Dynamic vibration absorbing device

Abstract

Provided is a dynamic vibration absorbing device with which an elastic member on a base member can be replaced and the elastic member can be positioned on an edge part of a mass body in a plan view.　This dynamic vibration absorbing device comprises an elastic member provided on a base member, a mass body provided on the elastic member, and a screwing member that screws from above onto an elastic-side screw part provided to the elastic member. The mass body has a fixed layer having an insertion hole through which the screwing member is inserted and removed from above, and a movable layer layered on top of the fixed layer. The base member and the fixed layer each have a through hole formed at positions where the through holes overlap in a plan view. The movable layer has a pressed surface facing downward at a position where the pressed surface overlaps the through holes. The fixed layer and the movable layer have a shape for releasing the screwing member so that the screwing member can be operated from above the fixed layer in a state where the fixed layer and the movable layer are spaced apart, and for storing the screwing member so as to regulate the operation of the screwing member in a state where the fixed layer and the movable layer are layered together.

Description

Dynamic vibration absorber

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

[0002] Conventionally, for example, a vibration damping device described in Patent Document 1 is known. The vibration damping device described in Patent Document 1 includes a base member, a mass fitting, and rubber mounts provided near four corners of the mass fitting between the base member and the mass fitting to elastically support the mass fitting with respect to the base member. Each of the four rubber mounts is fixed to the mass fitting from below by bolts via a bracket fitting connected to the upper portion of the rubber mount in a state where it is provided on the base member.

[0003] Further, the vibration damping device includes a stopper bolt protruding from the mass fitting toward the base member and inserted into an insertion hole of an engaging portion provided on the base member, and an abutting nut screwed onto the stopper bolt between the mass fitting and the base member.

[0004] In the vibration damping device described in Patent Document 1, when vertical vibration occurs in the base member, the mass fitting elastically supported by the rubber mounts on the base member moves in the opposite direction based on the inertial force with respect to the vertical vibration of the base member, so that the vibration of the base member can be suppressed. On the other hand, when tuning the vibration suppression characteristics of the vibration damping device, or when damage occurs to the rubber mounts, etc., it is necessary to remove the rubber mounts. In this case, the abutting nut abuts against the base member from above in response to a rotational operation on the stopper bolt, and the stopper bolt receiving the reaction force from the abutting nut is pushed up. As a result, the mass fitting moves upward with respect to the base member. In this state, the rubber mount can be removed by removing the bolts for fixing the mass fitting to the rubber mount.

[0005] By the way, not only vertical vibration but also horizontal vibration acts on the base member, and when the mass fitting vibrates in a direction inclined with respect to the horizontal direction, that is, when rocking vibration occurs. When rocking vibration occurs, the effect of suppressing the vertical vibration of the base member is reduced.

[0006] One possible strategy to suppress deformation associated with rocking vibrations in each rubber mount supporting the mass fitting on the base member is to increase the distance between each rubber mount within the mass fitting's range in a plan view. However, in the vibration damping device described in Patent Document 1, each rubber mount is fixed to the mass fitting by a bolt inserted from below into an extension portion of the bracket fitting that extends outward from the rubber mount. When fixing each rubber mount to the mass fitting from below with a bolt in this way, it is necessary to set the position of the bolt so that at least a part of the bolt is outside the position of each rubber mount in a plan view, taking into account rotational operation of the bolt from below. Therefore, when attempting to place the rubber mounts on the edge of the mass fitting in a plan view, it is necessary to position the rubber mounts inward from the edge of the mass fitting, taking into account the bolts protruding outward from the rubber mounts, and there are constraints on increasing the distance between each rubber mount. For this reason, there is room for improvement in effectively suppressing deformation associated with rocking vibrations in each rubber mount and effectively suppressing vertical vibrations of the base member.

[0007] Japanese Patent Publication No. 2003-343645

[0008] The object of the present invention is to provide a dynamic vibration absorber that allows for the replacement of elastic members on a base member and allows for the placement of elastic members on the edges of a mass body in a plan view.

[0009] A dynamic vibration absorber according to one aspect of the present invention comprises 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 itself and the base member, and a screw member that is screwed from above onto an elastic side screw portion provided on the elastic member for fixing the mass body to the elastic member. The mass body has a fixed layer having an insertion hole extending in the vertical direction so as to be insertable and removable from above by the screw member, and a movable layer laminated on the fixed layer so as to cover the insertion hole from above and be movable upward relative to the fixed layer. The base member and the fixed layer each have through holes that penetrate in the vertical direction at positions where they overlap in a plan view. The movable layer has a pressed surface facing downward at a position where it overlaps with the through hole in the vertical direction. The fixed layer and the movable layer are shaped to release the screwing member so that it can be operated from above the fixed layer when the fixed layer and the movable layer are separated, while housing the screwing member so that its operation is restricted when the fixed layer and the movable layer are stacked.

[0010] As described above, the present invention provides a dynamic vibration absorber that allows for the replacement of the elastic member on the base member and for the placement of the elastic member on the edge of the mass body in a plan view.

[0011] This is a perspective view illustrating the usage of a dynamic vibration-absorbing structure in a building to which a dynamic vibration-absorbing device according to an embodiment of the present invention is applied. This figure shows the dynamic vibration-absorbing structure as viewed from a predetermined direction. This is a cross-sectional view of the dynamic vibration-absorbing structure along the line III-III in Figure 2, showing the dynamic vibration-absorbing device as viewed from above. This is a plan view of the dynamic vibration-absorbing device as viewed from below. This is a cross-sectional view of the dynamic vibration-absorbing device along the line V-V in Figure 4. This is a cross-sectional view of the dynamic vibration-absorbing device corresponding to Figure 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. This is a cross-sectional view of the dynamic vibration-absorbing device corresponding to Figure 6, showing the state in which the movable layer has been moved upward relative to the fixed layer in the mass body. This is a cross-sectional view of the dynamic vibration-absorbing device corresponding to Figure 7, showing the state in which the fixed layer has been moved upward and the elastic member has been removed.

[0012] Embodiments of the present invention will be described below with reference to the attached 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.

[0013] Figure 1 is a perspective view illustrating the usage of a dynamic vibration-absorbing structure 1 to which a dynamic vibration-absorbing device 3 according to an embodiment of the present invention is applied in a building. The dynamic vibration-absorbing structure 1 to which the dynamic vibration-absorbing device 3 is applied is, for example, used to reduce vibrations of a predetermined frequency that occur in a beam 100 supporting the ceiling panel 101 of the lower floor and the floor panel 102 of the upper floor in a multi-story building. The dynamic vibration-absorbing structure 1 is placed in the space S between the ceiling panel 101 of the lower floor and the floor panel 102 of the upper floor. The ceiling panel 101 is provided with an inspection opening 101A for inspecting the space S. With the dynamic vibration-absorbing structure 1 placed in the space S, the vibration suppression characteristics of the dynamic vibration-absorbing device 3 are tuned by a worker through the inspection opening 101A.

[0014] The dynamic vibration absorption structure 1 and the dynamic vibration absorption device 3 will be described in detail with reference to Figures 2 to 8. The dynamic vibration absorption structure 1 comprises a pair of support members 2 extending in a predetermined direction D1 on a horizontal plane and spaced apart in an orthogonal direction D2 perpendicular to the predetermined direction D1 on a horizontal plane, and a dynamic vibration absorption device 3 supported by the pair of support members 2 so as to straddle the pair of support members 2. In the following description, the directional relationships will be defined as the predetermined direction D1 and the orthogonal direction D2, respectively, where each direction is orthogonal to the other on a horizontal plane, and the vertical direction perpendicular to the predetermined direction D1 and the orthogonal direction D2 will be defined as the up and down direction D3.

[0015] The pair of support members 2 are fixed to the beam 100 of the building. For example, as shown in Figures 2 and 3, each of the pair of support members 2 is, for example, a member with a C-shaped cross-section. Specifically, each of the pair of support members 2 has a flat plate-shaped support body portion 21 that extends in a predetermined direction D1 and a vertical direction D3, a flat plate-shaped upper projection portion 22 that protrudes from the upper end of the support body portion 21 in a direction perpendicular to the dynamic vibration absorber 3 in a direction D2 and extends in the predetermined direction D1, and a flat plate-shaped lower projection portion 23 that protrudes from the lower end of the support body portion 21 in a direction perpendicular to the dynamic vibration absorber 3 in a direction D2 and extends in the predetermined direction D1. Each of the pair of support members 2 has a surface on the lower projection portion 23 that faces upward in the vertical direction D3 and extends in the predetermined direction D1, which serves as the mounting surface 231.

[0016] The dynamic vibration absorber 3, as shown in Figures 2 to 5, for example, comprises a base member 4 placed on the mounting surfaces 231 of a 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.

[0017] The base member 4 is, for example, a rectangular flat plate. The base member 4 is made of, for example, steel. The base member 4 is placed on the mounting surface 231 of the pair of support members 2 in a state in which 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 base fixing bolts 91, its movement along the mounting surface 231 is restricted, while when the base fixing bolts 91 are removed, it can move along the mounting surface 231 in a predetermined direction D1.

[0018] As shown in Figure 4, the base member 4 has a rectangular mounting section 4A in plan view, located in the center of the base member 4 on which the mass body 6 is mounted, and a surrounding section 4B that surrounds the mounting section 4A. The base member 4 has base-side insertion holes 41 that penetrate in the vertical direction D3 at each of the four corners of the mounting section 4A, and a base-side through hole 42 that penetrates in the vertical direction D3 at the center of the mounting section 4A.

[0019] 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.

[0020] The base-side through-hole 42, as will be described in detail later with reference to Figure 7, is a through-hole that allows a first insertion 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 insertion member 83, which has been inserted into the base-side through-hole 42 from below, from coming out of the base member 4. When the first insertion member 83 is a bolt, the retaining portion 421 is formed on the inner surface of the base-side through-hole 42 and consists of a threaded portion that allows the first insertion member 83 to be screwed in.

[0021] 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 peripheral portion 4B in the direction D2 perpendicular to the mounting portion 4A. In the example shown in Figure 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 peripheral portion 4B in the direction D2 perpendicular to the mounting portion 4A. The base-side threaded portions 43 are threaded portions that allow a second insertion member 84, such as a bolt, to be screwed into the base member 4 so as to penetrate it in the vertical direction D3 in order to move the fixing layer 61 upward relative to the base member 4.

[0022] A first elastic threaded portion 51 is joined to the upper end of the elastic member 5, and a second elastic threaded portion 52 is joined to the lower end of the elastic member 5. The elastic member 5 is fixed to each of the four corners of the mounting portion 4A of the base member 4 by screwing a second threaded member 82, such as a bolt, which is inserted from below into the base-side insertion hole 41, into the second elastic 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 elastically deformable in accordance with the relative vertical movement D3 of the mass body 6 with respect to the base member 4 which is placed on the mounting surface 231 of the pair of support members 2. The elastic member 5 is made of, for example, a spring member.

[0023] 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 itself 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 taken from the vertical direction D3. The mass body 6 is fixed to each elastic member 5 by screwing a first threaded member 81, such as a bolt, onto the first elastic side threaded portion 51 from above.

[0024] In the dynamic vibration absorber 3, when the base member 4 vibrates via a pair of support members 2 in response to vibrations 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 to the vertical vibration D3 of the base member 4 based on inertial force, thereby suppressing the vibration of the base member 4.

[0025] The mass body 6, as shown in Figures 2 and 5, for example, includes a fixed layer 61 fixed to each elastic member 5 on the base member 4, a movable layer 62 laminated on the fixed layer 61 so as to be movable upward relative to the fixed layer 61, a first auxiliary layer 63 laminated on the movable layer 62, and a second auxiliary layer 64 laminated 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 made of, for example, rectangular flat steel material. The number of fixed layers 61, movable layers 62, first auxiliary layers 63, and second auxiliary layers 64 is not particularly limited and may be one or more. In this embodiment, the mass body 6 has, for example, two fixed layers 61, one movable layer 62, two first auxiliary layers 63, and two second auxiliary layers 64.

[0026] If the frequency of vibration generated in the base member 4 in response to the vibration of the beam 100 differs from a frequency preset in the dynamic vibration absorber 3, a tuning operation is performed by an operator, which involves changing the weight of the mass body 6 or replacing the elastic member 5. The first auxiliary layer 63 and the second auxiliary layer 64 are removed from the fixed layer 61 and the movable layer 62 when the tuning operation is performed.

[0027] The fixed layer 61 is formed in a rectangular shape similar to the mounting portion 4A of the base member 4 when viewed from the vertical direction D3 in a plan view. As shown in Figures 2 and 5, the fixed layer 61 has receiving portions 61A at each of the four corners of the lower portion of the fixed layer 61 to receive the upper parts of each elastic member 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 portion of the fixed layer 61. Furthermore, the fixed layer 61 has fixed layer-side insertion holes 611 that extend downward from each of the four corners of the upper portion of the fixed layer 61 and communicate with the receiving portions 61A. Each of the four fixed layer-side insertion holes 611 is located on the central axis of each elastic member 5 whose upper part is received in each receiving portion 61A. Each fixed layer-side insertion hole 611 of the fixed layer 61 and each base-side insertion hole 41 of the base member 4 overlap each other in a plan view from the vertical direction D3. Each fixed layer-side insertion hole 611 of the fixed layer 61 is an insertion hole that extends in the vertical direction D3 so that a first screwing member 81, such as a bolt, for fixing the fixed layer 61 to each elastic member 5 whose upper part is received in each receiving portion 61A can be inserted and removed from above. The fixed layer 61 is fixed to each elastic member 5 by screwing the first screwing member 81, which is inserted from above into each fixed layer-side insertion hole 611, onto the first elastic side threaded portion 51 of each elastic member 5 from above.

[0028] Furthermore, the fixed layer 61 has a fixed layer-side through hole 610 formed in the center of the fixed layer 61 that penetrates in the vertical direction D3. The fixed layer-side through hole 610 of the fixed layer 61 and the base-side through hole 42 of the base member 4 overlap each other in a plan view from the vertical direction D3. The fixed layer-side through hole 610 of the fixed layer 61 will be described in detail later with reference to Figure 7, but it is a through hole that allows a first insertion member 83, such as a bolt, to be inserted into the fixed layer 61 from below.

[0029] The movable layer 62 is formed in a rectangular shape similar to that of the fixed layer 61 when viewed from the vertical direction D3 in a plan view. The movable layer 62 is laminated on the fixed layer 61 so as to cover each fixed layer-side insertion hole 611 and fixed layer-side through hole 610 of the fixed layer 61 from above and so as to be movable upward relative to the fixed layer 61. As shown in Figure 5, the movable layer 62 has a downward-facing pressed surface 621 at a position that overlaps with the fixed layer-side through hole 610 of the fixed layer 61 in the vertical direction D3. The pressed surface 621 of the movable layer 62 has a region that overlaps with each fixed layer-side insertion hole 611 of the fixed layer 61 in a plan view and is formed as a flat surface.

[0030] In the mass body 6, the fixed layer 61 and the movable layer 62 are shaped to release the first screw member 81 so that it can be operated from above the fixed layer 61 when the fixed layer 61 and the movable layer 62 are separated, while housing the first screw member 81 so that its operation is restricted when the fixed layer 61 and the movable layer 62 are stacked. Specifically, as shown in Figures 2 and 5, the fixed layer 61 has a counterbore 612 that communicates with each fixed layer-side insertion hole 611 and can accommodate 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 insertion hole 611 from above the fixed layer 61 can be housed in the counterbore 612 of the fixed layer 61.

[0031] As described above, in a configuration in which the mass body 6 is fixed to each elastic member 5 by 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 detached 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. For this reason, it is possible to position each elastic member 5 at the edge of the mass body 6 in a plan view.

[0032] Furthermore, as previously described, each fixed layer-side insertion hole 611 of the fixed layer 61 is located on the central axis of each elastic member 5. The heads of the first screw members 81, which are inserted into each fixed layer-side insertion hole 611 from above the fixed layer 61, are positioned so as to fit within the range of each elastic member 5 in a plan view. In this case, it becomes possible to more reliably position each elastic member 5 on the edge of the mass body 6 in a plan view.

[0033] 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 restraining members 72, a pair of first damping members 721, a pair of second restraining members 73, and a pair of second damping members 731.

[0034] The number of connecting members 71 is not particularly limited and may be one or more. In this embodiment, the dynamic vibration absorber 3 is provided with two connecting members 71 spaced apart from each other in the orthogonal direction D2. The connecting members 71 are made of bolts, for example. 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 with respect 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 the horizontal movement of the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 relative to the fixed layer 61 (in a predetermined direction D1 and an orthogonal direction D2), and allow vertical movement D3 relative to the fixed layer 61.

[0035] The restricting member 711 is detachably attached to the portion of the connecting member 71 that is positioned on the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64. If the connecting member 71 is made up of bolts, the restricting member 711 is made up of nuts, for example. By being attached to the connecting member 71, the restricting member 711 restricts the upward movement of the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 relative to the fixed layer 61.

[0036] A pair of first restraint members 72 are attached to the periphery 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 the 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 in a non-contact state 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 the movement of the fixed layer 61 and the movable layer 62 in the predetermined direction D1 by the contact of the first restraint bolts 72A.

[0037] The pair of first damping members 721 are sandwiched between the fixed layer 61 and the movable layer 62 and the pair of first restraining members 72, respectively, and are members for damping vibrations 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.

[0038] The dynamic vibration absorber 3 includes a pair of first restraining members 72 and a pair of first damping members 721. This allows the mass body 6 to move in the vertical direction D3 in response to vibrations of the base member 4, while simultaneously suppressing unintended movement of the mass body 6 in a predetermined direction D1, and more effectively suppressing vertical vibrations D3 generated in the base member 4.

[0039] A pair of second restraint members 73 are attached to the periphery 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 orthogonal direction D2, so as to restrict the 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 restraint members 73 have, for example, second restraint bolts 73A extending in the orthogonal direction D2. The second restraint bolts 73A are normally not in 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 restraint members 73 can restrict the movement of the fixed layer 61 and the movable layer 62 in the orthogonal direction D2 by the contact of the second restraint bolts 73A.

[0040] The pair of second damping members 731 are sandwiched between the fixed layer 61 and the movable layer 62 and the pair of second restraining members 73, respectively, and are members for damping vibrations 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.

[0041] The dynamic vibration absorber 3 includes a pair of second restraining members 73 and a pair of second damping members 731. This allows the mass body 6 to move in the vertical direction D3 in response to vibrations of the base member 4, while simultaneously suppressing unintended movement of the mass body 6 in the orthogonal direction D2, and more effectively suppressing vertical vibrations D3 generated in the base member 4.

[0042] The base member 4 may be subjected not only to vibrations in the vertical direction D3, but also to horizontal vibrations in a predetermined direction D1 and a perpendicular direction D2. Since horizontal vibrations impose a horizontal inertial force on the mass body 6, the mass body 6 causes rocking vibrations relative to the base member 4. If deformation occurs in each elastic member 5 provided on the base member 4 due to the rocking vibrations of the base member 4, the effect of suppressing the vertical vibrations D3 of the base member 4 will decrease. As a measure to suppress the deformation of each elastic member 5 due to the rocking vibrations of the base member 4, it is conceivable to increase the distance between each elastic member 5 within the range of the mass body 6 in a plan view.

[0043] Therefore, in the dynamic vibration absorber 3 according to the present embodiment, each elastic member 5 is fixed to the fixing layer 61 from above by a first screwing member 81 inserted into a fixing layer side insertion hole 611 that extends downward from each of the four corners of the upper layer portion of the fixing layer 61 and communicates with the receiving portion 61A, with the upper portion of each elastic member 5 being received in the receiving portion 61A provided at each edge of the four corners of the lower layer portion of the fixing layer 61 in the mass body 6. In this case, the four elastic members 5 fixed to the base member 4 from below by the second screwing members 82 inserted into the base side insertion holes 41 are arranged at the edges of each corner of the fixing layer 61 so as to be in the most separated positional relationship from each other within the range of the fixing layer 61 of the mass body 6 in a plan view. Thereby, within the range surrounded by the peripheral portion of the fixing layer 61 of the mass body 6 in a plan view, the distance between the elastic members 5 can be made as long as possible. For this reason, when not only the vibration in the vertical direction D3 but also the horizontal vibrations in the predetermined direction D1 and the orthogonal direction D2 act on the base member 4 and the mass body 6 vibrates in a direction in which it tilts with respect to the horizontal direction, that is, when a rocking vibration occurs in the base member 4, the deformation accompanying the rocking vibration in each elastic member 5 can be effectively suppressed, and the vibration in the vertical direction D3 of the base member 4 can be effectively suppressed.

[0044] Furthermore, when tuning operations such as replacing each elastic member 5 are performed, the operator accesses the dynamic vibration absorber 3 through the inspection port 101A and releases the fixing state of the base member 4 with respect to the pair of support members 2 by removing the base fixing bolts 91. Then, the operator can move the dynamic vibration absorber 3 in the predetermined direction D1 to a position suitable for the tuning operation by moving the base member 4 along the mounting surface 231 of the pair of support members 2. In this way, in a state where the dynamic vibration absorber 3 is moved to a position suitable for the tuning operation, the operator removes the pair of first restraint members 72 and the pair of second restraint members 73 from the base member 4 by removing the restraint fixing bolts 92. The state in which the pair of first restraint members 72 and the pair of second restraint members 73 are removed from the base member 4 is shown in FIG. 5.

[0045] Furthermore, as previously described, the dynamic vibration absorber 3 includes a connecting member 71 and a restricting member 711 that is detachably attached to the connecting member 71. The connecting member 71 connects the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 to the fixed layer 61 in such a way that it restricts the horizontal movement of the movable layer 62, the first auxiliary layer 63, and the second auxiliary layer 64 relative to the fixed layer 61 (in a predetermined direction D1 and a perpendicular direction D2), while allowing vertical movement D3 relative to the fixed layer 61. By attaching the restricting member 711 to the connecting member 71 for restricting the 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 respect to the fixed layer 61 when absorbing vibrations to suppress vibrations of the base member 4.

[0046] On the other hand, when tuning work such as replacing each elastic member 5 is performed, as shown in Figure 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 further inserts the 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 from the vertical direction D3, the auxiliary plate side through hole P1 is formed at a position that overlaps with 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 the auxiliary plate side counterbore hole P2 is formed at a position that overlaps with the base side threaded portion 43 of the base member 4.

[0047] In the dynamic vibration absorber 3, as shown in FIG. 7, with the auxiliary plate P inserted between the base member 4 and the fixed layer 61, 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, and a pressing force is applied to the pressed surface 621 of the movable layer 62, whereby the movable layer 62 can be moved upward with respect to the fixed layer 61. In this state, the first screwed member 81 inserted into the fixed layer-side insertion hole 611 is removed from above the fixed layer 61, and the second screwed member 82 inserted into the base-side insertion hole 41 is removed from below the base member 4, whereby the elastic members 5 are released from the fixed layer 61 and the base member 4, and the elastic members 5 can be replaced.

[0048] Also, in the dynamic vibration absorber 3, as described above, the base member 4 has a retaining portion 421 on the inner surface of the base-side through hole 42 that restricts the first inserted member 83 from coming out downward from the base member 4. In this case, in the state where 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, by restricting the first inserted member 83 from coming out downward from the base member 4 by the retaining portion 421, even if the supply of the upward force to the first inserted member 83 is stopped, the position where the movable layer 62 is pushed up by the first inserted member 83 can be maintained. Therefore, in the state where the movable layer 62 is pushed up with respect to the fixed layer 61, the workability of the work of replacing the elastic members 5 can be improved.

[0049] Also, in the dynamic vibration absorber 3, as described above, since the horizontal movement of the movable layer 62 in the predetermined direction D1 and the orthogonal direction D2 with respect to the fixed layer 61 can be restricted by the connecting member 71, it becomes 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 the movable layer 62 can be stably moved upward with respect to the fixed layer 61. Therefore, in the state where the movable layer 62 is pushed up with respect to the fixed layer 61, the workability of the work of replacing the elastic members 5 can be improved.

[0050] Furthermore, in the dynamic vibration absorber 3, as previously described, the base member 4 has a base-side threaded portion 43, and the auxiliary plate P has an auxiliary plate-side counterbore hole P2. In this case, as shown in Figure 8, by screwing the second insertion member 84 onto the base-side threaded portion 43 from below while the base-side threaded portion 43 and the auxiliary plate-side counterbore hole P2 are overlapping, the fixing layer 61 can be pushed up relative to the base member 4 as the auxiliary plate P moves upward while the tip of the second insertion member 84 is in contact with the upper surface of the auxiliary plate-side counterbore hole P2, and each elastic member 5 can be replaced in this state.

[0051] The specific embodiments described above mainly include inventions having the following configurations.

[0052] A dynamic vibration absorber according to one aspect of the present invention comprises 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 itself and the base member, and a screw member that is screwed from above onto an elastic side screw portion provided on the elastic member for fixing the mass body to the elastic member. The mass body has a fixed layer having an insertion hole extending in the vertical direction so as to be insertable and removable from above by the screw member, and a movable layer laminated on the fixed layer so as to cover the insertion hole from above and be movable upward relative to the fixed layer. The base member and the fixed layer each have through holes that penetrate in the vertical direction at positions where they overlap in a plan view. The movable layer has a pressed surface facing downward at a position where it overlaps with the through hole in the vertical direction. The fixed layer and the movable layer are shaped to release the screwing member so that it can be operated from above the fixed layer when the fixed layer and the movable layer are separated, while housing the screwing member so that its operation is restricted when the fixed layer and the movable layer are stacked.

[0053] According to the dynamic vibration absorber described above, when the fixed layer and movable layer are separated in the mass body, the screw-in member inserted into the through hole from above the fixed layer is open so that it can be operated from above the fixed layer. On the other hand, when the fixed layer and movable layer are stacked in the mass body, the screw-in 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 a screw-in member inserted into the through hole from above the fixed layer, it is not necessary to set the position of the screw-in member so that it is outside the elastic member in a plan view, and it is possible to set the position of the screw-in member within the range of the elastic member. For this reason, it is possible to place the elastic member at the edge of the mass body in a plan view.

[0054] Furthermore, when replacing the elastic member in a dynamic vibration absorber, the movable layer can be moved upward relative to the fixed layer by inserting the member to be inserted, such as a bolt, from below through through holes formed in the base member and the fixed layer, respectively, and by applying pressure to the pressed surface of the movable layer. In this state, the elastic member can be released from the fixed layer by removing the screw member from above the fixed layer, and the elastic member can be replaced.

[0055] In the dynamic vibration absorber described above, the movable layer has a flat surface at a position that overlaps with the insertion hole in a plan view, and the fixed layer may have a counterbore that communicates with the insertion hole and can accommodate the head of the screw member.

[0056] According to the dynamic vibration absorber, with the fixed layer and the movable layer stacked, the head of the screw member inserted into the through hole from above the fixed layer can be housed in the counterbore of the fixed layer.

[0057] In the dynamic vibration absorber, the head of the screw member may be positioned so as to fall within the range of the elastic member in a plan view.

[0058] According to the aforementioned dynamic vibration absorber, the position of the screw member is set so that the head of the screw member is within the range of the elastic member in a plan view, making it possible to more reliably position the elastic member on the edge of the mass body in a plan view.

[0059] In the dynamic vibration absorber described above, the fixed layer is formed in a rectangular shape in plan view, and each of the four corners of the lower layer portion has a receiving portion for receiving the upper part of the elastic member, and the insertion hole may extend downward from each of the four corners of the upper layer portion of the fixed layer and communicate with the receiving portion.

[0060] According to the dynamic vibration absorber described above, the elastic members can be fixed to the fixed layer from above by screw members inserted into through holes that extend downward from each of the four corners of the lower part of the fixed layer of the mass, with the upper part of each elastic member being received in receiving portions provided at the edges of each of the four corners of the upper part of the fixed layer and communicating with the receiving portion. In this case, each of the four elastic members provided on the base member is positioned at the edges of each corner of the fixed layer so that, in a plan view, they are in the furthest possible position from each other within the range of the fixed layer of the mass. This makes it possible to maximize the distance between each elastic member within the range enclosed by the periphery of the fixed layer of the mass in a plan view. Therefore, when the base member is subjected to not only vertical vibrations but also horizontal vibrations, and the mass vibrates in a direction that is tilted relative to the horizontal, that is, when rocking vibrations occur in the base member, the deformation of each elastic member due to the rocking vibrations can be effectively suppressed, and the vertical vibrations of the base member can be effectively suppressed.

[0061] In the dynamic vibration absorber described above, the base member may have a retaining portion that prevents the inserted member, which is inserted into the through hole from below, from coming out of the base member.

[0062] According to the dynamic vibration absorber, when the member to be inserted is inserted from below through through holes formed in the base member and the fixed layer, the retaining part prevents the member to be inserted from coming out of the base member downwards. This allows the position in which the movable layer is pushed up by the member to be inserted to be maintained even when the supply of upward force to the member to be inserted is stopped. Therefore, the workability of replacing the elastic member can be improved when the movable layer is pushed up relative to the fixed layer.

[0063] The dynamic vibration absorber may further include a connecting member that connects the movable layer to the fixed layer in such a way that it restricts the horizontal movement of the movable layer relative to the fixed layer and allows vertical movement of the movable layer relative to the fixed layer.

[0064] According to the dynamic vibration absorber, the horizontal movement of the movable layer relative to the fixed layer can be restricted by the connecting member, making it easier to insert the member to be inserted from below through the through holes formed in the base member and the fixed layer, respectively, and allowing the movable layer to be stably moved upward relative to the fixed layer. Therefore, the workability of replacing the elastic member can be improved when the movable layer is pushed up relative to the fixed layer.

[0065] In the dynamic vibration absorber described above, the connecting member may further include a restricting member that extends upward from the fixed layer and penetrates the movable layer, and is detachably attached to a portion of the connecting member that is positioned on the movable layer, thereby restricting the upward movement of the movable layer relative to the fixed layer.

[0066] According to the dynamic vibration absorber, when replacing the elastic member, a restricting member is attached to the connecting member that restricts the horizontal movement of the movable layer, and the connecting member can be used to integrate the fixed layer and the movable layer when absorbing vibrations to suppress vibrations of the base member.

[0067] In the dynamic vibration absorber, the base member may have a base-side threaded portion formed thereon for moving the fixed layer upward relative to the base member.

[0068] According to the aforementioned dynamic vibration absorber, the fixed layer can be pushed up relative to the base member by screwing a bolt or the like into the threaded portion on the base side formed on the base member from below, and the elastic member can be replaced in this state.

Claims

1. A dynamic vibration absorber comprising: 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 itself and the base member; and a screw member that is screwed from above onto an elastic side screw portion provided on the elastic member for fixing the mass body to the elastic member, wherein the mass body has a fixed layer having an insertion hole extending in the vertical direction so as to allow the screw member to be inserted and removed from above; and a movable layer that covers the insertion hole from above and is laminated on the fixed layer so as to be movable upward relative to the fixed layer, wherein the base member and the fixed layer each have through holes formed in the vertical direction at positions where they overlap in a plan view, and the movable layer has a pressed surface facing downward at a position where it overlaps the through hole in the vertical direction. A dynamic vibration absorber, wherein the fixed layer and the movable layer have a shape that releases the screwing member so that it can be operated from above the fixed layer when the fixed layer and the movable layer are separated, and houses the screwing member so that its operation is restricted when the fixed layer and the movable layer are stacked.

2. The dynamic vibration absorber according to claim 1, wherein the movable layer has a flat surface in a position that overlaps with the insertion hole in a plan view, and the fixed layer communicates with the insertion hole and has a counterbore capable of housing the head of the screw member.

3. The dynamic vibration absorber according to claim 1 or 2, wherein the head of the screw member is positioned to fall within the range of the elastic member in a plan view.

4. The dynamic vibration absorber according to any one of claims 1 to 3, wherein the fixed layer is formed in a rectangular shape in plan view, and each of the four corners of the lower layer portion has a receiving portion for receiving the upper part of the elastic member, and the insertion hole extends downward from each of the four corners of the upper layer portion of the fixed layer and communicates with the receiving portion.

5. The dynamic vibration absorber according to any one of claims 1 to 4, wherein the base member has a retaining portion that prevents the inserted member, which is inserted into the through hole from below, from coming out of the base member.

6. The dynamic vibration absorber according to any one of claims 1 to 5, further comprising a connecting member that restricts the horizontal movement of the movable layer relative to the fixed layer and allows vertical movement of the movable layer relative to the fixed layer.

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

8. The dynamic vibration absorber according to any one of claims 1 to 7, wherein the base member has a base-side screw portion formed thereon for moving the fixed layer upward relative to the base member.

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