JP2008019941A - Base isolation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base isolation device with a damper having relatively simple construction not including a rod material or its joint portion easy to deform. <P>SOLUTION: An upper side mount 2 for supporting a building is installed on an lower side mount 3 via a plurality of base isolation mechanisms 4. Each base isolation mechanism 4 has a rolling element 7 laid between upper and lower recessed rolling surfaces 5a, 6a gradually getting deeper as going from the outer periphery toward the center. The base isolation device comprises the damper 8 laid between the upper side mount 2 and the lower side mount 3. The damper 8 has a brake pad 10 pushing a brake plate 9 provided facing downward to the lower side mount 3, from the upside of the lower side mount 3 by an elastic body. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the invention, an upper frame supporting a structure such as a building is installed on the lower frame via a plurality of seismic isolation mechanisms, and an attenuation device is interposed between the upper frame and the lower frame. It relates to seismic devices.

Examples of the seismic isolation device including the damping device include a seismic isolation device including a damping device having a function of increasing a frictional force based on a movement amount (displacement amount) of the device (for example, Patent Document 1). The seismic isolation device disclosed in Patent Document 1 has a structure in which an upper plate is arranged on the upper plate, a plurality of lower plates are arranged opposite to each other, and the upper plate is supported by a ball arranged between a pair of upper and lower plates. It is. The damping device installed in the seismic isolation device is composed of one or a plurality of guides and a guide rod integrally coupled orthogonally to each other, and has a function by sliding the guide and the guide rod. is there. In this damping device, the damping force can be arbitrarily set by adjusting the frictional force using a pad attached to the sliding contact portion between the guide and the guide rod.
JP 2005-201287 A

  In the damping device disclosed in Patent Document 1, it is pointed out that the bar used for the guide rod is thin, and therefore, it tends to cause elastic deformation when subjected to a large force during damping. Further, since the guide rod is a combination of the rod members orthogonal to each other, when the sliding contact pad receives a large frictional force, the entire guide rod may be distorted from the joint portion between the rod members. Furthermore, due to deformation of the guide rod, the contact of each sliding contact pad, that is, the generated frictional force becomes uneven, and the seismic isolation device may make unstable and dangerous movements when subjected to earthquake rolls. is expected. Further, the elastic deformation of the guide rod may cause the guide and the guide rod to bite and the seismic isolation device may be locked. In order to avoid such an inconvenience, a damping mechanism having a structure that does not include a long rod or a coupling portion in a portion that receives a frictional force is desired.

  An object of the present invention is to provide a seismic isolation device provided with a damping device having a relatively simple structure that does not include a bar material that easily deforms or a joint portion thereof.

  In the seismic isolation device according to the present invention, the upper frame supporting the structure is installed on the lower frame via a plurality of seismic isolation mechanisms, and each of the seismic isolation mechanisms extends from the outer periphery to the center. In the seismic isolation device in which rolling elements are interposed between the upper and lower rolling surfaces of a concave shape that becomes deep, an attenuation device is interposed between the upper frame and the lower frame, The brake pad is pressed against the brake plate provided downward by an elastic body from the lower frame.

In the seismic isolation device having this configuration, the upper frame supporting the structure is installed on the lower frame on the ground side via a plurality of seismic isolation mechanisms. In each seismic isolation mechanism, rolling elements are interposed between the upper and lower concave rolling surfaces that increase in depth from the outer periphery to the center, so the seismic motion on the fixed side is between the upper and lower rolling surfaces. The vibrations are absorbed by the rolling motion and the vibration transmission to the upper frame and the building supported on it is alleviated. When the upper frame moves relative to the lower frame in the horizontal direction due to rolling of the rolling elements accompanying the vibration, the upper frame also moves in the vertical direction due to the concave shape of the upper and lower rolling surfaces.
Further, since the damping device has a configuration in which the brake pad is pressed against the brake plate provided downward on the upper frame by the elastic body from above the lower frame, the elastic body moves along with the relative movement of the upper frame in the horizontal direction. The elastic pressing force against the brake plate changes, and the vibration is attenuated.

  In the present invention, the damping device has a concave shape in which a sliding surface for slidingly contacting the brake pad of the brake plate becomes deeper toward the center portion, and the brake pad has a tapered shape. The plane dimension may be the size of a part of the sliding surface of the brake plate. According to this configuration, the sliding surface that makes sliding contact with the brake pad of the brake plate has a concave shape that becomes deeper as it reaches the center portion, so that the upper frame relatively moves in the horizontal direction and the sliding surface of the brake pad. As the slidable contact position changes, the elastic restoring force acting on the sliding surface of the brake pad changes, and the vibration is effectively attenuated by the brake frictional force due to this elastic restoring force. In particular, when the amount of movement in the horizontal direction is large, the sliding contact range of the brake pad extends to the shallow concave portion far from the center of the brake plate, so that the elastic restoring force is increased and the damping action is further increased. Since the brake pad has a tapered shape and the plane dimension is a part of the sliding surface of the brake plate, the brake pad can be smoothly slid with respect to the brake plate, and the sliding range is also Widely secured and reliable attenuation function can be obtained.

  In this invention, the sliding surface of the brake plate is composed of a plurality of concentric taper surface portions having different taper angles, and the taper angle of the outer taper surface portion is steeper than that of the inner taper surface portion. It may be. According to this configuration, since the taper angle of the tapered surface portion on the outer peripheral side is steeper than that of the tapered surface portion on the inner peripheral side, the amount of movement in the horizontal direction is large, and the concave shape is far from the center portion of the brake plate. When the sliding contact range of the brake pad extends to a shallow portion, the elastic restoring force suddenly increases at the steep slope portion, and the damping action becomes more remarkable due to the brake friction force. Therefore, the greater the earthquake shake, the greater the brake friction force, and the excessive displacement of the device can be suppressed.

  In the seismic isolation device according to the present invention, the upper frame supporting the structure is installed on the lower frame via a plurality of seismic isolation mechanisms, and each of the seismic isolation mechanisms extends from the outer periphery to the center. In the seismic isolation device in which rolling elements are interposed between the upper and lower rolling surfaces of a concave shape that becomes deep, an attenuation device is interposed between the upper frame and the lower frame, Since the brake pad is pressed against the brake plate provided downward by the elastic body from the lower frame, it is equipped with a damping device with a relatively simple structure that does not include rods that easily deform and their coupling parts. Can be seismic isolation device.

An embodiment of the seismic isolation device of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the seismic isolation device 1 includes an upper frame 2 that supports a structure (not shown) such as a building, and a plurality of seismic isolation mechanisms 4 (illustrated) on a lower frame 3. 4).
Each seismic isolation mechanism 4 includes upper and lower support plates 5 and 6 fixed to the lower surface of the upper frame 2 and the upper surface of the lower frame 3 in an opposing relationship, and rolling plates that are opposed plate surfaces of the two support plates 5 and 6. It is comprised from the rolling element 7 which consists of a steel ball interposed between the moving surfaces 5a and 6a. Each of the rolling surfaces 5a and 6a has a conical concave shape that becomes deeper from the outer peripheral portion to the central portion. The four seismic isolation mechanisms 4 are arranged at substantially diagonal positions of the rectangular upper and lower frames 2 and 3, and the damping device 8 is interposed at a position where the diagonal lines intersect.

  The damping device 8 is configured such that the brake pad 10 is pressed from above the lower pedestal 3 by an elastic body 11 (see FIG. 4) against a brake tray 9 provided downward on the upper pedestal 2. The dish surface of the brake dish 9 is a sliding surface 9A that makes the brake pad 10 slide. The sliding surface 9A has a concave shape that becomes deeper toward the center, and is composed of a plurality of concentric tapered surface portions 9Aa and 9Ab having different taper angles. The taper angle of the taper surface portion 9Aa on the outer peripheral side is steeper than that of the taper surface portion 9Ab on the inner peripheral side.

  The brake pad 10 is made of an elastic friction member such as rubber, and has a tapered shape. The plane dimension D is a part of the sliding surface 9A of the brake tray 9. The elastic body 11 is composed of a compression coil spring and is housed vertically in a guide cylinder 8b fixed on the base plate 8a. The brake pad 10 is attached to the upper end of the elastic body 11 and is biased upward. The lower half portion of the brake pad 10 is fitted into the guide cylinder 8b, and the outer peripheral portion thereof is slidable along the axial direction with respect to the inner peripheral surface of the guide cylinder 8b.

  In the seismic isolation structure of a building using the seismic isolation device 1 having the above-described configuration, the lower pedestal 3 is installed on the ground side which is the fixed side, and a structure such as a building (not shown) is provided on the upper pedestal 2. ) Is supported. When the fixed side vibrates due to an earthquake or the like, the rolling element 7 rolls between the rolling surfaces 5a and 6a of the upper and lower support plates 5 and 6, and the vibration is absorbed, and the upper frame 2 and the building supported on the upper frame 2 are supported. The transmission of vibrations to objects is mitigated. Since this rolling is done two-dimensionally, it is absorbed in response to vibrations in all directions on the fixed side, and excellent seismic isolation is given to the building supported by this seismic isolation device 1. The Since rolling of the rolling element 7 between the support plates 5 and 6 is performed between the opposing concave rolling surfaces 5a and 6a, the rolling element 7 and the concave rolling surfaces 5a and 6a are in contact with each other. Due to the interaction, the upper support tray 5 moves relative to the lower support tray 6 in the horizontal direction and also in the vertical direction.

  The damping device 8 is always at a position (origin position) where the center of the brake pad 10 substantially coincides with the center of the brake plate 9 as shown in FIG. Along with the relative movement of the upper pedestal 2 due to the vibration, the brake plate 9 moves relative to the brake pad 10 in the horizontal direction and also moves in the vertical direction as shown in FIGS. FIG. 5A shows a state in which the amount of movement in the horizontal direction is small, and the tapered portion at the upper end of the brake pad 10 is formed on the inner peripheral side tapered surface portion 9Ab of the sliding surface 9A which is the tapered surface portion of the brake plate 9. Elastic sliding contact. In this state, the elastic restoring force by the elastic body 11 of the brake pad 10 is weak and the taper angle of the tapered surface portion 9Ab is small, so that the elastic body contraction amount (compression amount of the elastic body 11) is small, and the brake pad 10 slides. The brake frictional force due to the elastic sliding contact with the surface 9A acts small.

  FIG. 5B shows a state in which the amount of movement in the horizontal direction is large, and the upper end tapered portion of the brake pad 10 is elastic to the outer peripheral side tapered surface portion 9Aa of the sliding surface 9A which is the tapered surface portion of the brake plate 9. It is in a state of sliding contact. In this state, the elastic force of the brake pad 10 by the elastic body 11 is strong and the taper angle of the taper surface portion 9Aa is large, so that the elastic body contraction amount is large, and the brake by elastic sliding contact with the sliding surface 9A of the brake pad 10 is large. Frictional force acts greatly. Accordingly, the greater the shaking is and the greater the horizontal relative movement amount of the upper pedestal 2 is, the stronger the damping action of the damping device 8 is, and the excessive displacement of the upper pedestal 2 is suppressed.

  The damping device 8 of this embodiment is adapted to the seismic isolation mechanism of various seismic isolation devices, and also increases the brake friction force as the relative movement amount with respect to the lower frame 3 of the upper frame 2 increases, thereby causing excessive displacement. In order to suppress, the sliding surface 9A of the brake pan 9 is composed of tapered surface portions 9Aa and 9Ab. In the seismic isolation device 1 of this embodiment, when the upper gantry 2 moves relative to the lower gantry 3 in the horizontal direction at the time of an earthquake, it simultaneously moves in the vertical direction. The relationship between the two-way movement amounts is mainly determined by the structure of the seismic isolation mechanism 4. The taper surface structure of the sliding surface 9A in the brake plate 9 serves to prevent a decrease in the amount of contraction of the elastic body (that is, brake friction force) by offsetting the distance that the brake plate 9 moves away from the base plate 8a by this vertical movement. In addition, based on the relationship between the above two-way movement amounts, the taper angle change is continuously set so that the sliding surface 9A is spherical or no taper angle is provided, so that various structures can be isolated. Corresponding to the mechanism 4, it is possible to prevent the friction braking force from being lowered even if the upper frame 2 is relatively moved in the horizontal direction.

  Further, by increasing the taper angle, the amount of contraction of the elastic body can be increased so as to be proportional to the amount of relative movement of the upper frame 2 in the horizontal direction. As a result, a strong braking force can be applied to the large horizontal movement of the upper pedestal 2 to suppress excessive displacement. It is also possible to make the sliding surface 9A spherical by continuously changing the taper angle, and the friction brake force change can be arbitrarily set by the shape of the sliding surface 9A. As described above, the brake plate 9 is formed in the form of the seismic isolation mechanism 4 (the rolling surfaces 5a and 6a have a spherical filed bowl shape, and the upper frame 2 is moved in the vertical direction with the relative horizontal movement due to the rolling of the rolling elements 7. It is possible to arbitrarily set the damping characteristics of individual seismic isolation devices, in addition to moving types, types that do not involve vertical movement).

  Table 1 shows the dimensions and characteristics of each part of FIGS. The seismic isolation mechanism 4 and the damping device 8 having such dimensions and characteristics were incorporated, and the seismic isolation device 1 having the configuration shown in FIGS. 1 and 2 was assembled. In Table 1, the brake mechanism portion dimension h1 is a dimension from the upper surface of the base plate 8a to the tip of the brake pad 10 when the guide cylinder 8b, the brake pad 10 and the elastic body 11 are assembled.

FIG. 6 shows the relationship between the relative displacement of the damping device 8 and the frictional force in the seismic isolation device 1. As shown in FIG. 6, the brake friction force is constant until the horizontal relative displacement amount relative to the lower frame 3 of the upper frame 2 is 0.09 m, and when the relative displacement amount exceeds 0.09 m, the displacement amount increases. In addition, it is understood that the brake friction force is increased. This is because the taper angle β of the taper surface portion 9Ab is made equal to the taper angle θ of the rolling surfaces 5a and 6a of the support plates 5 and 6, and the taper angle α of the taper surface portion 9Aa is made larger than these. That is, in the range where the relative displacement in the horizontal direction with respect to the lower frame 3 of the upper frame 2 is 0.09 m, θ = β, so that the vertical movement associated with the horizontal movement of the upper frame 2 is caused by the brake pad 10. The elastic contraction is canceled out, so that the brake friction force by the brake pad 10 becomes constant. When the displacement exceeds 0.09 m, the taper angle α of the taper surface portion 9Aa is larger than the taper angle β of the taper surface portion 9Ab, so that the amount of contraction of the elastic body 11 increases, thereby causing the brake pad 10 to The brake friction force increases with displacement. As described above, the damping characteristics corresponding to the structure of the seismic isolation mechanism 4 can be arbitrarily set by appropriately setting the dimensions of the brake tray 9 and the diameters and angles of the tapered surface portions 9Aa and 9Ab.

  The number of the damping devices 8 is appropriately determined depending on the volume and weight of the seismic isolation target. Further, the friction coefficient of the brake can be arbitrarily set depending on the material of the brake pad 10 and the sliding surface 9A. The elastic body 11 that pushes up and biases the brake pad 10 is not limited to the elastic body as shown. The coefficient of friction in this example is 0.59. The elastic body 11 is set to an appropriate frictional force by changing its spring constant.

The result of the seismic isolation effect confirmation test by the seismic isolation device 1 having the above configuration is shown in FIGS. 7A and 7B show the standard deviation of the response acceleration when the seismic wave is applied to the seismic isolation device 1 by the seismic wave reproduction device. Here, the input acceleration is the acceleration of the seismic wave reproduction device, the response acceleration is the acceleration generated on the shelf imitating the seismic isolation object placed on the seismic isolation device 1, and the response acceleration without seismic isolation is an earthquake without using the seismic isolation device. The acceleration generated on this shelf when the above is reproduced. The total weight of the upper frame 2 and the shelf was 80 kg. FIG. 7A shows the north-south component of the reproduced seismic wave, and FIG. 7B shows the east-west component of the reproduced seismic wave. In addition, each name in the figure corresponds to the following earthquake reproduction.
Hyogoken Nanbu Earthquake (Kobe) × 1/2,
Niigata Chuetsu Earthquake (Ojiya) × 1/2,
Miyagi Prefecture Offshore Earthquake (Tsukidate),
Fukuoka West Offshore Earthquake (Karatsu),

  As shown in FIGS. 7A and 7B, when the seismic isolation device 1 is used, the response acceleration is reduced, and when the seismic isolation device is not used, the response acceleration is greatly amplified. It is understood that the seismic isolation effect by 1 is remarkable.

  8A and 8B show the movement of the upper gantry 2 of the seismic isolation device 1 during free vibration. FIG. 8A shows the case where the damping device 8 is not provided, and FIG. The case where it exists is shown. As shown in this figure, it is understood that when the damping device 8 is provided, the origin return is promptly performed after the earthquake.

  The shaking of the earthquake cannot be a rotational movement centered on the seismic isolation device 1 installation area in the horizontal plane. Therefore, it can be said that the magnitude | size of the twist motion which the upper frame 2 which is an upper part of the seismic isolation apparatus 1 raises relatively in a horizontal surface with respect to the lower frame 3 which is a lower part is small. Furthermore, in the seismic isolation device 1 using the damping device 8 and the plurality of seismic isolation mechanisms 4, considering the above-described shaking method, the torsional motion in the horizontal plane relative to the lower platform 3 of the upper platform 2 is It is thought not to grow. Therefore, even if there is no guide rod or the like as in the prior art, the torsional motion can be generally suppressed by the damping effect of the damping device 8, and the posture in the horizontal plane can be maintained.

  The shape of the sliding surface 9A of the brake plate 9, the material of the brake pad 10 (coefficient of friction between the brake plate 9 and the brake pad 10), the elastic body (spring constant), etc. are not limited to those in the embodiment, and these may be appropriately selected. By selection, it can be set arbitrarily according to the structure of the seismic isolation mechanism 4 and the like.

It is a top view which shows one Embodiment of the seismic isolation apparatus of this invention. It is the II-II sectional view taken on the line in FIG. It is an expanded sectional view of the seismic isolation mechanism used for the embodiment. It is an expanded sectional view of the attenuation device used for the embodiment. (A) (B) is a figure which shows the operation state of the attenuation device. It is a figure which shows the relationship between the horizontal direction displacement and brake frictional force in the damping device. (A) (B) is a figure which shows the seismic isolation effect confirmation test result in the same embodiment. (A) (B) is a figure which shows the motion at the time of the free vibration of the upper frame in the same embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Seismic isolation device 2 ... Upper frame 3 ... Lower frame 4 ... Seismic isolation mechanism 5 ... Upper support plate 5a ... Rolling surface 6 ... Lower support plate 6a ... Rolling surface 7 ... Rolling body 8 ... Damping device 9 ... Brake plate 9A ... Sliding surface (tapered surface)
9Aa ... Tapered surface portion 9Ab on the outer peripheral side ... Tapered surface portion 10 on the inner peripheral side ... Brake pad 11 ... Elastic body

Claims (3)

The upper frame supporting the structure is installed on the lower frame via a plurality of seismic isolation mechanisms, and each of the seismic isolation mechanisms is a concave-shaped upper and lower roll that deepens from the outer periphery to the center. In the seismic isolation device, which has rolling elements interposed between the moving surfaces,
An attenuation device is interposed between the upper frame and the lower frame, and this attenuation device is formed by pressing a brake pad from above the lower frame with an elastic body to a brake plate provided downward on the upper and lower frame. A seismic isolation device characterized by that.   2. The damping device according to claim 1, wherein the sliding surface of the brake plate that makes sliding contact with the brake pad has a concave shape that becomes deeper toward the center portion, and the brake pad has a tapered shape. A seismic isolation device in which the planar dimension of the pad is the size of a part of the sliding surface of the brake tray.   3. The sliding surface of the brake plate according to claim 2, comprising a plurality of concentric taper surface portions having different taper angles, and the taper angle of the outer taper surface portion is steeper than that of the inner taper surface portion. Is a seismic isolation device.

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