JP7732965B2 - Braking devices and seismic isolation structures for buildings - Google Patents

Description

The present invention relates to a braking device for absorbing energy generated by external forces, and to a seismic isolation structure for a building in which the device is installed.

Seismic isolation structures for buildings are known, in which seismic isolation devices are placed between the building and its foundation to reduce the transmission of earthquake vibrations. With such seismic isolation structures, if an unexpectedly large earthquake occurs that exceeds the level anticipated during structural design, there is a concern that excessive deformation will occur in the seismic isolation layer where the seismic isolation devices are placed, causing the building to collide with the surrounding retaining walls or damaging the seismic isolation layer due to excessive deformation of the seismic isolation devices. There is also a risk that the building above will be damaged by the impact force of the collision with the retaining wall.

As disclosed in Patent Document 1, rubber blocks that act as buffers are installed in advance at locations where collisions may occur due to excessive deformation during a major earthquake, thereby mitigating the impact. It is also known that rubber blocks absorb energy by plastically deforming when subjected to a large force.

Meanwhile, Patent Document 2 discloses a vibration suppression device equipped with a spring mechanism in which multiple disc springs are arranged in the direction of external force. This vibration suppression device increases the amount of spring movement when a displacement greater than a predetermined value occurs, thereby reducing rigidity as the displacement increases. Such vibration suppression devices can be used as spring material to generate a restoring force in a seismic isolation device, or as a damper material by adding damping material, etc.

Furthermore, Patent Documents 3 and 4 disclose the use of a spring member consisting of an array of disc springs as a vibration control mechanism for structures such as buildings. This spring member, which uses disc springs as elements, is configured to be able to withstand both compressive and tensile forces.

Japanese Patent Application Laid-Open No. 2018-71651 JP 2017-78432 A JP 2012-163134 A JP 2012-102793 A

However, devices that plasticize to absorb energy, such as those disclosed in Patent Document 1, need to be replaced when their performance deteriorates due to plasticization. This is difficult to do quickly after a major earthquake, and replacement costs are required.

Furthermore, in configurations in which multiple disc springs are lined up, such as those disclosed in Patent Documents 2-4, the amount of deformation per disc spring is small, so if a condition requires a certain amount of displacement in the direction of external force, such as in a vibration control mechanism, it is necessary to incorporate many disc springs, which increases the length and size of the device. The seismic isolation pit in which the seismic isolation device is placed is lined with numerous pipes and other structures, and there are limitations on the available space, so it is desirable for the device to be as small as possible.

The present invention aims to provide a braking device that has excellent energy absorption performance, can be used repeatedly, and can shorten the length in the direction in which external forces act, as well as a seismic isolation structure for a building in which it is installed.

To achieve the above-mentioned objective, the braking device of the present invention is a braking device for absorbing energy generated by an external force, and includes a movable plate formed in a disk shape with a peripheral surface serving as an acting surface; a first plate overlapping a first surface of the movable plate perpendicular to the peripheral surface; a second plate overlapping a second surface of the movable plate perpendicular to the peripheral surface; a core portion that penetrates the overlapping first plate, the movable plate, and the second plate and is fitted into a restraining hole in the first plate and the second plate; and a spring portion attached to an end of the core portion protruding from at least one of the first plate and the second plate so that the axial direction of the core portion is the expansion/contraction direction. The movable plate is provided with a through hole of a size that allows relative movement of the core portion in a direction perpendicular to the axis, and at least one of the first plate and the second plate and the movable plate are fitted with concave and convex portions that are formed so that sliding in the direction perpendicular to the axis occurs with the same force in both directions, and a restoring force from the spring portion is applied.

The spring portion can be formed by combining disc spring materials or coil spring materials with different rigidities. The unevenness can also be configured to be conical with the through hole as its center. Furthermore, it is preferable that the unevenness form a truncated conical recess on the movable plate side and a truncated conical protrusion on the first plate or second plate side.

The core portion may be configured to have a plurality of core portions. Furthermore, the recesses and protrusions may be fitted on both the first plate side and the second plate side. The spring portion may be attached to an end of the core portion that protrudes from either the first plate or the second plate, and the other end of the core portion may be fixed to the restraining hole in either the second plate or the first plate.

The invention for a seismic isolation structure for a building is a seismic isolation structure for a building in which a seismic isolation device is arranged, characterized in that it comprises any of the above-described braking devices installed in the seismic isolation layer in which the seismic isolation device is arranged, and a reaction force unit for activating the braking device before a predetermined level of deformation occurs in the seismic isolation layer.

Here, the braking device can be installed on the upper or lower side of the seismic isolation layer, and a cylindrical inner circumferential surface that serves as the reaction force section can be provided in a position facing the circumferential surface of the movable plate.

The braking device of the present invention, configured in this manner, is equipped with a spring portion that expands and contracts in a direction approximately perpendicular to the direction in which an external force acts. When an external force acts on the circumferential surface of the movable plate, causing it to move, the spring portion contracts as the recesses and protrusions between the first or second plate and the movable plate are released, and energy is absorbed by the sliding motion between them.

This provides excellent energy absorption performance for external forces acting from any direction within the plane. Furthermore, the mechanism that expands and contracts the spring section provides excellent recovery performance and allows for repeated use. Furthermore, because the direction in which the spring section expands and contracts is approximately perpendicular to the direction in which the external force acts, the length of the braking device in the direction in which the external force acts can be shortened.

Furthermore, if the spring portion is formed by combining disc spring materials or coil spring materials with different rigidities, it can be set to have a restoring force characteristic of increasing rigidity, allowing for gentle braking.

In addition, the invention for the seismic isolation structure for a building includes a braking device installed in the seismic isolation layer where the seismic isolation devices are located, and a reaction force unit for activating the braking device before the seismic isolation layer experiences a predetermined amount of deformation. This prevents the building from colliding with the surrounding retaining walls and the seismic isolation layer from being damaged by excessive deformation of the seismic isolation devices, even in the event of a major earthquake greater than anticipated at the time of design.

1A and 1B are diagrams illustrating the internal structure of a braking device according to an embodiment of the present invention, in which FIG. 1A is a cutaway perspective view showing a state under normal conditions, and FIG. 1B is a cutaway perspective view showing a state under a major earthquake. 1A and 1B are diagrams illustrating the seismic isolation structure of a building according to the present embodiment, in which FIG. 1A is a schematic diagram showing the state under normal conditions, and FIG. 1B is a schematic diagram showing the state under a major earthquake. FIG. 1 is a perspective view for explaining the configuration of a braking device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view for explaining the configuration of the braking device according to the present embodiment. 1 is a cross-sectional view illustrating a configuration of a braking device according to an embodiment of the present invention. 10A and 10B are explanatory diagrams illustrating the configuration of a spring portion. 10A and 10B are diagrams illustrating the restoring force characteristics of the spring section, where FIG. 10A is a graph illustrating the restoring force characteristics of the spring section with increased rigidity, and FIG. 10B is a graph illustrating the restoring force characteristics of the braking device including friction. 5A and 5B are diagrams illustrating the operation of the braking device, in which FIG. 5A is a cross-sectional view illustrating the initial state, and FIG. 5B is a cross-sectional view illustrating the state during operation. 1A and 1B are diagrams showing an example of the installation of a braking device in a seismic isolation structure for a building according to this embodiment, in which (a) is an oblique view with a portion of the target broken away, and (b) is a plan view illustrating the positional relationship between the target and the movable plate. 1 is an explanatory diagram showing the operating range of a braking device in a seismic isolation structure for a building according to the present embodiment. FIG. 1A and 1B are diagrams illustrating the configuration of the braking device of the first embodiment, in which FIG. 1A is a cross-sectional view showing a case where the upper plate is a flat plate, and FIG. 1B is a cross-sectional view showing a case where the lower plate is a flat plate. 10A and 10B are diagrams illustrating the configuration of a braking device according to a second embodiment, in which FIG. 10A is a plan view and FIG. 10A and 10B are diagrams illustrating the configuration of another braking device according to the second embodiment, in which FIG. 10A is a plan view and FIG. 10B is a cross-sectional view. FIG. 10 is a diagram illustrating the relationship between the number of axles and other specifications of the braking device and stability.

Embodiments of the present invention will now be described with reference to the drawings. Figures 1 and 3-5 are diagrams illustrating the configuration of a braking device 1 according to this embodiment. Figure 2 is an explanatory diagram that schematically illustrates the seismic isolation structure of a building according to this embodiment.

The braking device 1 of this embodiment is a device for absorbing energy generated by external forces. The braking device 1 of this embodiment can be used in combination with buildings with seismic isolation structures. The braking device 1 of this embodiment can also be attached to the bumpers of heavy machinery such as forklifts, mobile equipment controlled by artificial intelligence (AI), and the like.

In the following, this embodiment will mainly describe the case where a braking device 1 is installed in a building M in which a seismic isolation device E is installed, as shown in Figure 2(a). In a building M in which a seismic isolation device E is installed between the building M and foundation B to suppress the transmission of earthquake vibrations, deformation occurs in the seismic isolation layer in which the seismic isolation device E is installed during an earthquake (see Figure 2(b)).

In a building M with a seismic isolation structure, if an unexpected large earthquake occurs that exceeds the level assumed during structural design, excessive deformation may occur in the seismic isolation layer as shown in Figure 2(b), causing the building M to collide with the surrounding retaining wall M4 or causing excessive deformation of the seismic isolation device E, which could damage the seismic isolation layer. Therefore, in order to prevent such excessive deformation of the seismic isolation layer, the braking device 1 of this embodiment is installed.

As shown in Figures 1 and 3, the braking device 1 of this embodiment comprises a movable plate 5 formed in a disk shape with a peripheral surface 54 serving as the operating surface, a first plate 21 superimposed on a first surface of the movable plate 5 perpendicular to the peripheral surface 54, a second plate 22 superimposed on a second surface also perpendicular to the peripheral surface 54, a core portion 4 penetrating the superimposed plates (21, 5, 22), and a spring portion 3 attached to the end of the core portion 4. Here, Figure 1 is a cutaway perspective view of the braking device 1 taken at the position where the core portions 4 are lined up to show the internal structure, and Figure 3 is a perspective view of the exterior of the braking device 1 viewed from below.

As shown in Figure 4, the movable plate 5 is formed in a thick disk shape, with the cylindrical peripheral surface 54 being the acting surface that is pressed from the outside. In this figure, the upper surface of the movable plate 5 is the first surface perpendicular to the peripheral surface 54, and the lower surface of the movable plate 5 is the second surface perpendicular to the peripheral surface 54. The first plate 21, which is placed on the first surface of the movable plate 5, and the second plate 22, which is placed on the second surface, are each formed in a disk shape with a smaller diameter than the movable plate 5.

Through holes 53 with an inner diameter larger than the diameter of the core material 4 are drilled in the movable plate 5 to allow the core material 4 to pass through. In Figure 4, four through holes 53 are provided to match the number of core material 4 that will pass through the movable plate 5.

As shown in Figure 5, the inner diameter of the through hole 53 is sufficiently larger than the outer diameter of the core portion 4, and the distance between the outer surface of the core portion 4 and the inner surface of the through hole 53 is sufficient to allow relative movement of the core portion 4 in a direction perpendicular to the axis. The range over which the movable plate 5 can move horizontally is also determined by the length by which the movable plate 5 protrudes laterally beyond the first plate 21 or second plate 22.

Furthermore, as shown in Figure 4, the periphery of the through-hole 53 forms a sloped peripheral surface of a truncated cone-shaped recess 51. In other words, the conical recess 51 centered on the through-hole 53 is truncated by the through-hole 53, resulting in a truncated cone shape.

A truncated cone-shaped recess 52 is formed on the underside of the movable plate 5, similar to the upper side. Meanwhile, a truncated cone-shaped protrusion 222 is formed on the upper surface of the second plate 22, facing the recess 52 on the underside of the movable plate 5. The recess 52 on the underside of the movable plate 5 and the protrusion 222 on the upper side of the second plate 22 are fitted together.

Similarly, a truncated cone-shaped convex portion 212 is formed on the underside of the first plate 21, and the concave portion 51 on the upper surface of the movable plate 5 and the convex portion 212 on the underside of the first plate 21 are fitted together. Figure 5 shows the fitted convex and concave portions between the opposing first plate 21 and second plate 22 at the top and bottom of the movable plate 5.

The fitting relationship between the protrusions and recesses may be reversed between the movable plate 5 and the first plate 21 or second plate 22. In other words, the protrusions may be provided on the movable plate, and the recesses may be provided on the first or second plate.

The engagement of the truncated cone-shaped recesses and protrusions creates the same binding force in any direction (360°) perpendicular to the axis of the core part 4 (horizontal direction), so regardless of the horizontal direction from which force is applied, the same magnitude of force and the same state of sliding will occur.

The core portion 4 not only passes through the through-hole 53 of the movable plate 5, but also passes through the restraint holes 211, 221 of the first plate 21 and the second plate 22. Here, the "restraint" in the restraint holes 211, 221 means that the relative movement of the core portion 4 in the direction perpendicular to the axis (horizontal direction) is restricted.

In the braking device 1 of this embodiment, the spring portion 3 is attached only to the lower end of the core portion 4, so the upper end of the core portion 4 is fixed to the restraining hole 211 of the first plate 21. For example, a female thread can be provided on the inner surface of the restraining hole 211, and the male thread at the upper end of the core portion 4 can be screwed into it, thereby fixing the core portion 4 to the first plate 21 so that it does not move axially.

In contrast, the relationship between the restraining hole 221 of the second plate 22 and the core portion 4 restricts relative movement of the core portion 4 in a direction perpendicular to the axis, but does not restrict relative movement of the core portion 4 in the axial direction. In other words, the second plate 22 moves up and down depending on the amount of expansion and contraction of the spring portion 3, so the up and down movement of the second plate 22 along the core portion 4 is not restricted.

In the braking device 1 of this embodiment, the spring portion 3 is attached to the end of the core portion 4 that protrudes from below the second plate 22 so that the axial direction of the core portion 4 is the expansion/contraction direction. In other words, the direction of action of an external force input to the peripheral surface 54 of the movable plate 5 is perpendicular to the axis of the core portion 4, and the cylindrical spring portion 3 is positioned so that the axial direction of the core portion 4, which is approximately perpendicular to the acting direction, is the expansion/contraction direction of the spring portion 3.

In short, the cylindrical core portion 4 is inserted into the cylindrical hollow portion of the spring portion 3. The core portion 4 also functions as a guide for the spring portion 3. A washer 34 and a nut 35 are attached to the underside of the spring portion 3, and the position of the lower end of the spring portion 3 is fixed in a predetermined position on the core portion 4.

As shown in Figure 1(a), the spring portion 3 is in its most extended state under normal conditions when the braking device 1 is not operating. In other words, the nuts 35 are tightened to the extent that the recessed and protruding parts are maintained fitted together between the first plate 21 and the second plate 22 above and below the movable plate 5, fixing the position of the washer 34, and the restoring force of the spring portion 3 resting on the washer 34 presses the second plate 22 and movable plate 5 against the first plate 21.

On the other hand, as shown in Figure 1(b), during a major earthquake or other such event, when an external force acts on the peripheral surface 54 of the movable plate 5, causing the movable plate 5 to move in a direction perpendicular to the axis of the core portion 4 (horizontal direction), sliding occurs that releases the engagement of the concave and convex surfaces of the movable plate 5 with the first plate 21 and second plate 22.

When the convex portions 212, 222 rise up the concave portions 51, 52, widening the gap between the first plate 21 and the second plate 22, the spring portion 3 contracts. If the top surface of the first plate 21 is fixed to a structure, the movable plate 5 will descend at an angle, and the second plate 22 will descend straight along the core portion 4, pushing against it and contracting the spring portion 3.

When the movable plate 5 moves in a way that causes the spring portion 3 to contract, sliding with frictional resistance occurs between the movable plate 5 and the first plate 21, and between the movable plate 5 and the second plate 22, and energy is absorbed.

Next, the configuration and restoring force characteristics of the spring portion 3 will be described with reference to Figures 6 and 7. The spring portion 3 arranged in the braking device 1 of this embodiment is formed by combining multiple disc spring materials with different rigidities.

Figure 6 shows a configuration in which three types of disc spring materials with different stiffness are stacked. In detail, from the bottom, four first disc spring materials 31, four second disc spring materials 32, and six third disc spring materials 33 are stacked.

The first disc spring material 31, the second disc spring material 32, and the third disc spring material 33 have different rigidities due to differences in material thickness and material. Here, the first disc spring material 31, the second disc spring material 32, and the third disc spring material 33 are ordered in order of increasing rigidity. The rigidity of the entire spring portion 3 can also be adjusted by changing the number of disc spring materials (31, 32, 33) stacked on top of each other.

Figure 7(a) is a graph illustrating the restoring force characteristics of the spring section 3 with increased rigidity. The spring section 3 configured as described above can increase its rigidity as deformation increases, so that, for example, braking can be gradually applied as the deformation of the seismic isolation layer increases.

Point A in Figure 7(a), where the load acting on the spring portion 3 is 0 (kN) and the deformation is 0 (mm), represents the initial state as shown in Figure 6. When a load that contracts (compresses) the spring portion 3 is applied, the third disc spring material 33, which has the lowest rigidity, is the main deformed up to point B.

When the load acting on the spring portion 3 increases beyond point B, the second disc spring material 32 is primarily deformed up to point C, and once point C is exceeded, the first disc spring material 31, which has the highest rigidity, is primarily deformed. This restoring force characteristic of the spring portion 3, in which the rigidity of the entire system increases stepwise as deformation increases, is called the rigidity increasing type.

The braking device 1 of this embodiment performs braking by utilizing the restoring force characteristics of the spring portion 3 when it contracts. Furthermore, the braking device 1 of this embodiment also absorbs energy through sliding between the movable plate 5 and the first plate 21, and between the movable plate 5 and the second plate 22.

As described above, when the peripheral surface 54, which serves as the operating surface of the movable plate 5, is pushed and begins to move, the engagement of the recesses and protrusions between the movable plate 5 and the first plate 21 and second plate 22 is released, causing sliding with frictional resistance.

The magnitude of the frictional resistance (friction coefficient) at this time can be set as desired by adjusting the gradient of the peripheral surfaces of the convex portions 212, 222 and concave portions 51, 52, and the treatment of the contact surfaces. Furthermore, the restoring force of the compressed spring portion 3 presses the first plate 21, movable plate 5, and second plate 22 together, thereby increasing the frictional force.

In particular, the magnitude of the frictional force can be adjusted by the gradient (angle θ) of the peripheral surfaces of the convex portions 212, 222 and concave portions 51, 52. The smaller the angle θ (gentler gradient), the less deformation is required of the spring portion 3 and the greater the frictional force. However, if the angle θ is made too small, the frictional force will exceed the restoring force of the device, making it impossible to restore. For this reason, the angle θ must be large enough to ensure stable restoration. This angle θ should be set to 45° or less, for example, around 20° to 30°.

Figure 7(b) is a graph illustrating the restoring force characteristics of the braking device 1, including friction. The dashed line in the graph shows the restoring force characteristics of only the spring portion 3 described in Figure 7(a). When the frictional force generated between the sliding surfaces of the first plate 21, the movable plate 5, and the second plate 22 is added to this, the restoring force characteristics can be set as shown by the solid line.

In terms of the restoring force characteristics of the braking device 1, including friction, when the peripheral surface 54 of the movable plate 5 is pushed and begins to move, the frictional force between the sliding surfaces and the contraction of the third disc spring material 33 result in behavior that is more rigid than when only the spring portion 3 is used.

This behavior, in which the rigidity is greater than that of the spring portion 3 alone, continues as long as the deformation increases. Furthermore, as the deformation increases, the amount of contraction of the spring portion 3 increases, and the restoring force also increases, resulting in an increase in the friction force between the sliding surfaces.

Then, when the external force decreases and the spring part 3 begins to return to its original position (extend), the restoring force of the braking device 1 decreases by the amount of friction between the sliding surfaces, allowing for an increase in the amount of energy absorption. If the friction is further increased and the braking device 1 returns to its original position more slowly than the building M, the entire area enclosed by the dashed lines during compression becomes the energy absorption amount, allowing for even greater energy absorption.

Next, the operation of the braking device 1 of this embodiment will be described with reference to Figure 8. Figure 8(a) is a cross-sectional view illustrating the initial state of the braking device 1. As shown in Figure 2(a), for example, the braking device 1 is attached to a hanging part M2 that hangs down from the underside of a beam member M1, such as a foundation beam or floor beam, to the seismic isolation layer in which the seismic isolation device E is located.

Here, the first plate 21 serves as a fixed part in terms of its relative position within the braking device 1. Furthermore, to stabilize performance, an initial compression force is applied to the spring part 3, leaving it in a slightly compressed state. This initial compression force is adjusted so that a large impact force is not generated when the braking device 1 begins to operate.

Figure 8(b) is a cross-sectional view illustrating the state of braking device 1 when it is activated. As shown in Figure 2(b), when an earthquake occurs and the shaking of foundation B increases, braking device 1 comes into contact with target 6, which serves as a reaction force part and protrudes from foundation B into the seismic isolation layer.

For example, if contact with the target 6 occurs on the left side of Figure 8(b), the circumferential surface 54 of the movable plate 5 will be pushed toward the right. In other words, the arrow shown adjacent to the circumferential surface 54 in Figure 8(b) indicates the direction of the external force acting from the target 6. The movable plate 5, pushed in by the external force, will move in the direction of the external force.

At this time, the core portion 4 remains suspended from the first plate 21 and does not move. The recessed and protruding portions are released from their mating engagement, and the protruding portions 212, 222 move up the recessed portions 51, 52 while sliding, causing the movable plate 5 and second plate 22 to move downward. In other words, because the core portion 4 is passed through a through hole 53 that is larger than this amount of movement, the movable plate 5 can move without restriction until it hits the inner surface of the through hole 53. Note that the movement of the movable plate 5 may be restricted by the periphery of the first plate 21 or second plate 22.

When the second plate 22 moves downward in conjunction with the movement of the movable plate 5, the gap between the underside of the second plate 22 and the washer 34 narrows, causing the spring portion 3 to contract. When the core portion 4 hits the inner surface of the through hole 53 and the movement of the movable plate 5 stops, the spring portion 3 is no longer compressed, and the state shown in Figure 8 (b) is the maximum deformation (contraction) of the spring portion 3.

On the other hand, when the external force pressing against the peripheral surface 54 of the movable plate 5 is released, the spring portion 3 expands due to its restoring force, the second plate 22 moves upward, and the gap between the underside of the second plate 22 and the washer 34 widens, returning the movable plate 5, second plate 22, and spring portion 3 to their initial state as shown in Figure 8(a).

Next, the operation of the braking device 1 and the seismic isolation structure for a building according to this embodiment will be described.
The braking device 1 of this embodiment configured as described above includes the spring portion 3 whose expansion and contraction direction is substantially perpendicular to the direction in which the external force acts (see, for example, the arrow in FIG. 8(b)).

When an external force acts on the peripheral surface 54 of the movable plate 5, causing it to move, the spring portion 3 contracts as the recesses and protrusions between the first plate 21 and the second plate 22 and the movable plate 5 are released from their mating, and energy is absorbed by the sliding movement that occurs between them, accompanied by frictional resistance.

This sliding occurs under the action of the restoring force of the spring portion 3, so the pressing of the convex portions 212, 222 against the concave portions 51, 52 allows energy to be absorbed more efficiently.

This provides excellent energy absorption performance. Furthermore, the mechanism that expands and contracts the spring portion 3 provides excellent recovery performance and allows for repeated use. In particular, the disc spring material (31, 32, 33) is resistant to plastic deformation even after deformation, so even after the braking device 1 is activated by a major earthquake, it can be used repeatedly without any performance degradation due to plastic deformation.

In addition, during sliding, the movable plate 5 and the upper and lower plates (21, 22) are always in contact at three or more points, preventing unstable behavior such as rotation of the movable plate 5 and achieving the expected restoring force characteristics.

In addition, because the expansion and contraction direction of spring portion 3 is approximately perpendicular to the direction in which the external force acts, the length of braking device 1 in the direction in which the external force acts can be shortened. For example, if coned disc spring material, which has a small amount of deformation per piece, is used, many coned disc spring materials (31, 32, 33) would be incorporated to achieve a certain level of displacement. However, because they are simply stacked in a vertical direction approximately perpendicular to the direction in which the external force acts (horizontal direction), the length of braking device 1 in the direction in which the external force acts can be prevented from becoming too long. For this reason, a compact braking device 1 can be installed in various locations, even in seismic isolation pits, which serve as seismic isolation layers and are often subject to installation range restrictions due to piping, etc.

Furthermore, if the spring section 3 is formed by combining disc spring materials (31, 32, 33) with different rigidities, it can be set to have an increasing rigidity type restoring force characteristic, allowing for gentle damping. In other words, if a spring section 3 is used in which the rigidity of the entire system increases stepwise as deformation increases, not only can the generation of initial impact force be suppressed, but damping can also be performed against excessive deformation.

In this embodiment, the seismic isolation structure of building M has a braking device 1 installed in the seismic isolation layer where the seismic isolation device E is located, and is equipped with a reaction force unit for activating the braking device 1 before a predetermined level of deformation occurs in the seismic isolation layer or the seismic isolation device E.

Figures 9 and 10 are diagrams illustrating an example of the installation and operating range of the braking device 1 in the seismic isolation structure of building M of this embodiment. As shown in Figures 9(a) and (b), the target 6 can be provided by a steel pipe or a cylindrical reinforced concrete member whose lower end is fixed to the foundation B.

For example, the braking device 1 can be installed at the longitudinal center of the beam member M1 supported by the seismic isolation device E. As shown in Figure 9(a), the braking device 1 is attached by joining the upper surface of the first plate 21 to the underside of the hanging part M2 that hangs down from the underside of the beam member M1. The outermost diameter of the installed braking device 1 (the diameter of the movable plate 5) is, for example, approximately 1100 mm.

As shown in the plan view of Figure 9(b), the inner peripheral surface of a cylindrical target 6 is provided to surround the peripheral surface 54 of the movable plate 5, which faces in all directions in the horizontal plane. In order for the seismic isolation device E to fully function, the distance L1 between the peripheral surface 54 of this braking device 1 and the inner peripheral surface of the target 6 must be such that no contact occurs within the range of deformation of the seismic isolation layer due to an earthquake of the scale assumed at the time of design.

Figure 10 is a diagram illustrating the operating range of the braking device 1 in the seismic isolation structure for a building of this embodiment. The braking device 1 is activated by contacting it with a cylindrical target 6 that extends upward from the foundation B.

Here, if the distance between the end face of beam member M1 of building M and retaining wall M4 (see Figure 2) installed around building M is L2, then braking device 1 must be activated to absorb the energy of a major earthquake before deformation of L2 or more occurs in the seismic isolation layer. Therefore, the distance L1 (see Figure 9(b)) between the peripheral surface 54 of braking device 1 and target 6 is set smaller than L2.

In more detail, distance L1 is set so that the sum of distance L1 and the maximum deformation of braking device 1 is smaller than L2. By setting it in this way, even if a major earthquake occurs that is greater than anticipated at the time of design, it is possible to prevent building M from colliding with the surrounding retaining walls M4, and to prevent damage such as tensile fracture or buckling caused by excessive deformation of seismic isolation device E or damper material.

In addition, as the braking device 1 operates, the rigidity of the seismic isolation layer gradually increases, making it possible to suppress deformation of the seismic isolation layer while also limiting the amplification of the response acceleration of the building M located above.

The location of the braking device 1, the slope (angle θ) of the peripheral surfaces of the convex portions 212, 222 and concave portions 51, 52 of the braking device 1, the frictional resistance (friction coefficient) between the sliding surfaces, and the restoring force characteristics of the spring portion 3 can be set appropriately based on the restoring force characteristics of the entire seismic isolation layer.

Furthermore, because the braking device 1 of this embodiment can be activated against external forces from any direction within a 360° horizontal plane, the number of devices that need to be installed can be significantly reduced compared to devices that can only act against external forces from one or two directions.

Below, brake systems 1A and 1B, which are different embodiments from the brake system 1 of the embodiment described above, will be described with reference to Figure 11. Note that parts that are the same or equivalent to those described in the embodiment described above will be described using the same terms or symbols.

In the above embodiment, a case was described in which both the first plate 21 and the second plate 22 have convex portions 212, 222 that engage with the movable plate 5, but in Example 1, a configuration is described in which only one of the plates has a convex-concave engagement.

The braking device 1A shown in Figure 11(a) has a configuration in which the first plate 21A above the movable plate 5A is a flat plate that is circular in plan view. In other words, the first plate 21A does not have any protrusions, and the upper surface of the movable plate 5A facing the first plate 21A is also flat.

In contrast, the braking device 1B shown in Figure 11(b) has a configuration in which the second plate 22B below the movable plate 5B is a flat plate that is circular in plan view. In other words, the second plate 22B does not have a protrusion, and the lower surface of the movable plate 5B facing the second plate 22B is also formed flat.

When creating a concave-convex fit only between the movable plate 5A (5B) and the second plate 22 (first plate 21) on one side, the slope (angle θ) of the peripheral surface of the convex portion 222 (212) is set to, for example, approximately 20° to 30°.

In the braking device 1A shown in Figure 11(a), in which the upper first plate 21A is a flat plate, the movable plate 5A moves only horizontally, thereby improving the stability of operation and performance. Furthermore, because no protrusions are provided, the outer diameter of the first plate 21A can be reduced to the point where the through hole 53 is covered.

Note that other configurations and effects are generally similar to those of the above-described embodiment and other examples, so explanations will be omitted.

Below, braking systems 1C and 1D, which are different embodiments from the braking systems 1, 1A, and 1B of the embodiment and Example 1 described above, will be described with reference to Figures 12 and 13. Note that parts that are the same as or equivalent to those described in the embodiment or Example 1 will be described using the same terms or symbols.

The braking devices 1, 1A, and 1B described in the above embodiment and Example 1 were configured with multiple core portions 4 (four in the example), but Example 2 describes braking devices 1C and 1D configured with a single core portion 4.

Figure 12(a) shows a plan view of a braking device 1C in which one core portion 4 is arranged in the center, and Figure 12(b) shows a cross-sectional view of the braking device 1C taken along the dashed line in Figure 12(a). As shown in Figure 12(b), this braking device 1C has a single truncated cone-shaped protrusion 212 provided only in the center of the first plate 21C, and the second plate 22C is formed as a flat plate that is circular in plan view.

For this reason, the movable plate 5C also has a truncated cone-shaped recess 51 formed around the periphery of the through hole 53 only on the upper surface, with the lower surface being flat. This type of braking device 1C with one protrusion 212 on one axis can be manufactured with an outermost diameter (diameter of the movable plate 5C) of 600 mm, for example, which is about half the size of a four-axis braking device 1.

In contrast, the braking device 1D shown in Figure 13 has a single core portion 4, but the configuration of the convex portion is different from that of the braking device 1C shown in Figure 12. Here, Figure 13(a) shows a plan view, and Figure 13(b) shows a cross-sectional view.

In the braking device 1D shown in Figure 13, the convex portion 212D provided on the first plate 21D is arranged in a ring shape along the periphery of the through hole 53. That is, as shown in the cross-sectional view of Figure 13(b), the cross section of the convex portion 212D consists of two truncated cone-shaped peaks on both sides of the core portion 4. The concave portion 51D of the movable plate 5D, which fits into the convex portion 212D, is also arranged in a ring shape along the periphery of the through hole 53. On the other hand, the second plate 22D is formed as a flat plate that is circular in plan view.

In this way, the core material portion 4 does not necessarily have to be the central convex portion when the convex portion is fitted together. Even if an annular convex portion 212D is provided surrounding the core material portion 4, the movable plate 5D can slide with the same amount of force in either direction. Here, a braking device 1D with a two-ridged convex portion 212D can be manufactured slightly larger than a braking device 1C with a single ridge, with an outermost diameter (diameter of the movable plate 5D) of approximately 700 mm, for example.

As explained above, the number of core portions 4 arranged in the braking device and the shape of the convex portions can be set arbitrarily depending on the desired load capacity, etc. Figure 14 is a chart illustrating the relationship between the number of axles and other specifications of the braking device and stability.

As shown in the table in Figure 14, the number of core parts 4 (number of axes) arranged in the braking device can be set arbitrarily, from one to five or more. The length of the spring part 3 (total spring length), the diameter of the spring part 3 (outer spring diameter), and the diameter of the braking device (movable plate) (outer device diameter) will tend to change depending on the number of core parts 4 arranged.

Each configuration has its advantages; for example, a smaller number of axes in the core portion 4 allows for a smaller device outer diameter, while a larger number of axes in the core portion 4 allows for a smaller spring portion 3. Furthermore, in terms of stability during braking device operation, having three or more axes in the core portion 4 allows for more stable movement of the movable plate.

Note that other configurations and effects are generally similar to those of the above-described embodiment and other examples, so explanations will be omitted.

The above describes in detail an embodiment of the present invention with reference to the drawings, but the specific configuration is not limited to this embodiment and example, and design changes that do not deviate from the gist of the present invention are included in the present invention.

For example, the above embodiment mainly describes the case where the braking device 1 is installed in a building M with a seismic isolation structure, but this is not limited to this, and the braking devices 1, 1A-1D of this embodiment or example can also be used as damper materials for contact parts of robots, etc.

In addition, in the above embodiment, the spring portion 3 is formed by combining three types of disc spring material (31, 32, 33) with different rigidities, but this is not limited to this. The spring portion can also be formed by combining multiple coil spring materials, square spring materials, rubber materials, or similar materials with different rigidities.

In addition, in the above embodiment, the reaction force part was described using a cylindrical target 6 as an example, but this is not limited to this, and the reaction force part can also be polygonal, such as a square or hexagonal cylindrical shape.

Furthermore, in the above embodiment, the braking device 1 is installed on the upper side of the seismic isolation layer and the target 6 is provided on the lower side (foundation B side), but this is not limited to this. It is also possible to install the braking device 1 on the lower side of the seismic isolation layer and provide a reaction force unit on the upper side. Note that in the above embodiment, the lower side is foundation B, but this is merely an example; the braking device 1 can also be installed on a seismic isolation layer located in the middle floors of a building.

In addition, in the above-described embodiment and example, a configuration was described in which the spring portion 3 is attached only to the end of the core portion 4 protruding from the second plate 22, 22B, 22C, 22D side, but this is not limited to this. The spring portion 3 may be attached by causing the end of the core portion to protrude toward the first plate side, or the ends of the core portion may protrude from both plates and a spring portion 3 may be attached to each.

1, 1A-1D: Brake device 21, 21A, 21C, 21D: First plate 211: Restraint hole 212, 212D: Convex portion 22, 22B, 22C, 22D: Second plate 221: Restraint hole 222: Convex portion 3: Spring portion 31: First disc spring material (disc spring material)
32: Second disc spring material (disc spring material)
33: Third disc spring material (disc spring material)
4: Core portion 5, 5A-5D: Movable plate 51, 51D: Recess 52: Recess 53: Pass-through hole 54: Peripheral surface 6: Target (reaction portion)
M: Building E: Seismic isolation device

Claims (9)

A braking device for absorbing energy generated by an external force,
a movable plate formed in a disk shape, the peripheral surface of which serves as an operating surface;
a first plate superposed on a first surface of the movable plate that is perpendicular to the circumferential surface;
a second plate that is superimposed on a second surface of the movable plate that is perpendicular to the circumferential surface;
a core portion that penetrates the stacked first plate, the movable plate, and the second plate and is fitted into the restraining holes of the first plate and the second plate;
a spring portion attached to an end of the core portion protruding from at least one of the first plate and the second plate such that the axial direction of the core portion is the expansion/contraction direction,
The movable plate is provided with a through hole having a size that allows relative movement of the core portion in a direction perpendicular to the axis,
A braking device characterized in that at least one of the first plate and the second plate and the movable plate are subjected to a restoring force by the spring portion in a state in which concave and convex portions are fitted together so that sliding in the direction perpendicular to the axis occurs with the same force magnitude in either direction. The braking device described in claim 1, characterized in that the spring portion is formed by combining disc spring materials or coil spring materials with different rigidities. A braking device as described in claim 1 or 2, characterized in that the unevenness is formed in a conical shape centered on the passage hole. The braking device described in claim 3, characterized in that the unevenness is a truncated cone-shaped recess on the movable plate side and a truncated cone-shaped protrusion on the first plate or second plate side. The braking device described in claim 1 or 2, characterized in that multiple core portions are arranged. A braking device as described in claim 1 or 2, characterized in that the recessed and protruding portions are fitted on both the first plate side and the second plate side. A braking device as described in claim 1 or 2, characterized in that the spring portion is attached to an end of the core portion protruding from one of the first plate or the second plate, and the other end of the core portion is fixed to the restraining hole of the second plate or the first plate. A seismic isolation structure for a building in which a seismic isolation device is arranged,
The braking device according to claim 1 or 2, which is installed in a seismic isolation layer in which the seismic isolation device is arranged;
A seismic isolation structure for a building, characterized in that it is equipped with a reaction force section for activating the braking device before a predetermined level of deformation occurs in the seismic isolation layer. The braking device is installed on the upper or lower side of the seismic isolation layer,
The seismic isolation structure for a building according to claim 8, characterized in that a cylindrical inner peripheral surface serving as the reaction portion is provided at a position facing the peripheral surface of the movable plate.