Dynamic vibration absorption structure

Abstract

To provide a dynamic vibration absorbing structure capable of improving the efficiency of tuning work even when the structure is installed in a position unsuitable for tuning. [Solution] The dynamic vibration absorbing structure includes a pair of support members extending in a predetermined direction on a horizontal plane and spaced apart in an orthogonal direction, and a dynamic vibration absorbing device supported so as to straddle the pair of support members. The dynamic vibration absorbing device includes a base member placed on the mounting surfaces of the pair of support members, an elastic member provided on the base member, a mass body provided on the elastic member so as to sandwich the elastic member between the base member and the elastic member, and an attachment means for attaching the mass body to the base member. The base member is placed on the mounting surfaces of the pair of support members in a state where it can move in the predetermined direction relative to the pair of support members.

Description

[Technical Field]

[0001] The present invention relates to a dynamic vibration absorbing structure. [Background technology]

[0002] A conventional vibration damping device is described in, for example, Patent Document 1. The vibration damping device described in Patent Document 1 reduces vibrations of a predetermined frequency occurring in a beam by resonating a mass member. Specifically, the vibration damping device includes a pair of L-shaped brackets attached to opposing sides of two beams arranged parallel to each other and spaced apart on a ceiling, four rubber mounts (two on each L-shaped bracket), and one mass member placed and fixed on the rubber mounts.

[0003] The L-shaped bracket has a mounting base attached to the side of the beam and a support base bent at a right angle from one end of the mounting base. The mounting base has an oval insertion hole through which a mounting screw that is screwed into the side of the beam is inserted. The mounting position of the vibration damping device relative to the beam can be adjusted by moving the mounting screw within the insertion hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-161862 Summary of the Invention [Problem to be solved by the invention]

[0005] The vibration damping device described in Patent Document 1 can effectively reduce vibrations of a preset frequency using a mass member and a rubber mount. However, if the frequency of vibration generated in the beam differs from the preset frequency, it is necessary to change the weight of the mass member, i.e., perform so-called tuning.

[0006] When tuning, it is necessary to attach and detach the mass member through an inspection hatch formed under the two beams and the space between the two beams. The location of the inspection hatch is restricted by the layout of the building, so it may be located in a place that is unsuitable for tuning, such as directly below a vibration control device.

[0007] When the inspection hatch is located in a position unsuitable for tuning, the vibration damping device described in Patent Document 1 allows the L-shaped bracket (the entire vibration damping device) to be moved within the range of the insertion hole by loosening the mounting screws. However, because the range in which the entire vibration damping device can be moved is limited to the range of the insertion hole, it is difficult to move it to a position where tuning can be performed efficiently.

[0008] Here, it is possible to remove the mounting screws from the beam and move the entire vibration control device, but the vibration control device described in Patent Document 1 is supported on the beam only by the mounting screws, so if the mounting screws are removed, the worker will have to bear the weight of the vibration control device, which makes it difficult to work with.

[0009] An object of the present invention is to provide a dynamic vibration absorbing structure that can improve the efficiency of tuning work even when the dynamic vibration absorbing structure is provided in a position that is unsuitable for tuning. [Means for solving the problem]

[0010] A dynamic vibration absorbing structure according to a first aspect of the present invention includes a pair of support members extending in a predetermined direction on a horizontal plane and spaced apart in an orthogonal direction perpendicular to the predetermined direction on the horizontal plane, and a dynamic vibration absorbing device supported by the pair of support members so as to straddle the pair of support members. The dynamic vibration absorbing device includes a base member having a pair of mounting portions mounted on mounting surfaces extending in the predetermined direction on each of the pair of support members and a connecting portion connecting the pair of mounting portions, an elastic member provided on the base member, a mass body provided on the elastic member so as to sandwich the elastic member between the base member and the elastic member, and an attachment means for attaching the mass body to the base member in a switchable state between a restricted state that restricts movement in the predetermined direction and the orthogonal direction and allows movement in the up and down direction, and an allowable state that allows removal of the mass body by movement in the predetermined direction. The base member is placed on the mounting surfaces of the pair of support members so as to be movable in the predetermined direction relative to the pair of support members.

[0011] According to the dynamic vibration absorbing structure of the first aspect, by switching the mounting means to the restricting state, when vibrations of a predetermined frequency occur in the support member, the mass body can be moved vertically, thereby suppressing the vibrations. Furthermore, because the base member is mounted on the mounting surface while being movable in a predetermined direction relative to the pair of support members, the base member, i.e., the dynamic vibration absorber, can be moved in a predetermined direction to a position suitable for tuning while the mounting means is switched to the restricting state. In this way, when the dynamic vibration absorber has been moved to a position suitable for tuning, the mounting means can be switched to the allowing state to move the mass body in a predetermined direction relative to the base member, allowing, for example, the mass body to be removed. Therefore, according to the dynamic vibration absorbing structure, the entire dynamic vibration absorber can be moved in a predetermined direction to a position suitable for tuning, and the weight of the mass body can be changed for a dynamic vibration absorber located in a position suitable for tuning. This improves the efficiency of tuning work, even when the dynamic vibration absorber is located in a position unsuitable for tuning.

[0012] A dynamic vibration-absorbing structure according to a second aspect may be the dynamic vibration-absorbing structure of the first aspect, wherein the mass body has a first layer and a second layer stacked on the first layer, and the attachment means may include a restraining mechanism switchable between a restraining state in which the second layer is restrained relative to the first layer and a detaching state in which the second layer is allowed to move in the predetermined direction relative to the first layer so as to be detached from the first layer.

[0013] According to the dynamic vibration-absorbing structure of the second aspect, the second layer can be removed from the first layer by switching the restraint mechanism to the detached state. Here, since the second layer is stacked on the first layer, the second layer can be removed from the first layer by moving the second layer in a predetermined direction while the weight of the second layer is supported by the first layer. Therefore, the efficiency of tuning work can be improved compared to when the worker removes the second layer while bearing the weight of the second layer.

[0014] A dynamic vibration-absorbing structure according to a third aspect is the dynamic vibration-absorbing structure of the second aspect, wherein the mass body includes a support layer attached to the elastic member between the first layer and the elastic member. In this case, the restraint mechanism may include a restraint shaft extending from the support layer to above the second layer so as to penetrate the second layer and the first layer, and a clamping portion provided on the restraint shaft so as to be vertically displaceable relative to the support layer between a close state in which the restraint shaft is close to the support layer so as to clamp the second layer and the first layer in the vertical direction between the support layer and the restraint shaft and a separated state that is further away from the support layer than the close state. The second layer includes a second insertion portion through which the restraint shaft is inserted, and a second extension portion extending from the second insertion portion to an edge of the second layer in the predetermined direction so as to allow the restraint shaft to be guided from the second insertion portion to a position on one side of the second layer in the predetermined direction.

[0015] According to the dynamic vibration absorbing structure of the third aspect, the second layer can be moved in a predetermined direction from the first layer by guiding the restraint shaft in a predetermined direction from the second insertion portion along the second extension portion when the clamping portion is separated upward from the support layer.

[0016] A dynamic vibration absorbing structure according to a fourth aspect may be the dynamic vibration absorbing structure of the third aspect, wherein the first layer has a first insertion portion through which the restraining shaft is inserted, and a first extension portion extending from the first insertion portion to an edge of the first layer in the perpendicular direction so as to allow the restraining shaft to be guided from the first insertion portion to a position on one side of the first layer in the perpendicular direction.

[0017] According to the dynamic vibration-absorbing structure of the fourth aspect, after the second layer is removed from the first layer in a separated state in which the clamping portion is separated from the support layer, the first layer can be moved in a direction perpendicular to the restraining shaft from the first insertion portion along the first extension portion, thereby extracting the restraining shaft from the first layer, thereby removing the first layer from the restraining shaft. Here, the removal direction of the second layer is a predetermined direction, while the removal direction of the first layer is an orthogonal direction perpendicular to the predetermined direction, so that the first layer can be prevented from moving together with the second layer when the second layer is removed.

[0018] A dynamic vibration absorbing structure according to a fifth aspect may be the dynamic vibration absorbing structure of the fourth aspect, wherein the length of the first extension portion in the orthogonal direction is shorter than the length of the second extension portion in the predetermined direction.

[0019] According to the dynamic vibration-absorbing structure of the fifth aspect, because the base member is movable in a predetermined direction relative to the pair of support members, it is easy to ensure a larger working space in the predetermined direction than in the perpendicular direction during tuning. Under such circumstances, the length of the first extension portion in the perpendicular direction is shorter than the length of the second extension portion in the predetermined direction, i.e., the distance required to remove the first layer from the constraint shaft is shorter than the distance required to remove the second layer from the constraint shaft. Therefore, in the perpendicular direction, where space is relatively limited, the moving distance of the first layer to release the constraint of the first layer by the constraint shaft can be shortened.

[0020] A dynamic vibration-absorbing structure according to a sixth aspect is the dynamic vibration-absorbing structure of any one of the second to fifth aspects, wherein the first layer may have a first basic piece and a first adjacent piece adjacent to the first basic piece in the orthogonal direction. In this case, the second layer may have a size sufficient to cover the first basic piece and the first adjacent piece from above and may have a mass smaller than the total mass of the first basic piece and the first adjacent piece. The restraint mechanism attaches the first layer to the base member in the detached state such that the first adjacent piece and the first basic piece can be individually detached by detaching the second layer.

[0021] According to the dynamic vibration-absorbing structure of the sixth aspect, the first layer, which has a greater mass than the second layer, is divided into two pieces (a first basic piece and a first adjacent piece), and the first basic piece and the first adjacent piece can be removed individually in the removed state. Therefore, compared to removing the entire first layer at once, the weight burden when removing the first layer can be reduced, and tuning work can be made more efficient.

[0022] A dynamic vibration absorbing structure according to a seventh aspect may be any of the dynamic vibration absorbing structures according to the third to sixth aspects, wherein the mounting means includes a pair of regulating members attached to the base member on both sides of the support layer in the specified direction so as to regulate movement of the support layer of the mass body in the specified direction, and a pair of damping members sandwiched between the pair of regulating members and the support layer, respectively, for damping vibration of the mass body.

[0023] The dynamic vibration-absorbing structure according to the seventh aspect has a restricting member and a damping member, which can suppress vibration of the mass body in an unintended direction (a predetermined direction) and can more effectively suppress vibration generated in the support member. Furthermore, since the damping member is provided between the restricting member and the support layer, which is attached and detached less frequently than the first and second layers, the above-mentioned effects can be achieved while maintaining the ease of tuning. [Effects of the Invention]

[0024] As described above, according to the present invention, it is possible to provide a dynamic vibration absorbing structure that can improve the efficiency of tuning work even when the dynamic vibration absorbing structure is provided in a position that is unsuitable for tuning. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a perspective view showing the schematic configuration of a main part of a building to which a dynamic vibration absorbing structure according to an embodiment of the present invention is applied. [Figure 2] FIG. 2 is a diagram showing the dynamic vibration absorbing structure as viewed from a predetermined direction. [Figure 3] 3 is a cross-sectional view of the dynamic vibration absorbing structure taken along line III-III in FIG. 2, showing the dynamic vibration absorbing device as viewed from above. [Figure 4] 4 is a cross-sectional view of the dynamic vibration absorbing structure taken along line IV-IV in FIG. 2, showing the dynamic vibration absorber as viewed from the perpendicular direction. [Figure 5] FIG. 4 is a cross-sectional view of the dynamic vibration absorbing structure taken along line VV in FIG. 3. [Figure 6] FIG. 10 is a plan view of the second layer of the mass body provided in the dynamic vibration absorber of the dynamic vibration absorbing structure. [Figure 7] FIG. 2 is a plan view of a first layer of a mass body provided in a dynamic vibration absorber having a dynamic vibration absorbing structure. [Figure 8] 6 is a cross-sectional view of the dynamic vibration-absorbing structure corresponding to FIG. 5, showing a state in which the second layer of the mass body has been removed. FIG. [Figure 9] FIG. 4 is a diagram corresponding to FIG. 3, showing the dynamic vibration absorber as viewed from above, with the second layer of the mass body removed. [Figure 10] 9 is a cross-sectional view of the dynamic vibration-absorbing structure corresponding to FIG. 8, showing how the layer above the first layer of the mass body is removed. [Figure 11] 9 is a cross-sectional view of the dynamic vibration-absorbing structure corresponding to FIG. 8, showing how the layer below the first layer of the mass body is removed. DETAILED DESCRIPTION OF THE INVENTION

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention with reference to the accompanying drawings. Note that the following embodiments are examples that embody the present invention and are not intended to limit the technical scope of the present invention.

[0027] FIG. 1 is a perspective view showing a schematic configuration of a main part of a building to which a dynamic vibration absorbing structure 1 according to an embodiment of the present invention is applied. The dynamic vibration absorbing structure 1 is intended to reduce vibrations of a predetermined frequency that occur in a beam 100 that supports a ceiling panel 101 on a lower floor and a floor panel 102 on an upper floor in, for example, a multi-story building. The dynamic vibration absorbing structure 1 is disposed in a space S between the ceiling panel 101 on the lower floor and the floor panel 102 on the upper floor. The ceiling panel 101 is provided with an inspection hatch 101A for inspecting the interior of the space S. With the dynamic vibration absorbing structure 1 disposed in the space S, a tuning operation is performed by a worker through the inspection hatch 101A to tune the dynamic vibration absorbing structure 1 according to the frequency of the vibration of the beam 100 so that the dynamic vibration absorbing structure 1 can effectively reduce vibrations that occur in the beam 100.

[0028] The dynamic vibration absorbing structure 1 will be described in detail with reference to Figures 2 to 11. The dynamic vibration absorbing structure 1 includes a pair of support members 2 that extend in a predetermined direction D1 on a horizontal plane and are spaced apart in an orthogonal direction D2 that is orthogonal to the predetermined direction D1 on the horizontal plane, and a dynamic vibration absorbing device 3 that is supported by the pair of support members 2 so as to straddle the pair of support members 2. In the following description, with regard to directional relationships, directions that are orthogonal to each other on the horizontal plane are referred to as the predetermined direction D1 and the orthogonal direction D2, and a vertical direction perpendicular to the predetermined direction D1 and the orthogonal direction D2 is referred to as the up-down direction D3.

[0029] The pair of support members 2 are fixed to beams 100 of a building. For example, as shown in FIGS. 2 and 3 , each of the pair of support members 2 is a member having a C-shaped cross section. Specifically, the pair of support members 2 each has a flat support main body portion 21 extending in the predetermined direction D1 and the up-down direction D3, a flat upper protruding portion 22 protruding from the upper end of the support main body portion 21 in the orthogonal direction D2 toward the dynamic vibration absorber 3 and extending in the predetermined direction D1, and a flat lower protruding portion 23 protruding from the lower end of the support main body portion 21 in the orthogonal direction D2 toward the dynamic vibration absorber 3 and extending in the predetermined direction D1. Each of the pair of support members 2 has a surface of the lower protruding portion 23 facing upward in the up-down direction D3 and extending in the predetermined direction D1 as a mounting surface 231.

[0030] As shown in Figures 2 to 5, for example, the dynamic vibration absorber 3 includes a base member 4 placed on the mounting surfaces 231 of the pair of support members 2 so as to straddle the pair of support members 2, an elastic member 5 provided on the base member 4, a mass body 6 provided on the elastic member 5, and an attachment means 7 for attaching the mass body 6 to the base member 4.

[0031] 3 and 9, the base member 4 is, for example, a rectangular flat plate-shaped member. The base member 4 is made of, for example, steel. The base member 4 has a pair of mounting portions 41 placed on mounting surfaces 231 extending in the predetermined direction D1 on each of the pair of support members 2, and a connecting portion 42 connecting the pair of mounting portions 41. In the base member 4, the regions located at both ends in the orthogonal direction D2 form the pair of mounting portions 41, and the region located between the pair of mounting portions 41 in the orthogonal direction D2 forms the connecting portion 42.

[0032] The base member 4 is placed on the placement surfaces 231 of the pair of support members 2 in a state in which it is movable in a predetermined direction D1 relative to the pair of support members 2. When the pair of placement portions 41 are fixed to the lower protrusions 23 of the pair of support members 2 by the base fixing bolts 82, the movement of the base member 4 along the placement surfaces 231 is restricted, whereas when the base fixing bolts 82 are removed, the base member 4 is movable in the predetermined direction D1 along the placement surfaces 231.

[0033] As shown in FIG. 2 , the elastic member 5 is fixed onto the connection portion 42 of the base member 4 by an elastic fixing bolt 81. A mass body 6 is provided on this elastic member 5. The elastic member 5 is capable of elastic deformation in response to relative movement of the mass body 6 in the up-down direction D3 with respect to the base member 4 placed on the placement surface 231 of the pair of support members 2. The elastic member 5 is formed, for example, by a spring member. The number and positions of the elastic members 5 with respect to the connection portion 42 of the base member 4 are not particularly limited as long as the mass body 6 provided on the elastic member 5 can be maintained in a horizontal position with respect to the base member 4. In this embodiment, for example, four elastic members 5 are fixed onto the connection portion 42 of the base member 4.

[0034] The mass body 6 is made of, for example, steel. As shown in Fig. 2, the mass body 6 is provided on the elastic member 5 so as to sandwich the elastic member 5 between the mass body 6 and the base member 4. As shown in Fig. 3, the mass body 6 is provided on the elastic member 5 so as to be located within the range of the connection portion 42 of the base member 4 in a plan view seen from the up-down direction D3.

[0035] In the dynamic vibration absorbing structure 1, when a pair of support members 2 fixed to the beam 100 vibrate in response to the vibration of the beam 100, the mass body 6 supported by the elastic member 5 on the connection portion 42 of the base member 4 placed on the mounting surface 231 of the pair of support members 2 moves in the opposite direction based on inertial force to the vibration of the pair of support members 2 in the vertical direction D3, thereby suppressing the vibration of the beam 100 via the pair of support members 2.

[0036] The attachment means 7 attaches the mass body 6 to the base member 4 in a state switchable between a restrictive state and an allowable state. Figure 5 shows the state in which the attachment means 7 is switched to the restrictive state, and Figures 8, 10, and 11 show the states in which the attachment means 7 is switched to the allowable state. When the mass body 6 is attached to the base member 4 in the restrictive state, the attachment means 7 restricts movement of the mass body 6 in the predetermined direction D1 and the orthogonal direction D2, and allows movement of the mass body 6 in the up-down direction D3. When the mass body 6 is attached to the base member 4 in the allowable state, the attachment means 7 allows removal of the mass body 6 by movement in the predetermined direction D1.

[0037] According to the dynamic vibration-absorbing structure 1 described above, by switching the mounting means 7 to the restricting state, when vibrations of a preset frequency occur in the pair of support members 2 in response to vibration of the beam 100, the mass body 6 can be moved in the vertical direction D3 while movement in the predetermined direction D1 and the orthogonal direction D2 is restricted, thereby suppressing the vibrations. Furthermore, because the base member 4 is placed on the mounting surface 231 in a state in which it can move in the predetermined direction D1 relative to the pair of support members 2, with the mounting means 7 switched to the restricting state, the base member 4, i.e., the dynamic vibration absorber 3, can be moved in the predetermined direction D1 to a position suitable for tuning.

[0038] The position suitable for tuning refers to a position where an operator can efficiently perform tuning work, which involves changing the weight of the mass body 6, through the inspection hatch 101A when the frequency of vibrations generated in the pair of support members 2 in response to the vibration of the beam 100 differs from the preset frequency of the dynamic vibration absorber 3. When tuning the dynamic vibration absorber 3, the operator accesses the dynamic vibration absorbing structure 1 through the inspection hatch 101A and releases the fixed state of the base member 4 to the pair of support members 2 by removing the base fixing bolts 82. Then, the operator can move the base member 4 along the mounting surfaces 231 of the pair of support members 2 to move the dynamic vibration absorber 3 in the predetermined direction D1 to a position suitable for tuning. In this way, when the dynamic vibration absorber 3 has been moved to a position suitable for tuning, the operator can switch the mounting means 7 to the permissive state to move the mass body 6 in the predetermined direction D1 relative to the base member 4, thereby removing the mass body 6, for example. Therefore, according to the dynamic vibration absorbing structure 1, the position of the entire dynamic vibration absorbing device 3 can be moved in a predetermined direction D1 to a position suitable for tuning, and the weight of the mass body 6 can be changed for the dynamic vibration absorbing device 3 that is in a position suitable for tuning, so that even if the dynamic vibration absorbing structure 1 is installed in a position unsuitable for tuning, the efficiency of the tuning work can be improved.

[0039] After completing the tuning work, the worker can move the dynamic vibration absorber 3 to its original predetermined position in the predetermined direction D1 by switching the mounting means 7 to the restricted state and then moving the base member 4 along the mounting surfaces 231 of the pair of support members 2. Thereafter, the worker fixes the base member 4 to the pair of support members 2 with the base fixing bolts 82.

[0040] 2 and 4, the mass body 6 in the dynamic vibration absorber 3 may have a first layer 61 and a second layer 62 stacked on the first layer 61. In the mass body 6, the first layer 61 and the second layer 62 are formed, for example, from rectangular flat steel plates. The number of first layers 61 and second layers 62 is not particularly limited and may be one or more. In this embodiment, the mass body 6 has, for example, two first layers 61 and two second layers 62.

[0041] The attachment means 7 includes a constraint mechanism 71, as shown in, for example, FIGS. 5, 8, 10, and 11. The number of constraint mechanisms 71 is not particularly limited and may be one or more. In this embodiment, as shown in, for example, FIG. 2, the attachment means 7 includes two constraint mechanisms 71 spaced apart from each other in the orthogonal direction D2. When the second layer 62 is stacked on the first layer 61 in the mass body 6, the constraint mechanism 71 is switchable between a constraint state (the state shown in FIG. 5) in which the second layer 62 is constrained relative to the first layer 61, and a detachment state (the state shown in FIGS. 8, 10, and 11) in which the second layer 62 is permitted to move in the predetermined direction D1 relative to the first layer 61 so as to be detached from the first layer 61. By switching the constraint mechanism 71 to the constraint state, the attachment means 7 can be switched to the above-described restricted state. Moreover, by switching the restraining mechanism 71 to the detached state, it is possible to switch the attachment means 7 to the above-mentioned permitted state.

[0042] By switching the restraining mechanism 71 to the restraining state, when vibration occurs in the pair of support members 2, the mass body 6 can be moved in the vertical direction D3 while restraining the second layer 62 relative to the first layer 61, thereby suppressing the vibration. Furthermore, when tuning of the dynamic vibration absorber 3 is required, the dynamic vibration absorber 3 can be moved in the predetermined direction D1 to a position suitable for tuning by moving the base member 4 along the mounting surfaces 231 of the pair of support members 2 with the restraining mechanism 71 switched to the restraining state. In this manner, when the dynamic vibration absorber 3 has been moved to a position suitable for tuning, the second layer 62 of the mass body 6 can be detached from the first layer 61 by switching the restraining mechanism 71 to the detaching state. Here, because the second layer 62 is stacked on the first layer 61, the second layer 62 can be detached from the first layer 61 by moving the second layer 62 in the predetermined direction D1 with its weight resting on the first layer 61. Therefore, the efficiency of the tuning work can be improved compared to when the worker removes the second layer 62 while bearing the weight of the second layer 62.

[0043] Furthermore, in the dynamic vibration absorber 3, the mass body 6 may have a support layer 63 attached to the elastic member 5 between the first layer 61 and the elastic member 5. In the mass body 6, the support layer 63 is a layer that supports the first layer 61 and the second layer 62 from below while attached to the elastic member 5, and is made of, for example, a rectangular flat steel plate. Furthermore, the number of support layers 63 is not particularly limited, and may be one or more. In this embodiment, the mass body 6 has, for example, three support layers 63.

[0044] In the mounting means 7, the restraint mechanism 71 may have a restraint shaft 711 and a clamping portion 712. In the restraint mechanism 71, the restraint shaft 711 is formed, for example, by a bolt, and the clamping portion 712 is formed, for example, by a nut. The restraint shaft 711 is a shaft that extends from the support layer 63 to above the second layer 62 so as to penetrate the second layer 62 and the first layer 61 with respect to the mass body 6. The clamping portion 712 is provided on the restraint shaft 711 so as to be displaceable relative to the support layer 63 in the vertical direction D3 between a close state (the state shown in FIG. 5 ) in which the clamping portion 712 is close to the support layer 63 so as to clamp the second layer 62 and the first layer 61 in the vertical direction D3 between the support layer 63 and the clamping portion 712, and a separated state (the state shown in FIGS. 8 , 10 , and 11 ) in which the clamping portion 712 is further away from the support layer 63 than the close state. By providing the clamping portion 712 on the restraint shaft 711 in the close state, the restraint mechanism 71 can be switched to the above-mentioned restrained state. Furthermore, by providing the clamping portion 712 in a separated state on the restraining shaft 711, it becomes possible to switch the restraining mechanism 71 to the above-mentioned detached state.

[0045] 6, in the case where the restraint mechanism 71 has a restraint shaft 711 and a clamping portion 712, the second layer 62 of the mass body 6 may have a second insertion portion 62A through which the restraint shaft 711 is inserted, and a second extension portion 62B extending from the second insertion portion 62A to an edge of the second layer 62 in the predetermined direction D1 so as to allow for guiding the restraint shaft 711 from the second insertion portion 62A to a position on one side of the second layer 62 in the predetermined direction D1. In the example of FIG. 6, the second layer 62 has two second insertion portions 62A and two second extension portions 62B corresponding to each of the two restraint mechanisms 71 spaced apart from each other in the orthogonal direction D2.

[0046] 7, the first layer 61 of the mass body 6 may have a first insertion portion 61A through which the restraint shaft 711 is inserted, and a first extension portion 61B extending from the first insertion portion 61A to an edge of the first layer 61 in the orthogonal direction D2 so as to allow for guiding the restraint shaft 711 from the first insertion portion 61A to a position on one side of the first layer 61 in the orthogonal direction D2. In the example of FIG. 7, the first layer 61 has two first insertion portions 61A and two first extension portions 61B corresponding to each of the two restraint mechanisms 71 spaced apart from each other in the orthogonal direction D2.

[0047] 5, in the restraint mechanism 71, the clamping portion 712 is provided on the restraint shaft 711 in a proximal state, so that the clamping portion 712 clamps the second layer 62 and the first layer 61 in the vertical direction D3 between the clamping portion 712 and the support layer 63 attached to the elastic member 5. As a result, when vibration occurs in the pair of support members 2, the mass body 6 can be moved in the vertical direction D3 with the second layer 62 and the first layer 61 clamped against the support layer 63, thereby suppressing the vibration.

[0048] Furthermore, when tuning of the dynamic vibration absorber 3 is required, the dynamic vibration absorber 3 can be moved in the predetermined direction D1 to a position suitable for tuning by moving the base member 4 along the mounting surfaces 231 of the pair of support members 2 with the clamping portions 712 attached to the restraint shafts 711 in a close relationship. In this manner, when the dynamic vibration absorber 3 has been moved to a position suitable for tuning, with the clamping portions 712 attached to the restraint shafts 711 in a separated relationship as shown in FIG. 8 , the second layer 62 can be moved in the predetermined direction D1 from the first layer 61 by guiding the restraint shafts 711 along the second extension portions 62B from the second insertion portions 62A. This allows the second layer 62 of the mass body 6 to be removed from the first layer 61.

[0049] Furthermore, after the second layer 62 is removed from the first layer 61 with the clamping portion 712 provided on the restraining shaft 711 in a separated state, as shown in Figures 10 and 11, the first layer 61 can be moved in the orthogonal direction D2 from the first insertion portion 61A along the first extension portion 61B relative to the restraining shaft 711, thereby extracting the restraining shaft 711 from the first layer 61, thereby removing the first layer 61 from the restraining shaft 711. Here, the removal direction of the second layer 62 is the predetermined direction D1, while the removal direction of the first layer 61 is the orthogonal direction D2 perpendicular to the predetermined direction D1. Therefore, when the second layer 62 is removed, the first layer 61 can be prevented from moving together with the second layer 62.

[0050] 6 and 7 , the length L1 in the orthogonal direction D2 of the first extension portion 61B on the first layer 61 is shorter than the length L2 in the predetermined direction D1 of the second extension portion 62B on the second layer 62. In the dynamic vibration-absorbing structure 1, as described above, the base member 4 is movable in the predetermined direction D1 relative to the pair of support members 2. Therefore, during tuning of the dynamic vibration absorber 3, it is easy to ensure a larger working space in the predetermined direction D1 than in the orthogonal direction D2. Under these circumstances, the length L1 in the orthogonal direction D2 of the first extension portion 61B on the first layer 61 is shorter than the length L2 in the predetermined direction D1 of the second extension portion 62B on the second layer 62. In other words, the distance required to remove the first layer 61 from the constraint shaft 711 is shorter than the distance required to remove the second layer 62 from the constraint shaft 711. Therefore, in the orthogonal direction D2 where the working space is relatively limited, the moving distance of the first layer 61 for releasing the constraint of the first layer 61 by the constraint shaft 711 can be shortened.

[0051] 7, in the mass body 6, the first layer 61 may have a first basic piece 611 and a first adjacent piece 612 adjacent to the first basic piece 611 in the orthogonal direction D2. In this case, the second layer 62 may be large enough to cover the first basic piece 611 and the first adjacent piece 612 from above, and may have a mass smaller than the total mass of the first basic piece 611 and the first adjacent piece 612. Then, as shown in FIGS. 10 and 11, the restraint mechanism 71 attaches the first layer 61 to the base member 4 so that the first adjacent piece 612 and the first basic piece 611 can be individually removed by removing the second layer 62 in a detached state in which the clamping portion 712 is provided on the restraint shaft 711 in a separated state.

[0052] In the mass body 6, the first layer 61, which has a greater mass than the second layer 62, is divided into two pieces, a first basic piece 611 and a first adjacent piece 612, and the first basic piece 611 and the first adjacent piece 612 can be removed individually when the restraint mechanism 71 is in the removed state. This reduces the weight burden when removing the first layer 61 compared to removing the entire first layer 61 at once, making the tuning work more efficient.

[0053] 2 to 4, the mounting means 7 may include a pair of first restricting members 72 and a pair of first damping members 721. The pair of first restricting members 72 are attached to the base member 4 by restricting fixing bolts 83 on both sides of the support layer 63 in the predetermined direction D1 so as to restrict movement of the support layer 63 of the mass body 6 in the predetermined direction D1. The pair of first restricting members 72 include, for example, first restricting bolts 72A extending in the predetermined direction D1. The first restricting bolts 72A are normally out of contact with the support layer 63 and only come into contact with the support layer 63 when the support layer 63 moves slightly in the predetermined direction D1. The pair of first restricting members 72 can restrict movement of the support layer 63 of the mass body 6 in the predetermined direction D1 by contact with the first restricting bolts 72A. The pair of first damping members 721 are sandwiched between the pair of first restricting members 72 and the support layer 63, respectively, and serve to damp vibration of the mass body 6. The pair of first damping members 721 are in contact with the support layer 63. The pair of first damping members 721 are made of, for example, an elastically deformable rubber material.

[0054] By providing the mounting means 7 with the pair of first restricting members 72 and the pair of first damping members 721, it is possible to suppress unintended vibration of the mass body 6 in the predetermined direction D1 when the mass body 6 moves in the up-down direction D3 in response to vibration of the pair of support members 2, and to more effectively suppress vibrations occurring in the pair of support members 2. Furthermore, since the first damping members 721 are provided between the support layer 63 and the first restricting members 72, which are attached and detached less frequently than the first layer 61 and second layer 62 during tuning of the dynamic vibration absorber 3, it is possible to obtain the above-mentioned effects while maintaining the ease of tuning.

[0055] The mounting means 7 may also include a pair of second restricting members 73 and a pair of second damping members 731. The pair of second restricting members 73 are attached to the base member 4 by restricting fixing bolts 83 on both sides of the support layer 63 in the orthogonal direction D2 so as to restrict movement of the support layer 63 of the mass body 6 in the orthogonal direction D2. The pair of second restricting members 73 include, for example, second restricting bolts 73A extending in the orthogonal direction D2. The second restricting bolts 73A are normally out of contact with the support layer 63 and only come into contact with the support layer 63 when the support layer 63 moves slightly in the orthogonal direction D2. The pair of second restricting members 73 can restrict movement of the support layer 63 of the mass body 6 in the orthogonal direction D2 by contact with the second restricting bolts 73A. The pair of second damping members 731 are sandwiched between the pair of second restricting members 73 and the support layer 63, respectively, and are members for damping vibration of the mass body 6. The pair of second damping members 731 are in contact with the support layer 63. The pair of second damping members 731 are made of, for example, an elastically deformable rubber material.

[0056] Because the mounting means 7 has a pair of second regulating members 73 and a pair of second damping members 731, when the mass body 6 moves in the vertical direction D3 in response to vibration of the pair of support members 2, unintended vibration of the mass body 6 in the perpendicular direction D2 can be suppressed, and vibrations generated in the pair of support members 2 can be more effectively suppressed.

[0057] Note that movement of the mass body 6 in the vertical direction D3 can be constrained by slightly tightening the first restriction bolts 72A of the pair of first restriction members 72 while they are in contact with the support layer 63. Similarly, movement of the mass body 6 in the vertical direction D3 can be constrained by slightly tightening the second restriction bolts 73A of the pair of second restriction members 73 while they are in contact with the support layer 63. By constraining movement of the mass body 6 in the vertical direction D3 in this manner while the first restriction bolts 72A and the second restriction bolts 73A are in contact with the support layer 63, the effect of suppressing vibrations generated in the pair of support members 2 due to movement of the mass body 6 in the vertical direction D3 can be turned off. In this case, the effect of suppressing vibrations due to movement of the mass body 6 in the vertical direction D3 can be grasped by comparing the vibrations of the pair of support members 2 when the first restriction bolts 72A and the second restriction bolts 73A are not in contact with the support layer 63 with the vibrations of the pair of support members 2 when the first restriction bolts 72A and the second restriction bolts 73A are in contact with the support layer 63.

[0058] Furthermore, when the first restricting bolt 72A and the second restricting bolt 73A are not in contact with the support layer 63 and the movement of the mass body 6 in the vertical direction D3 is not restricted, removing the first layer 61 and the second layer 62 of the mass body 6 will make the mass body 6 lighter and more likely to move in the vertical direction D3, which could result in excessive deformation of the first damping member 721 and the second damping member 731. Therefore, when the first restricting bolt 72A and the second restricting bolt 73A are in contact with the support layer 63 and the movement of the mass body 6 in the vertical direction D3 is restricted, the dynamic vibration absorber 3 can be attached to or detached from the pair of support members 2 in the light state after the first layer 61 and the second layer 62 of the mass body 6 have been removed, thereby preventing excessive deformation of the first damping member 721 and the second damping member 731. [Explanation of symbols]

[0059] 1 Dynamic vibration absorption structure 2 Pair of support members 3 Dynamic vibration absorber 4 Base material 41 Pair of mounting parts 42 Connection 5 Elastic member 6 mass body 61 1st layer 611 1st basic piece 612 First adjacent piece 61A First insertion part 61B 1st extension section 62 2nd layer 62A Second insertion part 62B 2nd extension section 63 Support layer 7 Mounting means 71 Restraint mechanism 711 Restraint axis 712 Clamping part 72 Pair of first restricting members 721 Pair of first damping members 73 Pair of second restricting members 731 Pair of second damping members D1 Specified direction D2 Orthogonal direction D3 Up and down direction

Claims

1. A dynamic vibration absorbing structure, a pair of support members extending in a predetermined direction on a horizontal plane and spaced apart in an orthogonal direction perpendicular to the predetermined direction on the horizontal plane; a dynamic vibration absorbing device supported by the pair of support members so as to straddle the pair of support members, The dynamic vibration absorber is a base member including a pair of mounting portions placed on mounting surfaces extending in the predetermined direction in each of the pair of support members, and a connecting portion connecting the pair of mounting portions; an elastic member provided on the base member; a mass body provided on the elastic member so as to sandwich the elastic member between the mass body and the base member; and an attachment means for attaching the mass body to the base member in a state switchable between a restricted state in which movement of the mass body in the predetermined direction and the orthogonal direction is restricted and movement of the mass body in the up-and-down direction is permitted, and an allowable state in which removal of the mass body is permitted by movement in the predetermined direction is permitted; The base member is placed on the mounting surfaces of the pair of support members in a state in which the base member is movable in the predetermined direction relative to the pair of support members.

2. the mass body has a first layer and a second layer stacked on the first layer, 2. The dynamic vibration absorbing structure of claim 1, wherein the attachment means includes a restraint mechanism that can be switched between a restraint state that restrains the second layer relative to the first layer and a detachment state that allows movement in the specified direction relative to the first layer so that the second layer can be removed from the first layer.

3. the mass body includes a support layer attached to the elastic member between the first layer and the elastic member; the restraint mechanism includes a restraint shaft extending from the support layer to above the second layer so as to penetrate the second layer and the first layer, and a clamping portion provided on the restraint shaft in a state that is displaceable relative to the support layer in the vertical direction between a close state in which the restraint shaft is close to the support layer so as to clamp the second layer and the first layer between the support layer and the restraint shaft and a separated state in which the restraint shaft is spaced above the support layer relative to the close state, 3. The dynamic vibration absorbing structure of claim 2, wherein the second layer has a second insertion portion through which the restraining shaft is inserted, and a second extension portion extending from the second insertion portion to an edge of the second layer in the specified direction so as to allow the restraining shaft to be guided from the second insertion portion to a position on one side of the second layer in the specified direction.

4. 4. The dynamic vibration absorbing structure of claim 3, wherein the first layer has a first insertion portion through which the restraining shaft is inserted, and a first extension portion extending from the first insertion portion to an edge of the first layer in the perpendicular direction so as to allow guiding of the restraining shaft from the first insertion portion to a position on one side of the first layer in the perpendicular direction.

5. The dynamic vibration absorbing structure according to claim 4 , wherein the length of the first extension portion in the orthogonal direction is shorter than the length of the second extension portion in the predetermined direction.

6. the first layer has a first basic piece and a first adjacent piece adjacent to the first basic piece in the orthogonal direction, the second layer has a size capable of covering the first basic piece and the first adjacent piece from above, and has a mass smaller than a total mass of the first basic piece and the first adjacent piece, A dynamic vibration absorbing structure as described in any one of claims 2 to 5, wherein the restraint mechanism attaches the first layer to the base member so that, in the detached state, the first adjacent piece and the first basic piece can be individually removed by removing the second layer.

7. 6. The dynamic vibration absorbing structure according to claim 3, wherein the mounting means comprises: a pair of restricting members attached to the base member on both sides of the support layer in the predetermined direction so as to restrict movement of the support layer of the mass body in the predetermined direction; and a pair of damping members sandwiched between the pair of restricting members and the support layer, respectively, and for damping vibration of the mass body.

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