mass 30 are provided on both sides in a direction orthogonal to the vibration direction of the mass 30.

[0059] According to the tuned mass damper 50B, the mass 30 can be stably vibrated in a desired vibration direction while suppressing the torsion of the connecting member 20.

[0060] In addition, other embodiments in which other components are combined with the configurations and the like described in the above embodiments may be possible, and the present invention is not limited to the configurations shown here. In this regard, it can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form.

Description of Reference Numerals

[0061] 10: Stand 11: Bottom plate 12: Vertical plate 13: Through hole 14: Bearing mechanism 17: Pin hole 20, 20A: Connecting member 21: General part 22: Rotating part (one end) 22A: One end 23: Locking part 24: The other end 27: Pin hole 28: Locking pin 30: Mass 40: Motor 41: Driving shaft (rotor) 42: Stator 45: Regulation guide 50, 50A, 50B: Tuned mass damper (cantilever type tuned mass damper) 60: Floor 70: Small beam (beam) 71: Lower flange 75: Installation stand L1, L3: Rotating shaft L2, L4: Reference line P1: Centroid (centroid position) P3: Eccentric position

Claims

1. A cantilever type tuned mass damper, comprising: a pedestal installed on a building component; a connecting member directly or indirectly fixed at one end to the pedestal in a cantilever manner; a mass fixed to the other end of the connecting member; a cross-sectional shape perpendicular to the longitudinal direction of the connecting member is a rotationally symmetric cross-section a plurality of times; When the connecting member is rotated about a rotation axis along the longitudinal direction, the second moment of area with respect to a reference line perpendicular to the vibration direction passing through the centroid of the cross-sectional shape of the connecting member is changed, and the vibration frequency of the tuned mass damper is adjusted. A cantilever type tuned mass damper characterized by this.

2. The cantilever type tuned mass damper according to claim 1, wherein the rotation axis is set at the centroid position of the cross-sectional shape.

3. The cantilever type tuned mass damper according to claim 1, wherein the rotation axis is set at an eccentric position different from the centroid position in the cross-sectional shape.

4. One end at the rotation axis of the connecting member is attached to the drive shaft of a motor, and the motor is fixed to the pedestal. The cantilever type tuned mass damper according to any one of claims 1 to 3, wherein the connecting member is rotated about the rotation axis by the motor.

5. The cantilever type tuned mass damper according to any one of claims 1 to 3, characterized in that a plurality of the connecting members are provided side by side.

6. The cantilever type tuned mass damper according to any one of claims 1 to 3, characterized in that a pair of regulating guides for regulating the vibration direction of the mass are provided on both sides of the mass in a direction perpendicular to the vibration direction of the mass.

7. The pedestal is installed on the building component with the connecting member extending in the horizontal direction, The cantilever type tuned mass damper according to any one of claims 1 to 3, characterized in that the vertical vibration of the building or the building component is reduced by the vibration of the mass.

8. The pedestal is installed on the building component with the connecting member extending in the vertical direction, The cantilever type tuned mass damper according to any one of claims 1 to 3, characterized in that the horizontal vibration of the building or the building component is reduced by the vibration of the mass.

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