Seismic isolation device

Abstract

To suppress deterioration of seismic isolation performance due to heat generation even when vibration is repeatedly applied such as a long period and long time earthquake vibration, and to suppress increase in the cost of a seismic isolation device and construction cost of a seismic isolation structure.SOLUTION: A seismic isolation device includes: a laminate rubber body 12 where a plurality of rubber layers 15 and a plurality of metal layers 14 having holes 18, 19 respectively are laminated alternately, and formed by vulcanization molding; and a columnar member 12 disposed in the lamination direction inside the laminate rubber body 12 via each of the holes 18, 19 of the rubber layer 15 and the metal layer 14 and capable of plastic deformation. For example, by disposing a seal ring 30 on an inner periphery of the hole 19 of the rubber layer 15, the flow of un-vulcanized rubber is inhibited, and an inner peripheral surface of the hole 18 of the metal layer 14 and an outer peripheral surface of the columnar member 12 come into contact with each other directly without a thin skin coating rubber existing according to the vulcanization molding between them.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a seismic isolation device. [Background technology]

[0002] A known type of seismic isolation device is a lead-plugged seismic isolation device, in which lead plugs (hereinafter referred to as lead columns) are enclosed in a laminated rubber body. In this lead-plugged seismic isolation device, the lead plugs function as components that absorb vibration energy by undergoing elasto-plastic deformation in conjunction with the shear deformation of the laminated rubber body during an earthquake. However, recent repeated vibration tests of various seismic isolation devices targeting long-period, long-duration earthquake motion have revealed a decrease in resistance (energy absorption capacity) due to heat generation in the energy-absorbing components, which has become a problem.

[0003] In particular, a decrease in energy absorption capacity leads to an increase in horizontal movement of the seismic isolation structure during an earthquake, creating the problem of needing to ensure a larger clearance between the structure and the retaining walls surrounding it. Furthermore, an increase in horizontal movement of the seismic isolation structure leads to a decrease in the vertical support load area of ​​the seismic isolation device, which may lead to buckling. As a result, in order to ensure safety, seismic isolation structure designers currently use a large safety factor when designing seismic isolation devices for use in areas where long-period, long-duration earthquake motions must be taken into consideration, meaning that their seismic isolation design incorporates a decrease in seismic isolation performance.

[0004] As a result of seismic isolation design that takes into account the decline in seismic isolation performance, the seismic isolation device must be safer than a normal seismic isolation design, which generally results in the device being larger.In addition, additional damping devices such as oil dampers, friction dampers, and hysteretic dampers may be installed to suppress the response deformation, which inevitably increases the cost of seismic isolation structures.

[0005] In view of the above circumstances, it has become an important issue how to suppress heat generation in energy absorbing members such as lead plugs or how to transfer the generated heat outward from the energy absorbing members.

[0006] Patent Document 1 discloses a seismic isolation device that aims to prevent a mechanical deterioration of seismic isolation performance by quickly dissipating heat generated when the laminated rubber body is repeatedly deformed from the laminated rubber body. Patent Documents 2 and 3 disclose seismic isolation support devices that can minimize temperature rise in lead plugs or tin plugs even when subjected to long-period earthquake motion, and can effectively demonstrate seismic isolation function even when subjected to long-period earthquake motion.

[0007] However, none of the above prior arts attempt to solve the problem by focusing on the thin-film rubber layer (details of which will be described later) that is formed between the outer surface of an energy absorbing member such as a lead plug and a metal layer such as a steel plate during the manufacturing process of the seismic isolation device. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2011-141002 [Patent Document 2] Patent Publication No. 2016-142343 [Patent Document 3] Patent Publication No. 2016-176577 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made based on the above technical background and has the following objectives. The purpose of this invention is to avoid the increase in size of seismic isolation devices that occurs when designs incorporate a decline in seismic isolation performance, as described above, and to suppress the decline in seismic isolation performance due to heat generation even when subjected to repeated vibrations such as long-period, long-duration earthquake motion, thereby suppressing increases in the cost of seismic isolation devices and the construction costs of seismic isolation structures, and to enable the widespread construction of seismically isolated buildings to protect the lives and property of many people. [Means for solving the problem]

[0010] The general manufacturing method for lead-plugged laminated rubber products consists of a "lamination and molding process" in which steel plates (metal layers) that have been pre-finished to a predetermined shape are alternately laminated with unvulcanized rubber plates (rubber layers), a "vulcanization molding process," and a "lead plug insertion process."

[0011] Specifically, holes for inserting lead plugs after vulcanization molding are formed in the steel sheets and rubber sheets to be laminated, and in the lamination and molding process, plug pins for molding are erected on the lower part of the mold and passed through each hole in the steel sheets and unvulcanized rubber sheets, i.e., the steel sheets and unvulcanized rubber sheets are laminated in order using the plug pins as guide pins. The plug pins are finished to the same size as the diameter of the lead plugs that are pressed into the insertion holes formed by the connection of the holes in the steel sheets and rubber sheets after vulcanization molding.

[0012] If the diameter of the plug pin and the diameter of the hole pre-drilled in the steel plate are the same, there will be no clearance, making assembly difficult during the lamination and molding process.Furthermore, when the mold is dismantled (removed) after vulcanization molding, the plug pin will bite into the steel plate, making it impossible to remove.Not only that, but the movement in the lamination direction (up and down) caused by the bumping process to expel any air remaining in the mold after vulcanization molding, and the expansion of unvulcanized rubber due to heating during vulcanization, is restricted by the pin's biting against the steel plate, resulting in molding defects.

[0013] For this reason, the hole diameter (inner diameter) drilled in the steel plate is generally made larger than the diameter of the plug pin to create a specified clearance (for example, about 1 to 2 mm). Furthermore, measures such as tapering the plug pin are taken to ensure smooth lamination and molding, smooth vulcanization molding of the laminated rubber body, and the subsequent mold dismantling (removal) can also be carried out without any problems.

[0014] On the other hand, if this is done, heated and pressurized unvulcanized rubber will flow into the clearance between the plug pin and the inner circumferential surface of the hole in the steel plate during the vulcanization molding process, and a thin rubber coating will be formed on the inner circumferential surface of the hole for inserting the lead plug in the laminated rubber body after vulcanization molding. Even if such a thin rubber coating is formed, the plug pin has the same diameter as the design dimensions of the lead plug to be inserted after vulcanization molding, and the diameter of the insertion hole in the laminated rubber body after vulcanization molding is not reduced, so there is no problem with the subsequent lead plug insertion process, and the lead plug and laminated rubber body can be integrated.

[0015] Even though it is necessary to form the above-mentioned thin rubber coating during the manufacturing process of the seismic isolation device, such seismic isolation devices are offered to the market as being problem-free because their seismic isolation performance fully meets the currently required inspection conditions.

[0016] The inventors of this application, from the viewpoint that rubber material, even thin-film rubber, is a heat insulating material, have focused on the insulating and thermal conductive properties of the thin-film rubber that exists between the columnar lead and the inner periphery of the insertion hole in the laminated rubber body, which is not considered a particular problem and is accepted in the manufacture of conventional laminated rubber type seismic isolation devices; in other words, its presence is taken for granted.

[0017] The inventors of this application then conducted a simulation (using CAE thermal analysis) to verify the effect on thermal conduction of the thin-coated rubber present between the columnar lead and the inner periphery of the insertion hole of the laminated rubber body, and how the heat generated in the columnar lead is transferred to the steel plate disposed inside the laminated rubber body and surrounding the lead plug, depending on whether or not the thin-coated rubber is present.

[0018] As a result of the analysis, it was discovered that the thin rubber coating that exists between the lead pillars and the inner periphery of the insertion hole in the laminated rubber body, which had not been considered a problem in the past because it did not affect the basic performance of the seismic isolation device (at least no previous examples are known from the perspective of heat conduction), actually has a major impact on the ability of the lead pillars to release heat to the steel plate of the laminated rubber body, or in other words, the ability to transfer heat, which is a very troublesome problem.

[0019] To explain the details of the simulation, we assumed a case where a thin rubber coating (0.5 mm thick) was placed between the lead column and the inner surface of the insertion hole of the laminated rubber body, and a case where the lead column was in direct contact with the inner surface of the hole in the steel plate. In both cases, the center of the lead plug continued to generate heat (5 mW / mm 3 The input temperature was set to 30 degrees Celsius, and the heat was diffused into the laminated rubber through the steel plates of the laminated rubber, and the temperature at which the temperature of the lead column became saturated was displayed. The temperature of the outside air in contact with the outer surface of the laminated rubber was set to a constant 30 degrees Celsius, and all materials in contact with the top and bottom surfaces of the laminated rubber were made of steel (SS400), to standardize the heat diffusion conditions.

[0020] The specifications of the lead-plug laminated rubber were: laminated rubber diameter φ800mm, one φ160mm lead column (placed in the center), 33 rubber layers 6mm thick (198mm thick), 32 internal steel plates 4.5mm thick, rubber shear modulus G4, and respective thermal conductivities of rubber 0.13w / (m·k), lead 35w / (m·k), and steel plate 51.6(m·k). CAE thermal analysis showed that the temperature of the lead column saturated as follows:

[0021] Thin-skinned rubber: 260.6°C Without thin-skin coated rubber: 195.3°C Temperature difference: 65.3 degrees C

[0022] When we looked at how much heat generated in the lead pillars is transferred to the steel plates inside the laminated rubber and how much heat is stored inside the lead pillars with and without the thin-coated rubber, we found that when the thin-coated rubber, which is only about 0.5 mm thick and present on the outer surface of the lead pillars and the inner surface of the insertion hole of the laminated rubber, was removed, the lead plug temperature saturated at a significantly lower temperature (a difference of 65.3 degrees Celsius) than when it was present.

[0023] In other words, by adopting a structure in which the heat of the lead columns is directly transferred to the steel plates within the laminated rubber, even if the temperature of the lead columns rises due to repeated shear deformation, the temperature is kept low, and the decrease in the damping characteristics and energy absorption capacity of the seismic isolation device is suppressed. This is because the thermal conductivity of steel is 51.6 (m·k) and that of rubber is 0.13 w / (m·k), a difference of approximately 400 times.

[0024] Furthermore, while the above CAE thermal analysis compared a laminated rubber structure with one lead column, similar results can be obtained when there are multiple lead columns, depending on whether or not the thin-skin rubber is used.As such, regardless of the number of lead columns, if the thin-skin rubber is eliminated, the steel material, which has good thermal conductivity, can come into direct contact with the outer surface of the lead column, suppressing heat generation in the lead column and allowing for good seismic isolation performance even when subjected to repeated vibrations such as long-period, long-duration earthquake motion.

[0025] The present invention is based on the above findings and is specified as follows. That is, this invention is a seismic isolation device comprising a laminated rubber body formed by vulcanization molding in which a plurality of rubber layers and metal layers, each having a hole, are alternately laminated, and columnar members that are plastically deformable and are arranged in the laminated rubber body in the lamination direction via the holes in the rubber layers and the metal layers, This seismic isolation device is characterized in that the inner surface of the hole in the metal layer and the outer surface of the columnar member are in direct contact with each other, without any thin rubber coating between them that occurs during vulcanization molding.

[0026] More specifically, the columnar member is divided in its axial direction and stacked, and consists of a plurality of divided bodies with annular cutout step portions formed on the outer periphery, and the metal layer is fitted into the cutout step portions of the divided bodies through the hole, and the rubber layer is fitted into the outer periphery of the divided bodies other than the cutout step portions through the hole, making it a seismic isolation device.

[0027] The metal layer is fitted into the cutout step of the segment through the hole, so that the periphery of the hole in the metal layer is sandwiched between the upper and lower segments, and the inner surface of the hole in the metal layer comes into contact with the outer surface of the segment (the peripheral side of the cutout step) at a position spaced radially inward from the rubber layer. This makes it nearly impossible for unvulcanized rubber to get between the inner surface of the hole in the metal layer and the outer surface of the segment, maintaining direct contact between the inner surface of the hole in the metal layer and the outer surface of the segment. As a result, even if the seismic isolation device is subjected to repeated shear deformation and the columnar members generate heat, the heat is transferred directly to the metal layer, keeping the temperature low and preventing a decrease in the damping characteristics and energy absorption capacity of the seismic isolation device.

[0028] Furthermore, by providing a sealing ring on the inner periphery of the hole in the rubber layer to prevent unvulcanized rubber from flowing into the inner periphery of the hole in the metal layer during vulcanization molding, it is possible to obtain a seismic isolation device in which the inner surface of the hole in the metal layer and the outer surface of the columnar member are in direct contact with each other.

[0029] The seal ring can be made of any of the following materials: vulcanized rubber such as natural rubber or urethane rubber; resins such as fluororesin, nylon, or polyamide; or metals such as aluminum, lead, or tin. By providing such a seal ring, unvulcanized rubber is prevented from flowing into the inner periphery of the hole in the rubber layer during vulcanization molding, preventing the formation of a thin rubber coating on the inner periphery of the hole in the metal layer. This allows for a seismic isolation device in which the inner periphery of the hole in the metal layer is in direct contact with the outer periphery of the columnar member.

[0030] Furthermore, a highly thermally conductive material can be used as the seal ring. The highly thermally conductive material not only prevents unvulcanized rubber from flowing into the inner periphery of the hole in the rubber layer during vulcanization molding and prevents the formation of a thin rubber coating on the inner periphery of the hole in the metal layer, but also transfers heat from the upper and lower surfaces of the metal layer near the inner periphery of the hole that come into contact with the highly thermally conductive material. As a result, even when the seismic isolation device undergoes horizontal shear deformation due to an external disturbance such as an earthquake, the device quickly follows the deformation without any gaps and more effectively transfers heat generated in the columnar members to the metal layer.

[0031] High thermal conductivity materials can be made of high thermal conductivity rubber, which has a thermal conductivity higher than that of the rubber layer (0.13 w / (m·k)) and a thermal conductivity of over 10 w / (m·k). High thermal conductivity rubber is known to be made by mixing rubber material with carbon fiber, copper or aluminum nonwoven fabric, copper or aluminum fiber, carbon nanotubes, etc. [Effects of the Invention]

[0032] According to the present invention, it is possible to obtain a seismic isolation device that suppresses deterioration of seismic isolation performance due to heat generation in the energy absorbing member even when subjected to repeated vibrations such as long-period, long-duration earthquake motion. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a plan view showing an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view taken along the line AA in FIG. 1. [Figure 3] FIG. 2 is an enlarged cross-sectional view showing the divided lead pillars. [Figure 4] FIG. 4 is a cross-sectional view showing an outer peripheral portion of a divided body on a further enlarged scale. [Figure 5] FIG. 10 is a cross-sectional view showing another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a plan view showing the embodiment of the present invention, Fig. 2 is an enlarged cross-sectional view taken along line AA in Fig. 1, Fig. 3 is an enlarged cross-sectional view of a divided lead column, and Fig. 4 is a further enlarged cross-sectional view of the outer periphery of a divided body.

[0035] As shown in Figures 1 and 2, the seismic isolation device 10 has a laminated rubber body 11 and cylindrical lead columns 12 that form plastically deformable columnar members disposed inside the laminated rubber body 11. The laminated rubber body 11 is formed by stacking steel plates 13a, 13b, and 14 that form multiple metal layers, and multiple rubber layers 15. The steel plates 13a, 13b, and 14 and the rubber layers 15 are all circular, and therefore the laminated rubber body 11 is circular in plan view.

[0036] Of the steel plates 13a, 13b, and 14, the thick steel plates 13a and 13b are arranged at the top and bottom of the laminated rubber body 11 and are connecting steel plates that are connected to, for example, a seismic isolation structure and its foundation, respectively, via flange plates (not shown). The thin steel plate 14 is an internal steel plate that is arranged inside the laminated rubber body 11. Circular holes 16a, 16b, and 18 are drilled in these steel plates 13a, 13b, and 14, respectively.

[0037] Similarly, a circular hole 19 is also formed in the rubber layer 15. The holes 16a and 16b in the connecting steel plates 13a and 13b, the hole 18 in the internal steel plate 14, and the hole 19 in the rubber layer 15 are all located at the same position in a plan view, and the lead columns 12 are arranged in the stacking direction inside the laminated rubber body 11 via these holes 16a, 16b, 18, and 19.

[0038] The lead column 12 is divided in the axial direction into a plurality of lead segments 12a, 12b, and 12c (see FIG. 3). The upper and lower lead segments 12a and 12b are fitted into holes 16a and 16b in the connecting steel plates.

[0039] The lower lead segment 12b has a thickness that allows its upper end to protrude from the hole 16b in the connecting steel plate 13b, and this protruding upper end is made larger in diameter than the hole 16b and engages with the peripheral edge of the hole 16b. A recess 20 is formed in the upper surface of this protruding upper end, and an annular notched step 21 is formed on the outer periphery. This notched step 21 is fitted into the hole 18 in the lowermost inner steel plate 14. The outer periphery of the protruding upper end, excluding the notched step 21, is fitted into the hole 19 in the lowermost rubber layer 15.

[0040] The upper lead segment 12a has the same thickness as the connecting steel plate 13a, and the lower end thereof is formed with a smaller diameter than the hole 16a of the connecting steel plate 13a, thereby forming a protrusion 22.

[0041] The internal split lead 12c has a recess 23 on its upper surface and a protrusion 24 on its lower surface, and the recess 23 is fitted with the protrusion 24 of the adjacent internal split lead 12c on the upper side. An annular notched step 25 is formed on the outer periphery of the internal split lead 12c. This notched step 25 is fitted into a hole 18 in the internal steel plate 14. The outer periphery of the internal split lead 12c other than the notched step 25 is fitted into a hole 19 in the rubber layer 15.

[0042] The seismic isolation device 10 according to the above embodiment is manufactured as follows. 1. The lower lead segments 12b are fitted into the holes 16b of the lower connecting steel plate 13b and set. 2. Place the rubber plate 15 on the lower connecting steel plate 13b by fitting the upper end of the lower lead segment 12b protruding from the lower connecting steel plate 13b into the hole 19 of the lowest rubber plate 15 (unvulcanized, which will become the rubber layer 15 after vulcanization; the same applies below). 3. The lowermost inner steel plate 14 is placed on the lowermost rubber plate 15 by fitting the notched step portion 21 of the lower lead segment 12b into the hole 18 of the lowermost inner steel plate 14.

[0043] 4. The inner split lead 12c is placed on the lower split lead 12b by fitting the protrusion 24 of the inner split lead 12c into the recess 20 of the lower split lead 12b. 5. The rubber plate 15 is placed on the inner steel plate 14 by fitting the inner divided lead 12c into the hole 19 of the rubber plate 15. 6. The internal steel plate 14 is placed on the rubber plate 15 by fitting the notched step portion 25 of the internal lead division 12c into the hole 18 of the internal steel plate 14.

[0044] 7. The protrusions 24 of the internal split lead 12c disposed above the recesses 23 of the internal split lead 12c are fitted into the recesses 23 of the internal split lead 12c. 8. Repeat steps 5 to 7 until the number of layers in the design is minus 1. 9. Place the top rubber plate 15 on the top inner steel plate 14 by fitting the top inner lead division 12c into the hole 19 of the top rubber plate 15. 10. The upper split lead 12a is placed on the top inner split lead 12c by fitting the protrusion 22 of the upper split lead 12a into the recess 23 of the top inner split lead 12c. 11. The upper connecting steel plate 13a is set by fitting the upper lead segments 12a into the holes 16a of the upper connecting steel plate 13a. 12. Vulcanization molding is carried out.

[0045] According to the seismic isolation device 10 of the above embodiment, the notched step portions 21, 25 of the lead segments 12b, 12c are fitted into the hole 18 of the internal steel plate 14, so that the peripheral portion of the hole 18 of the internal steel plate 14 is clamped between the upper and lower internal lead segments 12c, 12c (or between the lead segments 12b, 12c), and as shown enlarged in Figure 4, the inner surface of the hole 18 of the internal steel plate 14 comes into contact with the outer surface of the lead segment 12c (the peripheral side surface of the notched step portions 21, 25) at a position spaced radially inward from the rubber plate 15 by a distance S.

[0046] For this reason, during vulcanization molding, the unvulcanized rubber of the rubber plate 15 cannot get in between the inner circumferential surface of the hole 18 in the internal steel plate 14 and the outer circumferential surface of the lead segments 12c, and the inner circumferential surface of the hole 18 in the internal steel plate 14 and the outer circumferential surface of the lead segments 12 are maintained in direct contact. As a result, even if the seismic isolation device is subjected to repeated shear deformation and the lead columns 12 generate heat, the heat is transferred directly to the internal steel plate 14, so the temperature is kept low and a decrease in the damping characteristics and energy absorption capacity of the seismic isolation device can be prevented.

[0047] Figure 5 is a partial cross-sectional view showing another embodiment. The lead column 12 in this embodiment is not divided as in the above embodiment, but is a commonly used cylindrical column. The laminated rubber body 11 constituting the seismic isolation device 10 is formed by laminating upper and lower circular connecting steel plates 13a, 13b, multiple internal steel plates 14, and multiple rubber layers 15, as in the above embodiment. Also, circular holes 16a, 16b, 18 are formed in the steel plates 13a, 13b, 14, respectively, and a circular hole 19 is formed in the rubber layer 15, and these holes are also formed in the same position in a plan view, as in the above embodiment.

[0048] In this embodiment, a seal ring 30 is provided on the inner periphery of the rubber layer 15. The inner diameter of the seal ring 30 is approximately equal to the diameter of the hole 18 in the inner steel plate 14, and therefore the diameter of the hole 19 in the rubber layer 15 is larger than the diameter of the hole 18 in the inner steel plate 14. The thickness of the seal ring 30 is set to be approximately 0.5 to 1.0 mm thicker than the thickness of the rubber layer 15 after vulcanization molding.

[0049] Any of the following materials can be used for the seal ring 30: natural rubber, vulcanized rubber such as urethane rubber, resin such as fluororesin, nylon, polyamide, or metal such as aluminum, lead, or tin. Furthermore, the seal ring can be made of a highly heat-conductive material, such as a rubber material mixed with carbon fiber, nonwoven fabric of copper or aluminum, fiber of copper or aluminum, or carbon nanotubes.

[0050] The seismic isolation device 10 according to the above embodiment is manufactured as follows. 1. Set the plug pin P for molding. Instead of using a plug pin, a lead column 12 or tin column having the same diameter as the plug pin P may be set during molding. 2. The plug pin P is passed through the hole 16b and the lower connecting steel plate 13b is installed. 3. The seal ring 30 is passed over the plug pin P, and this is placed on the lower connecting steel plate 13b.

[0051] 4. The plug pin P is passed through the hole 19 in the lowermost rubber plate 15 (which is unvulcanized and becomes the rubber layer 15 after vulcanization; the same applies below), and this is placed on the outer periphery of the seal ring 30 on the lower connecting steel plate 13b. 5. Insert the plug pin P into the hole 18 and place the inner steel plate 14 on the rubber plate 15. 6. Pass the seal ring 30 over the plug pin P and place it on the inner steel plate 14.

[0052] 7. The plug pin P is passed through the hole 19 in the rubber plate 15, and the outer periphery of the seal ring 30 is placed on the inner steel plate 14. 8. Repeat steps 5 to 7 until the number of layers in the design is minus 1.

[0053] 9. Pass the seal ring 30 over the plug pin P, and then pass it through the hole 19, and place the uppermost rubber plate 15 on the inner steel plate 14. 10. Insert the plug pin P through the hole 16a and install the upper connecting steel plate 13a. 11. Vulcanization molding is carried out. 12. After demolding, the plug pin P is removed and a lead column 12 is inserted into the hole formed.

[0054] According to the above embodiment, the seal ring 30 is provided on the inner periphery of the hole 19 in the rubber plate 15, which prevents unvulcanized rubber from flowing into the inner periphery of the hole 19 in the rubber plate 15 during vulcanization molding, and prevents a thin rubber coating from being formed on the inner periphery of the hole 18 in the internal steel plate 14. Therefore, a seismic isolation device can be obtained in which the inner periphery of the hole 18 in the internal steel plate 14 and the outer periphery of the lead column 12 are in direct contact with each other.

[0055] When a plug pin P is used in the above manufacturing process, a clearance is formed between the plug pin P and the inner circumferential surface of the hole 18 in the inner steel plate 14 to facilitate removal of the plug pin P after molding, as described above. Therefore, when a lead column 12 having the same diameter as the plug pin is inserted into an insertion hole formed by removing the plug pin P, a clearance is formed between the lead column 12 and the inner circumferential surface of the hole 18 in the inner steel plate 14. However, since the lead column 12 is usually inserted into the hole under pressure from above, it bulges outward in the radial direction, eliminating the clearance. In other words, the inner circumferential surface of the hole 18 in the inner steel plate 14 and the outer circumferential surface of the lead column 12 come into direct contact.

[0056] Furthermore, by using a highly thermally conductive material as the sealing ring, the highly thermally conductive material prevents unvulcanized rubber from flowing into the inner periphery of the hole in the rubber layer 15 during vulcanization molding, and not only prevents the formation of a thin rubber coating on the inner surface of the hole 18 in the internal steel plate 14, but also heat is transferred from the upper and lower surfaces T near the inner periphery of the hole 18 in the internal steel plate 14 that come into contact with the highly thermally conductive material.As a result, even when the seismic isolation device undergoes horizontal shear deformation due to an external disturbance such as an earthquake, the device quickly follows the deformation without any gaps, and the heat generated in the lead column 12 can be more effectively transferred to the metal layer.

[0057] Furthermore, since the thickness of the seal ring 30 is set to be approximately 0.5 to 1.0 mm thicker than the thickness of the rubber layer 15 after vulcanization molding, the seal ring is crushed in the thickness direction during vulcanization molding, completely preventing the flow of unvulcanized rubber to the inner periphery of the hole 18 in the internal steel plate 14.

[0058] The above-described embodiment is merely illustrative, and the present invention can take various forms. For example, while the above-described embodiment shows a seismic isolation device in which one lead column is disposed within the laminated rubber body, the present invention can also be applied to a seismic isolation device in which multiple lead columns are disposed. The present invention can also be applied to a seismic isolation device in which the lead columns are separated into upper and lower columns and disposed at a distance from each other within the laminated rubber body. Furthermore, the material of the columnar member is not limited to lead, and other metal materials such as tin can be used. [Explanation of symbols]

[0059] 10: Seismic isolation device 11: Laminated rubber body 12: Pillar lead 12a, 12b: Upper and lower divided lead 12c: Internal split lead 13a, 13b: Upper and lower connecting steel plates 14: Internal steel plate 15: Rubber layer 16a, 16b: Holes in the upper and lower connecting steel plates 18: Internal steel plate hole 19: Hole in rubber layer 21: Notched step of lower lead 25: Internally divided lead notched step 30: Seal ring

Claims

1. A seismic isolation device comprising a laminated rubber body formed by vulcanization molding in which a plurality of rubber layers and metal layers, each having a hole, are alternately laminated, and a columnar member capable of plastic deformation is disposed inside the laminated rubber body in the lamination direction via each hole in the rubber layer and the metal layer, A seismic isolation device characterized in that the inner surface of the hole in the metal layer and the outer surface of the columnar member are in direct contact with each other without the presence of a thin rubber coating between them that occurs during vulcanization molding.

2. The seismic isolation device described in claim 1, characterized in that the columnar member is divided in its axial direction and stacked, and consists of multiple divided bodies with annular cutout step portions formed on the outer periphery, and the metal layer is fitted into the cutout step portions of the divided bodies through the hole, and the rubber layer is fitted into the outer periphery of the divided bodies other than the cutout step portions through the hole.

3. The seismic isolation device according to claim 1, characterized in that a sealing ring is provided on the inner periphery of the hole in the rubber layer to prevent unvulcanized rubber from flowing into the inner periphery of the hole in the metal layer during vulcanization molding.

4. 4. The seismic isolation device according to claim 3, wherein the seal ring is made of any one of vulcanized rubber, resin, and metal.

5. 4. The seismic isolation device according to claim 3, wherein the seal ring is made of a highly heat-conductive material.

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