Rotational inertia device

Abstract

To provide a compact rotational inertia device capable of coping with swinging in two directions.SOLUTION: A rotational inertia device 100 for suppressing vibration of a vibration suppression target includes a first member 10 extending in one direction, and a second member 20 disposed parallel to the first member 10. A second member 12 that is fixed so as to be movable in one direction along the first member 10, a rack and pinion 14 that is fixed to the second member 12 and converts a translational movement of a rack 24 extending in one direction into a rotational movement of a pinion 26 rotatably fixed to the first member 10, a gear 16 or a wheel that is disposed coaxially with the pinion 26, and a rotation spring 18 that is installed between the pinion 26 and the gear 16 or the wheel in order to secure a biasing force in the rotational direction of the pinion 26.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotary inertia device that can cope with shaking in two directions. [Background technology]

[0002] Tuned mass dampers (TMDs) have traditionally been widely used as devices to suppress building vibration. Because TMDs are composed of a spring and a mass, they have their own natural period. By adjusting this natural period to synchronize with the building's vibration period, they can suppress building vibration. It is known that the heavier the mass of a TMD, the greater its vibration-damping effect can be (see Non-Patent Document 1). However, installing a large mass is structurally disadvantageous and increases the device size, which places constraints on layout planning and other aspects. Furthermore, while reducing the mass reduces the overall size, achieving the required vibration-damping effect requires the mounted mass to oscillate with a large amplitude in the control direction, necessitating the securing of a large drive space. This increases the size in the control direction, which places constraints on layout planning and other aspects. For example, the example shown in Non-Patent Document 1 requires a space approximately five times the maximum displacement of the building. On the other hand, an increasing number of seismic isolation structures have a clearance of around 60cm to 70cm (see Non-Patent Document 2), and when conventional tuned devices such as TMDs are applied to seismic isolation structures, a range of motion of around ±300cm to 350cm is required, which results in an even larger device overall.

[0003] To solve these problems, the inventors have already proposed a compact inertial mass damper (IMD) that converts translational deformation into rotational deformation by combining a rotationally effective spring (torsion spring) with an inertial mass, thereby significantly reducing the space required for TMD devices (see, for example, Non-Patent Document 3 and Patent Documents 1 and 2). This method ensures displacement by rotating a wheel a predetermined amount (300 cm) in place, rather than by moving the mass a predetermined amount (±300 cm) in the translational direction. For example, when using a wheel with a radius of 60 cm, the circumference of the wheel is 2 × 60 × 3.14 = approximately 370 cm. Rotating this wheel just slightly less than one full rotation in place provides the same control force as a conventional TMD, thereby achieving a significant reduction in the size of the device. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "Easy-to-Understand Building Vibration Control", Architectural Institute of Japan, 2014 [Non-patent document 2] "Database Construction and Current Status Analysis of Domestic Base-Isolated Buildings," Yuji Tanaka, Nobuo Fukuwa, Jun Tobita, Masashi Mamoru, Architectural Institute of Japan, Technical Report, Vol. 17, No. 35, pp. 79-84, 2011 [Non-patent document 3] "Proposal of a Dynamic Vibration Absorber Combining an Inertial Mass Device and a Rotating Spring", Akira Miyamoto, Koichi Watanabe, Jun Iba, Ken Ishii, Masaru Kikuchi, 16th Japan Earthquake Engineering Symposium, Day1-G403-04, 2023 [Patent documents]

[0005] [Patent Document 1] Patent Application No. 2022-164582 (currently unpublished) [Patent Document 2] Patent Application No. 2023-065886 (currently unpublished) Summary of the Invention [Problem to be solved by the invention]

[0006] When an earthquake occurs, a building will shake not only in one horizontal direction (for example, the x-axis direction) but also in a horizontal direction perpendicular to this direction (for example, the y-axis direction perpendicular to the x-axis direction), so it is desirable to be able to respond to shaking in two horizontal directions. However, the above-mentioned conventional inertial mass dampers (IMDs) can only respond to shaking in one direction, not two directions.

[0007] The present invention has been made in view of the above, and has an object to provide a compact rotary inertia device that can cope with vibrations in two directions. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the rotary inertia device of the present invention is a rotary inertia device for suppressing vibration of an object to be vibration-damped, and is characterized by comprising: a first member extending in one direction; a second member arranged parallel to the first member and fixed so as to be movable in one direction along the first member; a rack and pinion that converts translational movement of a rack fixed to the second member and extending in one direction into rotational movement of a pinion fixed so as to be rotatable relative to the first member; a gear or wheel arranged coaxially with the pinion; and a rotational spring installed between the pinion and the gear or wheel to ensure a rotational biasing force of the pinion.

[0009] Moreover, another rotary inertia device according to the present invention is characterized in that, in the above-mentioned invention, it further comprises a gear mechanism that adjusts the biasing force of the rotary spring to increase or decrease.

[0010] Furthermore, another rotary inertia device according to the present invention is characterized in that, in the above-described invention, the end of the first member is rotatably connected to one side of the object to be damped, and the end of the second member is rotatably connected to the other side of the object to be damped.

[0011] Furthermore, another rotary inertia device according to the present invention is characterized in that, in the above-mentioned invention, it further comprises a gear that is meshed with the gear or wheel and fixed to a rotation shaft, and a wheel that is fixed coaxially to the rotation shaft and can rotate integrally with the rotation shaft. [Effects of the Invention]

[0012] The rotary inertia device of the present invention is a rotary inertia device for suppressing vibrations of an object to be vibration-damped, and comprises a first member extending in one direction, a second member arranged parallel to the first member and fixed so as to be movable in one direction along the first member, a rack and pinion that converts translational movement of the rack fixed to the second member and extending in one direction into rotational movement of a pinion fixed so as to be rotatable relative to the first member, a gear or wheel arranged coaxially with the pinion, and a rotational spring installed between the pinion and the gear or wheel to ensure a rotational biasing force of the pinion.Therefore, by rotatably connecting an end of the first member to one side of the object to be vibration-damped and rotatably connecting an end of the second member to the other side of the object to be vibration-damped, it is possible to provide a compact rotary inertia device that can respond to two-directional shaking acting on the object to be vibration-damped due to an earthquake.

[0013] Furthermore, according to another rotary inertia device of the present invention, since it further comprises a gear mechanism that adjusts the biasing force of the rotary spring, the biasing force of the rotary spring can be easily adjusted.

[0014] In addition, according to another rotational inertia device of the present invention, the end of the first member is rotatably connected to one side of the vibration-damping object, and the end of the second member is rotatably connected to the other side of the vibration-damping object, thereby achieving the effect of being able to respond to vibrations acting in two directions on the vibration-damping object.

[0015] Furthermore, another rotary inertia device according to the present invention further comprises a gear that is meshed with the gear or wheel and fixed to the rotating shaft, and a wheel that is fixed coaxially to the rotating shaft and can rotate integrally with the rotating shaft, thereby achieving a high vibration damping effect and reducing the driving space, thereby enabling the device to be made smaller. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a plan view showing a rotary inertia device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing a modified example of the first embodiment of the rotary inertia device according to the present invention. [Figure 5] FIG. 5 is a plan view showing a second embodiment of a rotary inertia device according to the present invention. [Figure 6] FIG. 6 is a cross-sectional view taken along line CC in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line DD in FIG. [Figure 8] 8A and 8B are diagrams showing an example of installation of a rotational inertia device according to the present invention on a seismic isolation layer, where (1) is a front view, (2) is a plan view of the first embodiment, and (3) is a plan view of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a rotary inertia device according to the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0018] (Embodiment 1) First, a first embodiment of the present invention will be described. As shown in Figures 1 to 3, the rotational inertia device 100 of this embodiment 1 is a device for suppressing vibrations of a building S (a vibration-damping target), and includes a member 10, a member 12, a rack and pinion 14, a gear 16, and a rotational spring 18, and is provided, for example, in a seismic isolation layer of the building S.

[0019] The member 10 is a first member that extends in one direction. In the example shown in the figure, the member 10 is a rectangular parallelepiped member that extends in one horizontal direction.

[0020] Member 12 is a second member that is disposed parallel to member 10 and is fixed so as to be movable in one direction along member 10. In the example shown in the figure, member 12 is configured as a rectangular parallelepiped member extending in one horizontal direction. A slider 20 protrudes from the side surface of member 12. This slider 20 is fixed so as to be movable along a linear guide 22 that is provided on the side surface of member 10 so as to extend in one direction. In this way, member 10 and member 12 are fixed so as to be movable relative to each other in one direction.

[0021] The rack and pinion 14 is fixed to the upper surface of the member 12 and consists of a rack 24 extending in one direction and a pinion 26 meshing with the rack 24, converting translational movement of the rack 24 into rotational movement of the pinion 26. The tooth surface of the rack 24 faces in a lateral direction perpendicular to the one direction. The shaft 28 of the pinion 26 extends in the vertical direction and is rotatably fixed to the upper surface of the member 10 via a ball bearing (not shown). By using the rack and pinion 14, it is possible to convert translational displacement of the building S that is deformed by an earthquake into rotational displacement.

[0022] The gear 16 is disposed coaxially and parallel to the pinion 26. The shaft 30 of the gear 16 is rotatably fixed to the upper surface of the member 10 via a ball bearing (not shown), and is disconnected from the shaft 28 of the pinion 26. The diameter of the gear 16 is configured to be larger than the diameter of the pinion 26, but the present invention is not limited to this. Also, instead of the gear 16, a wheel, which is a mass body that generates an apparent large mass, may be used.

[0023] The rotation spring 18 is a spring that ensures a biasing force in the rotational direction of the pinion 26, and is installed between the pinion 26 and the gear 16. In the example shown in the figure, a coil torsion spring is used as the rotation spring 18. The central axis of the rotation spring 18 coincides with the rotation axis C of the pinion 26 and the gear 16. One end of the rotation spring 18 is fixed to the axial end face 26A of the pinion 26, and the other end is fixed to the axial end face 16A of the gear 16.

[0024] It is desirable to tune the specifications of the rotation spring 18 and the gear 16 to the frequency (target frequency) at which vibration is to be blocked or reduced, thereby making it possible to reduce vibration at the target frequency, especially during steady-state response.

[0025] End members 32 and 34 are provided at the ends of member 10 and member 12, respectively. End member 32 extends upward from member 10 and is rotatably attached to a beam of superstructure S1 of building S (one side of the vibration-damping object). End member 34 extends downward from member 12 and is rotatably attached to a beam of substructure S2 of building S (the other side of the vibration-damping object). End members 32 and 34 can be configured using, for example, pins or ball seats. By rotatably connecting members 10 and 12 to building S, they can accommodate shaking in two directions. Because member 10 is connected to the superstructure via end member 32, it displaces exactly the same as the superstructure. On the other hand, because member 12 is connected to the ground via end member 34 and the substructure, it displaces exactly the same as the ground. Therefore, if a displacement difference occurs between members 10 and 12 due to an earthquake or the like, this displacement difference will cause pinion 26 to operate.

[0026] The operation and function of the above configuration will now be described. When vibrations occur in building S, a displacement difference occurs between members 10 and 12, and rack-and-pinion 14 converts the translational movement of building S into a rotational movement, which rotates pinion 26. Pinion 26 is disconnected from shaft 30 of gear 16. As pinion 26 rotates, rotational displacement occurs in rotational spring 18. Torque is generated in rotational spring 18, causing rotational displacement in gear 16. As gear 16 rotates, a rotating mass is created, giving gear 16 a degree of freedom. In other words, rotational spring 18 and gear 16 function similarly to conventional TMDs, making it possible to suppress vibrations at tuned frequencies. This rotational inertia device 100 is rotatably connected to building S via end members 32 and 34 and is capable of responding to vibrations in two directions of building S, making it possible to suppress horizontal vibrations of building S in two directions caused by earthquakes.

[0027] Furthermore, it is possible to secure the space for the rotational inertia device 100 to move in the rotational direction, not in the translational direction, which allows for significant space savings. Furthermore, by rotating the gear 16 (rotating mass), an apparently large mass is generated, which allows for a reduction in actual mass compared to conventional TMDs, which is advantageous in terms of structure.

[0028] Therefore, according to this embodiment, it is possible to provide a compact rotational inertia device that can cope with shaking acting on building S in two directions due to an earthquake.

[0029] The rotation of a certain disk (hereinafter referred to as a wheel, corresponding to gear 16) makes it possible to amplify the actual amount of radiation. The amplification factor γ is calculated using the diameter L of the disk that rotates the wheel and the diameter D of the wheel, and is given by the following formula (1).

[0030]

number

[0031] This means that a large mass IMD can be achieved by placing an additional gear or wheel 17 on top of gear 16, or by increasing the radius of gear 16, as shown in Figure 4.

[0032] In the above-described first embodiment, the rack 24 and pinion 26 of the rack and pinion 14 are directly engaged with each other, but the present invention is not limited to this. The gear ratio may be adjusted by inserting a plurality of other gears (gear mechanisms) between the rack 24 and pinion 26, thereby amplifying the amount of rotation of the rotation spring 18 that is directly connected to the pinion 26. For example, when the amount of horizontal displacement is extremely small, amplification can be used to provide a sufficient amount of rotation to the rotation spring 18.

[0033] (Embodiment 2) Next, a second embodiment of the present invention will be described. As shown in FIGS. 5 to 7, a rotary inertia device 200 according to the second embodiment is configured by adding a third gear 36 to the first embodiment.

[0034] The gear 36 meshes with the adjacent gear 16. The gear 36 is fixed to a rotation shaft 38. The diameter of the gear 36 is smaller than the diameter of the gear 16, and the number of teeth of the gear 36 is smaller than the number of teeth of the gear 16. The rotation shaft 38 is arranged parallel to the rotation axis C of the gear 16 and the pinion 26, and one end of the rotation shaft 38 is fixed to the upper surface of the member 10 so as to be able to rotate freely. With this configuration, it is possible to increase the generated inertial mass in accordance with the ratio between the diameters of the two gears 16, 36, and it is possible to create a large mass effect even when it is difficult to use a large wheel.

[0035] An additional wheel 40 is coaxially fixed to the other end of the rotation shaft 38. This wheel 40 is a mass body that can rotate integrally with the rotation shaft 38. By rotating the wheel 40 via the rotation shaft 38, it is possible to generate an apparently large mass.

[0036] (Example) Next, an example will be described in which the rotational inertia device 100 (or the rotational inertia device 200) of this embodiment is installed in the seismic isolation layer of a building S. As shown in FIG. 8(1), a laminated rubber 44 is arranged in the seismic isolation layer 42.

[0037] The rotational inertia unit 100 of this embodiment utilizes the difference in displacement between the superstructure S1 of the building S and the ground. Therefore, when installing the rotational inertia unit 100, one of the two end members 32, 34 is connected to the substructure S2 connected to the ground, and the other is connected to the superstructure S1, as shown in FIG. 8(1). When installing the rotational inertia unit 100, as shown in Example 1 of FIG. 8(2), the members 10, 12 can be installed so that they extend horizontally and diagonally, as viewed from above, relative to the mutually perpendicular horizontal directions of the x-axis and y-axis. This allows the unit 100 to exert forces in two horizontal directions, the x-axis and y-axis. Alternatively, or in addition, the rotational inertia unit 100 can be installed so that the members 10, 12 extend horizontally and vertically and horizontally, as shown in Example 2 of FIG. 8(3). This allows the unit 100 to exert forces in two horizontal directions, the x-axis and y-axis.

[0038] As described above, the rotary inertia device of the present invention is a rotary inertia device for suppressing vibrations of an object to be vibration-damped, and comprises a first member extending in one direction, a second member arranged parallel to the first member and fixed so as to be movable in one direction along the first member, a rack and pinion that converts translational movement of a rack fixed to the second member and extending in one direction into rotational movement of a pinion fixed so as to be rotatable relative to the first member, a gear or wheel arranged coaxially with the pinion, and a rotational spring installed between the pinion and the gear or wheel to ensure a rotational biasing force of the pinion.Therefore, by rotatably connecting an end of the first member to one side of the object to be vibration-damped and an end of the second member to the other side of the object to be vibration-damped, it is possible to provide a compact rotary inertia device that can respond to shaking in two directions acting on the object to be vibration-damped due to an earthquake.

[0039] Furthermore, according to another rotary inertia device of the present invention, a gear mechanism for adjusting the biasing force of the rotary spring is further provided, so that the biasing force of the rotary spring can be easily adjusted.

[0040] In addition, according to another rotational inertia device of the present invention, the end of the first member is rotatably connected to one side of the vibration-damping object, and the end of the second member is rotatably connected to the other side of the vibration-damping object, so that it can respond to vibrations acting in two directions on the vibration-damping object.

[0041] Furthermore, another rotary inertia device according to the present invention further comprises a gear that is meshed with the gear or wheel and fixed to the rotating shaft, and a wheel that is fixed coaxially to the rotating shaft and can rotate integrally with the rotating shaft, thereby achieving a high vibration damping effect and reducing the driving space, thereby enabling the device to be made smaller.

[0042] The Sustainable Development Goals (SDGs) are 17 international goals that were adopted at the United Nations Summit in September 2015. The rotational inertial device according to this embodiment can contribute to the achievement of one of the 17 SDGs, for example, goal 11, "Make cities and towns inclusive and sustainable." [Industrial Applicability]

[0043] As described above, the rotational inertia device according to the present invention is useful for damping vibrations of buildings, and is particularly suited to dealing with vibrations in two directions. [Explanation of symbols]

[0044] 10 Component (first component) 12 Component (second component) 14 Rack and Pinion 16,36 gears 18 Rotating Spring 20 Slider 22 Linear guide 24 racks 26 Pinion 28,30 axes 32,34 End members 38 Rotation axis 40 wheels 100,200 Rotational Inertial Device S Building (vibration control target)

Claims

1. A rotary inertia device for suppressing vibration of an object to be damped, A rotary inertia device comprising: a first member extending in one direction; a second member arranged parallel to the first member and fixed to the first member so as to be movable in one direction along the first member; a rack and pinion that converts translational movement of a rack fixed to the second member and extending in one direction into rotational movement of a pinion fixed to the first member so as to be rotatable freely; a gear or wheel arranged coaxially with the pinion; and a rotational spring installed between the pinion and the gear or wheel to ensure a rotational biasing force of the pinion.

2. 2. The rotary inertia device according to claim 1, further comprising a gear mechanism for adjusting the biasing force of the rotary spring.

3. 3. A rotary inertia device as described in claim 1 or 2, characterized in that an end of the first member is rotatably connected to one side of the object to be damped, and an end of the second member is rotatably connected to the other side of the object to be damped.

4. 3. The rotary inertia device according to claim 1, further comprising: a gear that is meshed with the gear or wheel and is fixed to a rotation shaft; and a wheel that is fixed coaxially to the rotation shaft and can rotate integrally with the rotation shaft.

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