Dynamic vibration absorber

Abstract

A dynamic vibration absorber is provided that allows the elastic member on the base member to be replaced and allows the elastic member to be arranged on the edge of a mass body in a plan view. [Solution] The dynamic vibration absorber includes an elastic member provided on a base member, a mass body provided on the elastic member, and a screw member that screws onto an elastic-side threaded portion provided on the elastic member from above. The mass body includes a fixed layer having an insertion hole through which the screw member is inserted and removed from above, and a movable layer stacked on the fixed layer. The base member and the fixed layer each have a through hole formed in a position where they overlap in a plan view. The movable layer has a downward-facing pressure-receiving surface at a position where it overlaps with the through hole. The fixed layer and the movable layer are shaped to release the screw member so that the screw member can be operated from above the fixed layer when the fixed layer and the movable layer are separated, but to accommodate the screw member so that operation of the screw member is restricted when the fixed layer and the movable layer are stacked.

Description

[Technical Field]

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

[0002] A conventional vibration damping device is known, for example, from Patent Document 1. The vibration damping device described in Patent Document 1 includes a base member, a metal mass, and rubber mounts provided between the base member and the metal mass near each of the four corners of the metal mass to elastically support the metal mass relative to the base member. When provided on the base member, each of the four rubber mounts is fixed to the metal mass from below with a bolt via a metal bracket connected to the top of the rubber mount.

[0003] Furthermore, the vibration damping device includes a stopper bolt that protrudes from the mass fitting toward the base member and is inserted into an insertion hole of an engagement portion provided in the base member, and an abutment nut that is screwed onto the stopper bolt between the mass fitting and the base member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-343645 Summary of the Invention [Problem to be solved by the invention]

[0005] In the vibration damping device described in Patent Document 1, when vertical vibration occurs in the base member, a metal mass elastically supported by a rubber mount on the base member moves in the opposite direction due to inertial force relative to the vertical vibration of the base member, thereby suppressing the vibration of the base member. However, when tuning the vibration suppression characteristics of the vibration damping device or when the rubber mount is damaged, it is necessary to remove the rubber mount. In this case, the abutment nut abuts against the base member from above in response to rotation of the stopper bolt, and the stopper bolt is pushed up by the reaction force from the abutment nut. This causes the metal mass to move upward relative to the base member. In this state, the rubber mount can be removed by removing the bolt that secures the metal mass to the rubber mount.

[0006] However, the base member is subject to not only vertical vibrations but also horizontal vibrations, and the metal mass may vibrate in a direction inclined relative to the horizontal, i.e., rocking vibration may occur. When rocking vibration occurs, the effectiveness of suppressing the vertical vibration of the base member decreases.

[0007] One possible measure to suppress deformation due to rocking vibration in the rubber mounts supporting the metal mass on the base member is to increase the distance between the rubber mounts within the range of the metal mass in a plan view. However, in the vibration damping device described in Patent Document 1, each rubber mount is fixed to the metal mass with a bolt inserted from below into an extension portion of the bracket metal that extends outward beyond the rubber mount. When fixing each rubber mount to the metal mass with a bolt from below, the bolt position must be set so that at least a portion of the bolt is out of position with respect to each rubber mount in a plan view, taking into account the bolt's rotation from below. Therefore, when attempting to position a rubber mount on the edge of the metal mass in a plan view, the rubber mount must be positioned inward from the edge of the metal mass to account for the bolt protruding outward from the rubber mount, which limits the distance between the rubber mounts. Therefore, there is room for improvement in effectively suppressing deformation due to rocking vibration in each rubber mount and effectively suppressing vertical vibration of the base member.

[0008] An object of the present invention is to provide a dynamic vibration absorber in which the elastic member on the base member can be replaced and the elastic member can be arranged on the edge of the mass body in a plan view. [Means for solving the problem]

[0009] A dynamic vibration absorber according to a first aspect of the present invention includes a base member, 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 a screw member that screws from above into an elastic-side threaded portion provided on the elastic member to fix the mass body to the elastic member. The mass body includes a fixed layer having an insertion hole extending in the vertical direction so that the screw member can be inserted and removed from above, and a movable layer that covers the insertion hole from above and is stacked on the fixed layer so as to be movable upward relative to the fixed layer. The base member and the fixed layer each have a through hole that penetrates in the vertical direction at a position where they overlap in a plan view. The movable layer has a pressed surface that faces downward at a position where it vertically overlaps the through hole. The fixed layer and the movable layer have a shape that releases the screw member so that the screw member can be operated from above the fixed layer when the fixed layer and the movable layer are separated, while accommodating the screw member so that operation of the screw member is restricted when the fixed layer and the movable layer are stacked.

[0010] In the dynamic vibration absorber according to the first aspect, when the fixed layer and the movable layer of the mass body are separated, the threaded member inserted into the insertion hole from above the fixed layer is released so as to be operable from above the fixed layer. On the other hand, when the fixed layer and the movable layer of the mass body are stacked, the threaded member is housed by the fixed layer and the movable layer. In this configuration in which the mass body is fixed to the elastic member by the threaded member inserted into the insertion hole from above the fixed layer, it is not necessary to set the position of the threaded member so that it is removed from the elastic member in a plan view, and it is possible to set the position of the threaded member within the range of the elastic member. This makes it possible to arrange the elastic member on the edge of the mass body in a plan view.

[0011] Furthermore, when replacing the elastic member in the dynamic vibration absorber, an insertable member such as a bolt can be inserted from below through the through-holes formed in the base member and the fixed layer, and a pressing force can be applied to the pressed surface of the movable layer, thereby moving the movable layer upward relative to the fixed layer. In this state, the threaded member can be removed from above the fixed layer to release the elastic member from the fixed layer, allowing it to be replaced.

[0012] The dynamic vibration absorber of the second aspect is the dynamic vibration absorber of the first aspect, wherein the movable layer has a flat surface at a position that overlaps with the insertion hole in a planar view, and the fixed layer has a countersunk portion that communicates with the insertion hole and can accommodate the head of the screw member.

[0013] According to the dynamic vibration absorber of the second aspect, when the fixed layer and the movable layer are stacked, the head of the screw member inserted into the insertion hole from above the fixed layer can be stored in the countersunk portion of the fixed layer.

[0014] A dynamic vibration absorber according to a third aspect may be the dynamic vibration absorber according to the first or second aspect, wherein a head of the threaded member is disposed so as to be contained within the range of the elastic member in a plan view.

[0015] According to the dynamic vibration absorber of the third aspect, the position of the screw member is set so that the head of the screw member falls within the range of the elastic member in a planar view, making it possible to more reliably position the elastic member at the edge of the mass body in a planar view.

[0016] The dynamic vibration absorber of the fourth aspect is a dynamic vibration absorber of the first to third aspects, wherein the fixing layer is formed in a rectangular shape when viewed in a plane, and has receiving portions at the edges of each of the four corners of the lower layer portion for receiving the upper part of the elastic member, and the insertion holes may extend downward from each of the four corners of the upper layer portion of the fixing layer and communicate with the receiving portions.

[0017] According to the dynamic vibration absorber of the fourth aspect, the elastic members can be secured to the fixed layer from above with screw members inserted into through-holes extending downward from the four corners of the fixed layer and communicating with the receiving portions, with the upper portions of the elastic members received in receiving portions provided on the edges of the four corners of the lower layer of the fixed layer of the mass body. In this case, the four elastic members provided on the base member are arranged on the edges of the corners of the fixed layer so as to be furthest from each other within the fixed layer of the mass body in a plan view. This allows the distance between each elastic member to be as long as possible within the area surrounded by the peripheral edge of the fixed layer of the mass body in a plan view. Therefore, when the base member is subjected to not only vertical vibrations but also horizontal vibrations and the mass body vibrates in a direction inclined relative to the horizontal, i.e., when rocking vibrations occur in the base member, deformation of each elastic member associated with the rocking vibration can be effectively suppressed, thereby effectively suppressing the vertical vibrations of the base member.

[0018] The dynamic vibration absorber of the fifth aspect is a dynamic vibration absorber of the first to fourth aspects, wherein the base member has a retaining portion that prevents an inserted member inserted into the through hole from below from slipping out from the base member downward.

[0019] According to the dynamic vibration absorber of the fifth aspect, when an inserted member is inserted from below through the through-holes formed in the base member and the fixed layer, the retaining portion prevents the inserted member from slipping out of the base member downward, so that the position where the inserted member pushes up the movable layer can be maintained even when the supply of upward force to the inserted member is stopped. This improves the workability of replacing the elastic member when the movable layer is pushed up against the fixed layer.

[0020] The dynamic vibration absorber of the sixth aspect may be any of the dynamic vibration absorbers of the first to fifth aspects, further comprising a connecting member that connects the movable layer to the fixed layer so as to restrict horizontal movement of the movable layer relative to the fixed layer and allow vertical movement relative to the fixed layer.

[0021] According to the dynamic vibration absorber of the sixth aspect, the horizontal movement of the movable layer relative to the fixed layer can be restricted by the connecting member, making it easier to insert an inserted member from below through the through-holes formed in the base member and the fixed layer, and allowing the movable layer to stably move upward relative to the fixed layer. This improves the workability of replacing the elastic member when the movable layer is pushed up against the fixed layer.

[0022] A dynamic vibration absorber according to a seventh aspect may be the dynamic vibration absorber of the sixth aspect, wherein the connecting member extends upward from the fixed layer and penetrates the movable layer, and further comprises a regulating member that is detachably attached to a portion of the connecting member positioned above the movable layer, thereby regulating upward movement of the movable layer relative to the fixed layer.

[0023] According to the dynamic vibration absorber of the seventh aspect, by attaching a regulating member to the connecting member that regulates the horizontal movement of the movable layer when replacing the elastic member, the connecting member can be used to integrate the fixed layer and the movable layer during vibration absorption to suppress vibration of the base member.

[0024] The dynamic vibration absorber according to the eighth aspect is a dynamic vibration absorber according to any one of the first to seventh aspects, wherein the base member may be formed with a base-side screw portion for moving the fixed layer upward relative to the base member.

[0025] According to the dynamic vibration absorber of the eighth aspect, the fixing layer can be pushed up against the base member by screwing a bolt or the like from below into the base side threaded portion formed on the base member, and the elastic member can be replaced in this state. [Effects of the Invention]

[0026] As described above, according to the present invention, it is possible to provide a dynamic vibration absorber that allows the elastic member on the base member to be replaced and that allows the elastic member to be arranged on the edge of the mass body in a planar view. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a perspective view illustrating a state in which a dynamic vibration absorbing structure to which a dynamic vibration absorbing device according to an embodiment of the present invention is applied is used in a building. [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] FIG. 2 is a plan view of the dynamic vibration absorber as viewed from below. [Figure 5] FIG. 5 is a cross-sectional view of the dynamic vibration absorber taken along line VV in FIG. 4. [Figure 6] 6 is a cross-sectional view of the dynamic vibration absorber corresponding to FIG. 5, showing the state in which the first auxiliary layer and the second auxiliary layer of the mass body have been removed and the auxiliary plate has been inserted between the base member and the fixed layer. [Figure 7] FIG. 7 is a cross-sectional view of the dynamic vibration absorber corresponding to FIG. 6, showing a state in which the movable layer of the mass body has been moved upward relative to the fixed layer. [Figure 8] FIG. 8 is a cross-sectional view of the dynamic vibration absorber corresponding to FIG. 7, showing a state in which the fixed layer has been moved upward and the elastic member has been removed. DETAILED DESCRIPTION OF THE INVENTION

[0028] 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.

[0029] FIG. 1 is a perspective view illustrating a state in which a dynamic vibration absorbing structure 1 to which a dynamic vibration absorber 3 according to an embodiment of the present invention is applied is used in a building. The dynamic vibration absorbing structure 1 to which the dynamic vibration absorber 3 is applied is intended to reduce vibration of a predetermined frequency that occurs 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, an operator can tune the vibration suppression characteristics of the dynamic vibration absorber 3 through the inspection hatch 101A.

[0030] The dynamic vibration absorbing structure 1 and the dynamic vibration absorbing device 3 will be described in detail with reference to Figures 2 to 8. 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.

[0031] 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.

[0032] As shown in Figures 2 to 5, for example, the dynamic vibration absorber 3 comprises a base member 4 placed on the mounting surface 231 of each 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, and a mass body 6 provided on the elastic member 5.

[0033] 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 is placed on the mounting surfaces 231 of the pair of support members 2 in a state where it can move in a predetermined direction D1 relative to the pair of support members 2. When the base member 4 is fixed to the lower protrusions 23 of the pair of support members 2 by the base fixing bolts 91, its movement along the mounting surfaces 231 is restricted, but when the base fixing bolts 91 are removed, the base member 4 can move in the predetermined direction D1 along the mounting surfaces 231.

[0034] 4, the base member 4 has a mounting portion 4A that is rectangular in plan view and is located at the center of the base member 4 and on which the mass body 6 is mounted, and a peripheral portion 4B that surrounds the mounting portion 4A. The base member 4 has base-side insertion holes 41 formed at each of the four corners of the mounting portion 4A that penetrate in the up-down direction D3, and a base-side through-hole 42 formed at the center of the mounting portion 4A that penetrates in the up-down direction D3.

[0035] Each of the four base-side insertion holes 41 extends in the vertical direction D3 so that a second screw member 82 such as a bolt for fixing the elastic member 5 to each of the four corners of the mounting portion 4A of the base member 4 can be inserted and removed from below.

[0036] The base-side through-hole 42, the details of which will be described later with reference to Fig. 7, is a through-hole that allows a first inserted member 83, such as a bolt, to be inserted into the base member 4 from below. The base member 4 also has a retaining portion 421 that prevents the first inserted member 83, inserted into the base-side through-hole 42 from below, from slipping out downward from the base member 4. When the first inserted member 83 is a bolt, the retaining portion 421 is formed on the inner surface of the base-side through-hole 42 and is configured as a threaded portion that allows the first inserted member 83 to be screwed into it.

[0037] Furthermore, the base member 4 has base-side threaded portions 43 formed in each of the regions located on both sides of the mounting portion 4A in the orthogonal direction D2 in the peripheral portion 4B. In the example shown in Fig. 4, the base member 4 has two base-side threaded portions 43 formed in each of the regions located on both sides of the mounting portion 4A in the orthogonal direction D2 in the peripheral portion 4B. The base-side threaded portions 43, the details of which will be described later with reference to Fig. 8, are threaded portions that allow a second inserted member 84, such as a bolt, to be screwed into the base member 4 so as to penetrate the base member 4 in the up-down direction D3 in order to move the fixing layer 61 upward relative to the base member 4.

[0038] A first elastic-side threaded portion 51 is joined to the upper end of the elastic member 5, and a second elastic-side threaded portion 52 is joined to the lower end of the elastic member 5. The elastic members 5 are fixed to each of the four corners of the mounting portion 4A of the base member 4 by screwing a second screw member 82, such as a bolt, inserted into the base-side insertion hole 41 from below into the second elastic-side threaded portion 52. A mass body 6 is provided on each of the elastic members 5 fixed to each of the four corners of the mounting portion 4A of the base member 4. Each 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 mounting surface 231 of the pair of support members 2. The elastic members 5 are formed, for example, from a spring member or the like.

[0039] The mass body 6 is made of, for example, steel. The mass body 6 is provided on each elastic member 5 so as to sandwich each elastic member 5 between the mass body 6 and the base member 4. The mass body 6 is provided on each elastic member 5 so as to be located within the range of the mounting portion 4A of the base member 4 in a plan view seen from the up-down direction D3. The mass body 6 is fixed to each elastic member 5 by threading a first screw member 81 such as a bolt into the first elastic-side thread portion 51 from above.

[0040] In the dynamic vibration absorber 3, when the base member 4 vibrates via a pair of support members 2 in response to the vibration of the beam 100, the mass body 6 supported by each elastic member 5 on the mounting portion 4A of the base member 4 moves in the opposite direction based on inertial force relative to the vibration of the base member 4 in the vertical direction D3, thereby suppressing the vibration of the base member 4.

[0041] 2 and 5, the mass body 6 includes a fixed layer 61 fixed to each elastic member 5 on the base member 4, a movable layer 62 stacked on the fixed layer 61 so as to be movable upward relative to the fixed layer 61, a first auxiliary layer 63 stacked on the movable layer 62, and a second auxiliary layer 64 stacked on the first auxiliary layer 63. In the mass body 6, the fixed layer 61, the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 are each made of, for example, a rectangular flat steel plate. The number of the fixed layer 61, the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 is not particularly limited and may be one or more. In this embodiment, the mass body 6 includes, for example, two fixed layers 61, one movable layer 62, two first auxiliary layers 63, and two second auxiliary layers 64.

[0042] If the frequency of vibration generated in the base member 4 in response to the vibration of the beam 100 differs from the frequency preset in the dynamic vibration absorber 3, a tuning operation is performed by an operator to change the weight of the mass body 6 or replace the elastic member 5. When the tuning operation is performed, the first auxiliary layer 63 and the second auxiliary layer 64 are removed from the fixed layer 61 and the movable layer 62.

[0043] The fixing layer 61 is formed in a rectangular shape similar to the mounting portion 4A of the base member 4 in a plan view seen from the up-down direction D3. As shown in FIGS. 2 and 5 , the fixing layer 61 has receiving portions 61A at the edges of the four corners of the lower layer portion of the fixing layer 61, which receive the upper portions of the elastic members 5 fixed on the mounting portion 4A of the base member 4. Each of the four receiving portions 61A is formed by cutting inward from the edge at each corner of the lower layer portion of the fixing layer 61. Furthermore, the fixing layer 61 has fixing layer-side through-holes 611 that extend downward from each of the four corners of the upper layer portion of the fixing layer 61 and communicate with the receiving portions 61A. Each of the four fixing layer-side through-holes 611 is located on the central axis of each elastic member 5 whose upper portion is received in the corresponding receiving portion 61A. The fixing layer-side through-holes 611 of the fixing layer 61 and the base-side through-holes 41 of the base member 4 overlap each other in a plan view seen from the vertical direction D3. Each fixing layer-side through-hole 611 of the fixing layer 61 is an insertion hole extending in the vertical direction D3 so that a first screw member 81 such as a bolt for fixing the fixing layer 61 to each elastic member 5 whose upper portion is received in each receiving portion 61A can be inserted and removed from above. The fixing layer 61 is fixed to each elastic member 5 by the first screw member 81 inserted from above into each fixing layer-side through-hole 611 screwing into the first elastic-side thread portion 51 of each elastic member 5 from above.

[0044] Furthermore, the fixing layer 61 has a fixing layer-side through hole 610 formed in the center thereof, penetrating in the up-down direction D3. The fixing layer-side through hole 610 of the fixing layer 61 and the base-side through hole 42 of the base member 4 overlap each other in a plan view seen in the up-down direction D3. The fixing layer-side through hole 610 of the fixing layer 61, the details of which will be described later with reference to FIG. 7, is a through hole that allows a first inserted member 83, such as a bolt, to be inserted into the fixing layer 61 from below.

[0045] The movable layer 62 is formed in a rectangular shape similar to the fixed layer 61 in a plan view seen in the vertical direction D3. The movable layer 62 is stacked on the fixed layer 61 so as to cover the fixed-layer-side through-holes 611 and the fixed-layer-side through-holes 610 of the fixed layer 61 from above and be movable upward relative to the fixed layer 61. As shown in Fig. 5 , the movable layer 62 has a pressed surface 621 that faces downward at a position overlapping with the fixed-layer-side through-holes 610 of the fixed layer 61 in the vertical direction D3. The pressed surface 621 of the movable layer 62 has an area portion that is positioned to overlap with the fixed-layer-side through-holes 611 of the fixed layer 61 in a plan view and is formed as a flat surface.

[0046] In the mass body 6, the fixed layer 61 and the movable layer 62 have a shape that releases the first screw member 81 so that the first screw member 81 can be operated from above the fixed layer 61 when the fixed layer 61 and the movable layer 62 are separated, but that stores the first screw member 81 so that operation of the first screw member 81 is restricted when the fixed layer 61 and the movable layer 62 are stacked. Specifically, as shown in FIGS. 2 and 5 , the fixed layer 61 has counterbore portions 612 that communicate with each fixed-layer-side through-hole 611 and can store the head of the first screw member 81. In this case, the head of the first screw member 81 inserted into each fixed-layer-side through-hole 611 from above the fixed layer 61 can be stored in the counterbore portion 612 of the fixed layer 61.

[0047] As described above, in the configuration in which the mass body 6 is fixed to each elastic member 5 by the first screw members 81 inserted into each fixed-layer-side insertion hole 611 from above the fixed layer 61, it is not necessary to set the position of the first screw members 81 so that they are separated from each elastic member 5 in a plan view, and it is possible to set the position of the first screw members 81 within the range of each elastic member 5. This makes it possible to arrange each elastic member 5 on the edge of the mass body 6 in a plan view.

[0048] As described above, each of the fixed layer-side through-holes 611 of the fixed layer 61 is positioned on the central axis of each of the elastic members 5. The heads of the first screw members 81 inserted into each of the fixed layer-side through-holes 611 from above the fixed layer 61 are arranged so as to fall within the range of each of the elastic members 5 in plan view. In this case, each of the elastic members 5 can be more reliably arranged on the edge of the mass body 6 in plan view.

[0049] As shown in Figures 2 to 5, the dynamic vibration absorber 3 may include a connecting member 71, a regulating member 711, a pair of first restraint members 72, a pair of first damping members 721, a pair of second restraint members 73, and a pair of second damping members 731.

[0050] The number of connecting members 71 is not particularly limited and may be one or more. In this embodiment, the dynamic vibration absorber 3 includes two connecting members 71 spaced apart from each other in the orthogonal direction D2. The connecting members 71 are formed, for example, by bolts. The connecting members 71 extend from the fixed layer 61 to above the second auxiliary layer 64 so as to penetrate the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 relative to the mass body 6. The connecting members 71 connect the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 to the fixed layer 61 so as to restrict movement of the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 relative to the fixed layer 61 in the horizontal direction (the predetermined direction D1 and the orthogonal direction D2) and allow movement in the up-down direction D3 relative to the fixed layer 61.

[0051] The restricting member 711 is detachably attached to a portion of the connecting member 71 that is arranged above the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64. When the connecting member 71 is formed of a bolt, the restricting member 711 is formed of, for example, a nut. By being attached to the connecting member 71, the restricting member 711 restricts upward movement of the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 relative to the fixed layer 61.

[0052] The pair of first restraint members 72 are attached to the peripheral portion 4B of the base member 4 by restraint fixing bolts 92 on both sides of the fixed layer 61 and the movable layer 62 in the predetermined direction D1 so as to restrict movement of the fixed layer 61 and the movable layer 62 of the mass body 6 in the predetermined direction D1. The pair of first restraint members 72 have, for example, first restraint bolts 72A extending in the predetermined direction D1. The first restraint bolts 72A are normally out of contact with the fixed layer 61 and the movable layer 62 and only come into contact with the fixed layer 61 and the movable layer 62 when the fixed layer 61 and the movable layer 62 move slightly in the predetermined direction D1. The pair of first restraint members 72 can restrict movement of the fixed layer 61 and the movable layer 62 in the predetermined direction D1 by contact of the first restraint bolts 72A.

[0053] The pair of first damping members 721 are sandwiched between the fixed layer 61 and the pair of first constraint members 72, and are members for damping vibration of the mass body 6. The pair of first damping members 721 are in contact with the fixed layer 61 and the movable layer 62. The pair of first damping members 721 are made of, for example, an elastically deformable rubber material.

[0054] By providing the dynamic vibration absorber 3 with a pair of first restraint members 72 and a pair of first damping members 721, when the mass body 6 moves in the vertical direction D3 in response to vibration of the base member 4, unintended movement of the mass body 6 in the specified direction D1 can be suppressed, and vibration in the vertical direction D3 generated in the base member 4 can be more effectively suppressed.

[0055] The pair of second constraint members 73 are attached to the peripheral portion 4B of the base member 4 by constraint fixing bolts 92 on both sides of the fixed layer 61 and the movable layer 62 in the orthogonal direction D2 so as to restrict movement of the fixed layer 61 and the movable layer 62 of the mass body 6 in the orthogonal direction D2. The pair of second constraint members 73 have, for example, second constraint bolts 73A extending in the orthogonal direction D2. The second constraint bolts 73A are normally out of contact with the fixed layer 61 and the movable layer 62 and only come into contact with the fixed layer 61 and the movable layer 62 when the fixed layer 61 and the movable layer 62 move slightly in the orthogonal direction D2. The pair of second constraint members 73 can restrict movement of the fixed layer 61 and the movable layer 62 in the orthogonal direction D2 by contact of the second constraint bolts 73A.

[0056] The pair of second damping members 731 are sandwiched between the fixed layer 61 and the pair of second constraint members 73, and are members for damping vibration of the mass body 6. The pair of second damping members 731 are in contact with the fixed layer 61 and the movable layer 62. The pair of second damping members 731 are made of, for example, an elastically deformable rubber material.

[0057] By providing the dynamic vibration absorber 3 with a pair of second restraint 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 base member 4, unintended movement of the mass body 6 in the perpendicular direction D2 can be suppressed, and vibration in the vertical direction D3 generated in the base member 4 can be more effectively suppressed.

[0058] The base member 4 may be subjected to not only vibrations in the vertical direction D3 but also horizontal vibrations in the predetermined direction D1 and the orthogonal direction D2. The horizontal vibrations exert a horizontal inertial force on the mass body 6, causing the mass body 6 to generate rocking vibrations relative to the base member 4. If the rocking vibration of the base member 4 causes deformation of the elastic members 5 provided on the base member 4, the effect of suppressing the vibration of the base member 4 in the vertical direction D3 will be reduced. One possible measure to suppress deformation of the elastic members 5 due to the rocking vibration of the base member 4 is to increase the distance between the elastic members 5 within the range of the mass body 6 in a plan view.

[0059] Therefore, in the dynamic vibration absorber 3 according to this embodiment, each elastic member 5 is fixed from above to the fixed layer 61 with its upper portion received in receiving portions 61A provided on the edges of the four corners of the lower layer portion of the fixed layer 61 of the mass body 6. The first screw members 81 are inserted into fixing-layer-side through-holes 611 that extend downward from the four corners of the upper layer portion of the fixed layer 61 and communicate with the receiving portions 61A. In this case, the four elastic members 5 are fixed to the base member 4 from below by second screw members 82 inserted into the base-side through-holes 41, and are positioned on the edges of the corners of the fixed layer 61 so as to be furthest apart from one another within the fixed layer 61 of the mass body 6 in a plan view. This makes it possible to maximize the distance between the elastic members 5 within the area surrounded by the peripheral edge of the fixed layer 61 of the mass body 6 in a plan view. Therefore, when the base member 4 is subjected to not only vibrations in the vertical direction D3 but also horizontal vibrations in a specific direction D1 and an orthogonal direction D2, and the mass body 6 vibrates in a direction inclined relative to the horizontal direction, that is, when rocking vibrations occur in the base member 4, the deformation of each elastic member 5 caused by the rocking vibrations can be effectively suppressed, and the vibrations of the base member 4 in the vertical direction D3 can be effectively suppressed.

[0060] Furthermore, when tuning work such as replacing each elastic member 5 is performed, the worker accesses the dynamic vibration absorber 3 through the inspection hatch 101A and releases the fixed state of the base member 4 from the pair of support members 2 by removing the base fixing bolts 91. Then, the worker 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 the tuning work. After the dynamic vibration absorber 3 has been moved to a position suitable for the tuning work in this way, the worker removes the restraint fixing bolts 92 to remove the pair of first restraint members 72 and the pair of second restraint members 73 from the base member 4. FIG. 5 shows the state in which the pair of first restraint members 72 and the pair of second restraint members 73 have been removed from the base member 4.

[0061] As described above, the dynamic vibration absorber 3 also includes the connecting member 71 and the restricting member 711 detachably attached to the connecting member 71. The connecting member 71 restricts horizontal movement (predetermined direction D1 and orthogonal direction D2) of the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 relative to the fixed layer 61, and connects the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 to the fixed layer 61 so as to allow movement in the up-down direction D3 relative to the fixed layer 61. By attaching the restricting member 71 to the connecting member 71 that restricts horizontal movement of the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64, the connecting member 71 can be used to integrate the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 with the fixed layer 61 during vibration absorption to suppress vibrations of the base member 4.

[0062] On the other hand, when tuning work such as replacing each elastic member 5 is performed, as shown in Fig. 6 , the worker removes the restricting member 711 from the connecting member 71, removes the first auxiliary layer 63 and the second auxiliary layer 64 from the fixed layer 61, and inserts an auxiliary plate P between the base member 4 and the fixed layer 61. When the auxiliary plate P is inserted between the base member 4 and the fixed layer 61, in a plan view seen from the vertical direction D3, an auxiliary plate-side through hole P1 is formed in the auxiliary plate P at a position overlapping the base-side through hole 42 of the base member 4 and the fixed layer-side through hole 610 of the fixed layer 61, and an auxiliary plate-side seat recessed hole P2 is formed in a position overlapping the base-side threaded portion 43 of the base member 4.

[0063] 7 , in the dynamic vibration absorber 3, with the auxiliary plate P inserted between the base member 4 and the fixed layer 61, the first inserted member 83 can be inserted from below through the base-side through-hole 42, the auxiliary plate-side through-hole P1, and the fixed layer-side through-hole 610, and a pressing force can be applied to the pressed surface 621 of the movable layer 62, thereby moving the movable layer 62 upward relative to the fixed layer 61. In this state, the first screw member 81 inserted into the fixed layer-side through-hole 611 can be removed from above the fixed layer 61, and the second screw member 82 inserted into the base-side through-hole 41 can be removed from below the base member 4, thereby releasing the elastic members 5 from the fixed layer 61 and the base member 4, and replacing the elastic members 5.

[0064] Furthermore, in the dynamic vibration absorber 3, as described above, the base member 4 has, on the inner surface of the base-side through-hole 42, a retaining portion 421 that prevents the first inserted member 83 from slipping out downward from the base member 4. In this case, when the first inserted member 83 is inserted from below through the base-side through-hole 42, the auxiliary-plate-side through-hole P1, and the fixed-layer-side through-hole 610, the retaining portion 421 prevents the first inserted member 83 from slipping out downward from the base member 4. This makes it possible to maintain the raised position of the movable layer 62 by the first inserted member 83 even when the supply of upward force to the first inserted member 83 is stopped. This improves the ease of replacing each elastic member 5 when the movable layer 62 is pushed up relative to the fixed layer 61.

[0065] Furthermore, as described above, in the dynamic vibration absorber 3, the horizontal movement of the movable layer 62 relative to the fixed layer 61 in the predetermined direction D1 and the orthogonal direction D2 can be restricted by the connecting member 71, which makes it easier to insert the first inserted member 83 from below through the base-side through-hole 42, the auxiliary-plate-side through-hole P1, and the fixed-layer-side through-hole 610, and allows the movable layer 62 to stably move upward relative to the fixed layer 61. Therefore, the work of replacing each elastic member 5 can be performed more efficiently when the movable layer 62 is pushed up relative to the fixed layer 61.

[0066] As described above, in the dynamic vibration absorber 3, the base member 4 is formed with a base-side threaded portion 43, and the auxiliary plate P is formed with an auxiliary plate side seat bore hole P2. In this case, as shown in Fig. 8, by screwing the second inserted member 84 from below into the base-side threaded portion 43 with the base-side threaded portion 43 and the auxiliary plate side seat bore hole P2 overlapping each other, the auxiliary plate P moves upward with the tip of the second inserted member 84 abutting against the upper surface of the auxiliary plate side seat bore hole P2, and the fixing layer 61 can be pushed up against the base member 4 as the auxiliary plate P moves upward, and in this state each elastic member 5 can be replaced. [Explanation of symbols]

[0067] 1 Dynamic vibration absorption structure 2 Pair of support members 3 Dynamic vibration absorber 4 Base material 41 Base side insertion hole 42 Base side through hole 421 Retaining part 43 Base side thread 5 Elastic member 51 First elastic side thread portion 52 Second elastic side threaded portion 6 mass body 61 Fixed layer 610 Fixed layer side through hole 611 Fixed layer side insertion hole 612 Counterbore 61A Reception Department 62 Movable layer 621 Pressed surface 71 Connecting member 711 Regulatory components 81 First threaded member 82 Second threaded member 83 First inserted member 84 Second inserted member

Claims

1. A dynamic vibration absorber, A base member; 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; a screw member that screws into an elastic-side screw portion provided on the elastic member from above to fix the mass body to the elastic member, the mass body includes a fixed layer having an insertion hole extending in the vertical direction so that the screw member can be inserted and removed from above, and a movable layer covering the insertion hole from above and stacked on the fixed layer so as to be movable upward relative to the fixed layer, the base member and the fixing layer each have a through-hole extending therethrough in the up-down direction at a position where they overlap in a plan view, the movable layer has a pressed surface facing downward at a position overlapping the through hole in the vertical direction, and to which a pressing force is applied by an inserted member inserted into the through hole from below, The fixed layer and the movable layer have a shape that releases the screw member so that the screw member can be operated from above the fixed layer when the fixed layer and the movable layer are separated by the pressing force of the inserted member, while accommodating the screw member so that operation of the screw member is restricted when the fixed layer and the movable layer are stacked.

2. the movable layer has a flat surface at a position overlapping the insertion hole in a plan view, 2. The dynamic vibration absorber according to claim 1, wherein the fixing layer has a counterbore portion that communicates with the insertion hole and is capable of accommodating a head portion of the screw member.

3. The dynamic vibration absorber according to claim 1 , wherein a head of the screw member is disposed so as to be contained within a range of the elastic member in a plan view.

4. the fixing layer is formed in a rectangular shape in a plan view, and has receiving portions at four corner edges of a lower layer portion for receiving upper portions of the elastic members, 2. The dynamic vibration absorber according to claim 1, wherein the insertion holes extend downward from each of four corners of the upper layer portion of the fixed layer and communicate with the receiving portion.

5. 2. The dynamic vibration absorber according to claim 1, wherein the base member has a retaining portion that prevents the inserted member from slipping out downward from the base member.

6. 2. The dynamic vibration absorber according to claim 1, further comprising a connecting member that connects the movable layer to the fixed layer so as to restrict horizontal movement of the movable layer relative to the fixed layer and allow vertical movement of the movable layer relative to the fixed layer.

7. the connecting member extends upward from the fixed layer and penetrates the movable layer; The dynamic vibration absorber according to claim 6 , further comprising a restricting member that is detachably attached to a portion of the connecting member that is positioned above the movable layer, thereby restricting upward movement of the movable layer relative to the fixed layer.

8. A dynamic vibration absorber, A base member; 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; a screw member that screws into an elastic-side screw portion provided on the elastic member from above to fix the mass body to the elastic member, the mass body includes a fixed layer having an insertion hole extending in the vertical direction so that the screw member can be inserted and removed from above, and a movable layer covering the insertion hole from above and stacked on the fixed layer so as to be movable upward relative to the fixed layer, the base member and the fixing layer each have a through-hole extending therethrough in the up-down direction at a position where they overlap in a plan view, the movable layer has a downwardly facing pressed surface at a position overlapping the through hole in the vertical direction, the fixed layer and the movable layer have a shape that releases the screw member so that the screw member can be operated from above the fixed layer when the fixed layer and the movable layer are separated, and that stores the screw member so that operation of the screw member is restricted when the fixed layer and the movable layer are stacked, The dynamic vibration absorber has a base-side threaded portion formed on the base member for moving the fixed layer upward relative to the base member.

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