JP2014001797A - Base isolation device - Google Patents

Abstract

An object of the present invention is to provide a seismic isolation device that can be reduced in size and can return to its original position quickly when shaking is reduced.
A fixed member 2 disposed at a predetermined position, a movable member 6 that moves in a horizontal direction with respect to the fixed member 2 by external vibration, and the movable member 6 is slidable relative to the fixed member 2. In the seismic isolation device having a support member 5 for supporting and having a magnetic field generating means for returning the movable member 6 moved in the horizontal direction to the initial position by a magnetic attractive force, the fixed member 2 is installed by the movable member 6. The movable member 6 has a stage 7 on which an object is placed, and the support member 5 has a plurality of spheres 50 interposed between the base 3 and the movable member 6. The magnetic field generating means 10 is arranged at a position facing the permanent magnet 12 in a state where no vibration is generated and a permanent magnet 12 that generates a magnetic flux from the fixed member 2 or the movable member 6 toward the movable member 6 or the fixed member 2. A suction yoke 13 is provided.
[Selection] Figure 4

Description

The present invention relates to a seismic isolation device for preventing an object from falling or falling due to vibration caused by an earthquake or the like.

Various seismic isolation devices have been proposed to protect articles (arts and crafts, precision instruments, etc.) that require earthquake resistance from vibration caused by earthquakes. As this type of seismic isolation device, for example, a seismic isolation device is known in which a base isolation base is supported so as to be movable in a horizontal direction with respect to a fixed base, and is returned to its original position by a spring.

  In Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-34284), a plurality of balls are interposed between the fixed base and the base isolation table so that the base isolation base can be moved in the horizontal direction with respect to the fixed base. There is disclosed a seismic isolation device having a spring axis that supports and connects a fixed base and a base isolation base with a spring and has an angle of 35 ° to 90 ° with respect to the horizontal direction. According to this seismic isolation device, there are advantages such as suppression of the overall dimensions and reduction of the spring setting force, but there are the following problems. It is thought that the work of locking the spring to the fixed base and the base isolation table takes time and the man-hours for assembling the base isolation device increase. Considering assembly, it is not suitable for a small seismic isolation device and is limited to a large seismic isolation device. Therefore, as an improvement of the shortcomings of the spring-type seismic isolation device, a device that magnetically returns the seismic isolation table moved by the earthquake to its original position has been proposed.

  In Patent Document 2 (Japanese Patent No. 3100886), a movable weight is supported by a magnetic restoring force in a two-dimensional arbitrary direction so that a single movable weight can obtain a vibration damping effect regardless of the direction. In addition, by installing a conductor plate between the opposing magnets, it can be used as a magnetic damper, and the spring element and the damping element are all housed in the lower part of the movable weight, so that the size can be reduced and the bearing part can be used as the opposing magnet. There has been disclosed a dynamic vibration damping device that is installed in between or has a multiple structure so as to ensure a moving range of the movable part and further reduce the size in the radial direction.

However, according to this vibration damping device, since there is a repulsive force in addition to the attractive force of the magnet, there is an advantage that it is easy to hold in the center, but the return force to the center is large and the movable range is limited. There is a problem that the seismic isolation effect is reduced. In other words, if the force to return the seismic isolation table moved by vibration to the center is reduced, the resonance frequency shifts to the lower frequency side, so that the frequency at which the seismic isolation effect can be exerted spreads, but this cannot be achieved with the structure of Patent Document 2. . When manufacturing this vibration damping device, magnets with different shapes, such as cylindrical magnets and ring magnets, are used, which increases the manufacturing cost of the magnet, makes it impossible to share parts, and increases the number of parts, resulting in high costs. There are difficulties.

  Patent Document 3 (Japanese Patent No. 379974) discloses a horizontal fixing base covered with a nonmagnetic material having at least a flat upper surface, and a horizontal fixing base positioned above the fixing base and maintaining a constant interval with respect to the fixing base. A movable base relatively movable in the direction, a first magnetic member fixed to the movable base so as to be opposed to the upper surface of the fixed base, and a first magnetic member mounted on the fixed base so as to be freely movable up and down. Two magnetic members, and at least one of the first and second magnetic members is a permanent magnet, and the second magnetic member is attracted to the first magnetic member and raised when the movable base is at the return position. There is disclosed a seismic isolation base device that generates a holding force that is held at a position and holds a movable base at a predetermined return position.

  According to this seismic isolation device, since the magnetic member (magnet) on the base side needs to be loosened, it is necessary to assemble it as a separate part as a magnet holder unit, resulting in a complicated structure and an increased number of assembly steps. When the upper and lower magnets move in a close state, when the stage side magnet approaches the base side magnet, the base side magnet moves up and down by the magnetic attractive force. Moreover, the magnitude of the magnetic attractive force is half proportional to the square of the distance between the magnets, and the stage movement is not proportional in the horizontal direction. Therefore, the gap between the magnets (magnetic gap) changes and moves with an inclination, which makes it unstable. Furthermore, returning to the center requires separate parts (wires), resulting in increased costs and a complicated structure. In addition, since the magnet moves up and down, there is a problem that the magnet receiving portion is sufficiently predicted to be worn by sliding.

JP 2006-342884 A Japanese Patent No. 3100906 Japanese Patent No. 3791974

In the seismic isolation device described in Patent Documents 1 to 3 described above, there are problems that it cannot be applied to small articles, has a complicated structure, and increases the number of assembly steps.

  Accordingly, an object of the present invention is to provide a seismic isolation device that has a simple structure and can prevent the fall and fall of articles of various sizes due to vibrations such as earthquakes.

In order to achieve the above object, the seismic isolation device of the present invention comprises:
A fixed member disposed at a predetermined position; a movable member that moves in a horizontal direction with respect to the fixed member by vibration from outside; and a support member that slidably supports the movable member with respect to the fixed member. In the seismic isolation device having a magnetic field generating means adapted to return the movable member moved in the horizontal direction to the initial position by a magnetic attraction force,
The fixed member includes a base on which the movable member is installed,
The movable member has a stage movable in the horizontal direction,
The support member has a plurality of spheres interposed between the base and the movable member,
The magnetic field generating means includes a permanent magnet that generates a magnetic flux from the fixed member or the movable member toward the movable member or the fixed member, and a suction yoke that is disposed at a position facing the permanent magnet in a state where no vibration is generated. It is characterized by having.

  In the present invention, the support member is preferably three or more spheres arranged at equal angular intervals when viewed from the plane. The sphere is more preferably a non-magnetic material.

  In the present invention, the base and the movable frame are preferably formed of a nonmagnetic material. In particular, the movable frame and the stage are more preferably formed of a material having a large specific gravity, for example, a nonmagnetic metal material.

  In the present invention, the permanent magnet is a flat permanent magnet, and is a flat magnet (bipolar magnet) formed in such a manner that a pair of magnetic poles magnetized in the thickness direction and opposite in polarity face the attraction yoke. Are preferably used, or monopolar magnets magnetized in the thickness direction are preferably arranged side by side. In particular, when a dipole magnet is used, it is preferable to arrange three or more permanent magnets at equiangular intervals when viewed from the plane.

  In the present invention, the attraction yoke preferably has an area equivalent to the area of the permanent magnet.

  In the present invention, it is preferable to attach an anti-slip sheet made of a material having a large friction coefficient (for example, silicon rubber) to the lower surface of the base and / or the upper surface of the stage.

  According to the present invention, since a magnetic attractive force acts between the base and the stage, in a normal state, the stage is held at the center of the base, and a sphere is interposed between the base and the stage. When the vibration exceeding the magnetic attractive force is received, the stage moves in the horizontal direction, so that the article is prevented from falling. When the vibration is stopped, a magnetic attractive force acts between the base and the stage, so that the horizontally moved stage immediately returns to the initial position. According to the present invention, an excellent seismic isolation effect can be obtained even with a simple structure, so that it has extremely high practicality.

1 is an external perspective view of a seismic isolation device according to an embodiment of the present invention. It is the cut view which looked at the seismic isolation apparatus shown in FIG. 1 from the diagonal upper surface. It is the cut view which looked at the seismic isolation apparatus shown in FIG. 1 from the diagonal back. It is a disassembled perspective view of the seismic isolation apparatus shown in FIG. It is a figure which shows the base of the seismic isolation apparatus shown in FIG. 1, (a) is a top view, (b) is sectional drawing which cut | disconnected (a) by the AA line, (c) is (b) direction B The arrow view seen from (d) is the arrow view seen from the C direction of (b). It is a figure which shows the outer cover of the seismic isolation apparatus shown in FIG. 1, (a) is a top view, (b) is sectional drawing which cut | disconnected (a) by the DD line, (c) is (b) by E It is an arrow view seen from the direction. It is a figure which shows the movable frame of the seismic isolation apparatus shown in FIG. 1, (a) is a top view, (b) is sectional drawing which cut | disconnected (a) by the FF line, (c) is a rear view. It is a figure which shows the stage of the seismic isolation apparatus shown in FIG. 1, (a) is a top view, (b) is sectional drawing which cut | disconnected (a) by the GG line, (c) is (b) H direction. It is the arrow view seen from. It is a figure which shows the seismic isolation apparatus shown in FIG. 1, (a) is a top view, (b) is sectional drawing which cut | disconnected (a) by the JJ line. It is a figure which shows the state which excited the seismic isolation apparatus shown in FIG. 1 in the horizontal direction, (a) is a top view, (b) is sectional drawing which cut | disconnected (a) by the KK line | wire. It is a figure which shows the state which vibrated to the seismic isolation apparatus shown in FIG. 1 in the reverse direction to FIG. 10, (a) is a top view, (b) is sectional drawing which cut | disconnected (a) by the LL line. is there. It is a disassembled perspective view which shows the seismic isolation apparatus concerning the 2nd Embodiment of this invention. It is a figure which shows the result of the vibration test of the seismic isolation apparatus of this invention.

  A first embodiment of the present invention will be described below with reference to the accompanying drawings.

[overall structure]
As shown in FIGS. 1 to 4, the seismic isolation device 1 of the present invention moves the movable member 6 in the horizontal direction (X-axis direction and Y-axis direction) with respect to the fixed member 2, the movable member 6, and the fixed member 2. It is a flat disk-shaped unit which has the rolling member 5 supported so that it is possible. Referring also to FIGS. 5 to 8, the structure of each member is as follows.

[Fixing member]
The fixing member 2 includes, for example, a disk-shaped base 3 installed in a room (floor surface) or the like, and a ring-shaped outer cover 4 fastened to the base 3 via bolts 91a, 91b, 91c. In the base 3, a plurality of female thread portions 31a, 31b, and 31c into which bolts 91a, 91b, and 91c are respectively screwed are formed on a concentric circle at predetermined intervals (for example, equiangular intervals). As shown in FIG. 5, in the present embodiment, in order to reduce assembly man-hours, female screw portions 31d, 31e, and 31f are formed in the middle of the female screw portions 31a, 31b, and 31c. The parts 31d, 31e, 31f can be omitted. In addition, the base 3 has a ball receiver for receiving the rolling member 5 composed of a plurality of balls 50a, 50b, 50c in order to limit the range of movement of the rolling member 5 on the inner peripheral side of each female thread portion. Portions 32a, 32b, and 32c are formed. Each ball receiving portion has a height (for example, ½ to 2/3 of the diameter of the ball) such that the ball inserted therein can come into contact with the back surface of the movable frame 8. The inner diameters of these ball receiving portions are preferably set to a value slightly larger than the ball diameter (for example, about 1.1 to 1.3 times). On the back surface of the base 3, flat magnetic yokes 13a, 13b, 13c made of a plurality of ferromagnetic materials are provided on a double-sided tape 93a in order to generate a magnetic attractive force for returning the movable member moved by vibration to its original position. , 93b, 93c. The base 3 is preferably formed of a nonmagnetic material (for example, aluminum alloy or engineering plastic).

  As shown in FIG. 6, the outer cover 4 includes a hollow disk-shaped flange portion 41 and a ring portion 42 extending in the Z-axis direction from the inner peripheral edge thereof. In the flange portion 41, drill holes 411 a, 411 b, and 411 c are formed on concentric circles through which the male screw portions of the bolts 91 a, 91 b, and 91 c are inserted at predetermined intervals (for example, equiangular intervals). Drill holes 411d, 411e, and 411f are also formed in the middle of each drill hole, but these drill holes can be omitted. Further, in order to prevent the bolts 91a, 91b, and 91c from being inserted into the outer peripheral surface of the ring portion 42 (to avoid interference with the heads of the bolts), arc-shaped concave portions 421a to 421f viewed from the plane. Is provided. The outer cover 4 is preferably formed of a nonmagnetic material (for example, aluminum alloy or engineering plastic).

[Movable member]
The movable member 6 includes a stage 7 that supports an article (not shown), and a hollow disk-shaped movable frame 8 to which the stage 7 is integrally coupled in order to move the stage in a direction opposite to the shaking direction due to external vibration. Have As shown in FIG. 8, the stage 7 includes a disk-like table portion 71 on which an article is placed and a ring-shaped spacer portion 72 extending from the rear surface in the Z-axis direction. The table portion 71 is formed with counterbore portions 711a, 711b, 711c to which the heads of bolts 92a, 92b, 92c for fastening to the movable frame 8 are locked. The outer diameter of the spacer portion 72 is set to be smaller than the inner diameter of the ring portion 42 of the outer cover 4 so that the stage 7 can be moved horizontally. This dimensional difference is the moving distance of the stage 7. The stage 7 is preferably formed of a non-magnetic material, and more preferably formed of a material having a large mass (specific gravity), for example, a non-magnetic metal material, in order to lower the resonance frequency (expand the usable frequency band). . As such a material, an iron-based alloy such as austenitic stainless steel can be used. However, a weight member having a high specific gravity on a part (one or a plurality of locations) of a stage formed of a light alloy (for example, an aluminum alloy) ( For example, lead) may be embedded.

  As shown in FIG. 7, the movable frame 8 has a rectangular shape around the center hole 83 and the center hole 84 in order to hold the magnetic field generating means at predetermined intervals (for example, equiangular intervals) along the circumferential direction. Yoke holding holes 81a, 81b, 81c and smaller magnet holding holes 82a, 82b, 82c are formed. The corner of each yoke holding hole prevents the edge of the yoke from being lost when the back yokes 11a, 11b, and 11c are inserted therein, and an adhesive (not used for bonding the yoke and the movable frame). (Figure) Escape portions 811a, 811b, 811c having an arc shape are formed for accumulation. Similarly, in order to prevent the edge of the yoke from being lost when the permanent magnets 12a, 12b, 12c are inserted into the corners of the respective magnet holding holes, escape portions 821a, 821b having an arc shape are provided. 821c is formed. The movable frame 8 is formed with female thread portions 85a, 85b, and 85c into which bolts 92a, 92b, and 92c are screwed in between the yoke holding holes as viewed from above, and a predetermined interval (equal angular interval) on the back surface. A plurality of ball receiving portions 86a, 86b, 86c are formed.

[Rolling member]
As the rolling member 5, a plurality of balls 50a, 50b, and 50c are used to support the movable member 6 so as to be movable in the horizontal direction. The ball may be a sphere having a mechanical strength that does not break when the article is supported, and can be formed of a ferromagnetic material such as a steel material. For easy assembly, ceramic or austenite It is preferable to form a non-magnetic material such as a stainless steel (a ferromagnetic material is easily attracted to a magnet and thus becomes unstable).

[Magnetic circuit members]
The seismic isolation device of the present invention provides a magnetic attraction force by providing a magnetic circuit member on the fixed member and the movable member in order to return the movable member horizontally moved with respect to the fixed member to the original position by external vibration. It is clearly different from conventional seismic isolation devices in that it generates An example of the magnetic circuit member is as follows.

  Each of the magnetic circuit members 10a, 10b, and 10c has a flat plate shape, and is a back yoke 11a, 11b, 11c made of a ferromagnetic material mounted on the movable frame 8, and a surface facing the base 3 of each back yoke. A plurality of permanent magnets 12a, 12b, 12c magnetized in the thickness direction (Z-axis direction), and a suction yoke 13a made of a ferromagnetic material fixed to the base 3 at a position facing each permanent magnet, 13b and 13c.

The suction yoke preferably has a size equivalent to the areas of the permanent magnet and the back yoke. When the area of the attraction yoke is larger than the area of the permanent magnet, the range to be held at the center is widened, and the phenomenon of returning to the position deviated from the original position easily occurs even when the vibration is suppressed. On the other hand, if the attraction yoke has the same size as the areas of the permanent magnet and the back yoke, the attraction position becomes the center, and even if the magnetic attraction force is the same, the centripetal force (force to return to the center) can be increased. Therefore, a stable state can be maintained. Further, by making the suction yoke the same size (dimension) as the back yoke, the equipment can be shared and the manufacturing cost can be reduced.

  As the permanent magnets 12a, 12b, and 12c, a single magnet that is two-pole magnetized and has a pair of magnetic poles with different polarities on the surface facing the yoke can be used. Alternatively, two permanent magnets (single pole magnets) magnetized in the thickness direction may be arranged side by side so as to have different magnetization directions and attached to each magnet holding hole. When such a permanent magnet is used, a state in which the boundary of the magnetic pole and the center of the attraction yoke are attracted appears, so that it is easy to achieve a magnetic balance and to return to the neutral position. This is because when a single pole magnet is installed in each magnet holding hole, the edge portion of the magnet is easily attracted to the center of the yoke, making it difficult to hold it at the center.

As the permanent magnet, a known permanent magnet material, for example, a sintered magnet (ferrite magnet, rare earth magnet, etc.), or a resin magnet obtained by binding magnet powder with a resin can be used. It is possible to omit the back yoke, but care must be taken because the leakage magnetic flux increases and the magnetic attraction force tends to decrease.

  In the present invention, the following members can be added to the above members. The anti-slip member 14 can be attached to the lower surface of the base 3 and / or the anti-slip member 15 can be attached to the upper surface of the stage 7. By using these anti-slip members, it is possible to suppress the sliding movement of the article and the sliding movement of the seismic isolation device itself when the table is moved during seismic isolation (during vibration absorption). The opportunity to do this is reduced and the seismic isolation effect is increased. As this kind of anti-slip member, a sheet formed of a material (rubber) having a large friction coefficient can be used. Specific examples include silicon rubber, NBR, urethane rubber and the like, and silicon rubber is particularly preferable.

[assembly]
Said seismic isolation apparatus 1 can be assembled in the following procedure, for example. First, one side of the double-sided tape 93a, 93b, 93c is affixed to each of the suction yokes 13a, 13b, 13c, and the other side of the double-sided tape is affixed to the back surface of the base 3, thereby the suction yokes 13a, 13b, 13c. The base 3 having the suction yokes 13a, 13b, 13c and the anti-slip member 14 is prepared by fixing the anti-slip member 14 to the base 3 and the anti-slip member 14 to the back surface of the base 3. The suction yoke may be fixed to the base using an adhesive instead of the double-sided tape. The back yokes 11a, 11b, and 11c are inserted (press-fitted or bonded) into the yoke holding holes 81a, 81b, and 81c of the movable frame 8 and fixed thereto. The movable frame 8 is reversed, and permanent magnets 12a, 12b, 12c are inserted into the magnet holding holes 82a, 82b, 82c, respectively, and fixed thereto. Here, arc-shaped relief portions 811a, 811b, and 811c are formed in the corner portions of the respective yoke holding holes 81a, 81b, and 81c, and the arc portions are also formed in the corner portions of the respective magnet holding holes 82a, 82b, and 82c. Since the relief portions 821a, 821b, and 821c are formed, even if the back yokes 11a, 11b, and 11c and the permanent magnets 12a, 12b, and 12c are inserted (press-fitted), it is possible to prevent these edge portions from being lost. .

  After the balls 50a, 50b, 50c are arranged on the ball receiving portions 32a, 32b, 32c of the base 3, the movable frame 8 is placed on the base 3, the outer cover 4 is put on the movable frame 8, and the bolt 91a is placed on the base 3. , 91b, 91c are screwed in to secure the outer cover 4 to the base 3. Next, after the stage 7 is covered with the movable frame 8, the bolts 92 a, 92 b and 92 c are screwed into the movable frame 8, whereby the stage 7 and the movable frame 8 are integrated. Finally, the anti-slip member 15 is set on the surface of the table portion 71, and the assembly of the seismic isolation device 1 is completed. When the anti-slip sheet is affixed to the bottom surface of the article set in the seismic isolation device 1, the anti-slip member 14 can be omitted.

[Seismic isolation]
As shown in FIG. 9, when an article (not shown) is set on the seismic isolation device 1 and installed indoors, if the base 3 is shaken in the X2 direction due to the earthquake, the stage 7 passes through the rolling member 5. Therefore, as shown in FIG. 10, the stage 7 moves in the direction opposite to the shaking (X1 direction), and thus the shaking can be mitigated (seismic isolation operation). When the shaking of the earthquake stops, the permanent magnets 12a, 12b, 12c fixed to the movable frame 8 are magnetically attracted to the attraction yokes 13a, 13b, 13c, so that the movable frame 8 returns to its original position. That is, the movable frame 8 can return to a position where the center of the movable frame 8 substantially overlaps the center of the base 3 when viewed from the plane.

  In FIG. 9, when the base 3 is shaken in the X1 direction due to the earthquake, the stage 7 is supported so as to be movable through the rolling member 5, so that the stage 7 is in the direction opposite to the shake as shown in FIG. X2 direction), so that the shaking can be reduced (seismic isolation operation). When the shaking of the earthquake stops, the permanent magnets 12a, 12b, 12c fixed to the movable frame 8 are magnetically attracted to the attraction yokes 13a, 13b, 13c, so that the movable frame 8 returns to its original position. That is, the movable frame 8 can return to a position where the center of the movable frame 8 substantially overlaps the center of the base 3 when viewed from the plane.

  Here, when the sum of the mass of the article and the weight of the seismic isolation device is M (kg) and the spring constant is K (N / m), the resonance frequency f (Hz) of the member to be vibrated (the fixed member 2 and the article) is , (1).

In order to increase the seismic isolation effect from the equation (1), it is necessary to lower the resonance frequency f, and for that purpose, it is necessary to increase the mass. Therefore, as described above, it is desirable to make the stage heavy. That is, when moving away from the center, if the force (spring constant) for returning to the center is small, the resonance frequency is lowered, and the frequency at which the seismic isolation effect is obtained is widened.

A second embodiment of the seismic isolation device 1 of the present invention will be described with reference to FIG. 12, the same functional parts as those in FIG. 1 are denoted by the same reference numerals.

The seismic isolation device of FIG. 12 can move the movable member 6 in the horizontal direction (X-axis direction and Y-axis direction) with respect to the fixed member 2, the movable member 6, and the fixed member 2 in the same manner as the seismic isolation device of FIG. It is a flat disk-shaped unit which has the rolling member 5 to support. Since the fixed member 2 and the movable member 6 are the same as those in FIG. 1 except for the magnetic field generating member 10, the description thereof is omitted. Since the configuration of the magnetic field generating member is different from that of FIG. 1 in the present embodiment, the configuration of the magnetic field generating member will be described.

The magnetic field generating member 10 includes a disk-shaped back yoke 11, a disk-shaped permanent magnet 12 magnetized in the thickness direction (arrow Z direction), and a disk-shaped suction yoke 13. The back yoke 11 and the permanent magnet 12 are held in the yoke holding hole 81 and the magnet holding hole 82 of the movable frame 8. The suction yoke 13 is fixed to the base 3 via a double-sided tape 93. The area of the back yoke 11 is set to be larger than the area of the permanent magnet 12 and the area of the attraction yoke 13, and the area of the attraction yoke 13 is set to be larger than the area of the permanent magnet 12. Even if is shifted from the center, the stage 71 can quickly return to its original position after the earthquake has stopped.

[Experimental example]
The above seismic isolation device 1 was set on a vibration exciter (not shown), and the relationship between the vibration time and acceleration was determined. FIG. 13 shows the relationship between the vibration time and the acceleration in that case. In FIG. 13, the curve Ba represents the acceleration on the base 3, and the curve St represents the acceleration on the stage 7.

The experimental results in FIG. 13 are the results when the weight of the movable part is about 350 g and the spring constant is about 90 N / m.

As shown by the curve Ba, the maximum acceleration on the base 3 is 204 gal (corresponding to seismic intensity 5; unstable one falls or falls), and the instantaneous maximum acceleration reaches 307 gal. On the other hand, the acceleration on the stage 7 is greatly reduced (less than 25 gal) even if the base 3 sways at a seismic intensity 5 (90 to 250 gal) as shown by the curve St. It can be seen that the fall of can be prevented.

1: Seismic isolation device,
2: fixing member,
3: Base,
31a, 31b, 31c, 31d, 31e, 31f: female screw, 32a, 32b, 32c: ball receiving portion, 34a, 34b, 34c: yoke holding hole, 341a, 341b, 341c: escape portion,
4: Outer cover
41: flange part, 411a, 411b, 411c, 411d, 411e, 411f: drill hole,
42: cylindrical part, 421a, 421b, 421c, 421d, 421e, 421f: concave part,
5: Rolling member, 50a, 50b, 50c: Ball 6: Movable member,
7: stage, 71: table portion, 72: spacer portion, 73: drill hole 8: movable frame,
81, 81a, 81b, 81c: Yoke holding hole, 811a, 811b, 811c: relief part,
82, 82a, 82b, 82c: magnet holding hole, 821a, 821b, 821c: escape portion,
83: Center hole, 84: Center recess, 85a, 85b, 85c: Female thread portion, 86a, 86b, 86c: Ball receiving portion,
91a, 91b, 91c, 92a, 92b, 92c: bolts,
93, 93a, 93b, 93c: double-sided tape,
10, 10a, 10b, 10c: magnetic field generating member,
11, 11a, 11b, 11c: back yoke,
12, 12a, 12b, 12c: permanent magnets,
13, 13a, 13b, 13c: suction yoke,
14, 15: Anti-slip member

Claims (6)

A fixed member disposed at a predetermined position; a movable member that moves in a horizontal direction with respect to the fixed member by vibration from outside; and a support member that slidably supports the movable member with respect to the fixed member. In the seismic isolation device having a magnetic field generating means adapted to return the movable member moved in the horizontal direction to the initial position by a magnetic attraction force,
The fixed member has a base on which the movable member is installed,
The movable member has a stage movable in the horizontal direction,
The support member has a plurality of spheres interposed between the base and the movable member,
The magnetic field generating means includes a permanent magnet that generates a magnetic flux from the fixed member or the movable member toward the movable member or the fixed member, and a suction yoke that is disposed at a position facing the permanent magnet in a state where no vibration is generated. A seismic isolation device characterized by having. The seismic isolation device according to claim 1, wherein the support members are three or more spheres arranged at equal angular intervals when viewed from a plane.   The base isolation device according to claim 1 or 2, wherein the base and the movable frame are formed of a non-magnetic material.   The permanent magnet is a flat permanent magnet that uses a flat magnet that is magnetized in the thickness direction and is formed so that a pair of magnetic poles having different polarities face the attraction yoke, or in the thickness direction. The seismic isolation device according to claim 1, wherein magnetized monopolar magnets are arranged side by side. The seismic isolation device according to claim 1, wherein the attraction yoke has an area equivalent to that of the permanent magnet.   The seismic isolation device according to any one of claims 1 to 5, wherein an anti-slip sheet made of a material having a large friction coefficient is attached to the lower surface of the base and / or the upper surface of the stage.

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