Dynamic vibration absorber

Abstract

To provide a dynamic vibration absorber in which a load to an installation target is slight by the configuration being compact to a damping target, and a vibration damping property according to the damping target can be set.SOLUTION: A dynamic vibration absorber comprises: a first link 11 supported through coil springs 9, 10 fixed to an installation target such as a floor F of a building, and having the dynamic vibration absorber 1 for damping the vibration by inertia mass of an inertia mass body 3 with the vibration of the installation target being rotatably pivoted to the inertia mass body 3 at a proximal end; a first rotational inertia body 12 rotatably pivoted in a fixed manner regardless of the vibration of the inertia mass body 3, and slidably engaged so that a free end of the first link 11 may allow tilting of the first link 11 with the vibration of a weight part 7 on a rotating shaft; a second link 13 rotatably pivoted to the inertia mass body 3 at the proximal end; and a second rotational inertia body 14 fixed at the free end of the second link 13, and rotatably pivoted so as to be relatively movable in the direction perpendicular to the vibration in order to allow the tilting of the second link 13 with the vibration of the inertia mass body 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a dynamic vibration absorber, and more particularly to a dynamic vibration absorber that damps vibration by adding a rotating inertial mass to the inertial mass of an inertial mass body such as a weight. [Background technology]

[0002] A vibration control device for long structural parts such as beams and floors of large buildings is described in Patent Document 1 (particularly Figures 6 and 7). A Tuned Mass Damper (TMD) installed in the center of the floor where the amplitude of floor vibration is the largest comprises a viscoelastic rubber member fixed to the underside of the floor and a mass body fixed to the underside of the viscoelastic rubber member, and by setting the rigidity of the viscoelastic rubber member to be in tune with the natural vibration frequency of the floor, the mass body is made to resonate with the vibration of the floor and vibrate greatly, absorbing the vibration energy of the floor and reducing the vibration. Furthermore, Patent Document 2 (particularly Figs. 10 and 11) discloses a vibration control device that is installed along a direction perpendicular to the bridge axis between a pair of support cross beams installed between piers located at the end of the viaduct in the bridge axis direction. In this vibration control device, a movable mass penetrated by a support shaft erected on a base is elastically supported by upper and lower coil springs around each support shaft while being guided in its vertical movement. When the vibration of the viaduct is transmitted to the movable mass, the movable mass vibrates up and down along the support shaft while resisting the spring reaction force, vibrating in synchronization with the natural vibration of the viaduct, and an oil damper between the base frame and the movable mass generates viscous resistance of oil passing through an orifice, thereby damping the vibration of the viaduct. Furthermore, Patent Document 3 (particularly Figs. 1 and 2) discloses a dynamic vibration absorber for a plurality of divided floor panels. This dynamic vibration absorber includes a beam-shaped spring member, a mass, and a viscoelastic body. The beam-shaped spring member has one end fixed to the lower surface of the plurality of divided floor panels, and receives vibration of the divided floor panels, and the other end vibrates with the spring force of bending deformation against the divided floor panels. The mass is fixed to the lower surface of the other end side of the beam-shaped spring member. The viscoelastic body is provided on the other end side of the beam-shaped spring member, and strikes the divided floor panels or imparts a compressive force according to the contact state in response to vibration of the other end of the beam-shaped spring member. The vibration of the divided floor panels is transmitted to the mass of the dynamic vibration absorber, thereby suppressing the vibration of the divided floor panels, and the viscoelastic body of the dynamic vibration absorber comes into contact with the divided floor panels, thereby further suppressing the vibration of the divided floor panels. Furthermore, because dynamic vibration absorbers are highly effective at reducing steady-state vibration, they are not only used to counter traffic vibration, but in recent years have also been used to counter wind vibration in high-rise buildings and long-period earthquake motion. A representative example is shown in Patent Document 4. Patent Document 4 describes a dynamic vibration absorber that has a structure that allows springs to be arranged appropriately for the direction of vibration while preventing the structure from becoming complicated, for structures that have different natural frequencies depending on the direction of vibration. However, it is the same as conventional dynamic vibration absorbers in that it uses a large mass weight to reduce vibration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-145627 A [Patent Document 2] JP 2017-82493 A [Patent Document 3] JP 2016-118031 A [Patent Document 4] JP 2017-025943 A Summary of the Invention [Problem to be solved by the invention]

[0004] In both of the above-mentioned conventional vibration control devices and dynamic vibration absorbers, a weight is used as the inertial mass. Therefore, when applying them to long structures such as large buildings or high-rise buildings, it is necessary to use a weight with a mass corresponding to the weight of the object to be damped. This results in a large load on the strength due to the weight of the weight itself, and also results in fixed vibration damping characteristics that are determined by the inertial mass of the weight. Therefore, an object of the present invention is to provide a dynamic vibration absorber that is compact for relatively long and large vibration control objects such as beams and floors, imposes only a small load on the vibration control object, and yet can be configured to have vibration characteristics that are appropriate for the vibration control object. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a dynamic vibration absorber 1 that is connected to an installation target such as a floor F of a building via elastic bodies such as coil springs 9, 10 and that attenuates vibrations by the inertial mass of an inertial mass body 3 accompanying the vibration of the vibration-damping target, the dynamic vibration absorber 1 being provided with rotating inertia bodies 12, 14 rotatably supported on the vibration-damping target via a mounting member such as a frame body 2, and links 11, 13 that are pivotally supported at one end to the inertial mass body 7 and at the other end on the rotation axes 12a, 14a of the rotating inertia bodies 12, 14, respectively, and that rotate the rotating inertia bodies 12, 14 accompanying the vibration of the inertia mass body. By superimposing the rotating inertia masses of the rotating inertia bodies 12, 14 on the inertial mass of the inertia mass body 3 accompanying the vibration of the vibration-damping target, the inertial mass of the inertia mass body 3 is increased or decreased to impart a vibration damping force suitable for the vibration-damping target. Effect of the Invention

[0006] According to the present invention, the rotational inertial mass of the rotating inertial body is added to the inertial mass of the inertial mass body, increasing or decreasing the inertial mass. Therefore, despite the overall configuration being compact and imposing only a small load on the object to be damped, an appropriate inertial mass can be obtained, and by appropriate adjustment of the inertial mass, it is possible to impart optimal vibration damping characteristics to the anticipated vibrations. [Brief description of the drawings]

[0007] [Figure 1] 1 is a front view of a dynamic vibration absorber according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a rear view of the dynamic vibration absorber of FIG. [Diagram 3] FIG. 2 is a side view of the dynamic vibration absorber of FIG. [Figure 4] FIG. 2 is a plan view of the dynamic vibration absorber of FIG. [Diagram 5] 5A to 5C are diagrams illustrating the operation of the first rotary inertia mechanism. [Figure 6] 5A to 5C are diagrams illustrating the operation of the second rotational inertia mechanism. [Figure 7] 1A is a graph showing the relationship between the rotation angle of a first rotational inertia mechanism and the magnification of the equivalent mass with respect to an inertial mass body, and FIG. 1B is a graph showing the relationship between the rotation angle of a second rotational inertia mechanism and the magnification of the equivalent mass with respect to an inertial mass body. [Figure 8] 11 is a graph showing a change in amplitude magnification with respect to an input frequency ratio when the magnification of the equivalent mass of an inertial mass body is increased or decreased by 10% and 20%. [Figure 9A] 11 is a graph showing a comparison of changes in amplitude magnification with respect to input frequency ratio when the equivalent mass of an inertial mass body is reduced by 10%. [Figure 9B] 11 is a graph showing a comparison of changes in amplitude magnification with respect to input frequency ratio when the equivalent mass of an inertial mass body is increased by 10%. [Figure 9C] 11 is a graph showing a comparison of changes in amplitude magnification with respect to input frequency ratio when the equivalent mass of the inertial mass body is reduced by 20%. [Figure 9D] 11 is a graph showing a comparison of changes in amplitude magnification with respect to input frequency ratio when the equivalent mass of the inertial mass body is increased by 20%. [Figure 10] 2 is an explanatory diagram of the operation of the dynamic vibration absorber of FIG. 1. [Figure 11A] 11 is a graph showing the relationship between the rotation angle and equivalent mass of a dynamic vibration absorber that combines a first rotary inertia mechanism and a second rotary inertia mechanism, the link length ratio and the rotary inertia mass ratio being set to Condition 1 shown in Table 1. [Figure 11B] 11 is a graph showing the relationship between the rotation angle and equivalent mass of a dynamic vibration absorber that combines a first rotational inertia mechanism and a second rotational inertia mechanism, the link length ratio and the rotational inertia mass ratio being set to Condition 2 shown in Table 1. [Figure 11C] 13 is a graph showing the relationship between the rotation angle and equivalent mass of a dynamic vibration absorber that combines a first rotational inertia mechanism and a second rotational inertia mechanism, the link length ratio and the rotational inertia mass ratio being set to Condition 3 shown in Table 1. [Figure 11D] 13 is a graph showing the relationship between the rotation angle and equivalent mass of a dynamic vibration absorber that combines a first rotational inertia mechanism and a second rotational inertia mechanism, the link length ratio and the rotational inertia mass ratio being set to Condition 4 shown in Table 1. [Figure 11E] 13 is a graph showing the relationship between the rotation angle and equivalent mass of a dynamic vibration absorber that combines a first rotational inertia mechanism and a second rotational inertia mechanism, with the link length ratio and rotational inertia mass ratio set to Condition 5 shown in Table 1. [Figure 12] FIG. 11 is a front view of a dynamic vibration absorber according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of the present invention will be described with reference to the drawings. 1 to 4, the dynamic vibration absorber 1 comprises a substantially cross-shaped frame 2 which is attached to the underside of a floor F, which is the object of vibration damping, and which constitutes a mounting member for the following accessories to the floor F, an inertial mass body 3 which is supported vertically along the vertical plate portion of the frame body 2 and performs a damping action by resonating with the vertical vibration of the floor F, first and second rotational inertia mechanisms 4 and 5 which are supported on both sides of the horizontal plate portion of the frame body 2 and increase or decrease the inertial mass by adding a rotational inertial mass to the inertial mass body 3, and a vibration damping means 6 which damps the vibration of the floor F. The frame body 2 comprises an upper frame 2a for fixing to the underside of the floor F, a lower frame 2b which faces the upper frame 2a at the lower part, a substantially cross-shaped support plate 2c which connects the upper frame 2a and the lower frame 2b to the upper and lower ends, and a connecting rod 2d which connects the upper frame 2a and the lower frame 2b.

[0009] The inertial mass body 3 comprises a rectangular weight section 7 supported in the up-down direction along a vertical piece of the support plate 2c of the frame body 2, and a guide shaft section 8 extending in the up-down direction from the weight section 7 and slidably penetrating the upper frame 2a and the lower frame 2b. The inertial mass body 3 is held in the frame body 2 so as to be vertically movable by coil springs 9, 10 engaged between the weight section 7 and the upper frame 2a and the lower frame 2b. The vibration damping means 6 connected to the lower end of the guide shaft section 8 reinforces the damping effect as necessary to prevent the inertial mass body 3 from continuing to vibrate up and down, and various well-known dampers that impart resistance to the behavior of the inertial mass body can be used.

[0010] The first rotary inertia mechanism 4 includes a first link 11 rotatably supported by the pivot 7a of the weight section 7 and extending along one of the horizontal pieces of the support plate 2c, and a first rotary inertia body 12 whose center is pivoted to the support plate 2c and engages with the tip of the first link 11. The base end of the first link 11 is supported rotatably around the pivot 7a located at the front center of the weight section 7, extends horizontally along the horizontal piece of the support plate 2c at the initial position of the weight section 7, and has a small diameter part 11a of a predetermined length in the longitudinal direction at its tip. The first rotary inertia body 12 has a predetermined rotary inertia mass, is disk-shaped integral with the central rotary shaft 12a, and is supported by the support plate 2c rotatably in the vertical direction around the rotary shaft 12a. An engagement cylinder 12b horizontal in the direction perpendicular to the axis is fixed to the tip of the extended rotary shaft 12a. The small diameter portion 11a of the first link 11 slidably passes through the engagement cylinder 12b, and allows the first rotating inertia body 12 to rotate together with the tilting of the first link 11 accompanying the vertical movement of the inertia mass body 3.

[0011] The second rotary inertia mechanism 5 comprises a second link 13 rotatably supported by the pivot 7a of the weight section 7 and extending horizontally along the other side of the support plate 2c, and a second rotary inertia body 14 whose center is pivoted to the support plate 2c and engages with the tip of the second link 13. The base end of the second link 13 is rotatably supported at the front center of the pivot 7a of the weight section 7, extends horizontally to the opposite side to the first link 11 at the initial position of the weight section 7, and is coupled to the rotary shaft 14a of the second rotary inertia body 14 at its tip. The second rotary inertia body 14 has a predetermined rotary inertia mass, is disk-shaped integral with the rotary shaft 14a at the center, and is supported by the support plate 2c so as to be rotatable vertically around the rotary shaft 14a. The second rotating inertia body 14 is supported so as to be movable horizontally within a longitudinal hole 15 formed in the support plate 2c, and allows the second rotating inertia body 14 to rotate together with the tilting of the second link 13 accompanying the up and down movement of the inertial mass body 3.

[0012] When vibration of the floor F is transmitted to the dynamic vibration absorber 1 and the inertial mass body 3 moves upward as shown in FIG. 5, the equivalent mass of the first rotating inertia mechanism 4 is as follows:

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[0013] 7(A) and (B), the equivalent mass of the inertial mass body 3 has the characteristic of increasing or decreasing with the rotation angle of the first and second rotary inertia mechanisms 4 and 5. The dashed lines in the figures indicate the region where the magnification of the equivalent mass exceeds 10%.

[0014] As shown in Fig. 8, the amplitude magnification curve changes according to the equivalent mass of the inertial mass body 3, and the vibration characteristics change. In particular, as shown in Figs. 9A and 9B, if the increase or decrease in the equivalent mass is within 10%, the amplitude amplification factor changes relatively little, but as shown in Figs. 9C and 9D, if the increase or decrease in the equivalent mass exceeds 20%, the amplitude magnification changes significantly. In other words, if the increase or decrease in the equivalent mass of the inertial mass body 3 is within 10%, the displacement of the inertial mass body 3 is permissible in terms of the dynamic vibration absorber function, but if the increase or decrease in the equivalent mass is in a range exceeding 10%, the displacement of the inertial mass body 3 becomes excessive, which may be undesirable in terms of the dynamic vibration absorber function. However, the effect of increasing or decreasing the equivalent mass of the inertial mass body 3 by the first and second rotating inertia mechanisms 4 and 5 alone is limited but effective.

[0015] In this embodiment, vibrations of a floor F on which the dynamic vibration absorber 1 having the first and second rotational inertia mechanisms 4, 5 are transmitted, and when the inertial mass body moves upward as shown in FIG. 10, the equivalent mass of the inertial mass body 3 is as follows:

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[0016] Depending on how the link length ratio α and the rotational inertia mass ratio β are set, it is also possible to increase the amplification factor of the equivalent mass of the inertia mass body 3 compared to the case of the first and second rotational inertia mechanisms 4, 5 alone. 11A to 11E show changes in the amplification ratio of the equivalent mass of the inertia mass body 3 with respect to the displacement angle of the first link 11 for five conditions of the link length ratio α and the rotational inertia mass ratio β shown in Table 1 below. [Table 1] 7, the change in the magnification of the equivalent mass when the first and second rotary inertia mechanisms 4 and 5 are used alone is within a region of 10% at rotation angles of approximately 13 degrees or less for the first rotary inertia mechanism 4 and at rotation angles of approximately 17.5 degrees or less for the second rotary inertia mechanism 5. In contrast, as shown in Figures 11A to 11E, it can be confirmed that in the dynamic vibration absorber 1 of this embodiment, the range of motion of the inertial mass body 3 is expanded to a range exceeding a rotation angle of approximately 30 degrees under all conditions.

[0017] As described above, in the dynamic vibration absorber 1, if the first and second rotary inertia mechanisms 4 and 5 are connected to the inertial mass body 3 individually, the equivalent mass increases or decreases according to the displacement of the inertial mass body 3, so that the fixed inertial mass of the inertial mass body 3 can be adjusted according to the displacement of the vibration. Furthermore, by combining the first and second rotary inertia mechanisms 4 and 5, the changes in the rotary inertia mass caused by the displacement of the inertial mass body 3 are cancelled out by each other, the changes in the rotary inertia mass are suppressed, and the movable range in which the inertial mass body 3 has an inertial mass of a substantially constant magnification can be expanded. Therefore, the dynamic vibration absorber 1 of the present invention can set vibration damping characteristics suitable for the vibration damping target while suppressing the mass of the inertial mass body 3. Furthermore, by combining the first rotary inertia mechanism 4 having a characteristic of reducing the equivalent mass with the second rotary inertia mechanism 5 having a characteristic of amplifying the equivalent mass, the displacement range of the inertial mass body 3 in which the increase or decrease in the equivalent mass effective for the dynamic vibration absorber is within 10% can be expanded.

[0018] Furthermore, this dynamic vibration absorber 1 has the characteristic of shifting from a region where the equivalent mass of the inertial mass body 3 is at a nearly constant magnification to a region where it increases or decreases in response to the displacement of the inertial mass body 3, so for example, when the object to be damped is vibration of small amplitude such as wind, the vibration is suppressed in a region where the variation in the equivalent mass is within 10%, while when the object to be damped is vibration of excessive amplitude such as earthquake, the equivalent mass is increased in a region where the variation in the equivalent mass exceeds the 10% threshold to suppress the vibration. In this way, the dynamic vibration absorber 1 can suppress vibrations of various amplitudes and can also be applied to general building structures.

[0019] In addition, the dynamic vibration absorber 1 of the present invention is also effective against lateral vibrations in the same manner as in the above embodiment when installed on a wall surface W of a structure, as shown in Figure 12, and the present invention is not limited to the vibration direction of the object to be damped. [Explanation of symbols]

[0020] 1 Dynamic vibration absorber 2 frame 2a Upper frame 2b Bottom frame 2c support plate 2d connecting rod 3 Inertial mass 4. First Rotational Inertia Mechanism 5 Second Rotational Inertia Mechanism 6. Vibration damping means 7 Weight section 7a Axis 8 Guide shaft 9 Coil spring 10 Coil spring 11 First link 11a Small diameter section 12 First rotating inertial body 12a Rotation axis 12b Engagement tube 13 Second Link 14 Second rotating inertial body 14a Rotation axis 15 long hole F floor W Wall

Claims

1. A dynamic vibration absorber that is connected to a vibration damping target via an elastic body so as to be capable of relative movement, and that attenuates vibration of the vibration damping target by relative displacement of an inertial mass body in response to vibration of the vibration damping target, a rotating inertia body that is rotatably supported on a vibration damping target via a mounting member and has a rotation axis perpendicular to a relative displacement direction of the inertia mass body; a link having one end pivotally supported on the inertial mass body and the other end pivotally supported on the rotating inertia body, the link rotating the rotating inertia body in response to a relative displacement of the inertial mass body caused by vibration of the vibration damping target, A dynamic vibration absorber comprising an inertial mass body and a rotary inertial mass body, the rotary inertial mass body being superimposed on the inertial mass of the rotary inertial mass body to impart a vibration damping force to an object to be damped.

2. 2. The dynamic vibration absorber according to claim 1, wherein the rotary inertia body is a first rotary inertia body slidably engaged with the link to allow the relative displacement of the inertia mass body.

3. 2. The dynamic vibration absorber according to claim 1, wherein the rotary inertia body is a second rotary inertia body having a rotary shaft movably engaged with the mounting member so as to allow the relative displacement of the inertia mass body.

4. A dynamic vibration absorber as described in claim 1, characterized in that the rotating inertia body comprises a first rotating inertia body that slidably engages with the link to allow relative displacement of the inertial mass body, and a second rotating inertia body whose rotating shaft movably engages with the mounting member to allow relative displacement of the inertia mass body.

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