JPH08326812A - Layered rubber body using high damping rubber - Google Patents

Abstract

PURPOSE: To provide a layered rubber body whose hysteresis characteristic is stable and clear and whose damping performance is large, in the case of a layered rubber body using a high damping rubber composition. CONSTITUTION: In the case of a layered rubber body 3 made up by accumulating alternately and in multi-steps a rubber layer 1 consisting of a high damping rubber composition and a hard flat slablike reinforcement slab 2, one or more than two cylindrical lead plugs 4 to penetrate the layered rubber body 3 are embedded in the state of restriction and by meeting at right angles with a layered surface.

Description

Detailed Description of the Invention

A. OBJECT OF THE INVENTION (1) Industrial field of use The present invention relates to a laminated rubber body as an energy absorber used as a laminated rubber bearing or a laminated rubber damper, and more specifically, a laminated body using a high damping rubber composition. Regarding rubber body. Here, the laminated rubber bearing refers to a laminated rubber body with load support, and the laminated rubber damper refers to a laminated rubber body without load support.

(2) Prior Art A laminated rubber body is one in which a rubber layer as a soft layer and a reinforcing plate as a hard layer are alternately stacked and integrally formed by vulcanization adhesion, and is orthogonal to the plate surface. It exhibits great rigidity with respect to a load acting in the direction (vertical direction) and exhibits flexibility with respect to a load acting in the direction along the plate surface (lateral direction). For a laminated rubber bearing that is interposed between a bridge girder (or building, the same below) and a bridge pier (or foundation, the same below) that transmits the load of the bridge girder to the ground, supports the bridge girder's load with vertical rigidity. However, in the event of an earthquake, the input rigidity of the earthquake is reduced by the lateral rigidity characteristics of the laminated rubber bearings, and the vibration of the bridge girder is alleviated, which is effective as a seismic isolation device. Furthermore, the damping device such as an oil damper, which is separately arranged, absorbs the energy of the seismic force and quickly reduces the shaking of the bridge girder. Therefore, by providing a damping property to the rubber layer of the laminated rubber bearing, the damping device is omitted and the arrangement space is saved. Therefore, active development of a highly damping rubber composition has been made. ing.

However, in a laminated rubber body having a rubber layer made of this highly dampening rubber composition, the properties are variously changed by the composition of the composition constituting the highly dampening rubber composition, and the properties are constant. Is difficult to obtain, and its damping property (loss factor) is also limited practically, and the damping ratio is generally 20% or less. Further, as indicated by the alternate long and short dash line (b) in FIG. 5, it is difficult to give linearity to the history curve showing the shear load-displacement characteristic, and especially in the large displacement range (left and right ends of the δ axis). It is not possible to suppress the phenomenon of large fluctuations. Further, a laminated rubber body using this highly dampenable rubber composition has a drawback that a difference in shear load-displacement characteristics due to a temperature difference is large and it is difficult to make a rational design.

(3) Problems to be Solved by the Invention The present invention has been made in view of the above circumstances, and in a laminated rubber body using a high damping rubber composition of this type,
The purpose of the present invention is to obtain a laminated rubber body having stable and clear hysteresis characteristics and having a large damping performance. The present invention shows that, as a result of various experiments, by adding a lead plug to a laminated rubber body using this high damping rubber composition, the characteristics of the laminated rubber body of the high damping rubber composition are improved and a large damping is achieved. It was made based on the finding that performance can be obtained.

B. Structure of the Invention (1) Means for Solving Problems The highly damping laminated rubber body of the present invention specifically adopts the following technical means. That is, in a laminated rubber body in which a rubber layer made of a high damping rubber composition and hard plate-like reinforcing plates are alternately laminated in multiple stages, a cylindrical lead plug penetrating the laminated rubber body is 1 or It is characterized in that two or more layers are embedded orthogonally to the laminated surface in a restrained state.

(2) Action The laminated body excluding the cross section of the lead plug exhibits greater rigidity with respect to the force orthogonal to the laminated surface. The rubber layer easily bends against the force along the laminated surface, that is, the shearing force. When the shearing force is small, the lead plug exerts an initial resistance force to prevent the bending, and when the shearing force increases, the lead plug becomes plastic. It deforms and shears together with the rubber layer. And
When the shearing force is large and acts as a forced vibrational force, the rubber layer and the lead plug cooperate to absorb the shearing energy and exert a large damping property.

(3) Example An example of the highly damping laminated rubber body of the present invention will be described with reference to the drawings. 1 to 4 show a highly damping laminated rubber body S of one embodiment. That is, FIG. 1 shows the entire structure, and FIGS. 2 to 4 show the partial structure.

The laminated rubber body S having high damping properties is a rectangular parallelepiped as a whole, and a laminated body 3 in which a soft rubber layer 1 and a hard reinforcing plate 2 are alternately laminated is embedded in the laminated body 3. And a plurality of (5 in this embodiment) cylindrical lead plugs 4.

The detailed structure of the laminated rubber body S will be described below. Laminate 3 The laminate 3 includes a rubber layer 1 made of a high damping rubber composition and a hard reinforcing plate 2. A plurality of holes 6 are formed in the laminated body 3, and the lead plugs 4 are enclosed in the holes 6. (Rubber Layer 1) The rubber layer 1 is made of a highly damping rubber composition. The high damping rubber composition includes natural rubber, styrene butadiene rubber (SBR), nitrile butadiene rubber (NB
R), butadiene rubber material (BR), isoprene rubber (IR), butyl rubber (IIR), halogenated butyl rubber (X-IIR), chlorobrene rubber (CR) rubber material with an additive exhibiting high damping properties. Generated. As a high damping rubber composition, a. Usually a rubber material with carbon black added, b. 100 parts by weight of a rubber component containing natural rubber as a main component and 70 parts by weight of silica as a filler, c. An example is a blend of 15 parts by weight of coumarone indene resin with 100 parts by weight of a rubber component containing natural rubber and high styrene rubber in a ratio of 4/1. (Reinforcement plate 2) As the reinforcement plate 2, a steel plate is usually used. It may be a fiber reinforced hard rubber plate, a fiber reinforced rigid resin plate, or canvas. The reinforcing plate 2 includes a thick upper reinforcing plate 2a arranged on the upper end surface, a thick lower reinforcing plate 2b arranged on the lower end surface, and a plurality of thin intermediate reinforcing plates 2c arranged in the middle thereof. Consists of. Screw holes 8 for mounting are formed on the exposed surfaces of the upper reinforcing plate 2a and the lower reinforcing plate 2b.

The rubber layer 1 has a crossover length larger than the outer edge of the reinforcing plate 2 by the amount of fogging, and the rubber layer 1 and the reinforcing plate 2 are integrally molded by vulcanization adhesion.

Lead plug 4 The lead plug 4 is formed in a columnar shape with a lead body, is closely sealed in the hole 6 of the laminated body 3, and is restrained by the laminated body 3. The lead body 4 contains, in addition to pure lead, a lead alloy or a mixture of lead and other substances. Pure lead has a density (g / cm ³ ) of 1
It has a melting point of 1.36, a melting point of 327.4 ° C., and mechanical properties include an elastic modulus of 13,631 MPa, an elastic limit of 1.66 MPa,
Tensile strength 14MPa, elongation 40-50%, compressive strength 49M
Pa, hardness 3 to 7 HBS. Thus, pure lead is highly malleable and easily undergoes plastic deformation. The lead body absorbs vibration energy during plastic deformation, releases it as heat energy, and recrystallizes. Therefore, the energy absorption performance does not change even with repeated plastic deformation.

The lead plugs 4 in this embodiment all have the same diameter, and as shown in the drawing, the lead plugs 4 are arranged in the laminated body 3 at one location at the center and four locations at each corner, at equal intervals. To be done. The lead plug 4 occupies as much of the stack 3 as possible in the vertical projection plane. That is, this arrangement ratio is based on the knowledge that the effectiveness of the lead plug 4 is defined by its diameter. In other words, a large number of small-diameter lead plugs having a ratio of diameter to height within a predetermined range is more effective and effective than one large-diameter lead plug.

(Seismically isolated laminated rubber bearing H) This laminated rubber body S
As shown in FIG. 4, the upper and lower face plates 10 and 11 are attached to the upper and lower end plates 2a and 2b exposed on the upper and lower faces of the laminated body 3, respectively, and the building G and the foundation B are attached via these upper and lower face plates 10 and 11. Installed as an intermediary and used as a base isolation rubber bearing H. In the figure, 12 is a mounting bolt screwed from the upper and lower face plates 10 and 11 into the screw holes 8 of the upper and lower end plates 2a and 2b of the laminated body 3, 13 is an upper anchor member planted in the upper face plate 10, 14 Is a lower anchor member implanted in the lower plate 11.

(Operation / Effect of Embodiment) The highly damped laminated rubber body S of this embodiment having the above-described structure exhibits the following operation. The laminated body 3 excluding the cross section of the lead plug 4 exhibits greater rigidity against the force orthogonal to the laminated surface. The rubber layer 1 easily bends against the shearing force along the laminated surface,
When the shearing force is small, the lead plug 4 exerts an initial resistance force to prevent bending, and when the shearing force is large, the lead plug 4
Causes plastic deformation and shear deformation together with the rubber layer 1. When the shearing force is large and acts as a forced vibrational force, the rubber layer 1 and the lead plug 4 cooperate to absorb the shearing energy and exert a large damping property.

FIG. 5 is a load-displacement diagram showing hysteresis characteristics of the highly damping laminated rubber body S. In the figure, the vertical axis represents the shearing force F (ton), and the horizontal axis represents the displacement amount δ (millimeter). The solid line (a) shows the hysteresis curve of the highly damping laminated rubber body S. The one-dot chain line in (b) shows a hysteresis curve of a laminated rubber body using a high damping rubber composition having the same specifications and having no lead plug. Further, the two-dot chain line of C shows the hysteresis curve of a laminated rubber body in which a lead plug is enclosed in an ordinary laminated body which does not use a high damping rubber composition with the same specifications. The d-dashed line indicates the history curve of only the rubber body under the same specifications. As shown in the figure, the hysteresis characteristic of the highly damping rubber laminated body S (a) is significantly larger than that of the laminated rubber body (b) using the highly damping rubber composition and having no lead plug. Hysteretic characteristics are obtained, and thus a large damping property is exhibited. In addition, a hysteresis curve showing a clear linearity can be obtained without using an instability such as a laminated rubber body (b) having a lead plug and using a high damping rubber composition.

Further, FIG. 6 shows the change in the hysteresis curve between the present highly damping rubber laminated body S (a) and the laminated rubber body (b) using the highly damping rubber composition and having no lead plug based on the temperature difference. Indicates. According to this, at 0 ° C. and 20 ° C., both have a change of only a load of Δ, but the influence appears relatively small in the highly damping rubber laminated body S, and the highly damping rubber composition It is possible to overcome the shortcomings of the laminated rubber body which does not have the lead plug by using the product.

As described above, according to the highly damped laminated rubber body S of this embodiment, not only a great damping performance is obtained, but also the hysteresis characteristic is linear, stable and clear. Further, it has little influence on the temperature change. When expressed by the damping ratio h, it is 20% or less in a laminated rubber body using a conventional high damping rubber composition and no lead plug, and a lead is used in an ordinary laminated body not using the high damping rubber composition. In the laminated rubber body with the plug enclosed, the limit is 20 to 30%, but with the present highly damping laminated rubber body, a damping rate of 40%, which is higher than that, can be obtained.

In the above embodiment, the embodiment in which the laminated rubber body S is applied to the seismic isolated laminated rubber bearing H has been shown, but it goes without saying that it is also applied to the damping device itself without load support. .

The present invention is not limited to the above embodiment, but various design changes can be made within the scope of the basic technical idea of the present invention. That is, the following aspects are included in the technical scope of the present invention. In the illustrated example, the lead plugs 4 are arranged at five locations on the laminated body 3, but they may be arranged at only one location at the center or at four locations at the corners. Further, a larger number of lead plugs 4 may be arranged and arranged in a staggered pattern. The laminated rubber body is not limited to a rectangular parallelepiped having a square cross section, and may have a rectangular or polygonal cross section. Furthermore,
A circular cross section is also taken. FIG. 7 shows an example of the laminated rubber body S1.
The lead plugs 4 are arranged in six places at equal intervals in the circular direction.

C. EFFECTS OF THE INVENTION According to the highly damping laminated rubber body of the present invention, not only a great damping performance is obtained, but also a linear hysteresis characteristic is obtained, and the characteristic is stable and clear. Further, it has little influence on the temperature change. Therefore, the properties of the conventional laminated rubber body using the high damping rubber composition are greatly improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an entire embodiment of a highly damping laminated rubber body of the present invention.

FIG. 2 is a plan view of this embodiment.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG.

FIG. 4 is a block diagram of a base-isolated laminated rubber bearing. .

FIG. 5 is a history characteristic diagram.

FIG. 6 is a history characteristic diagram showing a temperature difference.

FIG. 7 is a plan view showing another embodiment of the highly damping laminated rubber body of the present invention.

[Explanation of symbols]

S, S1 ... Highly damping laminated rubber body, 1 ... Rubber layer, 2 ... Reinforcing plate, 3 ... Laminated body, 4 ... Lead plug

Claims (1)

[Claims] 1. A laminated rubber body in which a rubber layer made of a high damping rubber composition and hard plate-like reinforcing plates are alternately laminated in multiple stages, and a cylindrical lead plug penetrating the laminated rubber body. Is 1 or 2
A high-damping laminated rubber body, characterized in that it is embedded orthogonally to the laminated surface in a constrained state.