JP2014222093A - Base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation device capable of easily coping with not only a heavy load but also a light load.SOLUTION: A base isolation device includes a slide plate, a retainer, and a base plate. The slide plate, the retainer, and the base plate have a magnet generating attraction force in the center. The slide plate and the base plate respectively have an upper plate 23 and a lower plate 43 having opposite magnetic polarity to that of the magnet around the magnet. The retainer is movable in a horizontal direction by a rolling element 35. The rolling element 35 is a high magnetic permeability material part, and can be rolled between the upper plate 23 and the lower plate 43. A supporting part 33 is a low magnetic permeability material part, and supports the rolling element 35 so as to be rolled. Thereby, a magnetic circuit is formed around the supporting part 33, and magnetic attraction force can be efficiently generated.

Description

  The present invention relates to a seismic isolation device, and more particularly, to a seismic isolation device that supports a base isolation object on a ground or a structure in a vertical direction and can be deformed and restored in a horizontal direction.

  The seismic motion countermeasures for seismic isolation objects (for example, houses, offices, high-rise buildings, bridges, plants, etc.) are large, earthquake resistance (improvement of strength, reinforcement, etc.), vibration control (reduction of amplitude by the vibration control device, energy absorption) Etc.) and seismic isolation (vibration isolation by seismic isolation devices, natural period extension, etc.) are known.

  The seismic isolation device is for insulating the seismic isolation object from the seismic motion, and makes it difficult for the seismic input energy to enter the seismic isolation object and not to shake vigorously. Seismic isolation devices are also used for base isolation floors and tables. In conventional seismic isolation devices, the horizontal natural period is extended. At present, for natural seismic waves with spectral characteristics, the horizontal natural period has been extended so that the period is 4 seconds or more. As representative examples of seismic isolation devices, laminated rubber bearings and rolling seismic isolation bearings are known. The laminated rubber bearing is an elastic type utilizing the shear rigidity of rubber. Rolling seismic isolation bearings allow a rollable object to be sandwiched in a shape that is wide at the center and narrowed at both sides, so that it can return to a wide center like a pendulum, even when a horizontal force is applied. , Using gravity.

  It is known to use a magnet as a vibration control device. For example, in Patent Documents 1 and 2, a plurality of magnets are provided concentrically or alternately on a flat surface on a vibration control target structure and a movable weight, respectively, and positions using the attractive force and repulsive force of these magnets. Is described to restore.

Japanese Patent No. 3038347 Japanese Patent No. 4040123

  Laminated rubber bearings have many achievements as seismic isolation devices for large structures such as high-rise buildings and bridges. However, due to the characteristics of the ratio between the horizontal rigidity and the vertical rigidity of laminated rubber, the laminated rubber achieves the small horizontal rigidity required for the extension of the natural period in small structures such as ordinary houses that have a smaller vertical reaction force than large structures. Difficult to do. In addition, fire prevention equipment is required for structures that require safety against fire.

  In addition, the rolling seismic isolation bearing can cope with a large vertical reaction force by, for example, a method of combining a large number of rolling elements and a planar rolling surface, but does not generate a restoring force for horizontal movement. Therefore, it is necessary to provide a restoring force device such as a laminated rubber or an elastic spring, and further to provide a damping device because frictional damping is small. In addition, for example, in the method of combining a single rolling element and a curved rolling surface, a restoring force is generated by gravity, but the seismic isolation device is operated at a small amplitude with a small restoring force in consideration of habitability such as wind. There is often a stop device to stop, and since the damping of the seismic isolation device itself is extremely small, it is necessary to provide a damping device. Furthermore, it is necessary to install a number of seismic isolation devices in order to cope with a large vertical reaction force, which is difficult to apply to large structures.

  As described above, the existing seismic isolation devices are provided with different types of seismic isolation devices, damping devices such as damping devices, and anti-vibration devices in order to compensate for the shortcomings.

  In addition, the use of conventional magnets is mainly related to a vibration damping device that uses a simple attractive force and repulsive force by using a plurality of magnets to absorb energy and suppress acceleration and deformation. Met. In these apparatuses, it is assumed that the restoring force by the magnet changes substantially linearly with respect to the displacement (for example, see the description of “magnetic spring constant” in Patent Document 1 and the graphs of FIGS. 7 and 19). ).

  Therefore, an object of the present invention is to propose a seismic isolation device that can easily cope with not only a heavy load but also a light load.

  A first aspect of the present invention is a seismic isolation device that supports a seismic isolation object on a ground or a structure in a vertical direction and can be deformed and restored in a horizontal direction, and is fixed to the seismic isolation object. A slide plate, a base plate to be fixed to the ground or the structure, and a retainer that is movable in a horizontal direction between the slide plate and the base plate, the slide plate being the retainer An upper magnetic part having a first magnetic pole on the side, and an upper plate part having a second magnetic pole opposite to the first magnetic pole on the retainer side, and the base plate has a lower magnetic pole having the second magnetic pole on the retainer side A magnetic part and a lower plate part having the first magnetic pole on the retainer side, wherein the retainer is A middle magnetic part that exists at a position opposite to the upper magnetic part and the lower magnetic part, has the second magnetic pole on the slide plate side, and has the first magnetic pole on the base plate side; A rolling element of a magnetic body that is in contact with the plate part and the lower plate part and is rollable, and a support part that is present at least between the middle magnetic part and the rolling element and has lower magnetism than the rolling element. It is characterized by.

  A second aspect of the present invention is the seismic isolation device according to the first aspect, wherein the slide plate has an upper groove portion formed between the upper magnetic portion and the upper plate portion, and the base plate Has a lower groove portion formed between the lower magnetic portion and the lower plate portion, and the retainer retains the middle magnetic portion of the retainer overlapping the upper magnetic portion and the upper groove portion of the slide plate. Compared to the tangential rigidity when it does not overlap the upper plate part on the side and does not overlap the lower magnetic part and the lower groove part of the base plate and does not overlap the lower plate part on the retainer side, The middle magnetic part of the retainer overlaps with a part of the upper plate part on the retainer side and overlaps with a part of the lower plate part on the retainer side. It is intended to reduce the tangential stiffness when that.

  A third aspect of the present invention is the seismic isolation device according to the first or second aspect, wherein the upper magnetic part, the middle magnetic part and the lower magnetic part face each other in the same size, On the retainer side of the slide plate, a portion having the first magnetic pole of the upper magnetic portion is disposed on the inside, and a portion having the second magnetic pole of the upper plate portion is disposed on the outside, and on the retainer side of the base plate The upper magnetic part, the middle magnetic part, and the lower magnetic part are arranged such that a part having the second magnetic pole of the lower magnetic part is disposed inside and a part having the first magnetic pole of the lower plate part is disposed outside. The lower plate portion, the rolling element and the upper plate portion form a magnetic circuit around the support portion having low magnetism.

  A fourth aspect of the present invention is the seismic isolation device according to any one of the first to third aspects, between the slide plate and the retainer and / or between the retainer and the base plate. Friction control means for controlling the generated friction is provided.

  A fifth aspect of the present invention is the seismic isolation device according to any one of the first to fourth aspects, wherein the retainer includes a gap control means for controlling a gap between the slide plate and the base plate. It is.

  A sixth aspect of the present invention is the seismic isolation device according to any one of the first to fifth aspects, wherein the rolling elements are a plurality of cylindrical rollers whose rotation axes are parallel to each other, or three The above spheres, at least one of which is not on a straight line connecting the other two spheres.

  A part of the upper plate part, the lower plate part, the upper magnetic part, the middle magnetic part, and the lower magnetic part may be used as a magnetic generator (for example, a magnet), and the other may be a magnetic body having higher magnetism than the support part. . By using a part of the magnetic body, a magnetic circuit in the base plate, the retainer, and the base plate can be formed using a minimum number of magnets. As a magnet etc., a high magnetic flux neodymium magnet, a low magnetic flux ferrite magnet, etc. can be used, for example. The type of magnet may be selected according to the mass of the seismic isolation object and the social importance. The fixing of the magnet can be easily realized by a technique such as an existing adhesive or a tight spring.

  Here, deformable and recoverable means that the slide plate, the retainer, and the base plate of the seismic isolation device move in the horizontal direction relative to each other in the horizontal direction due to the action of the disturbance, and when the action of the disturbance disappears, Indicates that the retainer and base plate return to their original positions.

  Further, in the seismic isolation device of each aspect of the present invention, the magnetic flux density of each material constituting the low magnetic part of the support part (low magnetic permeability material part) is the same as that of the rolling element (high magnetic permeability material part). Compared to the magnetic flux density of each material that constitutes a portion with a high value, it is desirable that it be negligibly small. For example, if the magnetic flux density of the high permeability material portion is 50 times or more than the magnetic flux density of the low permeability material portion, the influence of the magnetic field of the low permeability material portion can be sufficiently ignored.

  According to each aspect of the present invention, the magnetic circuit formed by the magnetic lines of force is generated around the support portion having low magnetism, and the gap between the lower magnetic portion and the middle magnetic portion of the retainer from the lower magnetic portion of the base plate, the middle portion Passing through the gap between the magnetic part, the middle magnetic part and the upper magnetic part of the slide plate, going to the upper magnetic part, penetrating from the upper magnetic part to the upper plate part in the slide plate, from the upper plate part of the slide plate It passes through the inside of the rolling element toward the lower plate portion of the base plate, and passes through the base plate from the lower plate portion toward the lower magnetic portion, or in reverse order. As a result, a magnetic circuit that forms a magnetic circuit with less magnetic resistance is formed to enhance the magnetic flux, and a magnetic circuit that efficiently generates magnetic attraction force and magnetic restoring force is configured. It becomes possible to cope easily.

  Furthermore, the action of the mutual magnetic attractive force between the upper magnetic part of the slide plate, the middle magnetic part of the retainer, and the lower magnetic part of the base plate by the magnetic circuit, and the lower plate part of the slide plate, the rolling element, and the lower part of the base plate The action of the mutual magnetic attractive force between the plate portions not only generates a magnetic restoring force that restores the horizontal mutual displacement generated between the slide plate, retainer, and base plate, but also the slide plate, retainer, and As the horizontal displacement between the base plates increases, the tangential rigidity of the magnetic restoring force decreases. Since the magnetic restoring force has such a dynamic characteristic, it has a non-linear natural vibration characteristic in which the horizontal natural period increases as the horizontal displacement increases. The resonance condition of the seismic isolation device of the present invention having this nonlinear natural vibration characteristic is that the natural period of the vibrator and the period of the disturbance coincide with each other, and that the natural amplitude corresponding to the natural period of the vibrator and the action of the disturbance It is two of coincidence of amplitude. For example, in the case of a seismic isolation device having a linear natural vibration characteristic in which the natural period is constant regardless of the amplitude, the resonance condition is only the coincidence between the natural period of the vibrating body and the period of the disturbance. Therefore, the seismic isolation device of each aspect of the present invention having a nonlinear natural vibration characteristic in which the resonance condition is two of the natural period and the natural amplitude is an isolation device having linear natural vibration characteristics such as laminated rubber bearings and rolling seismic isolation bearings. Compared with seismic devices, the possibility of resonance with ground motion can be significantly reduced.

  Furthermore, the action of the mutual magnetic attractive force and magnetic restoring force between the slide plate, retainer, and base plate can prevent the retainer (especially rolling elements) from deviating, and the seismic isolation device can operate stably during an earthquake. Can be realized. Generally, a plurality of seismic isolation devices are used for one seismic isolation object. The rolling planes of the seismic isolation devices are preferably ideally parallel to each other, but the rolling planes of the devices may not be parallel to each other due to installation errors of the devices. In addition, during the earthquake, due to deformation of the ground or structure, any of the seismic isolation devices may be tilted or uneven settlement may occur. In such a case, in the conventional apparatus, the rolling element is separated from the rolling plane during operation, resulting in insufficient rotation of the rolling element. If insufficient rotation of the rolling element is biased in the retainer or spreads throughout the retainer, the moving direction of the retainer deviates from the direction in which the retainer should originally move or the retainer rotates. In the worst case, the retainer may deviate, the rolling element may come off the rolling plane, and the function of the seismic isolation device may be lost. According to the seismic isolation device of each aspect of the present invention, the magnetic attractive force and the magnetic restoring force act so that the retainer stays at an intermediate position between the displacements of the slide plate and the base plate. Compared to the case where only the motion of the rolling element depends only on, it is possible to significantly reduce the possibility of the deviation of the retainer at the time of the earthquake, that is, the deviation of the rolling element from the rolling plane.

  According to each aspect of the present invention, it is possible to efficiently generate a magnetic attractive force and a magnetic restoring force to realize the extension of the horizontal natural period of the seismic isolation object, and easily handle not only heavy loads but also light loads. In addition to improving the habitability, it is possible to reduce the possibility of resonance or reduce the possibility of deviation of the retainer by the non-linear natural vibration characteristics. Furthermore, since it is not necessary to use a combustible material such as rubber as a material for a member that supports the seismic isolation object in the vertical direction, safety against fire can be improved. Thus, according to each aspect of the present invention, it is possible to contribute to the maintenance and construction of a safe society against earthquakes.

  Furthermore, according to the second aspect of the present invention, an upper groove portion formed between the upper magnetic portion and the upper plate portion in the slide plate, and a lower magnetic portion and the lower plate portion in the base plate are formed. By using the lower groove portion, the tangential rigidity of the magnetic restoring force can be formed on the side where the horizontal relative displacement is small, and the low rigidity region can be formed on the large side. According to each aspect of the present invention, the magnetic attraction force and the magnetic restoring force are efficiently generated, and the necessity of the anti-vibration device is low compared to the conventional device when the amplitude is small due to wind or the like. Furthermore, it is generally considered that seismic isolation target earthquakes ensure sufficient safety for small vibrations. According to the 2nd viewpoint of this invention, compared with a small vibration, it implement | achieves a seismic isolation effect efficiently by extending a natural period more with respect to large vibrations, such as an earthquake, and improving a seismic isolation effect. Is possible.

  Furthermore, according to the third aspect of the present invention, in the retainer, the middle magnetism generating portion is arranged on the inner side, and the rolling elements are arranged on the outer side, thereby corresponding to a large vertical supporting force and a small restoring force. Is possible. That is, by increasing the area of the upper plate part and the lower plate part and increasing the number of rolling elements, the vertical support force is increased, and the areas of the upper magnet generator, the lower magnet generator, and the middle magnet generator are reduced. It is possible to reduce the magnetic restoring force by reducing the magnetomotive force of the magnetic source. This is particularly economically suitable when the seismic isolation object has a large weight and requires a large vertical force but does not require a large restoring force.

  Furthermore, according to the fourth aspect of the present invention, damping can be added to the apparatus by controlling the friction generated between the slide plate and the retainer and / or between the base plate and the retainer. Further, according to the fifth aspect of the present invention, the magnetic resistance is adjusted by the distance between the upper gap and the lower gap, thereby easily adjusting the magnetic flux of the magnetic circuit, that is, the magnetic attractive force and the magnetic restoring force. The size can be easily adjusted. The magnetic resistance of the upper gap and the lower gap varies greatly depending on the distance between them. Therefore, by maintaining the gap between the upper gap and the lower gap constant by the gap holding means, the magnetic resistance of both gaps can be made constant and the magnetic circuit can be stabilized. Note that the addition of attenuation according to the fourth aspect and the gap interval holding according to the fifth aspect can be simultaneously performed by one means.

  Furthermore, according to the sixth aspect of the present invention, when the rolling element is constituted by a plurality of cylindrical rollers, the seismic isolation direction of the seismic isolation object can be limited to one direction. Since the bearing strength per one piece is larger than that of the sphere, the operation direction of the seismic isolation object is limited, and it is possible to cope with the case where the mass is large. On the other hand, when the rolling element is composed of a plurality of spheres, it can exert a seismic isolation effect on any horizontal seismic motion, and the vertical bearing capacity depends on the number of spheres according to the mass of the seismic isolation object. Can be adjusted.

It is a figure which shows an example of a structure of the seismic isolation system which concerns on embodiment of this invention. It is a figure which shows the outline | summary of the slide plate 11 of FIG. 1, (a) Center sectional drawing, (b) Bottom view. It is a 1st figure which shows the outline | summary of the retainer 13 of FIG. 1, and is a top view. FIG. 2 is a second sectional view showing an outline of the retainer 13 of FIG. FIG. 3 is a third view showing an outline of the retainer 13 of FIG. 1, (a) a central sectional view including a gap retainer 37, and (b) an enlarged view of the gap retainer 37. It is a figure which shows the outline | summary of the baseplate 15 of FIG. 1, (a) Center sectional drawing, (b) Plan view. FIG. 2 is a central sectional view of the seismic isolation device 3 of FIG. 1, which includes (a) a rolling element 35 and (b) a gap retainer 37. It is a figure which shows an example of the magnetic circuit of the seismic isolation apparatus 3 of FIG. It is a figure which shows the magnetic circuit equivalent to the magnetic circuit of FIG. It is a figure which shows the main magnetic field lines in the center sectional drawing containing the rolling element 35 in the stationary state I about the seismic isolation apparatus 3 of FIG. FIG. 2 is a diagram showing the state of shear deformation and the position of main magnetic lines of force in the state II in which the relative displacement u between the slide plate and the base plate satisfies 0 <u <2e, with respect to the seismic isolation device 3 of FIG. (B) It is an enlarged view of the center part. It is a figure which shows the mode of the shear deformation | transformation in the state III with which the relative displacement u satisfy | fills u = 2e, and the position of main magnetic field lines about the seismic isolation apparatus 3 of FIG. It is an enlarged view. FIG. 4 is a diagram showing the state of shear deformation and the positions of main magnetic lines of force in the state IV where the relative displacement u satisfies 2e <u <a, with respect to the seismic isolation device 3 of FIG. It is an enlarged view of a part. It is a figure which shows the main force which acts on the retainer 13, and the force which acts on the slide plate 11 and the base plate 15 corresponding to them. It is a figure which shows the main force which acts on the rolling element 35, and the force which acts on the slide plate 11 and the base plate 15 corresponding to these. It is a figure which shows another example of the clearance gap holder 37 of FIG.5 (b). When it implement | achieves with a roller as the rolling element 35, it is a figure which shows the example which produces | generates a magnetic path in an operation | movement direction and an operation right angle direction, (a) Side view, (b) Bottom view of a slide plate, (c) Retainer It is a top view, (d) It is a top view of a base plate. It is a figure which shows the example which produces | generates a magnetic path in an operation | movement right angle direction, when implement | achieving with a roller as the rolling element 35, (a) Side view, (b) Bottom view of a slide plate, (c) Plan view of a retainer, (D) It is a top view of a base plate. It is a graph which shows distribution of the magnetic flux density of the upper magnet 21 and the upper plate 23 of the slide plate 11 before an assembly. It is a graph which shows distribution of the magnetic flux density of the retainer 13 before assembling. 6 is a graph showing the distribution of magnetic flux density on the upper surface of the lower magnet 41 and the upper surface of the lower plate 43 of the base plate 15 before assembly. It is a graph which shows the hysteresis curve of the relative displacement u of the assembled seismic isolation apparatus 3, and the restoring force R. FIG. It is an example of a free vibration record of the seismic isolation device 3. It is a graph which shows the relationship between the amplitude obtained by repeating the test similar to FIG. 23 10 times, and a period.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment.

  FIG. 1 is a diagram showing an outline of an example of a seismic isolation system according to an embodiment of the present invention. The seismic isolation system of FIG. 1 includes a seismic isolation object 1, a seismic isolation device 3, and a lower structure 5 (an example of “structure” in the claims of the present application) on the ground 7. The lower structure 5 is located on the ground 7. The seismic isolation device 3 supports the seismic isolation object 1 in the vertical direction on the lower structure 5, and the relative between the seismic isolation object 1 and the lower structure 5 in an arbitrary horizontal direction in a horizontal plane perpendicular to the vertical direction. Has resilience to displacement. Here, the resilience related to the relative displacement in the horizontal direction means that the seismic isolation device 3 is sheared and deformed in the horizontal direction against the action of an external force parallel to the horizontal direction on the seismic isolation target 1. When 1 moves from the original position when stationary to the acting direction of the external force and the external force is removed, the shear deformation of the seismic isolation device 3 returns to the original, so that the seismic isolation object 1 returns to the original position when stationary. Means that. The restoring force that restores the shear deformation of the seismic isolation device 3 exhibits a gradual soft spring type mechanical characteristic in which the tangential rigidity of the restoring force decreases with increasing shear deformation. Here, the tangential rigidity of the restoring force is a ratio between the minute increase in deformation and the increase in the restoring force caused by the minute increase in deformation, and is defined by Equation (1). “Deformation” in equation (1) may be read as shear deformation, displacement, and relative displacement.

  The seismic isolation device 3 includes a slide plate 11 (an example of “slide plate” in the claims of the present application), a retainer 13 (an example of “retainer” in the claims of the present application), and a base plate 15 (an example of “base plate” in the claims of the present application). ).

  FIG. 2 is a diagram showing an outline of the slide plate 11. (A) is center sectional drawing, (b) is a bottom view from the retainer 13 side. The slide plate 11 is fixed to the seismic isolation object 1. The slide plate 11 includes an upper magnet 21 (an example of an “upper magnetic part” in the claims), an upper plate 23 (an example of an “upper plate part” in the claims), and an upper groove 25 (an “upper magnetic part” in the claims). An example of an “upper groove portion”.

  The slide plate 11 has a generally disc shape. The surface facing the retainer 13 has the upper magnet 21 inside, and the upper plate 23 is arranged so as to surround it. The upper groove 25 is located at the boundary between the upper magnet 21 and the upper plate 23. Let the diameter of the upper magnet 21 be a. The width of the upper groove 25 is assumed to be e. The diameter a of the upper magnet 21 and the width e of the upper groove 25 are related to the amount of shear deformation and the restoring force characteristic of the seismic isolation device 3, respectively.

  3, 4 and 5 are diagrams showing an outline of the retainer 13. FIG. 3 is a plan view. FIG. 4 is a central cross-sectional view of a plane including rolling elements. 5A is a cross-sectional view of a surface including the gap retainer, and FIG. 5B is an enlarged view of the vicinity of the gap retainer. The retainer 13 exists between the slide plate 11 and the base plate 15 and can move in the horizontal direction. The retainer 13 includes a middle magnet 31 (an example of a “middle magnetic part” in the claims), a support part 33 (an example of a “support part” in the claims), and a rolling element 35 (a “rolling element” in the claims). And a gap retainer 37 (an example of “friction control means” and “gap control means” in the claims).

  The retainer 13 includes a middle magnet 31 that is a substantially disk-shaped magnetic generator at the center, and a support portion 33 that is a generally disk-shaped low-permeability material portion so as to surround the outside. In the support portion 33, a rolling element 35 (shown by a large circle in the support portion 33) is stored so as to be able to roll, and a gap holder 37 (shown by a small circle in the support portion 33) is provided. . The middle magnet 31 is fixed to a cylindrical hole provided in the center of the support portion 33, and the rolling element 35 is stored in a hole (for example, a cylindrical hole) provided in the support portion 33 so as to be able to roll. The holes for storing the gap retainer 37 are, for example, blind cylindrical holes that open on the side facing the slide plate 11 and the side facing the base plate 15 and are arranged in a vertical pair. The hole for storing the rolling element 35 is not limited to the cylindrical hole as long as the rolling element 35 can be stored freely. For example, the relative displacement in the vertical direction between the rolling elements 35 and the retainer 13 may be limited, and the vertical distance between the slide plate 11 and the retainer 13 and the vertical distance between the retainer 13 and the base plate 15 may be constant. With such a configuration, the hole for storing the rolling element 35 can also serve as a gap holding means.

  The middle magnet 31 has a disk shape with a diameter b and a height c. The middle magnet 31 has different magnetic poles on the slide plate 11 side and the base plate 15 side. The middle magnet 31 may be partly made of a high permeability material. For example, a part of the middle magnet 21 on the slide plate 11 side and / or the base plate 13 side may be a yoke of high magnetic permeability material.

  The rolling element 35 will be described with reference to FIG. The rolling element 35 is in a position facing the upper plate 23 and the lower plate 43 at the restored position, and rotates and moves between the upper plate 23 and the lower plate 43. The slide plate 11, the retainer 13, and the base plate 15 are displaced relative to each other in the horizontal direction due to the horizontal movement accompanying the rolling of the rolling elements 35. The movement of the slide plate 11, the retainer 13, and the base plate 15 in the horizontal direction as the rolling elements 35 roll is defined as shear deformation of the seismic isolation device 3. The horizontal displacement of the retainer 13 is intermediate between the horizontal displacements of the slide plate 11 and the base plate 15.

  The rolling element 35 is a sphere having a diameter d (d> c) and is made of a high magnetic permeability material. The rolling element 35 is stored in the support portion 33 so as to be freely rotatable and freely movable in the vertical direction. In FIG. 3, the rolling elements 35 are arranged in a staggered arrangement in which the rolling elements 35 are alternately arranged on two circumferences q and r having different diameters. The arrangement of the rolling elements 35 is desirably large in the number of rolling elements 35 per unit area, and the position of the rolling elements 35 with respect to the axis connecting the center of the middle magnet 31 on the slide plate 11 side and the center on the base plate 15 side. It is preferable that is symmetrical about the axis. The arrangement of the rolling elements 35 may be appropriately determined according to the maximum shear deformation amount of the seismic isolation device 3, the number and diameter d of the rolling elements 35, the diameter b of the middle magnet 31, and the like.

  The gap holder 37 will be described with reference to FIG. The gap holder 37 is located between the slide plate 3 and the retainer 5 and between the base plate 7 and the retainer 5, and the vertical distance between the slide plate 3 and the retainer 5 and the vertical distance between the base plate 7 and the retainer 5 are respectively constant. While maintaining, it provides friction damping to the seismic isolation device 3.

  The gap holder 37 includes a compression body 371, a sub rolling element 373, and a sub rolling element holder 375, which are formed of a low magnetic permeability material. The auxiliary rolling element holder 375 has a substantially cylindrical shape. The auxiliary rolling element holder 375 includes a compression body 371 at one end, and holds the auxiliary rolling element 373 with a semispherical concave surface provided at the other end. A small rolling element made of a low magnetic permeability material may be interposed between the concave surface and the sub rolling element 373. The compression body 371 has a substantially disc shape, and can be deformed and restored by a compression force V in the vertical direction. The compression body 371 is not limited to elasticity, and may be formed of a material exhibiting mechanical characteristics such as elastoplasticity and viscoelasticity, and the shape may be other shapes that can be stored. Furthermore, the compression body 371 may use a form such as a disc spring or a string spring. In this embodiment, the auxiliary rolling element 373 is a sphere.

  The gap retainer 37 is provided in the storage portion of the support portion 33 so that the auxiliary rolling member 373 and the compression member 371 are positioned outward and inward of the retainer 13 and are freely movable in the vertical direction. Inserted into. Moreover, as shown in FIG. 5, the clearance gap holder 37 is arrange | positioned so that it may become a pair of upper and lower sides in a perpendicular direction. The upper tip of the pair of upper and lower gap holders 37 contacts the slide plate 11, and the lower tip contacts the base plate 15. A vertical distance d between the upper tip and the lower tip is equal to the diameter of the rolling element 35. A pair of upper and lower compression forces V act on the upper tip and the lower tip. Under the action of the pair of upper and lower compression forces V, the protrusion height j from the support portion 33 of the gap retainer 37 is kept constant. That is, the gap holder 37 keeps the distance between the retainer 13 and the slide plate 11 in the vertical direction and the distance between the retainer 13 and the base plate 15 in the vertical direction constant.

  FIG. 6 is a view showing an outline of the base plate 15. (A) is center sectional drawing, (b) is a top view from the retainer 13 side. The configuration of the base plate 15 is the same as the configuration of the slide plate 11, but the top and bottom are reversed and the magnetic poles are different. The base plate 15 is fixed to the lower structure 5. The base plate 15 includes a lower magnet 41 (an example of a “lower magnetic part” in the claims), a lower plate 43 (an example of a “lower plate part” in the claims), and a lower groove 45 (an “lower part” in the claims). An example of “groove”.

  The base plate 15 has a generally disc shape. The surface facing the retainer 13 has the lower magnet 41 inside, and the lower plate 43 is disposed so as to surround it. The lower groove 45 is located at the boundary between the lower magnet 41 and the lower plate 43. Let the diameter of the lower magnet 41 be a. Let the width of the lower groove 45 be e. The diameter a of the lower magnet 41 and the width e of the lower groove 45 are related to the amount of shear deformation and the restoring force characteristic of the seismic isolation device 3, respectively.

  FIG. 7 is a vertical sectional view of the seismic isolation device 3 when the seismic isolation device 3 is stationary, that is, when the relative displacement between the slide plate 11 and the base plate 15 is zero. (A) includes a rolling element 35, and (b) includes a gap retainer 37.

  In FIG. 7, the lower surface of the upper magnet 21 of the slide plate 11 and the upper surface of the middle magnet 31 of the retainer 13 face each other in the vertical direction with a gap therebetween. The lower surface of the middle magnet 31 of the retainer 13 and the upper surface of the lower magnet 41 of the base plate 15 face each other in the vertical direction with a gap therebetween. The lower surface of the upper magnet 21 of the slide plate 11 and the upper surface of the lower magnet of the base plate 15 face each other in the vertical direction with the retainer 13 interposed therebetween. The gap between the lower surface of the upper magnet 21 of the slide plate 11 and the upper surface of the middle magnet 31 of the retainer 13, and the gap between the lower surface of the middle magnet 31 of the retainer 13 and the upper surface of the lower magnet 41 of the base plate 15, respectively, This is called the lower gap.

  In FIG. 7A, the lower surface of the upper plate 23 of the slide plate 11 and the upper surface of the lower plate 15 of the base plate 15 face each other in the vertical direction with the retainer 13 interposed therebetween. The seismic isolation device 3 is assembled so that the lower surface of the upper plate 23 of the slide plate 11 and the upper surface of the lower plate 43 of the base plate 15 are in contact with the rolling elements 35. If the elastic deformation of the rolling element 35 is ignored, the vertical distance between the lower surface of the upper plate 23 of the slide plate 11 and the upper surface of the lower plate 43 of the base plate 15 is equal to the diameter d of the rolling element. The contact portions where the lower surface of the upper plate 23 of the slide plate 11 and the upper surface of the lower plate 43 of the base plate 15 are in contact with the rolling elements 35 are referred to as an upper contact portion and a lower contact portion, respectively.

  In FIG. 7B, the lower surface of the upper plate 23 of the slide plate 11 and the upper surface of the lower plate 43 of the base plate 15 are in contact with the upper and lower tips of the gap retainer 37, respectively. The vertical distance between the lower surface of the upper plate 23 of the slide plate 11 and the upper surface of the lower plate 43 of the base plate 15 is equal to the diameter d of the rolling element 35.

  In this embodiment, the diameter a of the upper magnet 21 of the slide plate 11 and the lower magnet 41 of the base plate 15 is equal to the diameter b of the upper surface and the lower surface of the middle magnet 31 of the retainer 13. The reason for this will be described later.

  Here, the high permeability material and the low permeability material will be described. Compared with a low-permeability material, for example, the high-permeability material has a magnetic flux density of one material in the same condition, regardless of the magnetic field generated by the seismic isolation device 3. It is conceivable to use a magnetic flux density that is 50 times greater than the magnetic flux density. The high permeability material and the low permeability material may each be a metal or non-metal material. If the magnetic flux density of the low-permeability material is 1/50 (the reciprocal of 50 times the above) or less than the magnetic flux density of the high-permeability material, the magnetic field generated by the slide plate, retainer, and base plate magnet in the seismic isolation device is low. The influence of the magnetic permeability material can be ignored practically.

  Next, the configuration and magnetic poles of the slide plate 11, the retainer 13, and the base plate 15 will be described. In the following description, the first magnetic pole is assumed to be the S pole, and the second magnetic pole is assumed to be the N pole. Further, magnetic flux leakage is ignored in portions other than the upper gap, the lower gap, the vicinity of the upper contact portion, and the vicinity of the lower contact portion.

  First, the slide plate 11 will be described. FIG. 2A shows an example of the magnetic polarity of the slide plate 11. The upper magnet 21 is a magnet having an S pole on the retainer 13 side (lower side) and an N pole on a different side (upper side). On the retainer 13 side of the slide plate 11, the upper magnet 21 is disposed inside. The upper plate 23 is made of a high permeability material, and is disposed outside the upper magnet 21 on the retainer 13 side, and is disposed so as to cover the N pole side of the upper magnet 21 on the opposite side to the retainer 13. In the present embodiment, the upper plate 23 is recessed at the center for storing the upper magnet 21, and the upper magnet 21 is fixed to the recessed portion with an adhesive or the like. In this embodiment, the retainer 13 side of the slide plate 11 is flat. The rolling elements 35 roll on the upper plate 23 but do not enter the upper magnet 21. The upper plate 23 becomes an N pole on the retainer 15 side by the N pole of the upper magnet 21.

  Next, the retainer 13 will be described. 4 and 5A show an example of the magnetic polarity of the retainer 13. FIG. The middle magnet 31 is a magnet having an N pole on the slide plate 11 side (upper side) and an S pole on the base plate 15 side (lower side). The support portion 33 is made of a low magnetic permeability material. The rolling element 35 is made of a high magnetic permeability material. The gap retainer 37 is made of a low magnetic permeability material.

  Next, the base plate 15 will be described. FIG. 6 shows an example of the magnetic polarity of the base plate 15. The configuration of the base plate 15 is the same as the configuration of the slide plate 11, but the top and bottom are reversed and the magnetic poles are different. The lower magnet 41 is a magnet having an N pole on the retainer 13 side (upper side) and an S pole on a different side (lower side). On the retainer 13 side of the base plate 15, the lower magnet 41 is disposed inside. The lower plate 43 is made of a high magnetic permeability material, and is disposed outside the lower magnet 41 on the retainer 13 side, and is disposed so as to cover the S pole side of the lower magnet 41 on the side opposite to the retainer 13. In the present embodiment, the lower plate 43 is recessed at the center for storing the lower magnet 41, and the lower magnet 41 is fixed to the recessed portion with an adhesive or the like. In this embodiment, the retainer 13 side of the base plate 15 is flat. The rolling element 35 rolls on the lower plate 43, but does not enter the lower magnet 41. The lower plate 43 becomes an S pole on the retainer 13 side by the S pole of the lower magnet 41.

  The upper groove 25 and / or the lower groove 45 may be filled with a low magnetic permeability material and closed. This makes it difficult for the upper magnet 21 and the upper plate 23 and / or the lower magnet 41 and the lower plate 43 to be magnetically short-circuited by foreign matter or the like. Moreover, this may fix the upper magnet 21 and the upper plate 23 and / or the lower magnet 41 and the lower plate 43. Further, the upper magnet 21 and / or the lower magnet 41 may be coiled electromagnets. In this case, it is effective to install the coil portion in the upper groove 25 and / or the lower groove 45, and the upper magnet 21 and the upper plate 23 and / or the lower magnet 41 and the lower plate 43 are connected to a continuous magnetic core. You may comprise as.

  The slide plate 11, the retainer 13, and the base plate 15 are provided with a gradual soft spring type restoring force characteristic related to the shearing deformation in the horizontal direction due to the structural characteristics related to the magnetic characteristics, and against the earthquake motion of the ground 7. Exhibits excellent seismic isolation effect. Due to the gradual soft spring type restoring force characteristics of the seismic isolation device 3, the horizontal natural period of the vibrating body (the seismic isolation object 1 and the seismic isolation device 3) is the shear deformation amplitude of the seismic isolation device 3 (seismic isolation). The relative amplitude of the object 1 and the substructure 5 increases with an increase. According to the present invention, the vibrating body has a gradual soft spring type nonlinear natural vibration characteristic. By appropriately adjusting the restoring force characteristics of the seismic isolation device 3, it is possible to extend the natural period of the vibrating body and obtain the required nonlinear natural vibration characteristics.

  FIG. 8 is a diagram illustrating an example of a magnetic circuit of the seismic isolation device 3. The magnetic circuit formed by the magnetic lines of force is as follows. First, the lower magnet 41 of the base plate 15 passes through the lower gap, the middle magnet 31 of the retainer 13, and the upper gap to go to the upper magnet 21 of the slide plate 11. Since the upper plate 23 is made of a high magnetic permeability material, the slide plate 11 penetrates from the upper magnet 21 toward the upper plate 23. Since the rolling element 35 is made of a high magnetic permeability material, the rolling element 35 passes through the rolling element 35 from the upper plate 23 of the slide plate 11 toward the lower plate 43 of the base plate 15. Since the lower plate 43 is made of a high magnetic permeability material, the base plate 15 penetrates from the lower plate 43 toward the lower magnet 41. When the S pole and the N pole are reversed, the order is reversed. In this way, a magnetic circuit that forms a magnetic circuit with less magnetic resistance and forms a peripheral circuit is formed to enhance magnetic flux, and a magnetic circuit that efficiently generates magnetic attractive force and magnetic restoring force is configured, so that not only heavy load but also light load Can be easily handled.

  Further, in the magnetic circuit of FIG. 8, the mutual magnetic attraction force between the lower magnet 41, the middle magnet 31, and the upper magnet 21, and the mutual interaction between the upper plate 23, the rolling element 35, and the lower plate 43. Due to the action of the magnetic attraction force, a magnetic restoring force is generated between the slide plate 11, the retainer 13 and the base plate 15 to restore the mutual displacement in the horizontal direction. Furthermore, as the mutual displacement in the horizontal direction among the slide plate 11, the retainer 13, and the base plate 15 increases, the tangential rigidity of the magnetic restoring force decreases. Since the magnetic restoring force has such a mechanical characteristic, the magnetic restoring force has a non-linear natural vibration characteristic in which the horizontal natural period increases as the horizontal displacement increases. Therefore, there are two resonance conditions for the seismic isolation device 3; the coincidence between the natural period of the vibrator and the period of the disturbance, and the coincidence between the natural amplitude corresponding to the natural period of the vibrator and the amplitude of the vibrator due to the action of the disturbance. is there. Therefore, the seismic isolation device 3 can remarkably reduce the possibility of resonance with seismic motion as compared with the seismic isolation device having linear natural vibration characteristics.

  Furthermore, the action of the mutual magnetic attraction force and magnetic restoring force between the slide plate 11, the retainer 13, and the base plate 15 can prevent the retainer 13 from deviating, and the seismic isolation device can be stably operated during an earthquake. It becomes possible. Since the magnetic attraction force and the magnetic restoring force generated in the retainer 13 act so that the retainer 13 stays at an intermediate position between the displacements of the slide plate 11 and the base plate 15, the movement of the retainer 13 is limited to the movement of the rolling element 35. Compared with the case where it depends, the possibility of deviation of the retainer 11 during an earthquake, that is, the possibility of deviation from the rolling plane of the rolling element 35 can be significantly reduced.

  FIG. 9 shows a magnetic circuit equivalent to the magnetic circuit formed by the upper magnet 21 and the upper plate 23 of the slide plate 11, the middle magnet 31 and the rolling element 35 of the retainer 13, and the lower magnet 41 and the lower plate 43 of the base plate 15. FIG. Here, the magnetism generating portions 151, 153, and 155 are magnetomotive forces of the upper magnet 21, the middle magnet 31, and the lower magnet 41, respectively. The magnetic resistances 157 and 159 are the magnetic resistances of the upper gap and the lower gap, respectively. The magnetic resistances 161, 163, and 165 respectively include an upper plate 23 (including a contact portion between the upper plate 23 and the upper magnet 21), a rolling element 35 (including an upper contact portion and a lower contact portion), and a lower portion. The magnetic resistance of the plate 43 (including the contact portion between the lower plate 43 and the lower magnet 41). Φ is a magnetic flux.

  The magnitude of the magnetic flux Φ of the equivalent magnetic circuit of FIG. 9 can be easily adjusted by the magnitude of the magnetomotive force of the magnetic generators 151, 153, and 155 and the magnitude of the magnetic resistances 157 and 159. That is, the magnitude of the magnetic flux Φ flowing through the equivalent magnetic circuit can be adjusted by the magnetomotive forces of the upper magnet 21, the middle magnet 31, and the lower magnet 41 and the magnitudes of the upper gap and the lower gap. The magnetic attraction force of the seismic isolation device is determined by the magnitude of the magnetic flux Φ. When the direction of the magnetomotive force of each of the magnetism generators 151, 153, and 155 is reversed, the direction of the magnetic flux Φ is reversed.

  Note that at least one of the upper magnet, the middle magnet, and the lower magnet may be an electromagnet. In such a configuration, the magnitude of the magnetic flux Φ, that is, the magnetic attraction force of the seismic isolation device can be changed with time by changing the magnetomotive force of the electromagnet with time.

  Further, any one or two of the upper magnet 21, the middle magnet 31 and the lower magnet 41 may be replaced with a yoke. With such a configuration, in the equivalent magnetic circuit, a magnetic circuit in which any one or two of the magnetomotive forces of the corresponding magnetic generators are replaced with the magnetic resistance is established. Accordingly, in such a configuration, the magnetic flux of the magnetic circuit is significantly reduced as compared with the embodiment, and as a result, the magnetic attractive force is also significantly reduced.

  A feature of the present invention is that the slide plate 11, the retainer 13, and the base plate 15 have the required magnetic characteristics in order to establish the magnetic circuit shown in FIG. Are in place. Accompanying this feature, the present embodiment distributes the magnetic source to the slide plate 11, the retainer 13 and the base plate 15, and increases the magnetomotive force of the magnetic circuit by these three magnetic sources. Thus, there is a feature that a device that is compact in volume can be realized.

  Further, in this embodiment, in consideration of the distribution of the magnetic flux density of the magnet, the upper magnet 21, the middle magnet 31, and the lower magnet 41 have the same diameter, and the outer edge portions where the magnetic flux density of each magnetic pole is high are opposed to each other. Increase power. The magnetic flux density of the magnet is larger at the outer edge than at the inner side, and the magnetic flux density of the magnetic material in the magnetic field has a property of increasing at the portion where the magnetic path is shortened. Further, the magnetic attractive force has a property of increasing when portions having different polarities and high magnetic flux densities face each other. In the present embodiment, in the stationary seismic isolation device 3, in order to increase the magnetic attractive force, the upper magnet 21, the middle magnet 31, and the lower magnet 41 have the same diameter, and the upper magnet 21 and the middle magnet. Each outer edge part of 31 was faced, and each outer edge part of the lower magnet 41 and the middle magnet 31 was faced.

  The diameter b of the middle magnet 31 may be smaller than the diameter a of the upper magnet 21 and the lower magnet 41, but the magnetic attractive force is smaller than that of the present embodiment. Although the diameter b of the middle magnet 31 may be larger than the diameter a of the upper magnet 21 and the lower magnet 41, the magnetic attractive force is further reduced as compared with the present embodiment.

  Next, characteristics of the restoring force in the horizontal displacement direction of the seismic isolation device will be described.

  FIG. 10 is a diagram showing main magnetic lines of force in the central cross-sectional view including the rolling elements 35 for the seismic isolation device 3. The magnetic flux density of the magnet is larger at the outer edge portion than at the inner side, and the magnetic flux density of the magnetic material in the magnetic field has a property of increasing at the portion where the magnetic path is shortened. Therefore, as shown by the magnetic field lines in FIG. 10, the magnetic flux density near the outer edge portions of the upper magnet and the lower magnet is particularly increased.

  FIG. 10 is a sectional view of the seismic isolation device 3 in a stationary state, in which the relative displacement between the slide plate 11 and the base plate 15 in the horizontal direction is zero. This is called state I. In this state, the lower surface of the upper magnet 21 and the upper surface of the middle magnet 31, which have different polarities, face each other, and the lower surface of the middle magnet 31 and the upper surface of the lower magnet 41 face each other. Therefore, the magnetic field (lines of magnetic force) from the upper surface of the lower magnet 41 toward the lower surface of the middle magnet 31 linearly penetrates the lower gap. Similarly, the magnetic field (lines of magnetic force) from the upper surface of the middle magnet 31 toward the lower surface of the upper magnet 21 linearly penetrates the upper gap. In particular, the magnetic flux density of each magnetic pole surface of the upper magnet 21, the middle magnet 31, and the lower magnet 41 increases from the center of the magnetic pole surface toward the outer edge, and the magnetic path of the magnetic circuit is the shortest path in the upper plate of the slide plate. And the shortest path in the lower plate of the base plate. Therefore, the lower surface of the upper magnet 21, the upper and lower surfaces of the middle magnet 31, and the inner peripheral portion of each outer edge of the upper surface of the lower magnet 41 form a main magnetic path, and the magnetic flux density of these portions increases. . A magnetic attractive force is mainly generated by the magnetic field in the inner peripheral portion of these outer edge portions.

  As shown in FIG. 3, the rolling elements 35 are arranged radially in the horizontal plane around the middle magnet 31 (magnetic generator). Therefore, there are radial magnetic lines as shown in FIG. 10 that pass through the rolling elements 35. That is, the upper magnet 21 and the upper plate 23 of the slide plate 11, the middle magnet 31 and the rolling element 35 of the retainer 13, and the lower magnet 41 and the lower plate 43 of the base plate are composed of magnetic path groups as indicated by the magnetic lines of force in FIG. 10. Configure the magnetic circuit. Due to the action of this magnetic circuit, a vertical magnetic attractive force acts between the magnets of the slide plate 11, the retainer 13 and the base plate 15, and between the slide plate 11, the rolling elements 35 and the base plate 15. That is, a magnetic attraction force is generated in the vertical direction in the seismic isolation device. The rolling element 35 resists the magnetic attraction force and keeps the vertical distance between the base plate 11 and the slide plate 15 constant.

  FIG. 11 shows a state of shear deformation of the seismic isolation device in a state where a pair of horizontal forces R act on the slide plate and the base plate and the relative displacement u between the horizontal slide plate and the base plate satisfies 0 <u <2e. And the position of the main magnetic field lines. This is called state II. (A) is an overall view, and (b) is an enlarged view of a central portion.

  As shown in FIG. 11, the lower surface of the upper magnet 21 and the upper surface of the middle magnet 31, and the lower surface of the middle magnet 31 and the upper surface of the lower magnet 41 are displaced in the horizontal direction, respectively. Are partially overlapped, and the magnetic field is bent by the magnetic field from the upper surface of the middle magnet 31 toward the lower surface of the upper magnet 21. Similarly, the upper surface of the lower magnet 41 and the lower surface of the middle magnet 31 partially overlap, and a magnetic field is bent by a magnetic field from the upper surface of the lower magnet 41 toward the lower surface of the middle magnet 31. The bending of these magnetic fields generates a horizontal restoring force that balances the force R. Since the direction of the restoring force is orthogonal to the direction of the magnetic attractive force generated in the magnetic circuit, this restoring force is particularly called a magnetic transverse attractive force here. The magnitude of the magnetic attraction force is determined by the direction of the magnetic field and the strength of the magnetic field. When the force R is removed, the relative displacement between the slide plate 11 and the base plate 15 becomes zero by this magnetic lateral attractive force, and the shear deformation of the seismic isolation device 3 is restored.

  FIG. 12 shows the state of shear deformation of the seismic isolation device 3 in a state in which the force R and the relative displacement u are larger than the state of FIG. Show. This is called state III. (A) is an overall view, and (b) is an enlarged view of a central portion.

  As shown in FIG. 12, the upper surface of the middle magnet 31 and the lower surface of the upper magnet 21 partially overlap, and one of the upper grooves 25 overlaps the upper surface of the middle magnet 31, and the upper surface of the middle magnet 31 and the lower surface of the upper plate 23. Do not overlap. The width of the portion where the upper surface of the middle magnet 31 and the upper groove 25 overlap most is equal to the width e of the upper groove 25. In a portion where the upper surface of the middle magnet 31 and the upper groove 25 overlap, a magnetic field is bent by a magnetic field from the upper surface of the middle magnet 31 toward the lower surface of the upper magnet 21. Similarly, the upper surface of the lower magnet 41 and the lower surface of the middle magnet 31 partially overlap, one of the lower grooves 45 overlaps the lower surface of the middle magnet 31, and the upper surface of the middle magnet 31 and the upper surface of the lower plate 43 do not overlap. The width of the portion where the lower groove 45 and the lower surface of the middle magnet 31 overlap most is equal to the width e of the lower groove. In a portion where the lower groove 45 and the lower surface of the middle magnet 31 overlap, a magnetic field is bent by a magnetic field from the upper surface of the lower magnet 41 toward the lower surface of the middle magnet 31. The bending of these magnetic fields generates a horizontal magnetic attraction force that balances the force R.

  FIG. 13 shows the state of shear deformation of the seismic isolation device in which the force R and the relative displacement u are larger than those in FIG. 12 and the relative displacement u satisfies 2e <u <a, and the main magnetic field lines. Indicates the position. This is called state IV. (A) is an overall view, and (b) is an enlarged view of a central portion.

  As shown in FIG. 13, the upper surface of the middle magnet 31 and the lower surface of the upper magnet 21 partially overlap, and one of the upper grooves 25 overlaps the upper surface of the middle magnet 31, and the upper surface of the middle magnet 31 and the lower surface of the upper plate 23. Partially overlap. In a portion where the upper groove 25 and the upper surface of the middle magnet 31 overlap, a magnetic field is bent by a magnetic field from the upper surface of the middle magnet 31 toward the lower surface of the upper magnet 21 as in the state III. Further, since the lower surface of the upper plate 23 and the upper surface of the middle magnet 31 are magnetic poles having the same polarity, a magnetic field repulsion occurs in the portion where the upper surface of the middle magnet 31 and the lower surface of the upper plate 23 overlap, and the direction of the magnetic field is horizontal. Parallel to the direction. While the magnetic transverse attractive force is generated by the bending of the magnetic field, the magnetic repulsive force is generated in the repulsive part of the magnetic field, and the action of weakening the magnetic transverse attractive force occurs. Similarly, the upper surface of the lower magnet 41 and the lower surface of the middle magnet 31 partially overlap, one of the lower grooves 45 overlaps the lower surface of the middle magnet 31, and the lower surface of the middle magnet 31 and the upper surface of the lower plate 43 partially Overlap. In the portion where the lower groove 45 and the lower surface of the middle magnet 31 overlap, the magnetic field is bent by the magnetic field from the upper surface of the lower magnet 41 toward the lower surface of the middle magnet 31 as in the state III. Further, since the upper surface of the lower plate 43 and the lower surface of the middle magnet 31 are magnetic poles having the same polarity, a magnetic field repulsion occurs in the portion where the lower surface of the middle magnet 31 and the upper surface of the lower plate 43 overlap, and the direction of the magnetic field is horizontal. Parallel to the direction. While the magnetic transverse attractive force is generated by the bending of the magnetic field, the magnetic repulsive force is generated in the repulsive part of the magnetic field, and the action of weakening the magnetic transverse attractive force occurs.

Comparing State II, State III, and State IV, there is no portion where the magnetic field repels in State II and State III, and a portion where the magnetic field repels occurs in State IV. Therefore, in the state IV, the action of weakening the increase in the magnetic transverse attractive force is rapidly increased as compared with the state II. State III is located between state II and state IV. That is, the tangential stiffness of the magnetic transverse attractive force in the state IV is abruptly smaller than that in the state II, and the state III may be considered as a branch point where the tangential stiffness changes abruptly. Here, it referred to the range of relative displacement u in the state II and the high rigidity region, the range of relative displacement u in the state IV is referred to as a low rigidity region, called the displacement u states III and branch relative displacement u _b. As in state II, branching relative displacement u _b of the low rigidity region and the high rigidity region is twice the width e of the upper groove 25 and lower groove 45. From the above characteristics of the magnetic transverse attractive force, the seismic isolation device 3 has a gradually soft spring type restoring force characteristic that is divided into a high rigidity region and a low rigidity region in order from the smaller relative displacement.

  When the relative displacement u approaches the diameter a of the upper surface of the upper magnet 21 and the upper surface of the lower magnet 41 and the diameter b of the upper surface and the lower surface of the middle magnet 31, the repulsive part of the magnetic field rapidly expands. The upper limit is desirably a diameter a.

  Further, since the magnitude of the magnetic transverse attractive force in states I to IV is determined by the strength of the magnetic field of the seismic isolation device 3, the magnetic lateral attractive force of the seismic isolation device 3 is the magnetic flux Φ of the magnetic circuit shown in FIG. It can be adjusted by the size of Moreover, the vibrating body including the seismic isolation device 3 of the present embodiment has a gradually soft spring type restoring force characteristic. Since the magnitude of the restoring force can be easily adjusted by the magnetomotive force of each of the upper magnet 21, the middle magnet 31, and the lower magnet 41 and the magnetic resistance of the upper gap and the lower gap, according to the assumed spectral characteristics of the earthquake motion, The natural period of the vibrating body in the horizontal direction can be extended. By extending the natural period, the seismic force acting on the seismic isolation object can be reduced.

  Furthermore, when the amplitude of the shear deformation of the seismic isolation device 3 increases, the natural period in the horizontal direction of the vibrating body increases. That is, the vibrating body is a nonlinear vibrating body having a gradual soft spring type nonlinear natural vibration characteristic. In order for the vibrating body to resonate with the disturbance, the period of the disturbance must match the natural period of the vibrating body, and the amplitude of the vibrating body due to the action of the disturbance must match the natural amplitude corresponding to the natural period of the vibrating body. is there. The resonance condition of the linear vibrator having the linear natural vibration characteristic in which the natural period is constant regardless of the amplitude is only the coincidence between the period of the disturbance and the natural period. In general seismic motion, it is very rare that the two conditions of the period and the amplitude are met. Therefore, compared to other seismic isolation devices that are linear oscillators, the seismic isolation device 3 of the present invention is less The possibility of resonance can be greatly reduced.

  Next, the operation of the gap retainer 37 will be described. In the assembled seismic isolation device 3, the distance between the upper tip and the lower tip of the pair of upper and lower gap holders 37 is equal to the diameter d of the rolling element 35. Moreover, the protrusion height of the gap holder 37 from the support portion 33 of the retainer 13 is j on both the upper side and the lower side. Since the height of the middle magnet 31 is c, the gap intervals g of the upper gap and the lower gap are expressed by Expression (2). The gap interval g determines the magnetic resistance between the upper gap and the lower gap. The gap retainer 37 stabilizes the magnetic circuit by making the gap resistance g constant, thereby making the magnetic resistance of both gaps constant.

  The interval between the upper tip and the lower tip of the gap retainer 37 immediately before assembly, that is, immediately before the pair of compressive forces V in FIG. The initial height h is set to be larger than the diameter d of the rolling element 35 (that is, h> d). When the seismic isolation device 3 is assembled under the condition of h> d, the pair of upper and lower gap retainers 37 are compressed from the slide plate 11 and the base plate 15 to cause compressive deformation, and as shown in FIG. The compressive force V is applied. Since the amount of compressive deformation is hd, the compression force V is expressed by Equation (3). Here, k is a spring constant of compressive deformation in the vertical direction of one gap retainer 37. The compression body 371 adjusts the spring constant k.

  When relative movement occurs between the gap retainer 37 and the upper plate 23, or when relative movement occurs between the gap retainer 37 and the lower plate 43, the gap retainer 37 and the upper plate 23 or the lower plate 43 between each surface. Both of the movement resistance forces F acting on are expressed by equation (4). Here, μ is a motion resistance coefficient. The movement resistance force F of Expression (4) acts on the gap holder 37, the upper plate 23, and the lower plate 43 in a direction that prevents the relative movement of each. This motion resistance force F is mainly generated by friction between the auxiliary rolling element 373 and the auxiliary rolling element holder 375. The movement resistance force F is also a rolling friction resistance force of the auxiliary rolling element 373.

  In the process in which the seismic isolation device 3 moves from the state I in the stationary state to the state II in the operating state, the motion resistance force becomes a static frictional force immediately before leaving the state I. By appropriately setting the spring constant k, height difference (hd), and motion resistance coefficient μ of the gap retainer 37, the inertial force of the seismic isolation object 1 at which the seismic isolation device 3 starts shear deformation or The magnitude of the external force can be adjusted. For example, since the seismic isolation device 3 does not need to be operated in a small earthquake or a low wind speed, the operation of the seismic isolation device 3 can be stopped using the movement resistance force of the gap retainer 37. That is, the gap retainer 37 can be provided with a trigger function for starting the operation of the seismic isolation device 3.

  Further, when the seismic isolation device 3 is operated, that is, from the state II to the state IV, the motion resistance force F of the gap retainer 37 becomes a dynamic friction force that hinders the shear deformation motion of the seismic isolation device 3. Therefore, the gap holder 37 imparts friction damping to the seismic isolation device 3 by appropriately setting the spring constant k, the height difference (h−d), and the motion resistance coefficient μ of the gap holder 37. Can do. Even when resonance with long-period ground motion is assumed, resonance can be avoided by making the assumed amplitude smaller than the natural amplitude by appropriately applying frictional damping.

  FIG. 14 illustrates the main forces acting on the retainer 13 and the corresponding forces acting on the slide plate 11 and the base plate 15. The retainer 13 is subjected to a magnetic attractive force P and a magnetic lateral attractive force S generated in the upper gap and the lower gap, a compressive force V and a motion resistance force F acting on the gap retainer 37. The magnetic attractive force P and the magnetic lateral attractive force S act so that the retainer 13 stays at an intermediate position between the slide plate 11 and the base plate 15. Therefore, even when a contact failure occurs between the rolling element 35 and the slide plate 11 or between the rolling element 35 and the base plate 15, and insufficient rotation occurs in the rolling element 35, the relative displacement between the slide plate 11 and the base plate 15 is intermediate. The retainer 13 acts on the rolling element 35 so that the rolling element 35 remains at the position. That is, the magnetic attractive force P and the magnetic lateral attractive force S acting on the retainer 13 prevent the retainer 13 from deviating from the slide plate 11 and the base plate 15, that is, the rolling element 35.

  In FIG. 14, as the force acting on the slide plate 11, the external force R, the self-weight W of the seismic isolation object 1 and the slide plate 11, the magnetic attractive force P and the magnetic lateral attractive force S, and the compressive force V acting on the gap retainer 37. And the frictional force F was shown. In addition to these forces, a force acts on the slide plate 11 at the contact portion with the rolling element 35. This will be described later.

  In FIG. 14, as the force acting on the base plate 15, the magnetic attractive force P and the magnetic lateral attractive force S, the compressive force V and the motion resistance force F acting on the gap retainer 37, and the reaction force Z received from the lower structure 5 are obtained. Indicated. The weight of the retainer 13 and the weight of the base plate 15 are ignored. In addition to these forces, a force acts at the contact portion with the rolling element 35. This will be described later.

  FIG. 15 illustrates a vertical force Q and a rolling resistance force Fb acting on the rolling element 35. Corresponding to these, the forces acting on the slide plate 11 and the base plate 15 are shown. Further, the magnetic attractive force P and the lateral magnetic attractive force S shown in FIG. 14 are also shown.

From the balance formula of the vertical force acting on the slide plate 11 shown in FIGS. 14 and 15, the vertical force Q acting on the rolling element 35 is expressed by Equation (5). The rolling resistance force Fb of one rolling element is expressed by equation (6). Here, μ _b is a rolling resistance coefficient of the rolling element 35.

From the balance formula of the horizontal force acting on the slide plate 11 shown in FIGS. 14 and 15, the external force R, that is, the restoring force of the seismic isolation device is expressed by the equation (7). Here, ΣF is the sum of the movement resistance forces acting on the gap retainer 37, and ΣFb is the sum of the rolling resistance forces of the rolling elements 35. Since Equation (7) includes ΣF and ΣFb whose directions change depending on the sign of the relative velocity corresponding to the relative displacement u in the restoring force R, the seismic isolation device has a damping characteristic of Coulomb friction damping. However, since the rolling resistance coefficient μ _b of the rolling element 35 is a small value of about 1/1000 determined by the form of the rolling element, the coulomb of the seismic isolation device 4 is determined by the compressive force V of the gap holder 37 or the motion resistance coefficient μ. It is desirable to adjust the friction damping amount.

  FIG. 16 shows another form of the gap retainer 37 described in FIG. In the form of FIG. 16, the gap retainer is composed of a compression body 51 and a friction body 53. The feature of the compression body 51 is the same as that of the compression body 371 in FIG. The friction body 53 has a substantially cylindrical shape made of a soft, low-permeability material compared to the upper plate 23 and the lower plate 43, and includes a compression body 51 at one end, and the other end is the upper plate 23 or the lower plate. 43 and a friction surface. The gap retainer is inserted into the storage portion of the support portion 33 so that the friction surface and the compression body are positioned outward and inward of the retainer and are freely movable in the vertical direction. A pair of vertical compressive forces V act on the pair of upper and lower friction surfaces. The initial height between the pair of upper and lower friction surfaces before assembly is assumed to be h. The compression force V acting on the gap retainer after assembly is expressed by equation (3).

  When relative movement occurs between the gap holder and the upper plate 23, or when relative movement occurs between the gap holder and the lower plate 43, the motion resistance force F acting between the gap holder 37 and each rolling plane is It is expressed by equation (4). Here, the dynamic friction coefficient between the friction body 53 and the upper plate 23 and the lower plate 43 is the movement resistance coefficient μ. The movement resistance force F of the equation (4) acts on each of the gap retainer, the upper plate 23, and the lower plate 43 in the direction of preventing the relative movement. This movement resistance force F is a frictional force. Necessary frictional damping can be imparted to the seismic isolation device 3 by making the compression body 51 and the friction body 53 each have an appropriate material and an appropriate form.

  Thus, the gap holder of the present invention can be grasped as follows, for example. In other words, a blind hole-shaped gap retainer storage section is arranged on the retainer support section so that the respective positions on the slide plate side and the base plate side are symmetrical in the vertical direction, and the secondary rolling element is freely rollable at one end. And a substantially cylindrical gap retainer having a compression body at the other end so that the secondary rolling element and the compression body can be freely moved in the vertical direction so as to face outward and inward of the retainer, respectively. Thus, it can be set as the structure which attaches to a clearance holder storage part and makes the height between the top parts of a pair of sub rolling elements larger than the diameter of a rolling element in a perpendicular direction. According to this configuration, the compression force acting on the gap retainer due to the magnetic attractive force and the compression deformation of the gap retainer due to the compression force are used to keep the upper gap and the lower gap constant and compress Attenuation can be imparted to the seismic isolation device by the rolling resistance of the secondary rolling elements generated by the force.

  Moreover, the clearance gap holder of this invention can be caught as follows, for example. In other words, a blind hole-shaped gap retainer storage portion is arranged on the support portion of the retainer so that the respective positions on the slide plate side and the base plate side are paired in the vertical direction, and one end is provided with a friction body and the other Mounts a generally cylindrical gap holder with a compression body at the tip in the gap holder housing so that the friction body and the compression body face the outside and the inside of the retainer and are freely movable in the vertical direction. And the structure which makes the height between the front-end | tips of a pair of friction body larger than the diameter of a rolling element in the perpendicular direction was shown. According to this configuration, the gap between the upper gap and the lower gap is kept constant by using the compression force acting on the gap holder due to the magnetic attractive force and the compression deformation of the gap holder by the compression force, and Damping can be imparted to the seismic isolation device by friction between the friction body and the rolling plane. It is possible to simultaneously maintain the gap interval, add attenuation, and adjust the attenuation performance. In the above configuration, the rolling resistance of the secondary rolling element is much smaller than the friction resistance between the solid and the solid, so there is a limit to increase the damping. According to this configuration, by appropriately setting the spring constants of the friction body and the compression body, a necessary frictional force can be generated and the damping performance required by the device can be imparted. Further, it is possible to perform steadying at a minute amplitude by using a static friction force.

  Then, the case where it implement | achieves with a roller about the other example of a rolling element is demonstrated. FIG. 17 shows an example in which the magnetic path is generated in the direction perpendicular to the operation direction. FIG. 18 shows an example in which the magnetic path is generated in the direction perpendicular to the operation. 17 and 18, (a) is a side view, (b) is a view of the retainer side of the slide plate, (c) is a plan view of the retainer, and (d) is a view of the retainer side of the base plate. .

  Referring to FIG. 17, each of the slide plate and the base plate has an upper magnet and a lower magnet arranged at the center, and an upper plate and a lower plate are arranged around the upper and lower magnets. Is formed. In the retainer, the middle magnet is arranged at the center, and a small circle is a portion for storing the gap retainer, and a rectangle around the middle magnet is a portion for storing the roller which is a rolling element. In this case, a gradually soft spring type restoring force characteristic is shown, but the magnetic path in the direction perpendicular to the operation is stronger than in the operation direction. Therefore, the change in tangential rigidity due to the upper groove and the lower groove is considered to be smaller than that in the case of a sphere.

  Referring to FIG. 18, in the slide plate and the base plate, an upper magnet and a lower magnet are arranged at the center, and an upper plate and a lower plate are arranged around the upper and lower magnets. Is formed. In the retainer, the middle magnet is arranged in the center, and a small circle is a portion for storing the gap retainer, and the upper and lower rectangles of the middle magnet are portions for storing the rollers that are rolling elements. Compared with FIG. 17, the rolling element is not provided in the operating direction of the magnet. In this case, a gradually soft spring type restoring force characteristic is shown, but the magnetic path in the direction perpendicular to the operation is stronger than in the operation direction. Therefore, the change in tangential rigidity due to the upper groove and the lower groove is considered to be smaller than that in the case of a sphere.

  Subsequently, the operation test will be described. Table 1 shows the main external dimensions of the components of the seismic isolation device used in the operation test. Table 2 shows dimensions related to magnetic characteristics. As shown in Table 1, the outer diameters of the slide plate, retainer, and base plate were 340 mm, 280 mm, and 390 mm, respectively. The diameter of the rolling elements was 28.6 mm, and the rolling elements were arranged in a staggered arrangement with rolling elements alternately arranged on a circumference of 240 mm in diameter and 180 mm in diameter. The number of rolling elements is 30. The diameters of the lower surface of the upper magnet, the upper and lower surfaces of the middle magnet, and the upper surface of the lower magnet were all 80 mm. The widths of the upper and lower grooves were both 5 mm. Both the upper gap and the lower gap were 1.8 mm. The mass of each component is as shown in Table 1.

  Table 3 shows the specifications of the upper magnet 21, the lower magnet 41, and the middle magnet 31. The middle magnet 31 of the retainer 13 is configured such that the upper side is a magnet and the lower side is a yoke. The magnet used was a neodymium magnet with an outer diameter × thickness of 80 mm × 5 mm.

  Table 4 shows the material of each component. As the high magnetic permeability material, carbon steel for machine structure (S50C) was used for the slide plate 11 and the base plate 15, and high carbon chromium bearing steel was used for the rolling elements 35. As the low permeability material, an aluminum alloy (A5052) is used for the retainer 13, an austenitic stainless steel is used for the auxiliary rolling element 373 and the auxiliary rolling element holder 375 of the gap retainer 37, and the gap retainer 37 Polyurethane rubber was used for the compression body 371. The vertical support force of the rolling elements 35 is about 4 kN / piece, and the vertical support force of the seismic isolation device 3 is about 120 kN.

  FIG. 19 is a graph showing the magnetic flux density distribution of the upper magnet 21 and the upper plate 23 of the slide plate 11 before assembly. The lower surface of the upper magnet 21 is an S pole, and the upper surface of the middle magnet 31 is an N pole. Surfaces other than the lower surface of the upper magnet 21 of the slide plate 11 are all N poles. It is confirmed that the magnetic flux density increases from the central part of the lower surface of the upper magnet 21 toward the outer edge, and the magnetic flux density decreases from the inner edge of the lower surface of the upper plate 24 toward the outer side.

  FIG. 20 is a graph showing the magnetic flux density distribution of the retainer before assembly. The upper surface of the middle magnet 31 is an N pole, and the lower surface is an S pole. The magnetic flux density on the lower surface of the middle magnet 31 is about ½ of the magnetic flux density on the upper surface. This is because the magnetic flux density on the lower surface is smaller than the upper surface due to the magnetic resistance of the yoke. It is confirmed that the magnetic flux density increases from the central part of the magnetic pole surface toward the outer edge.

  FIG. 21 is a graph showing the magnetic flux density distribution on the upper surface of the lower magnet 41 and the upper surface of the lower plate 43 of the base plate 15 before assembly. The upper surface of the lower magnet 41 is an N pole, and the upper surface of the lower plate 43 is an S pole. Surfaces other than the upper surface of the lower magnet 41 of the base plate 15 are all S poles. It is confirmed that the magnetic flux density increases from the central portion of the upper surface of the lower magnet 41 toward the outer edge, and the magnetic flux density decreases from the inner edge of the upper surface of the lower plate 43 toward the outer side.

  Table 5 shows the test results of the magnetic attractive force P of the assembled seismic isolation device 3. By pulling the slide plate 11 and the base plate 15 in the vertical direction, the magnetic attractive force P when the rolling element 35 is separated from the slide plate 11 or the base plate 15 was obtained. The magnetic weight of Table 5 excludes the weight of the slide plate 11, the rolling element 35 and the retainer 13. The magnetic attractive force was 2098N, and according to the technical data of the magnet manufacturer, the magnetic attractive force of the used neodymium magnet and iron plate (SS400) was 170N. Therefore, it was confirmed by the magnetic circuit shown in FIG. 9 that the magnetic attractive force of the seismic isolation device 3 is about 12 times the magnetic attractive force of the magnet and the iron plate. From this, it was confirmed that the magnetic circuit shown in FIG.

  FIG. 22 is a history curve of the relative displacement u and the restoring force R shown in FIGS. 11, 12, and 13 of the assembled seismic isolation device 3. The horizontal axis is u, and the vertical axis is R. The seismic isolation device 3 is not equipped with the seismic isolation object 1. The displacement at the boundary III between the high rigidity region II and the low rigidity region IV is 10 mm, which is twice the width of the upper groove and the lower groove. When the relative displacement u is gradually increased from the stationary state I, the restoring force increases in proportion to the increase in the relative displacement. As the relative displacement approaches 10 mm of state III, the tangential rigidity decreases.When the relative displacement exceeds state III and enters the low rigidity region IV, the decrease in tangential rigidity increases, and as the relative displacement moves away from state III, The characteristic that the restoring force increases in proportion to the increase in relative displacement is confirmed.

  It is confirmed that when the relative displacement is decreased, the restoring force is reduced by about 24N compared to the case where the relative displacement is increased. This is because the rolling resistance force of the rolling element 35 and the motion resistance force of the gap retainer 37 acted by the equation (7). In addition, before installing the magnet of the upper magnet 11, the lower magnet 41, and the middle magnet 31, the movement resistance force mainly generated in the gap holder 37 was measured. Its resistance to movement was about 10N. Therefore, of the decrease in restoring force of about 24N, about 20N is the movement resistance force generated by the gap retainer 37, and the remaining about 4N is the rolling resistance force of the rolling element 35 mainly generated by the magnetic attraction force. Is considered. Since the rolling resistance coefficient of the rolling element 35 is about 1/1000, the magnetic attraction force is 2098N, so the rolling resistance force is estimated to be about 2N. Since twice this rolling resistance appears in the hysteresis curve, it is considered that about 4N of the decrease in the restoring force of about 24N was caused by the rolling resistance of the rolling element 35.

  From FIG. 22, the seismic isolation device 3 has a bilinear type restoring force characteristic in which a branch point is defined by the width of the upper groove and the lower groove, and has a Coulomb attenuation mainly due to a movement resistance force generated in the gap holder 37. That is confirmed.

  FIG. 23 is an example of free vibration recording of the seismic isolation device 3. The horizontal axis is time, and the vertical axis is the relative displacement between the slide plate 11 and the base plate 15. The seismic isolation device 3 was vibrated several times by hand, and then the relative displacement in the free vibration state was measured. From the figure, it is confirmed that the period decreases as the amplitude decreases and that the amplitude decreases over time due to the Coulomb attenuation.

  FIG. 24 is a graph showing the relationship between the amplitude and the period obtained by repeating the same test as in FIG. 23 ten times. The period when the amplitude is a few millimeters is about 0.32 seconds, and the period increases as the amplitude increases. In particular, in the region where the amplitude exceeds 10 mm, the characteristic that the period increases in proportion to the increase in the amplitude can be clearly confirmed. From this, it is confirmed that the seismic isolation device 3 has nonlinear natural vibration characteristics in which the natural period increases in proportion to the increase in amplitude.

  22 shows that the tangential stiffness of the restoring force at a small amplitude, that is, the spring constant is 6.0 N / mm, and the mass of the seismic isolation object 1 is 5000 kg, and the seismic isolation object supported by the seismic isolation device 3. Estimate the natural period of one.

  The natural period of the seismic isolation device 3 on which the seismic isolation object 1 is not mounted is calculated as shown in Equation 7. This natural period 0.33 s corresponds well with the experimental result of FIG.

  Next, the natural period of the seismic isolation device 3 when the seismic isolation object 1 is mounted is calculated as in Equation 8 in the case of a minute amplitude. In FIG. 24, the period of the minute amplitude is about 0.32 s, and the calculated value and the experimental value show a good correspondence. Next, in FIG. 24, the period with an amplitude of 40 mm is about 5.2 s. Therefore, when the seismic isolation object 1 is mounted, the natural period when the amplitude is 40 mm is about 1.6 of the natural period 4.59 s of minute amplitude. It is estimated to be about 7.3s.

  Generally, in the base isolation structure 1, the spring constant of the base isolation device 3 is set so that the natural period is 4 seconds or more. Since the natural period of the seismic isolation device 3 of the embodiment is 4.59 s or more, it is confirmed that the seismic isolation device 3 can realize an effective natural period extension in the seismic design for the seismic isolation object 1 having a mass of 5000 kg. Is done.

  In addition, the following method can be taken for rust prevention of a rolling plane and a rolling element. As the friction control means and the clearance control means, the circumferential groove-shaped gap retainer storage portions are arranged on the slide plate side and the base plate side of the retainer support portion so as to surround all the rolling element storage portions of the retainer from the outside. The gap holders are arranged in pairs in the vertical direction, and the gap retainer is ring-shaped when viewed in plan, and has a friction body on one side and a compression body on the other side when viewed in cross section of the ring. The gap holder is attached to the gap holder storage portion so that the friction body is located outside the retainer and the compression body side is located inside the retainer, and the height between the tips of the pair of friction bodies is set in the vertical direction. The structure larger than the diameter of a rolling element may be sufficient. According to this configuration, a pair of friction bodies are brought into contact with the upper plate and the lower plate, respectively, and the compressive force acting on the gap retainer mainly due to the magnetic attractive force and the compression deformation of the gap retainer due to the compressive force are utilized. The upper gap and the lower gap are kept constant, the friction between the friction body and the upper plate, and the friction between the friction body and the lower plate are applied to the seismic isolation device. It can be sealed and the air inside the device can be replaced with an inert / nonflammable fluid. With this configuration, it is possible to simultaneously maintain the gap interval, add attenuation, adjust attenuation, and prevent rust inside the apparatus. Furthermore, it is also possible to give viscous damping to the seismic isolation device by imparting viscosity to the inert / nonflammable fluid.

  Rust prevention inside the device is a major issue in realizing the device. Rust prevention of the rolling plane and rolling elements is particularly important. An inexpensive nitrogen gas can be used as the inert / nonflammable fluid. Thereby, periodic maintenance such as additional filling with an inert / incombustible fluid is necessary, but rust prevention inside the apparatus can be achieved.

  1 Seismic isolation object, 3 seismic isolation device, 5 substructure, 7 ground, 11 slide plate, 13 retainer, 15 base plate, 21 upper magnet, 23 upper plate, 25 upper groove, 31 middle magnet, 33 support, 35 rolls Moving body, 37 Gap retainer, 371 Compressor, 373 Sub rolling element, 375 Sub rolling element retainer, 41 Lower magnet, 43 Lower plate, 45 Lower groove, 151, 153, 155 Magnetomotive force, 157, 159, 161, 163 , 165 Magnetoresistive, 51 compression body, 53 friction body

Claims (6)

A seismic isolation device that supports seismic isolation objects on the ground or structure in the vertical direction and can be deformed and restored in the horizontal direction,
A slide plate for fixing to the seismic isolation object;
A base plate for fixing to the ground or the structure;
A retainer that is movable in a horizontal direction between the slide plate and the base plate;
The slide plate is
An upper magnetic part having a first magnetic pole on the retainer side;
An upper plate portion having a second magnetic pole as a counter electrode to the first magnetic pole on the retainer side;
The base plate is
A lower magnetic part having the second magnetic pole on the retainer side;
A lower plate portion having the first magnetic pole on the retainer side;
The retainer is
A middle magnetic part that exists at a position facing the upper magnetic part and the lower magnetic part when restored, has the second magnetic pole on the slide plate side, and has the first magnetic pole on the base plate side;
A rolling element made of a magnetic material that comes into contact with the upper plate part and the lower plate part when it is restored;
A seismic isolation device comprising a support portion that exists at least between the middle magnetic portion and the rolling element and is lower in magnetism than the rolling element. The slide plate has an upper groove formed between the upper magnetic part and the upper plate part,
The base plate has a lower groove formed between the lower magnetic part and the lower plate part,
The middle magnetic part of the retainer overlaps the upper magnetic part and the upper groove part of the slide plate and does not overlap the upper plate part on the retainer side, and the lower magnetic part and the lower part of the base plate Compared to the tangential rigidity when overlapping with the groove portion and not the lower plate portion on the retainer side, the middle magnetic portion of the retainer overlaps with a part of the upper plate portion on the retainer side, and The seismic isolation device according to claim 1, wherein the tangential rigidity when overlapping with a part of the lower plate portion on the retainer side is reduced. The upper magnetic part, the middle magnetic part, and the lower magnetic part face each other in the same size,
On the retainer side of the slide plate, a portion having the first magnetic pole of the upper magnetic portion is disposed inside, and a portion having the second magnetic pole of the upper plate portion is disposed outside,
On the retainer side of the base plate, the portion having the second magnetic pole of the lower magnetic portion is disposed on the inside, and the portion having the first magnetic pole of the lower plate portion is disposed on the outside,
The magnetic circuit is formed around the support part having low magnetism by the upper magnetic part, the middle magnetic part, the lower magnetic part, the lower plate part, the rolling element, and the upper plate part. The seismic isolation device described in 1.   The seismic isolation device according to any one of claims 1 to 3, further comprising friction control means for controlling friction generated between the slide plate and the retainer and / or between the retainer and the base plate.   The seismic isolation device according to any one of claims 1 to 4, wherein the retainer includes a gap control unit that controls a gap between the slide plate and the base plate. The rolling element is
A plurality of cylindrical rollers whose rotation axes are parallel to each other, or
The seismic isolation device according to any one of claims 1 to 5, wherein three or more spheres, at least one of which is not on a straight line connecting the other two spheres.

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