JP2006250300A - Laminated rubber body with incorporated lead plug - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated rubber body with incorporated lead plugs, comprising a laminated rubber which prevents a hardening phenomenon and has a stable hysteresis characteristic. <P>SOLUTION: The laminated rubber body 1 with the incorporated lead plugs comprises the laminated rubber 4 in which a rubber elastic layer 2 and a hard plate layer 3 are alternately laminated, the lead plugs 5 embedded in the laminated rubber 4 while being kept under restraint, and a tubular coating layer 13 that covers an outer peripheral surface 12 of the rubber elastic layer 2 and is formed integrally with the outer peripheral surface 12 of the rubber elastic layer 2 by vulcanization molding. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminated rubber body containing lead plugs that is suitable for use in seismic isolation bearings, and more particularly to a laminated rubber body containing lead plugs that have high damping performance and stable hysteresis characteristics while being hard to cause a hardening phenomenon.

Japanese Examined Patent Publication No. 6-22958 JP 2000-1820 A JP 2002-188122 A

  Laminated rubber formed by alternately laminating a rubber elastic layer and a hard plate layer, and a lead plug that penetrates the laminated rubber in the laminating direction and is embedded by being restrained by the laminated rubber to give an appropriate damping function to the laminated rubber The laminated rubber body with lead plugs having a large number of is used not only as a support for bridges but also as a support for other structures.

  In this respect, Patent Document 1 discloses that in order to obtain a laminated structure having two or more excellent properties, the peripheral portion and the inner portion of the soft plate are formed of materials having different properties from each other. In order to suppress the occurrence of local distortion in the rubber layer and to prevent local destruction of the rubber layer, the reinforcing rubber is applied to at least the peripheral portion of the rubber layer near the end steel plates on both upper and lower end surfaces of the laminate. Arranging and making the shear elastic modulus of the reinforcing rubber higher than that of the main rubber of the rubber layer, and Patent Document 3 provides a rubber bearing for a bridge with improved damping characteristics and excellent durability. Therefore, it has been proposed to make the outer peripheral portion of the rubber layer a low damping rubber and to make the inner portion a high damping rubber.

  By the way, rubber materials used for laminated rubber are roughly classified into natural rubber and high damping rubber having an equivalent damping constant of 0.10 or more and having damping characteristics larger than that of natural rubber. In laminated rubber, the characteristics of the rubber material used directly affect its performance and durability, and when viewed from the functions required as a bearing, for example, natural rubber is likely to cause hardening and be relatively ozone. On the other hand, there is little deterioration in the hysteresis characteristics, and when a high damping rubber is used, hardening is difficult to occur and it is relatively resistant to the ozone environment, while the hysteresis characteristics are relatively significantly reduced.

  The laminated structure proposed in Patent Document 1 is formed by simply forming the peripheral portion and the inner portion of the soft plate from materials having different characteristics from each other, and at the time of large deformation that is considered to have contradictory characteristics. Hardening phenomenon does not occur, and it does not have a stable hysteresis characteristic that does not change even after large deformation, and the laminated rubber bearing of Patent Document 2 also has a higher shear elastic modulus than the main rubber of the rubber layer The reinforcing rubber is merely disposed at the peripheral edge of the rubber layer, and does not have a stable hysteresis characteristic by eliminating the hardening phenomenon. Further, the rubber support for a bridge in Patent Document 3 is also a rubber layer. The outer part is made of low-damping rubber and the inner part is made of high-damping rubber, and it has only improved damping characteristics and excellent durability. Not having sex.

  In view of the above points, the present invention has a specific positional relationship between a portion made of natural rubber and a portion made of high damping rubber in the rubber elastic layer, and a volume of the portion made of high damping rubber and the entire rubber elastic layer. When the ratio is in a certain range, it has been found that a hardened phenomenon does not occur at the time of large deformation, and it becomes a laminated rubber having stable hysteresis characteristics that does not change even after large deformation. Therefore, an object of the present invention is to provide a laminated rubber body with a lead plug having a laminated rubber having a stable hysteresis characteristic in addition to the occurrence of the above-mentioned hardening phenomenon. is there.

  The laminated rubber body with lead plugs according to the present invention includes a laminated rubber formed by alternately laminating a rubber elastic layer and a hard plate layer, and at least embedded in the laminated rubber while being penetrated in the laminating direction and restrained by the laminated rubber. The rubber elastic layer has an outer peripheral side portion made of high-damping rubber, and the inner peripheral side portion of the rubber elastic layer surrounded by the outer peripheral side portion is natural rubber. The volume ratio of the outer peripheral side portion made of high-damping rubber of the rubber elastic layer to the whole rubber elastic layer is 0.2 to 0.8.

  The laminated rubber body with lead plugs according to the present invention is a laminated rubber formed by alternately laminating a rubber elastic layer and a hard plate layer, and penetrates the laminated rubber in the laminating direction and is restrained and embedded in the laminated rubber. A laminated rubber body with a lead plug having at least one columnar lead plug, wherein a pair of outer portions in one direction orthogonal to the laminating direction of the rubber elastic layer is made of a high damping rubber. The inner portion of the rubber elastic layer sandwiched between the pair of outer portions is made of natural rubber, and the volume ratio of the outer portion made of high-damping rubber of the rubber elastic layer to the entire rubber elastic layer is 0. .2 to 0.8.

  Furthermore, the laminated rubber body with lead plugs according to the present invention is embedded with laminated rubber formed by alternately laminating rubber elastic layers and hard plate layers, and through the laminated rubber in the laminating direction and restrained by the laminated rubber. At least one pillar-shaped lead plug, and the lead plug surrounding portion surrounding the lead plug of the rubber elastic layer is made of natural rubber, and the other portion of the rubber elastic layer excluding the lead plug surrounding portion is It is made of high-damping rubber, and the volume ratio of the portion of the rubber elastic layer made of high-damping rubber to the whole rubber elastic layer is 0.2 to 0.8.

  According to the laminated rubber body with a lead plug according to the present invention, at least one pair of outer portions in one direction out of the directions orthogonal to the laminating direction of the rubber elastic layer is made of high-attenuation rubber. Since the inner part of the rubber elastic layer sandwiched between the pair of outer parts is made of natural rubber, it is possible to protect the inner part made of natural rubber that is relatively weak in the ozone environment with the outer part made of high damping rubber. In addition, since it has an outer portion made of high damping rubber having a volume ratio of 0.2 to 0.8 with respect to the entire rubber elastic layer, the lead plug is coupled with the cylindrical lead plug. The vibration of the structure in the shear direction (horizontal direction) of the laminated laminated rubber body can be damped as quickly as possible.

  Laminated rubber bodies with lead plugs that use only natural rubber for the rubber elastic layer are prone to hardening during large deformations in the shearing direction. In other words, a large post-yield stiffness kd due to large deformations in the shearing direction. On the other hand, a laminated rubber body that uses only high-damping rubber for the rubber elastic layer has a large elongation characteristic and causes a hardening phenomenon even during large deformation in the shear direction. Although it is difficult (the linear region of rigidity kd after yielding is wide), in such a laminated rubber body with lead plug, the outer portion made of high damping rubber has a volume ratio of less than 0.2 with respect to the entire rubber elastic layer. Then, the large elongation characteristics of the high-damping rubber cannot be fully used, and the hardening phenomenon is likely to occur. Therefore, the outer portion made of the high-damping rubber has an effect of the hardening phenomenon. It is the is required in terms of Do suppression is 0.2 or more by volume ratio to the total of the rubber elastic layer.

  In addition, high damping rubber is greatly affected by repeated deformation of its elastic properties and lacks stability against repeated deformation. In particular, natural rubber is repeatedly affected by hysteresis properties after large deformation. Even if it is deformed, it is not affected by the elastic properties so much, and it has stable elastic properties against repeated deformation, but in the laminated rubber body with lead plug, the outer part made of high damping rubber is the whole rubber elastic layer When the volume ratio is larger than 0.8, the hysteresis characteristics deteriorate due to the elastic characteristics lacking the stability of the high-damping rubber than the stable elastic characteristics of the natural rubber, in other words, the equivalent stiffness keq in the shear direction. Therefore, the outer portion made of high-damping rubber has a volume of 0.8 or less with respect to the entire rubber elastic layer from the viewpoint of maintaining the equivalent rigidity keq in repeated deformation. It is required that rate.

  More stable hysteresis characteristics can be obtained when the volume ratio of the outer part or outer peripheral part made of high-damping rubber to the entire rubber elastic layer is 0.5 or less.

  In the present invention, the high damping rubber polymer may be ethylene propylene rubber, nitrile rubber, butyl rubber, halogenated butyl rubber, chloroprene rubber, isoprene rubber, styrene butadiene copolymer rubber, acrylonitrile butadiene rubber, butadiene rubber or silicone rubber, or a mixture thereof. And a mixture of these and natural rubber, and examples of materials other than the polymer of the high-damping rubber include carbon black, silica, or resin as representative examples. It has an equivalent damping constant of 0.10 to 0.20. In this case, the natural rubber may have an equivalent damping constant of 0.01 to 0.06 in the design strain. Additives such as a filler, a plasticizer, an anti-aging agent, a vulcanizing agent, a vulcanization accelerator, and a vulcanization acceleration aid may be blended with the high-damping rubber and the natural rubber as necessary.

  In general, the rubber elastic layers preferably have the same thickness, but may have different thicknesses, and the hard plate layer may also have the same thickness. The thick hard plate layer disposed at both ends in the laminating direction and the thin hard plate layer alternately laminated with the rubber elastic layer between the thick hard plate layers may be included. A mounting plate may be attached to a structure including a bridge girder and a foundation including a bridge pier via bolts, dowel pins, etc. on the plate layer. When a thick hard plate layer is not used, a rubber elastic layer or a hard plate is used. The mounting plate may be attached directly to the layer via an adhesive or to the rubber elastic layer by vulcanization adhesion. As the hard plate layer, plate-like materials made of various materials having required rigidity such as metal, ceramics, plastic, and FPR can be used.

  Each of the rubber elastic layer and the hard plate layer is a quadrangle including a square, a pentagon, a hexagon, or a circle in a plan view, preferably a quadrangle or a circle, and a square or a circle including a square for a bridge. In addition, the laminated rubber is also quadrangular, pentagonal, hexagonal or circular corresponding to the shapes of the rubber elastic layer and the hard plate layer, but any of them is not limited thereto.

  Only one lead plug may be embedded in the central portion of the laminated rubber, but instead of this, a plurality of lead plugs may be embedded around the central portion of the laminated rubber, and the purity is preferably 99.9. % Or more lead material may be used. The lead plug may be a prism such as a cylinder, a quadrangular cylinder, or a hexagonal cylinder, and preferably a cylinder. Further, the lead plug may be restrained and embedded in a portion of the rubber elastic layer made of natural rubber, or may be restrained and embedded in a portion of the rubber elastic layer made of high damping rubber. May be constrained and embedded in a part extending over both the part made of high-damping rubber and the part made of high-damping rubber, but the effect of high-damping rubber that is preferably inferior in stability to repeated deformation when embedded in a part made of natural rubber It is good because the lead plug does not receive.

  The structure is isolated from vibrations only in one of the directions perpendicular to the stacking direction. For example, a lead plug for a bridge is used to isolate the structure from vibrations only in the bridge axis direction. In the case of a laminated rubber body, as described above, a pair of outer portions in one direction orthogonal to the laminating direction of the rubber elastic layer is made of high-damping rubber and is sandwiched between the pair of outer portions. The inner part of the rubber elastic layer may be made of natural rubber, and in the case of such a laminated rubber body with a lead plug, one direction out of the directions perpendicular to the lamination direction is the bridge axis direction. The laminated rubber body with the lead plug is preferably arranged so that a pair of outer portions made of high-damping rubber and an inner portion made of natural rubber sandwiched between the pair of outer portions are aligned in the bridge axis direction.

  The laminated rubber body with a lead plug of the present invention may have a coating layer that covers the outer peripheral surface of the laminated rubber, and the coating layer may be made of high-attenuation rubber. From the viewpoint of the above, it is preferably made of natural rubber having an ozone degradation inhibitor and an antioxidant. The coating layer covering the outer peripheral surface of the laminated rubber is preferably integrated by being bonded to the outer peripheral surface of the laminated rubber via an adhesive or by vulcanization. Although the thickness of the coating layer depends on the size of the laminated rubber, it may be sufficiently thin as long as the weather resistance can be obtained for a long time with sufficient durability, for example, a laminated layer having a height of 73 mm and a height and width of 250 mm. An example of rubber is about 5 mm.

  In the laminated rubber body with lead plugs according to the present invention, one end face of the laminated rubber in the laminating direction is directly fixed to, for example, the foundation, and the other end face of the laminated rubber in the laminating direction is directly fixed to, for example, the building to be supported. Alternatively, instead of this, one mounting plate that is in contact with one end surface in the laminating direction of the laminated rubber on one plate surface, and the other that is in contact with the other end surface in the laminating direction of the laminated rubber on one plate surface The laminated rubber body with lead plugs may be configured by further including a mounting plate, and the laminated rubber body with lead plugs may be fixed to the foundation and the building via the mounting plate. One mounting plate is fixed to the laminated rubber via a screw member on one plate surface, and the other mounting plate may be fixed to the laminated rubber via another screw member on the one plate surface. Instead of or together with this, one attachment plate is fixed to the laminated rubber on one plate surface with respect to the plate surface direction via a dowel pin fitted to each of the one attachment plate and the laminated rubber, The other mounting plate may be fixed to the laminated rubber on one plate surface with respect to the plate surface direction via another dowel pin fitted to each of the other mounting plate and the laminated rubber. In combination with the above or alone, each mounting plate may be directly fixed to the corresponding end face in the lamination direction of the laminated rubber by vulcanization adhesion.

  According to the present invention, it is possible to provide a laminated rubber body with a lead plug that includes a laminated rubber having a stable hysteresis characteristic without causing a hardening phenomenon.

  Next, the present invention and its embodiments will be described in more detail based on preferred examples shown in the drawings. The present invention is not limited to these examples.

  1 to 3, a laminated rubber body 1 with lead plugs of this example is formed by alternately laminating a plurality of rectangular rubber elastic layers 2 in plan view and rectangular hard plate layers 3 in plan view. The rubber 4 and at least one that penetrates the laminated rubber 4 in the laminating direction, that is, the vertical direction V, and are embedded by being restrained by the laminated rubber 4, in this example, four columnar lead plugs 5, and a lead plug 5 And a mounting plate 8 in contact with one end surface 6 in the vertical direction V of the laminated rubber 4 on one plate surface 7 and a plate surface 10 on the other end surface 9 in the vertical direction V of the lead plug 5 and the laminated rubber 4. The mounting plate 11 is in contact with the outer peripheral surface 12 of the rubber elastic layer 2 and has a cylindrical covering layer 13 integrally formed on the outer peripheral surface 12 of the rubber elastic layer 2 by vulcanization.

  The plurality of hard plate layers 3 are located on the outermost side in the vertical direction V and between a pair of thick hard plate layers 21 and 22 made of a thick steel plate and the pair of thick hard plate layers 21 and 22. And a plurality of thin hard plate layers 23 made of steel plates and the like which are thinner than the thick hard plate layers 21 and 22. A circular recess 24 is formed on one surface of the thick hard plate layer 21, and a circular recess 25 is formed on one surface of the thick hard plate layer 22.

  The plurality of rubber elastic layers 2 arranged alternately with the plurality of thin hard plate layers 23 between the pair of thick hard plate layers 21 and 22 are vulcanized and bonded to each other. The thin hard plate layer 23 is fixed.

  The annular outer peripheral side portion 32 of the rubber elastic layer 2 bounded by the rectangular boundary line 31 is made of high attenuation rubber having an equivalent attenuation constant of 0.10 or more in design strain, and is surrounded by the outer peripheral side portion 32. The inner peripheral side portion 33 of the rubber elastic layer 2 is made of natural rubber having an equivalent damping constant of 0.01 to 0.06 in the design strain. The volume ratio of the outer peripheral side portion 32 of the rubber elastic layer 2 made of high damping rubber is 0.2 to 0.8. That is, when the total volume of the plurality of rubber elastic layers 2 without including the lead plug 5 portion is Vall and the volume of the annular outer peripheral side portion 32 of the plurality of rubber elastic layers 2 is Vout, the volume ratio (= Vout / Vall) is 0.2 to 0.8 (Vout / Vall = 0.2 to 0.8).

  Four columnar lead plugs 5 are constrained and embedded in the laminated rubber 4 in the inner peripheral side portion 33.

  The mounting plate 8 made of a steel plate or the like has a circular recess 35 in the plate surface 7, and contacts the end surface 6 of the laminated rubber 4 with the plate surface 7 and is a thick hard plate of the laminated rubber 4. The mounting plate 11, which is fixed to the layer 21 via a screw member 36 and is made of a steel plate or the like like the mounting plate 8, has a circular recess 37 in the plate surface 10. It contacts the end surface 9 of the laminated rubber 4 and is fixed to the thick hard plate layer 22 of the laminated rubber 4 via a screw member 38. A shear key 39 is fitted in the recesses 24 and 35 between the attachment plate 8 and the thick hard plate layer 21, and the recesses 25 and 25 are provided between the attachment plate 11 and the thick hard plate layer 22. 37, a shear key 40 is fitted, and the attachment plate 8 is fixed to the thick hard plate layer 21 with respect to the direction perpendicular to the vertical direction V, that is, the horizontal direction H by the shear key 39, The attachment plate 11 is fixed in the horizontal direction H with respect to the thick hard plate layer 22 by the shear key 40.

  The covering layer 13 covering the outer peripheral surface 12 of the rubber elastic layer 2 is made of natural rubber, and the plate surface 7 and the mounting plate 8 of the mounting plate 8 are attached at the end surfaces in the vertical direction V that are flush with the end surfaces 6 and 9 respectively. The plate 11 is in contact with each of the plate surfaces 10.

  The laminated rubber 4 can be manufactured as follows, for example. First, an unvulcanized natural rubber material plate having a hole for inserting the lead plug 5 and having the outer shape of the inner peripheral side portion 33 is similarly used. Adhering to the thick steel plate to be the layer 21, and with or after the adhering, has the same thickness as the above-mentioned unvulcanized natural rubber material plate having the outer shape of the inner peripheral side portion 33 The unvulcanized high-damping rubber material plate having the outer shape of the outer peripheral side portion 32 is replaced with the unvulcanized natural material having the outer shape of the inner peripheral side portion 33 to the thick steel plate to be the thick hard plate layer 21. A hole for inserting a lead plug 5 in a natural rubber material plate and a high damping rubber material plate, which are attached in contact with the end face of the rubber material plate, and are attached to a thick steel plate which becomes the thick hard plate layer 21. And a thin steel plate which becomes the thin hard plate layer 23 is pasted, and thereafter, the above operation is repeated so as to obtain the required number of layers. A thick steel plate having a hole for inserting a lead plug 5 and a thick hard plate layer 22 is attached to a natural rubber material plate and a high damping rubber material plate which are attached to a thin steel plate to be the hard plate layer 23. And after sticking, these are integrally vulcanized (processed) and the laminated rubber 4 is obtained. The lead plug 5 is preferably press-fitted into a hole formed orthogonal to the lamination direction of the vulcanized laminated rubber 4.

  In the laminated rubber body 1 with lead plugs described above, the mounting plate 8 is fixed to the foundation via an anchor bolt or the like, and the mounting plate 11 is fixed to the structure via a bolt or the like, and is arranged between the structure and the foundation. In addition to supporting the load in the vertical direction V of the structure and preventing vibrations in the horizontal direction H of the foundation due to the earthquake from being transmitted to the structure by shear deformation in the horizontal direction H of the laminated rubber 4 including the lead plug 5, the lead plug 5 is mainly used. The horizontal deformation H of the rubber elastic layer 2 and the horizontal deformation H of the outer peripheral side portion 32 of the rubber elastic layer 2 are used to quickly attenuate the vibration of the structure in the horizontal direction H.

  According to the laminated rubber body 1 with a lead plug, the outer peripheral side portion 32 of the rubber elastic layer 2 is made of high damping rubber, while the inner peripheral side portion 33 surrounded by the outer peripheral side portion 32 of the rubber elastic layer 2 is natural. Since it is made of rubber, the inner peripheral side portion 33 made of natural rubber, which is relatively weak against ozone environment, can be protected by the outer peripheral side portion 32 made of high damping rubber, and the entire rubber elastic layer 2 can be protected. In addition, the outer peripheral side portion 32 made of a high damping rubber having a volume ratio of 0.2 to 0.8 has no hardening phenomenon and has a stable hysteresis characteristic. Combined with the plug 5, the vibration in the horizontal direction H of the lead plug-containing laminated rubber body 1 can be damped as quickly as possible, and a large damping can be obtained. Can be miniaturized and lowers manufacturing costs It is possible to facilitate the construction it is possible.

  In the above-described laminated rubber body 1 with a lead plug, the annular outer peripheral side portion 32 of the rubber elastic layer 2 is made of high damping rubber, and the inner peripheral side portion 33 of the rubber elastic layer 2 surrounded by the outer peripheral side portion 32 is made of natural rubber. However, as shown in FIG. 4, a pair of one direction X in the horizontal direction H orthogonal to the vertical direction V of the rubber elastic layer 2 bounded by a pair of linear boundary lines 41 and 42. The outer parts 43 and 44 may be made of high-damping rubber, and the inner part 45 of the rubber elastic layer 2 sandwiched between the pair of outer parts 43 and 44 may be made of natural rubber. The volume ratio of the outer portions 43 and 44 of the rubber elastic layer 2 made of high damping rubber to the entire layer 2, that is, the total volume of the plurality of rubber elastic layers 2 excluding the lead plug 5 portion, A pair of rectangular outer sides of the rubber elastic layer 2 If the volume of the minute 43 and 44 and Vout, the volume ratio (= Vout / Vall) or equal to 0.2 from 0.8.

  When the laminated rubber body 1 with lead plugs having the pair of outer portions 43 and 44 and the inner portion 45 shown in FIG. 4 is used for a bridge, the direction X is made to coincide with the bridge axis direction of the bridge girder of the bridge, while the horizontal The laminated rubber body 1 with the lead plug is installed between the bridge pier and the bridge girder so that the elastic rubber layer 2 is not shear-deformed by a movement restricting member such as a side block in the direction Y orthogonal to the direction X of the directions H. Good.

  Also in the laminated rubber body 1 with a lead plug for a bridge, the pair of outer portions 43 and 44 of the rubber elastic layer 2 are made of high-damping rubber, while the rubber elastic layer 2 sandwiched between the pair of outer portions 43 and 44 is formed. Since the inner portion 45 is made of natural rubber, the inner portion 45 made of natural rubber that is relatively weak against ozone environment can be protected by a pair of outer portions 43 and 44 made of high-damping rubber, and rubber elasticity Since it has a pair of outer portions 43 and 44 made of high-damping rubber having a volume ratio of 0.2 to 0.8 with respect to the entire layer 2, no hardening phenomenon occurs and a stable history is obtained. In addition, in combination with the lead plug 5, the vibration in the direction X which is one of the shear directions H of the laminated rubber body 1 containing the lead plug and the direction of the bridge axis is damped as quickly as possible. Can be made.

  Moreover, you may form the laminated rubber body 1 containing a lead plug as shown in FIG. 5 or FIG. That is, in the laminated rubber body 1 with lead plugs shown in FIG. 5, a plurality of rectangular parts (for example, squares) in the plan view surrounding the lead plugs surrounding each of the plurality of lead plugs 5 in the rubber elastic layer 2 one by one. 47 is made of natural rubber, and the other part 48 of the rubber elastic layer 2 excluding the lead plug peripheral part 47 is made of high damping rubber. In the laminated rubber body 1 with lead plug shown in FIG. A lead plug peripheral portion 47 having a rectangular shape (for example, a rectangle) in plan view surrounding each of the plurality of lead plugs 5 each having a plurality of m (four in the drawing) every n (provided that m> n, two in the drawing). The rubber elastic layer 2 other than the lead plug peripheral portion 47 is made of natural rubber, and the other portion 48 of the rubber elastic layer 2 is made of high-damping rubber. The rubber elastic layer 2 is made of a highly damped rubber. The volume ratio of the portion 48 is 0.8 0.2.

  The laminated rubber body 1 with a lead plug shown in FIG. 5 or 6 also has a stable hysteresis characteristic without causing a hardening phenomenon, and as a result of being able to obtain a large attenuation in combination with the lead plug 5, lead The plug-in laminated rubber body can be reduced in size, and the manufacturing cost can be reduced and the construction can be facilitated.

Height h = 73.5 mm, vertical and horizontal length d = 240 mm, each thickness t1 = 6 mm of the six rubber elastic layers 2, each thickness t2 = 16 mm of the thick hard plate layers 21 and 22, and five thin hard plates Each thickness t3 = 2.3 mm of the layer 23, the center O is the diameter φ of each of the four lead plugs 5 positioned on the diagonal of the rubber elastic layer 2, and the distance D between the centers O of the lead plugs 5 = 100 mm, the distance L from the center O of each lead plug 5 to each side of the rubber elastic layer 2 = 70 mm, and the volume ratio = Vout / Vall is 0, 0.2, 0.5, 0.8 and 1 1 to 3 shown in FIG. 1 to FIG. 3 are provided, and five laminated rubbers 4 with a coating layer 13 (thickness t4 = 5 mm) are prepared, and the load in the vertical direction V with a surface pressure of 6 N / mm ² is applied to each of the laminated rubbers 4. Below, a shear deformation in the horizontal direction H with a shear strain rate of 175% is applied to obtain a displacement-stress history characteristic curve. From the displacement-stress history characteristic curve, the post-yield stiffness kd (0), kd (0.2), kd when the volume ratio = Vout / Vall is 0, 0.2, 0.5, 0.8, and 1, respectively. (0.5), kd (0.8), and kd (1) were determined. These post-yield stiffnesses kd (0), kd (0.2), kd (0.5), kd (0.8) and kd (1) are normalized by post-yield stiffness kd (0). The values are shown in FIG.

Further, with respect to each of the five laminated rubbers 4 with the coating layers 13, repeated horizontal shear deformation in the horizontal direction H with a shear strain rate of 175% under a load in the vertical direction V with a surface pressure of 6 N / mm ² is 11. The cycle was added, and then left for 10 minutes. Then, 11 cycles of repeated shear deformation in the horizontal direction H with a shear strain rate of 175% were applied again under the load in the vertical direction V with a surface pressure of 6 N / mm ² , and the previous 11 cycles of shear From the displacement-stress history characteristic curve due to the deformation and the subsequent 11-cycle shear deformation, the amount of decrease in the equivalent stiffness keq of the 11th cycle in the previous 11 cycles relative to the equivalent stiffness keq of the 2nd cycle in the previous 11 cycles The amount of decrease in the equivalent stiffness keq in the eleventh cycle in the subsequent 11 cycles was obtained with the equivalent stiffness keq in the second cycle in the previous 11 cycles as the reference level “1”. FIG. 8 shows values obtained by standardizing the reduction amount of the equivalent stiffness keq from the reference “1” with the reduction amount of the equivalent stiffness keq of the laminated rubber 4 in which the volume ratio = Vout / Vall is zero. In FIG. 8, a curve 51 is a reduction amount of the standardized equivalent stiffness keq in the 11th cycle in the previous 11 cycles, and a curve 52 is an 11th cycle in the subsequent 11 cycles (the 22nd cycle as a whole). ) Of the standardized equivalent rigidity keq.

  As is apparent from FIG. 7, when the volume ratio = Vout / Vall is smaller than 0.2, no change in the rigidity kd after yielding is observed, and as a result, the lamination of the volume ratio = Vout / Vall smaller than 0.2. While it can be said that the hardening phenomenon is likely to occur in the rubber 4, when the volume ratio = Vout / Vall is 0.2 or more, the rigidity kd after yielding linearly changes, resulting in a volume of 0.2 or more. It can be seen that the hardened phenomenon can be effectively suppressed in the laminated rubber 4 having the ratio = Vout / Vall.

  Further, as apparent from FIG. 8, when the volume ratio = Vout / Vall is larger than 0.8, the amount of decrease in the equivalent stiffness keq is large, and as a result, the hysteresis stability is poor when repeatedly subjected to shear deformation. On the other hand, if the volume ratio = Vout / Vall is 0.8 or less, there is almost no decrease in the equivalent stiffness keq, so that stable hysteresis characteristics can be obtained even when subjected to repeated shear deformation. Can do.

It is a perspective explanatory view of a preferred example of an embodiment of the invention. It is an II-II arrow directional cross-sectional explanatory drawing of the example shown in FIG. It is a plane explanatory view of the example shown in FIG. It is a plane explanatory view of other preferred examples of an embodiment of the invention. It is a plane explanatory view of other preferred examples of an embodiment of the invention. It is a plane explanatory view of other preferred examples of an embodiment of the invention. It is a volume ratio-standardized rigidity curve figure of the Example of this invention. It is a volume ratio-standardization equivalent rigidity fall amount curve figure of the Example of this invention.

Explanation of symbols

1 Laminated rubber body with lead plug 2 Rubber elastic layer 3 Hard plate layer 4 Laminated rubber 5 Lead plug 32 Outer peripheral portion 33 Inner peripheral portion

Claims (4)

  Lead having laminated rubber formed by alternately laminating a rubber elastic layer and a hard plate layer, and at least one columnar lead plug embedded through the laminated rubber in the lamination direction and restrained by the laminated rubber It is a laminated rubber body with a plug, and the outer peripheral portion of the rubber elastic layer is made of high-damping rubber, and the inner peripheral portion of the rubber elastic layer surrounded by the outer peripheral portion is made of natural rubber. A laminated rubber body with lead plugs, wherein the volume ratio of the outer peripheral side portion made of the high damping rubber of the rubber elastic layer to the whole rubber elastic layer is 0.2 to 0.8.   Lead having laminated rubber formed by alternately laminating a rubber elastic layer and a hard plate layer, and at least one columnar lead plug embedded through the laminated rubber in the lamination direction and restrained by the laminated rubber It is a laminated rubber body with a plug, and a pair of outer portions in one direction orthogonal to the laminating direction of the rubber elastic layer is made of high-attenuating rubber, and is sandwiched between the pair of outer portions. The inner portion of the rubber elastic layer is made of natural rubber, and the volume ratio of the outer portion made of high-damping rubber of the rubber elastic layer to the entire rubber elastic layer is 0.2 to 0.8. Laminated rubber body with lead plug.   Lead having laminated rubber formed by alternately laminating a rubber elastic layer and a hard plate layer, and at least one columnar lead plug embedded through the laminated rubber in the lamination direction and restrained by the laminated rubber It is a laminated rubber body with a plug, and the portion around the lead plug surrounding the lead plug of the rubber elastic layer is made of natural rubber, and the other portion of the rubber elastic layer excluding the portion around the lead plug is made of high damping rubber. A laminated rubber body with a lead plug, wherein a volume ratio of a portion of the rubber elastic layer made of high-damping rubber to the entire rubber elastic layer is 0.2 to 0.8.   The high damping rubber has an equivalent damping constant of 0.10 to 0.20 at the design strain, and the natural rubber has an equivalent damping constant of 0.01 to 0.06 at the design strain. The laminated rubber body with a lead plug as described in any one of Claims 1 to 3 characterized by the above-mentioned.

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