JP2005265165A - Laminated rubber bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably maintain shearing performance over a long time by forming the whole part into a low-height and light-weight with thin steel sheets and restraining local bending deformation of an internal rigid plate due to stress concentration while reducing an adverse effect to vertical characteristics. <P>SOLUTION: This laminated rubber bearing 10 is formed with a hole 6 passing through, in a laminating direction, a laminated rubber section 5 formed by alternately laminating a plurality of elastic rubber layers 1 and the thin steel sheets and intgrating these into one piece. At a peripheral portion of the through hole 6 in each thin steel sheet, respective local thick-wall portions 2A are formed by welding ring-shaped members 7 or in a similar way. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laminated rubber bearing used as a seismic isolation device that supports a building such as a building and a structure such as a bridge or a highway bridge girder and absorbs vibration energy input from the outside such as an earthquake. Insert a damping material such as lead into the laminated rubber part formed by alternately laminating multiple elastic rubber layers and hard internal rigid plates such as steel plates and integrating them, or reduce the shear modulus The present invention relates to a laminated rubber bearing in which a hole penetrating in the laminating direction is formed to insert a heat source for heating at the time of vulcanization molding of the laminated rubber portion.

  In this type of laminated rubber bearing, conventionally, a damping material such as lead that exhibits a good damping (tamper) characteristic against vibration due to plastic deformation is inserted and installed in a through hole formed in the laminated direction in the laminated rubber portion. In addition, there is known a structure in which a rigid intermediate plate surrounding the outer periphery of the damping material is disposed in each elastic rubber layer of the laminated rubber portion so as to restrain the damping material (see, for example, Patent Document 1).

  In addition, an elastic-plastic material such as lead that exhibits damping (damper) characteristics due to plastic deformation is inserted into the through-hole formed in the lamination direction in the laminated rubber portion in the same manner as described above, and the through-hole is formed around the elastic-plastic material. A constraining portion is formed by laminating a plurality of shrouds having openings that define the width, and a horizontal sliding that has an overlap allowance even during a predetermined shear deformation between adjacent stacks of the shrouds constituting the restraining portion. There is also known one in which a portion is formed (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 2001-355677 JP-A-10-159897

  However, all of the conventional laminated rubber bearings disclosed in Patent Documents 1 and 2 described above employ a rigid intermediate plate or a plurality of attenuating materials and elastic-plastic materials installed in the through holes in order to exhibit damping characteristics. By restraining with a restraining part made of a shroud, the damping material or elastic-plastic material is prevented from getting into the elastic rubber layer, and the predetermined damping characteristics can be maintained stably over a long period of time. If a large shear force is applied to the laminated rubber bearing under the condition that a large vertical load is applied to an earthquake, etc., a bending moment is generated in the rigid internal rigid plate and the bending is caused around the through hole of the internal rigid plate. Concentration of stress is likely to cause local bending deformation in the part, and as a result, not only the buckling characteristics and fracture characteristics of the laminated rubber bearing as a whole deteriorate, but also the horizontal deformation capacity, Reduction of the shear deformation performance there is a problem that is inevitable.

  In particular, in the case where the thickness of the hard internal rigid plate that is roughly determined with respect to the primary shape factor and the secondary shape factor is set to be thin, a large shear force is applied under the condition that a large vertical load is applied as described above. If it is added, the internal rigid plate part around the through hole is distorted locally due to the bending moment generated in the internal rigid plate, and it is easy to bend and deform.If the thickness of the internal rigid plate is set thick, the vertical rigidity becomes high. Not only is the vertical characteristic deteriorated, but the entire laminated rubber bearing becomes bulky and heavy unless the number of laminated stages is reduced, and the degree of freedom in design is low, and the application is likely to be limited.

  The present invention has been made in view of the above circumstances, and the overall thickness of the internal rigid plate is made low and light by using a thin internal rigid plate, and the influence on the vertical characteristics is reduced, while the internal rigid plate due to stress concentration is reduced. An object of the present invention is to provide a laminated rubber bearing capable of suppressing local bending deformation and stably maintaining shear performance over a long period of time.

  In order to achieve the above object, the laminated rubber bearing according to the present invention penetrates in a laminated rubber part formed by alternately laminating a plurality of elastic rubber layers and a hard internal rigid plate and integrating them in the laminating direction. In the laminated rubber bearing in which a hole to be formed is formed, a local thick part is formed in the peripheral part of the through hole of each of the hard internal rigid plates.

  According to the present invention having the above-described features, bending stress is concentrated due to a bending moment generated in the internal rigid plate when a large shear force is applied to an earthquake or the like under an installation condition where a large vertical load is applied. Since the internal rigid plate portion around the easy through hole is locally thickened and reinforced, it does not increase the vertical rigidity as in the case of increasing the thickness of the entire internal rigid plate, but around the through hole of the internal rigid plate Bending deformation of the part can be suppressed, and this ensures stable shear performance over a long period of time without deteriorating the vertical characteristics, that is, the buckling characteristics and breaking characteristics of the laminated rubber bearing as a whole. The deformation ability can be improved. In addition, since the same shear deformation capability as before can be obtained using a thin internal rigid plate, the entire laminated rubber bearing can be configured to be low in volume and light weight, and the design flexibility is increased, and the laminated rubber bearing is used. The effect is that it is easy to enlarge, and in particular, it can be effectively used as a rubber bearing for bridges where it is desired that the elastic rubber layer is thick and the number of laminated steps is small.

  In the laminated rubber bearing according to the present invention, the through hole formed in the laminated rubber portion may be a hole for inserting an attenuation material such as lead as described in claim 2, It may be a through hole for reducing the shear elastic modulus or inserting a heat source for heating at the time of vulcanization molding of the laminated rubber part.

  Further, in the laminated rubber bearing according to the present invention, as a locally thick part formed around the through hole of the hard internal rigid plate, the thickness of the internal rigid plate is larger than the thickness of the internal rigid plate. Even if it is formed by welding a ring-shaped member having a large thickness, it is formed by bending the peripheral end of the through hole of the rigid internal rigid plate integrally in the laminating direction as described in claim 4 Even if it was made, as described in claim 5, it may be formed by burring the peripheral edge of the through hole of the hard internal rigid plate in the laminating direction.

  Furthermore, the cross-sectional shape of the locally thick portion of the rigid internal rigid plate may be any shape such as a square or a circle, but in order to prevent an edge from causing cracks during excessive shear deformation. In addition, it is desirable that the corner is a chamfered or rounded quadrangular or circular shape or a similar shape.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of the entire laminated rubber bearing according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is an enlarged longitudinal sectional view of an essential part of FIG. 1. This laminated rubber bearing 10 has a plurality of elastic rubber layers. 1 and a hard internal rigid plate (usually a thin steel plate, hereinafter referred to as a thin steel plate) 2 and thick steel plates 3 and 3 arranged at the upper end and the lower end are alternately laminated. The outer peripheral portions of the elastic rubber layer 1, the thin steel plate 2 and the thick steel plates 3, 3 are surrounded and covered with a weather-resistant protective rubber layer 4, and these are integrally vulcanized to form a laminated rubber portion 5 having a rectangular parallelepiped shape as a whole. Is formed, and a hole 6 is formed in the central portion of the laminated rubber portion 5 so as to penetrate in the laminating direction of the members 1, 2, 3, 3.

  The through-hole 6 formed in the center of the laminated rubber portion 5 is inserted with a cylindrical damping material such as lead, for example, to enhance the vibration suppressing effect by the energy absorption action accompanying plastic deformation of the damping material, or the laminated rubber portion 5. It is formed to reduce the shear elastic modulus of the laminated rubber part 5 or insert a heat source for heating when the laminated rubber part 5 is vulcanized.

  In the laminated rubber bearing 10 having the above-described configuration, as shown in FIG. 3, the steel rubber having a thickness t <b> 1 larger than the thickness t of the thin steel plates 2 is provided at the peripheral end portions of the thin steel plates 2. The ring-shaped member 7 is welded symmetrically with respect to the thickness center line of each thin steel plate 2, whereby a local thick portion 2 </ b> A is formed around the through hole 6 of each thin steel plate 2.

  As shown in FIG. 3, the cross-sectional shape of the ring-shaped member 7 forming these thick portions 2A is a circular shape as shown in FIG. 4, even if the four corners are rounded or chamfered. These ring-shaped members 7 may be welded asymmetrically with respect to the thickness center line of the thin steel plate 2 as shown in FIG. 5, and further, as shown in FIG. The thin steel plate 2 may be welded slightly outside the peripheral edge of the through hole 6.

  In the laminated rubber bearing 10 configured as described above, a condition in which such a large vertical load is applied while supporting the vertical load of an upper structure such as a building or a bridge girder by the large vertical rigidity of the laminated rubber portion 5. When a greater shearing force is applied to an earthquake or the like below, the plurality of elastic rubber layers 1 in the laminated rubber portion 5 are shear-deformed to absorb vibration energy such as an earthquake and alleviate the vibration. Here, since the peripheral portion 2A of the through-hole 6 of the thin steel plate 2 of the laminated rubber portion 5 is formed to be locally thickened and reinforced by welding the ring-shaped member 7, vibration energy due to shear deformation of the elastic rubber layer 1 is obtained. It is possible to suppress the bending deformation of the peripheral portion of the through hole of the thin steel plate 2 where the bending stress is likely to be concentrated due to the bending moment generated in the thin steel plate 2 at the time of the absorption action of the steel plate, thereby providing stable shear performance for a long time. It is possible to improve the shear deformation capacity by maintaining the entire length.

  Further, it is not necessary to increase the thickness of the thin steel plate 2 as a whole, and it is possible to ensure the above-described bending deformation suppressing function only by locally forming the peripheral portion 2A of the through hole 6 of the thin steel plate 2 to be thick. Since it is possible, there is almost no influence on the vertical characteristics, and the laminated rubber bearing 10 as a whole can maintain the vertical load support performance (buckling characteristics) and the fracture characteristics, and maintain the shear performance stably over a long period of time. Not only can it be made, but the entire laminated rubber bearing 10 can be easily made low in volume and light in weight.

  Incidentally, the inventor can maintain the stable shear performance by suppressing the bending deformation of the thin steel plate 2 due to the stress concentration while reducing the influence on the vertical characteristics in the configuration shown in FIGS. 1 to 3. Experiments were conducted on the specifications of a laminated rubber bearing capable of satisfying the object of the present invention. As a result, the thickness t2 of the elastic rubber layer 1 was 5 to 80 mm, preferably 20 to 60 mm, and the thickness t of the thin steel plate 2 was 2.3 to 2.3. A laminated rubber bearing capable of sufficiently satisfying the object of the present invention can be obtained by setting the thickness to 12 mm, preferably 4.5 to 9.0 mm, and the number of laminated layers in the range of 4 to 30 layers, preferably 6 to 30 layers. I understood.

  In the embodiment described above, the local thick portion 2A is formed by welding the ring-shaped member 7, but in addition to this, as shown in FIG. Even if the end portion is integrally bent at right angles toward the lamination direction of the laminated rubber portion 5 to form the thick portion 2A, as shown in FIG. 8, the peripheral end portion of the through hole 6 of the thin steel plate 2 is laminated. The thick portion 2A may be formed by burring in the stacking direction of the rubber portion 5, and further, as shown in FIG. The small-diameter circular ring-shaped members 7a and 7a may be welded to form the thick portion 2A.

  Moreover, although the said embodiment demonstrated what formed the single through-hole 6 in the center part of the laminated rubber part 5, as shown, for example to the virtual line of FIG. 2, of the laminated rubber support 10 of a rectangular parallelepiped shape A total of four through-holes 6 may be formed in each central portion of the quarterly divided region, and the thin steel plate portions positioned around each of the through-holes 6 may be formed as local thick portions, Alternatively, two or three through-holes may be formed, and the thin steel plate portion positioned around them may be formed as a locally thick portion.

  Furthermore, in the above-described embodiment, a rectangular parallelepiped laminated rubber bearing has been described, but it is needless to say that the above-described configuration may be adopted for a laminated rubber bearing such as a columnar shape or an elliptic cylinder shape.

1 is an overall longitudinal sectional view showing an embodiment of a laminated rubber bearing according to the present invention. It is a whole top view showing an embodiment of a laminated rubber bearing same as the above. FIG. 2 is an enlarged vertical cross-sectional view of a main part of FIG. 1. It is an expanded longitudinal cross-sectional view of the principal part which shows an example of the deformation pattern of the thick part in a laminated rubber bearing same as the above. It is an expanded vertical sectional view of the principal part which shows the other example of the deformation | transformation pattern of the thick part in a laminated rubber bearing same as the above. It is an expanded vertical sectional view of the principal part which shows another example of the deformation pattern of the thick part in a laminated rubber bearing same as the above. It is an expanded longitudinal cross-sectional view of the principal part which shows one of the patterns of a thick part in other embodiment of the laminated rubber bearing which concerns on this invention. It is an expanded longitudinal cross-sectional view of the principal part which shows another one of the pattern of a thick part in other embodiment of the laminated rubber bearing which concerns on this invention. It is an expanded longitudinal cross-sectional view of the principal part which shows another of the pattern of a thick part in other embodiment of the laminated rubber support which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Elastic rubber layer, 2 ... Thin steel plate (hard internal rigid board), 2A ... Thick part, 5 ... Laminated rubber part, 6 ... Through-hole, 7, 7a ... Ring-shaped member, 10 ... Laminated rubber support,

Claims (4)

In a laminated rubber bearing in which a plurality of elastic rubber layers and a hard internal rigid plate are alternately laminated and the laminated rubber portion formed by integrating them is formed with a hole penetrating in the laminating direction,
A laminated rubber bearing, wherein a local thick portion is formed in each peripheral portion of the through hole of each of the hard internal rigid plates.   The laminated rubber bearing according to claim 1, wherein the through hole formed in the laminated rubber portion is a hole for inserting a damping material.   The local thick portion is formed by welding a ring-shaped member having a thickness larger than the thickness of the internal rigid plate to a peripheral end portion of the through hole of the hard internal rigid plate. The laminated rubber bearing described. 3. The laminated rubber bearing according to claim 1, wherein the locally thick portion is formed by integrally bending a peripheral end portion of a through hole of a hard internal rigid plate in a laminating direction.

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