JP2018054109A - Recovering rubber and its fixing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aseismic base isolation recovering rubber enabling a stable large shearing deformation to be attained and at the same time a cost reduction to be attained.SOLUTION: This invention relates to an aseismic base isolation recovering rubber installed between a substructure and a superstructure. Each of hard upper flange and hard lower flange is integrally arranged at both upper and lower end surfaces of a column-like rubber layer. The upper flange and the lower flange have bolt fixing holes each of which is engaged with bolts within thicknesses of the upper flange and the lower flange. At the rubber layer, a primary shape factor Sin which a constraint area of the rubber layer is divided by a free surface area of the rubber layer satisfies 0.3>S>0.1 and at the same time a secondary shape factor Ssatisfies 1.1>S>0.8, and a ratio A/B between an outer diameter A of the rubber layer and the shortest length B passing through a center in at least one plane of the upper flange 12 or the lower flange 13 satisfies 0.95≥A/B≥0.75.SELECTED DRAWING: Figure 2

Description

  TECHNICAL FIELD The present invention relates to a seismic isolation rubber used for seismic isolation systems such as a detached house, a low-rise building, and a lightweight building, and a mounting structure thereof.

  Seismic isolation systems for lightweight buildings use seismic isolation members that have horizontal rigidity much lower than that of the structure between the foundation such as the ground and structures such as low-rise buildings. . This type of seismic isolation member includes a sliding bearing (including rolling bearings) that has almost zero rigidity after the start of sliding, and a restoration rubber that is made of laminated rubber or vibration-proof rubber and has the function of restoring the sliding bearing to its origin. There is a seismic isolation system installed in combination. In this seismic isolation system, almost all the load of the structure is supported by a sliding bearing and almost no load is applied to the restoring rubber, and both the sliding bearing and the restoring rubber have a load bearing function. There is something to let you.

There are two types of sliding bearings: elastic sliding bearings with laminated rubber rubber and metal plates laminated in series, and rigid sliding bearings with thin rubbery elastic bodies in series. . Each sliding bearing is provided with a sliding plate and a sliding material that are slidably provided on a foundation such as the ground or floor and a structure such as a detached house, a low-rise building, or a lightweight building.
In the seismic isolation system, the sliding material normally supports the structural load, and the sliding material slides on the sliding plate during an earthquake, and the seismic energy is converted into thermal energy by the horizontal force (vertical load x dynamic friction coefficient) generated by the dynamic friction coefficient. As absorb. The structure moved horizontally during the earthquake is almost restored to the origin (normal structure position) by the restoration rubber.

In recent years, unexpected large-scale ground motions such as long-period and long-time ground motions have been observed, and in the event of a large earthquake exceeding the assumed seismic intensity of seismic isolation bearings, the restoration rubber is more than ever. Deformation ability is required.
The restoring rubber is disposed between the upper and lower structures, and is attached to each of the upper and lower structures using hexagon bolts (bolts). In the restoration rubber attached to the upper and lower structures, the hexagon bolt interferes with the rubber portion when the rubber portion provided between the upper and lower flanges is greatly deformed.
In order to avoid this, it is necessary to form the upper and lower flanges to a certain size or more, which increases the size of the flange and increases the cost.
In order to prevent the bolt from interfering with the rubber part, for example, in Patent Document 1, in a laminated rubber bearing body having a laminated rubber in which an intermediate steel plate and a rubber plate are laminated as the rubber part, the periphery of the rigid plate provided above and below the laminated rubber Are provided with a plurality of recesses and bolt insertion holes located in the recesses. As a result, when the rubber bearing body is attached between the upper and lower structures, the laminated rubber bearing body does not abut the intermediate rigid plate against the bolt head, and the laminated rubber bearing body can freely undergo shear deformation. it can.
Further, Patent Document 2 discloses a restoration rubber having a plurality of intermediate steel plates laminated and arranged at a predetermined interval between main rubbers and having stable rigidity and deformation ability at the time of shear deformation.

Japanese Utility Model Publication No. 7-21807 JP 2003-148538 A

However, the conventional mounting structure for a laminate including a plurality of intermediate rigid plates has a problem that the plurality of intermediate rigid plates are expensive.
There is a demand for a restoration rubber that can reduce the cost, has a softer horizontal rigidity, and can follow a shear deformation exceeding the diameter of the rubber.

  An object of the present invention is to provide a restoration rubber and a restoration rubber mounting structure that can stably obtain a large shear deformation and can reduce the cost.

One aspect of the restoration rubber of the present invention is:
It is a restoration rubber for seismic isolation installed between the lower structure and the upper structure,
A columnar rubber layer;
A hard upper flange and a lower flange that are integrally provided on the upper and lower end surfaces of the rubber layer, and are fixed to the lower structure and the upper structure via respective engaging bolts;
Have
The upper flange and the lower flange each have a bolt mounting hole that engages with the bolt within the thickness of the upper flange and the lower flange,
The rubber layer has a primary shape factor S _{1 obtained} by dividing the restrained area (pressure-receiving area) of the rubber layer by the free surface area (side area) of the rubber layer, and satisfies 0.3> S ₁ > 0.1, the secondary shape coefficient S ₂ that the outer diameter divided by the thickness of the rubber layer of the rubber layer satisfies 1.1> S 2> _0.8, and the outer diameter a of the rubber layer, the top flange and the The ratio A / B of the shortest length B passing through the center in at least one plane of the lower flange is configured to satisfy 0.95 ≧ A / B ≧ 0.75.

One aspect of the restoration rubber mounting structure of the present invention is:
A restoration rubber having the above configuration;
An upper structure disposed on the restoration rubber;
A lower structure disposed under the restoration rubber;
Have
The restoration rubber is configured to be fixed to each of the upper structure and the lower structure via bolts engaged with the bolt mounting holes.

  According to the present invention, a large shear deformation can be obtained stably and the cost can be reduced.

It is a figure which shows the attachment structure of the decompression | restoration rubber | gum of one Embodiment which concerns on this invention. It is sectional drawing of the decompression | restoration rubber | gum of one Embodiment which concerns on this invention. It is a top view of the restoration rubber. It is a figure which shows the deformation | transformation operation | movement of the restoration rubber | gum. It is a figure which shows the modification of the decompression | restoration rubber | gum of one Embodiment which concerns on this invention. It is a figure which shows the attachment structure of the modification of the same restoration | restoration rubber | gum. It is an expanded sectional view of the attachment hole which shows the attachment state of the decompression | restoration rubber | gum in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Reset rubber mounting structure>
FIG. 1 is a view showing a restoration rubber mounting structure 1 according to an embodiment of the present invention.
In the mounting structure 1 for the restoration rubber 10, the restoration rubber 10 is installed between the upper structure 2 and the lower structure 3, and is fixed to the upper structure 2 and the lower structure 3 via bolts 5. . The restoring rubber 10 is disposed between the upper structure 2 and the lower structure 3 together with, for example, a sliding bearing, and is used with a reference surface pressure of zero in principle.

<Configuration of the restoration rubber 10>
FIG. 1 is a cross-sectional view showing a main configuration of a restoration rubber according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a restoration rubber according to an embodiment of the present invention, and FIG. 3 is a plan view of the restoration rubber 10.
The restoration rubber 10 shown in FIG. 1 includes a columnar rubber layer 11, upper and lower flanges 12 and 13 joined to upper and lower ends of the rubber layer 11, and a center hole 15.
In the restoration rubber 10, the rubber layer 11 and the upper and lower flanges 12 and 13 are shear-deformed with a soft rigidity in the horizontal direction, so that the vibration due to the earthquake is transmitted at a slow cycle.

The rubber layer 11 is made of a rubber material based on natural rubber having excellent creep resistance. The rubber layer 11 is formed so that the shear modulus G is 0.60 ≧ G ≧ 0.29 N / mm ² by blending an additive as a reinforcing agent with natural rubber. Examples of the additive include carbon black, a vulcanizing agent, a vulcanization accelerator, a vulcanization acceleration aid, a softening agent, an antiaging agent, a processing aid, and a tackifier. From the viewpoint of maintaining the excellent creep resistance of natural rubber, it is preferable that at least natural rubber is blended in an amount of 50% by mass or more of the entire rubber component. Even when a synthetic rubber having physical properties equivalent to natural rubber is used, the effect of the present invention remains unchanged.

The rubber layer 11 is formed in a columnar shape in the present embodiment. The rubber layer 11 is used at a surface pressure of 0 in principle, and the primary shape factor S1 (S1 = rubber) calculated by dividing the restrained area (pressure receiving area) of the rubber layer 11 by the free surface area (side area) of the rubber layer 11. The constrained area of the layer (pressure-receiving area) / free surface area (side area) of the rubber layer) is larger than 0.1 and smaller than 0.3 (0.3>S1> 0.1). The restrained area (pressure receiving area) here refers to an area where the rubber layer 11 is restrained by the upper and lower flanges 12 and 13. Although the surface pressure can be used on the plus side, it is preferably 0.25 N / mm ² or less, and it is necessary to confirm the behavior during deformation.
In the rubber layer 11, the secondary shape factor S2 (S2 = A / rubber layer thickness) calculated by dividing the diameter (outer diameter) A of the rubber layer 11 by the thickness of the rubber layer 11 is 0.8. Greater than 1.1 (1.1>S2> 0.8). As long as the rubber layer 11 satisfies the above conditions, the rubber layer 11 may be formed by laminating a rubber elastic plate formed in a plate shape with the same material as the rubber layer 11 and an intermediate steel plate. The rubber layer 11 of the present embodiment is a single layer and is a rubber layer 11 in a state where a plurality of intermediate steel plates are not interposed therein.
The outer diameter A of the rubber layer 11 corresponds to the shortest length passing through the center on the end face of the rubber layer 11. Therefore, when the rubber layer 11 has a quadrangular prism shape, the length between opposite sides passing through the central axis of the rubber layer 11, that is, the length of the short side at the end face of the rubber layer 11 (the length of the short rubber side). . Thereby, when the rubber layer 11 is prismatic, the primary shape factor S ₁ = represented by a restrained area (pressure-receiving area) / free surface area, and the secondary shape factor S ₂ = the length of the short rubber side / the thickness of the rubber layer. expressed.

At the upper and lower ends 11 a and 11 b of the rubber layer 11, the outer peripheral portion 21 is curved and joined to the upper and lower flanges 12 and 13. That is, the outer peripheries of both end portions 11a and 11b have curved round portions 21. The rounded portion 21 is R2 or more, preferably R8.
Since R is attached to the outer surface of the connection portion between the rubber layer 11 and the upper and lower flanges 12 and 13, it is possible to prevent peeling when the rubber layer 11 is deformed by applying a load in the horizontal direction. Note that the surface area of the rounded portion 21 is not included in the pressure receiving area or the free surface area, and the rounded portion 21 calculates the primary shape factor S ₁ and the secondary shape factor S ₂ in the rubber layer 11. Not added.

The upper and lower flanges 12 and 13 each have a circular shape or a polygonal shape in plan view, and have outer peripheral portions that project outward from the outer periphery of the rubber layer 11.
The upper and lower flanges 12 and 13 are respectively disposed on both end faces of the rubber layer 11, and the rubber layer 11 is integrated with each of the upper and lower flanges 12 and 13 by vulcanization bonding. The upper and lower flanges 12 and 13 may be integrally formed on both end surfaces of the rubber layer 11, and may be integrally formed with the rubber layer 11. The upper and lower flanges 12 and 13 are bonded to the rubber layer 11. It may be fixed with. The upper and lower flanges 12 and 13 fix the rubber layer 11 to the upper structure 2 and the lower structure 3. The upper and lower flanges 12 and 13 are each a hard plate. The upper and lower flanges 12 and 13 may be a metal plate or a non-metal plate such as ceramic, plastic, fiber reinforced plastic, etc. in addition to a steel plate. In the present embodiment, the upper and lower flanges 12 and 13 are formed in a rectangular shape in plan view with rectangular plate materials formed in the same shape, but may be formed of a disk-shaped material.
Bolt mounting holes (hereinafter referred to as “mounting holes”) 16 and 16 for fixing the restoring rubber are provided in the upper and lower flanges 12 and 13 on the outer peripheral portion protruding from the outer periphery of the rubber layer 11.

  When the upper and lower flanges 12 and 13 are fixed to the upper structure 2 and the lower structure 3 via the bolts 5, the bolts 5 do not protrude from the lower surface of the upper flange 12. The lower surface of the lower flange 13 is fixed in a smooth state, and the bolt 5 does not protrude from the upper surface of the lower flange 13, and the upper surface of the lower flange 13 is fixed in a smooth state. The mounting hole 16 engages within the thickness of the bolt 5 and the upper flange 12 and the lower flange 13.

In the present embodiment, the attachment hole 16 is an insertion hole into which a bolt is inserted, and penetrates the upper flange 12 and the lower flange 13 in the thickness direction. The mounting hole 16 has a plurality of counterbore (concave portions) 161 around the lower surface of the upper flange 12 and an insertion hole 162 communicating therewith, and a plurality of counterbore (periphery) around the upper surface of the lower flange 13. (Recessed portion) 161 and an insertion hole 162 communicating therewith.
The counterbore (recess) 161 accommodates the head of the bolt 5 to be inserted into the mounting hole 16. In the mounting hole 16 of the present embodiment, the counterbore (recessed portion) 161 is formed in a truncated cone shape with an increased outer diameter on the rubber layer 11 side, and a through-hole 162 is formed continuously with the truncated cone-shaped counterbore 161. Has been. The mounting hole 16 is formed as a hole penetrating in the thickness direction of the upper and lower flanges 12 and 13 together with the counterbore 161 and the through hole 162. The bolt 5 is preferably a countersunk bolt whose head is housed in a truncated cone-shaped counterbore 161. Thereby, the top | upper surface of the head of the volt | bolt 5 after attachment does not protrude from the surface at the side of the rubber layer 11 in the up-and-down flanges 12 and 13, and tends to become substantially flush.

A central hole 15 is formed in the center of the rubber layer 11 and the upper and lower flanges 12 and 13 so as to penetrate vertically. The center hole 15 is generated by raising a center pin during molding. By raising the center pin at the time of vulcanization, the thermal conductivity in the mold for molding the restored rubber 10 can be increased, and the vulcanization time can be shortened.
Even if there is no central hole, the effect of this consideration remains the same.

  The restoration rubber 10 configured in this way is on the lower structure 3 (for example, the foundation or the structure on the foundation side) and below the upper structure 2 (the building or the upper structure of the building). Placed in. The restoration rubber 10 is formed in the upper structure 2 and the lower structure 3 by means of bolts 5 inserted into the upper and lower structures 2 and 3 through the attachment holes 16 on the peripheral edges of the flanges 12 and 13, respectively. It is fixed by being fixed to the structures 2 and 3.

The mounting hole 16 is a mounting hole (through hole) having a counterbore (recessed portion) 161 for accommodating the bolt head 18 (see FIG. 4). Thereby, the bolt 5 for fixing the restoring rubber 11 to the upper structure 2 and the lower structure 3 through the mounting hole 16 is such that the end on the rubber layer 11 side, here the head of the bolt 5 is the upper flange. 12 does not protrude beyond the lower surface of 12 or the upper surface of the upper flange 13.
As a result, as shown in FIG. 4A, the bolt head 18 does not contact the rubber layer 11 even if the rubber layer 11 is greatly deformed horizontally due to shaking such as an earthquake.
Thereby, as shown in FIG. 4B, the laminated body 100 in which the elastic portion 103 formed by laminating the intermediate steel plate 101 and the rubber elastic plate 102 is joined between the upper and lower flanges 120 and 130 through the bolt 50. Compared to the conventional mounting structure in which the head 50a of the bolt 50 is protruded from the upper and lower flanges 120 and 130, the restoration rubber 10 of the embodiment shown in FIG. The amount of deformation in the direction can be increased, and the outer diameter of the flanges 12 and 13 can be made smaller than the outer diameter of the flanges 120 and 130 when the same amount of deformation as in the prior art is ensured.

<Relationship between rubber layer 11 and upper and lower flange portions 12, 13>
The ratio A / B between the outer diameter A of the rubber layer 11 and the shortest length B passing through the center in at least one plane of the upper and lower flanges 12 and 13 is 0.75 or more and 0.95 or less (0.95 ≧ A / B ≧ 0.75) is satisfied. Note that at least one plane of the upper and lower flanges 12 and 13 is a joint surface with the rubber layer 11 and corresponds to both the lower surface of the upper flange 12 and the upper surface of the lower flange 13 in the present embodiment. The shortest length B passing through the center in the plane of the upper and lower flanges 12 and 13 is the length of the shortest line segment among the line segments passing through the center and partitioned by the outer periphery on the surface joined to the rubber layer 11. is there. Since the upper and lower flanges 12 and 13 are formed in a rectangular shape in the present embodiment, the respective planes of the upper and lower flanges 12 and 13 (specifically, the lower surface of the upper flange 12 joined to the rubber layer 11, The shortest length B passing through the center in the upper surface of the lower flange 13 corresponds to the length of the short side. When the upper flange 12 and the lower flange 13 are formed of a plate-like member having a circular shape in plan view, the short side length B described above is equal to the outer diameter of the lower surface of the upper flange 12 or the upper surface of the lower flange 13. Become. When at least one of the upper and lower flanges 12 and 13 has a polygonal square shape other than a quadrangle, the length B is the length between opposite sides passing through the center in a rectangular plane (joint surface with the rubber layer 11), or , The length of the opposite side and the diagonal passing through the center.

  In the restoration rubber 10, the ratio C / A between the diameter C of the center hole 15 and the outer diameter (diameter) A of the rubber layer 11 is 0.1 or more and less than 0.56 (0.56> C / A ≧ 0). .1).

  For this reason, when the ratio C / A between the diameter C of the center hole 15 and the diameter A of the rubber layer 11 is less than 10%, the above-described effect as the center hole 15 cannot be sufficiently obtained. Further, when the ratio A / C between the diameter C of the center hole 15 and the diameter C of the rubber layer 11 exceeds 56.3%, the buckling characteristics are affected, and the effect of improving the surface pressure dependency is insufficient. .

  In the restoration rubber 10, when the mounting hole 16 is fixed to the upper and lower structures 2 and 3 via the bolt 5, the bolt 5 does not protrude from the lower surface of the upper flange 12, and the bolt 5 does not protrude from the upper surface of the lower flange 13. As long as the lower surface of the upper flange 12 and the upper surface of the lower flange 13 are made smooth without projecting from the upper flange 12, any configuration may be used.

<Modification>
FIG. 5 is a view showing a modified example of the restoration rubber according to one embodiment of the present invention, FIG. 5A is a plan view of the restoration rubber, and FIG. 5B is a cross-sectional view of the restoration rubber. Moreover, FIG. 6 is a figure which shows the attachment structure of the modification of the same restoration rubber, and FIG. 7 is an expanded sectional view of the attachment hole which shows the attachment state of the restoration rubber in FIG.
The restoration rubber 10A shown in FIG. 5 is different from the restoration rubber 10 only in the configuration of the mounting hole 16A, and the other components are the same. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted.

  In the restoring rubber 10A, upper and lower flanges 12A and 13A, which are different from the upper and lower flanges 12 and 13 only in the configuration of the mounting hole 16A, are joined to the upper and lower ends of the cylindrical rubber layer 11. In the restoration rubber 10A, a central hole 15A is formed through the rubber layer 11 and the upper and lower flanges 12A and 13A so as to penetrate vertically. Since the function of the center hole 15A is the same as that of the center hole 15, the description thereof is omitted. The mounting hole 16A in the restoration rubber 10A is a plurality of tap holes provided in the outer peripheral portion of the upper and lower flanges 12A and 13A. Here, the mounting hole 16A is a female screw for screwing with a female screw portion formed on the inner peripheral surface. is there.

As shown in FIG. 6, the restoring rubber 10A has upper and lower flanges 12A and 13A abutted against the upper and lower structures 2A and 3A, and a bolt 5A inserted from the upper and lower structures 2A and 3A is screwed into the mounting holes 16A. By joining, it is fixed to the upper and lower structure 2A, 3A. Here, each of the upper and lower structures 2A and 3A has H steel (in FIG. 6, the H steel of the upper structure is indicated by reference numeral 2A, and the H steel of the lower structure 3A is indicated by reference numeral 3A1).
The restoration rubber 10A is disposed between the upper and lower structures 2A and 3A, the H steel lower flange 2A1a of the H steel of the upper structure 2A, and the H steel of the H steel 3A1 disposed on the foundation 3A2 in the lower structure 3A. It is fixed between the upper flange 3A1a.
As shown in FIG. 7, the lower flange 13A is disposed on the H steel upper flange 3A1a of the H steel 3A1, and the mounting hole 16A, which is a female thread of the lower flange 13A, passes through the through hole 30 of the H steel upper flange 3A1a. The bolt 5A inserted from the base 3A2 side is screwed together. Thereby, the lower flange 13A is fixed to the lower structure 3A side.

Similarly, in the upper flange 12A, the shaft portion of the bolt 5A whose head is locked to the upper surface of the H steel lower flange 2A1a of the H steel of the upper structure 2A is screwed into the mounting hole 16A which is a female screw for screwing the upper flange 12A. By combining, the upper flange 12A is fixed to the H steel of the upper structure 2A.
The female screw for bolt screwing as the mounting hole 16A is engaged with the shaft portion of the bolt inserted from the upper and lower structures within the thickness of the upper flange 12A and the lower flange 13A, and the tip of the bolt is the upper flange. 12A and the lower flange 13A do not protrude toward the rubber layer 11 side. Thereby, the lower surface of the upper flange 12A and the upper surface of the lower flange 13A become smooth surfaces, and the bolt does not interfere with the deformed rubber layer 11.

In the restoring rubber 10A, the bolt 5A is inserted from the structure side through the mounting hole 16A, and the shaft portion of the bolt 5A is the surface on the rubber layer 11 side of the upper and lower flanges 12A and 13A (the lower surface of the upper flange 12A, the lower flange It is fixed to the structure so as not to protrude from the upper surface of 13A. Thereby, the same effect as the restoration rubber 10 can be obtained.
In the configuration of the restoration rubber 10 according to the embodiment, a female thread portion may be provided on the inner peripheral surface of the through hole 162 of the mounting hole 16 of the upper and lower flanges 12 and 13 to form a tapped hole continuous with the counterbore. That is, the restoring rubber may have a configuration in which each of the upper and lower flanges 12 and 13 is provided with an attachment hole formed by a through hole that is a tap hole and a counterbore. According to this configuration, when the restoration rubber is arranged between the upper and lower structures and fastened to both sides with the bolts, the bolt insertion direction is either the rubber layer 11 side or the upper structure side. Even if it is limited to the direction, the restoring rubber is suitably fixed to both the upper and lower structures by bolts.
Further, in the restoration rubber 10A of the embodiment, the mounting holes formed on the outer periphery of the upper and lower flanges 12A and 13A are opened to the upper and lower structure side, and on the surface of the upper and lower flanges 12A and 13A on the rubber layer 11 side. A concave hole that does not penetrate, a so-called stop hole, and a female threaded stop hole in which a female screw that is screwed into a bolt is provided on the inner peripheral surface of the stop hole. The same operational effects as when the mounting holes 16 and 16A of the embodiment are applied can be obtained.

  The embodiment of the present invention has been described above. The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this. That is, the description of the configuration of the restoration rubber and the shape of each part is an example, and it is obvious that various modifications and additions to these examples are possible within the scope of the present invention.

  The restoring rubber according to the present invention can stably produce a large shear deformation and can reduce the cost, and is useful as a material used in a seismic isolation structure such as a building or a mechanical device.

2, 2A Upper structure 3, 3A Lower structure 5, 5A Bolt 10, 10A Restoring rubber 11 Rubber layer 12, 12A Upper flange 13, 13A, Lower flange 15, 15A Center hole 16, 16A Mounting hole 161 Counterbore

Claims (9)

It is a restoration rubber for seismic isolation installed between the lower structure and the upper structure,
A columnar rubber layer;
A hard upper flange and a lower flange that are integrally provided on the upper and lower end surfaces of the rubber layer, and are fixed to the lower structure and the upper structure via respective engaging bolts;
Have
The upper flange and the lower flange each have a bolt mounting hole that engages with the bolt within the thickness of the upper flange and the lower flange,
The rubber layer has a primary shape factor S ₁ obtained by dividing the restrained area of the rubber layer by the free surface area of the rubber layer, and satisfies 0.3> S ₁ > 0.1, and the outer diameter of the rubber layer is The secondary shape factor S ₂ divided by the thickness of the rubber layer satisfies 1.1> S ₂ > 0.8, and the outer diameter A of the rubber layer and at least one plane of the upper flange and the lower flange The ratio A / B of the shortest length B passing through the center is configured to satisfy 0.95 ≧ A / B ≧ 0.75.
Restore rubber. The rubber layer is a single layer,
The restoration rubber according to claim 1. Shear modulus G of the rubber layer satisfies ^{0.6N / mm 2 ≧ G ≧ 0.29N} / mm 2, according to claim 1 or 2 restored rubber according. The bolt mounting holes are respectively formed on the lower surface of the upper flange and the upper surface of the lower flange, and have counterbores that receive and engage the heads of the bolts.
The restoration rubber according to any one of claims 1 to 3. The bolt mounting hole is a female screw for screwing,
The restoration rubber according to any one of claims 1 to 3. A center hole is provided along the axis of the rubber layer, the upper flange, and the lower flange,
The restoration rubber according to any one of claims 1 to 5. When the diameter of the center hole is C and the outer diameter of the rubber layer is A, C / A ≧ 0.1 is satisfied.
The restoration rubber according to claim 6. On the outer periphery of the end portion of the rubber layer to be joined to the upper flange and the lower flange, a rounded portion is provided,
The restoration rubber according to any one of claims 1 to 7. The restoration rubber according to any one of claims 1 to 8,
An upper structure disposed on the restoration rubber;
A lower structure disposed under the restoration rubber;
Have
The restoration rubber is fixed to each of the upper structure and the lower structure via bolts that engage with the bolt mounting holes.
Restoration rubber mounting structure.

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