JP2007303497A - Laminated rubber bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated rubber bearing device with a hollow laminate advantageous in view of the prolongation of the quake-absorbing period, that is further improved so as to avoid the occurrence of buckling in the case of large deformation. <P>SOLUTION: The laminated rubber bearing device includes the laminate 3 formed by alternately stacking a plurality of rubber layers 1 and rigid plates 2, a hole 6 formed at or near the central part of the laminate 3 so as to penetrate the laminate in the laminating direction, and a buckling-preventing columnar body 7 arranged in the hole 6. The buckling-preventing columnar body 7 is composed of a plurality of slide members 8 laminated in such a manner that they can slide laterally with respect to one another. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laminated rubber bearing device, and more particularly to a laminated rubber bearing device having a hollow laminated body in which a plurality of rubber layers and rigid plates are alternately laminated.

  In general, in a base-isolated building, a base-isolating device is arranged under the foundation, and the load of the building is supported by the base-isolating device, and a means for demonstrating the base-isolating performance by increasing the natural period of the building is taken. The natural period of a base-isolated building by a laminated rubber bearing device is determined by the building load and the restoring force of the laminated body (laminated rubber). This natural period becomes longer as the load supported by the laminated rubber increases, and the restoring force increases. Shorter. Therefore, it can be understood that the load acting on the laminated rubber may be set large in order to increase the period.

  However, there is a limit to the load per unit area on which the laminated body is supported, and the load per unit area acting on the laminated body cannot be so large. Therefore, a large-sized laminate is required for a large load, but a large-sized laminate exhibits a large restoring force, reducing the above-mentioned “effect of increasing the period by increasing the load”. In addition, there is a limit (approximately 3 seconds) to lengthening the natural period of base-isolated buildings using laminated rubber bearings.

  Therefore, in a laminated body for seismic isolation for a light-weight structure such as a house, a means for reducing horizontal rigidity (corresponding to the restoring force described above) is adopted as a means for prolonging the seismic isolation period. is there. That is, since it is necessary to reduce the pressure receiving area and increase the total thickness of the rubber, the laminated rubber bearing device has been devised so that the laminated body is hollow and the outer diameter and inner diameter are increased. For example, the one disclosed in Patent Document 1 is known. If such a hollow laminate is used, the apparent S2 can be increased, which has the advantage that the buckling prevention function can be enhanced.

Here, S2 is the secondary shape factor of the laminate, and the secondary shape factor S2 is obtained by multiplying the length of the rigid plate in the laminate by the thickness of the rubber layer in the stacking direction and the total number of rubber layers. Defined as the value divided by the value. That is, the length of the rigid plate (a diameter when the shape in plan view is a circle, or a side length on the seismic isolation direction side when it is a rectangle) is a, the thickness of the rubber layer is t, and the number of layers is n. Then
S2 = a / n · t (1)
Represented as:

In the laminated rubber bearing device having a hollow laminated body disclosed in Patent Document 1 and the like, the secondary shape factor S2 obtained from the above equation (1) is a large value, which means that “apparent S2 becomes large”. "It turns out that. However, since it is not considered that this equation (1) is hollow, in reality, when the length of the hollow portion is b, the true secondary shape factor S2r is S2r = (a / n · t)-(b / n · t) (2)
Thus, it is clearly smaller than the above formula (1). Therefore, although it is possible to increase the secondary shape factor by making the laminated body large in diameter and hollow, if the diameter of the hollow part is increased with the aim of increasing the period, as understood from the above equation (2) However, since the secondary shape factor tends to become small rather than large, the risk of buckling during large deformation tends to increase.
JP-A-5-141463

  The object of the present invention is to improve the structure so as to avoid the risk of buckling during large deformations while having a hollow laminate that is advantageous in extending the seismic isolation period by further structural improvements. It is in the point which implement | achieves and provides the laminated rubber bearing apparatus made.

  The invention according to claim 1 is a laminated rubber bearing device, wherein a laminated body 3 in which a plurality of rubber layers 1 and rigid plates 2 are alternately laminated, and a central portion of the laminated body 3 or a peripheral portion thereof. And a buckling prevention columnar body 7 disposed in the hole 6, and the buckling prevention columnar bodies 7 are stacked in such a manner that they can be slidably moved side by side. It is characterized by comprising the sliding member 8.

  According to a second aspect of the present invention, in the laminated rubber bearing device according to the first aspect, a sliding plate 9 is provided between the plurality of sliding members 8 for promoting the side-sliding movement of the sliding members 8. It is characterized by being.

  The invention according to claim 3 is the laminated rubber bearing device according to claim 2, wherein the sliding plate 9 is formed of a PTFE sheet.

  The invention according to claim 4 is the laminated rubber bearing device according to any one of claims 1 to 3, wherein one or a plurality of the plurality of sliding members 8 is provided with an elastic layer 10. It is characterized by this.

  The invention according to claim 5 is the laminated rubber bearing device according to claim 4, characterized in that the elastic layer 10 is made of high-damping rubber.

  According to the invention of claim 1, since the columnar body for buckling prevention is provided in the through-hole formed in the laminated body, the laminated rubber bearing device is largely deformed due to a severe earthquake or the like, and the laminated body is largely shear-deformed. In this case, the buckling prevention columnar body is regulated so that the vertical compression displacement accompanying the large shear deformation does not become larger than a predetermined value. That is, buckling of the laminate is prevented by the presence of the columnar body for buckling prevention. At the time of great shear deformation, a shear load may also act on the buckling prevention columnar body arranged in the through hole. In that case, the buckling prevention columnar body is laminated to constitute the buckling prevention columnar body. Since the plurality of sliding members move sideways, the above-mentioned buckling prevention action can be exhibited without causing problems such as hindering shear deformation of the laminate or breaking the buckling prevention columnar body. As a result, in order to improve the seismic isolation performance, it has a hollow laminate that is advantageous for extending the seismic isolation period, while improving the possibility of buckling during large deformations. A laminated rubber bearing device can be provided.

  According to the invention of claim 2, the sliding plate interposed between the sliding members facilitates the lateral movement of the sliding members accompanying the shear deformation of the laminate, and the effect of the invention of claim 1 is enhanced. There are advantages to being. In this case, if the sliding plate is formed of a PTFE sheet made of a fluororesin as in claim 3, smoother side-sliding movement can be obtained.

  According to the invention of claim 4, since the elastic layer is formed on at least one sliding member, the vertical compressive load at the time of large deformation acts abruptly, and the buckling prevention columnar body Even if a flange plate or the like collides, the impact shock is mitigated by the buffering action of the elastic layer, the building's vibration prevention behavior is softened, and the possibility of damage to components such as cracks and crushing of each part can also be avoided There is a good point. In this case, if the elastic layer is formed of a high damping rubber as in claim 5, not only the shock is alleviated, but also the action of quickly damping the shock is exhibited. There is an advantage that can be further strengthened.

  Hereinafter, embodiments of a laminated rubber bearing device according to the present invention will be described with reference to the drawings. 1 and 2 are a longitudinal sectional view and a transverse sectional view showing the structure of the laminated rubber bearing device, respectively, FIG. 3 is a longitudinal sectional view showing a buckling prevention state at the time of large deformation, and FIG. It is a comparison figure of each characteristic with the laminated body of a cross section.

[Example 1]
As shown in FIGS. 1 and 2, the laminated rubber bearing device A according to the first embodiment includes a plurality of annular rubber plates (rubber layers) between the upper and lower annular flange plates 4 and 4. Example 1) and a plurality of annular rigid plates 2 made of thin steel plates are alternately arranged and laminated, and a laminate (rubber plate 1, rigid plate 2, thick flanges 4, 4) formed by them. ) Are provided on the inner and outer circumferences of the cylindrical laminated body 3 formed by integrating the rubbers 1A and 1B by vulcanization and bonding, and the mounting plates 5 having a diameter larger than that of the flange plate 4 are provided at both upper and lower ends. , 5 are fixedly joined. The upper structure K is mounted and fixed on the upper mounting plate 5, and the lower mounting plate 5 is mounted and fixed on the lower structure B.

  The rubber plate 1, the rigid plate 2, and the thick flange 4 are set to have the same inner diameter, and a through-hole 6 that penetrates up and down with a large diameter is formed so that the inside of the thin-walled inner peripheral covering rubber 1 </ b> A is hollow. The through-hole 6 is provided with a buckling prevention columnar body 7. The columnar body 7 for buckling prevention is composed of five (a plurality of examples) sliding members 8 stacked one above the other so as to be able to slide sideways. Each sliding member 8 is formed of a hard plate such as a steel plate, and a sliding plate 9 made of PTFE is provided between the sliding members 8 for promoting the side-sliding movement of the sliding members 8. Only the uppermost sliding member 8 has a sandwich structure in which an elastic layer 10 made of high-damping rubber is interposed between the upper and lower thin sliding plates 8a and 8a.

  The sliding plate 9 may be made of a material having a low friction coefficient, and may be made of a material other than a fluororesin such as PTFE. Further, the elastic layer 10 can be made of general rubber such as natural rubber, EPDM, or the like. Now, in such a laminated rubber bearing device A, the weight of the upper structure K is received only by the laminated body 3, that is, the rubber plate 1 at the time of normal support or an earthquake within a set range, and is effective. Seismic isolation effect is demonstrated.

  However, when a large roll outside the set range acts due to a strong earthquake or the like, the deformation is as shown in FIG. That is, when the laminated body 3 sinks without being able to endure due to a large deformation and starts to buckle, the buckling prevention columnar body 7 provided in the through hole 6 moves to the side by sliding each sliding member 8 sideways. While following and deforming so as not to hinder the shear deformation of the body 3, the upper mounting plate 5 that descends while laterally moving is received and strung, and further downward displacement, that is, the buckling of the laminate 3 Is prevented.

  In this case, the elastic layer 10 provided in the uppermost sliding member 8 acts as a cushion to provide a buffering effect, avoiding a sudden load on each sliding plate 8a, and shock as the laminated rubber bearing device A. Will also be reduced. Further, since the sliding plate 9 is interposed between the sliding plates 8a and 8a adjacent to each other in the vertical direction, the following movement of the heavy sliding member 8 made of a steel plate or the like is performed smoothly and lightly. Regardless of this, it is also preferable that the lateral movement of the sliding member 8 hardly resists the shear deformation of the laminate 3.

It has been found that the primary shape factor S <b> 1 of the laminate 3 may be reduced to increase the length of the seismic isolation cycle described above. When the area of the rubber plate 1 (area in plan view) is Ar and the area of the side surface (circumferential surface) per layer of the rubber plate 1 is Af, the primary shape factor S1 is:
S1 = Ar / Af (3)
It is defined as

  Here, as an example, as shown in FIG. 4, the outer diameter is 3 / √5R and the inner diameter is 3 / √5R so that the area in plan view is the same as the solid laminated first laminated rubber bearing device G1 having a diameter of R. Suppose that there is a second laminated rubber bearing device G2 having a hollow laminated body of 2 / √5R, and S1 and S2 and their ratios L1 and L2 of both are obtained, L1 = 0.745, L2 = 0. 477. Here, the denominator of each ratio is G2, and the numerator is G1. In FIG. 4, the symbols for the area Af of the side surface (circumferential surface), the thickness t of the rubber plate 1 and the number n of the layers are used as they are. For simplicity, it is assumed that the rubber layer and the rigid plate have the same diameter and the same inner diameter.

  In this way, the laminated body of the second laminated rubber bearing device G2 is formed into a hollow (tubular shape) in which the laminated body of the first laminated rubber bearing device G1 has a diameter 3 / √5 times and an inner diameter 2 / √5 times. In the case of the shape and size, the primary shape factor S1 can be clearly reduced to effectively increase the period, and the apparent secondary shape factor S2 that serves as a guide for horizontal rigidity Seems to be the same, so it seems that the difficulty of buckling can be maintained. However, as shown in FIG. 4, since the true secondary shape factor S2 of the second laminated rubber bearing device G2 is greatly lowered, it can be understood that the conditions for buckling are severe. In other words, in the means for increasing the diameter and hollowing of the laminated body so as to equalize the cross-sectional area to increase the period as the laminated rubber bearing device, the secondary shape factor S2 decreases, There is a need to deal with the risk of buckling.

  Therefore, in the present invention, as described above, the buckling prevention columnar body 7 is provided in the through-hole 6 that is the hollow portion of the laminated body 3, so that the buckling prevention columnar body 7 applies a load during large deformation. As a result, it can be stood and held, and the risk of buckling of the laminated rubber bearing device A is prevented. Therefore, an improved laminated rubber bearing device capable of exhibiting the above-described excellent seismic isolation performance due to the longer period without any risk of buckling can be realized.

[Another Example]
The columnar body 7 for buckling prevention may be configured such that the sliding member 8 is laminated in a plurality of stages other than five stages, or has a single sliding member 8. Further, the sliding member 8 having the elastic layer 10 may be set at a position other than the uppermost stage, and the elastic layer 10 may be laminated on or below the single sliding plate 8a. Moreover, the laminated body 3 may have a structure in which neither the inner peripheral covering rubber 1A and the outer peripheral covering rubber 1B or one of them is provided.

Longitudinal sectional view showing structure of laminated rubber bearing device (Example 1) Sectional drawing in the XX line of FIG. Longitudinal sectional view of laminated rubber bearing device showing buckling prevention state during large deformation The figure which shows the comparative example of each characteristic of a solid laminated body and a hollow laminated body

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rubber layer 2 Rigid board 3 Laminated body 6 Hole 7 Columnar body for buckling prevention 8 Sliding member 9 Sliding board 10 Elastic layer A Laminated rubber bearing device

Claims (5)

  A laminate formed by alternately laminating a plurality of rubber layers and rigid plates, a hole penetrating in the laminating direction formed in a central portion of the laminate or its peripheral portion, and a buckling provided in the hole And a buckling prevention columnar body comprising a plurality of sliding members stacked so as to be capable of sliding sideways to each other.   The laminated rubber bearing device according to claim 1, wherein a sliding plate is provided between the plurality of sliding members to promote a side-sliding movement of the sliding members.   The laminated rubber bearing device according to claim 2, wherein the sliding plate is formed of a PTFE sheet.   The laminated rubber bearing device according to any one of claims 1 to 3, wherein an elastic layer is provided on one or more of the plurality of sliding members. The laminated rubber bearing device according to claim 4, wherein the elastic layer is made of a high damping rubber.

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