JP2005325850A - Base isolation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base isolation device capable of providing upper and lower plates and ball itself with friction damper function having constant coefficient of friction and preventing it from staggering at a central position and having a simple structure. <P>SOLUTION: In this base isolation device having upper and lower plates 2, 1 having a recessed spherical face or cylindrical faces 4, 3 and a ball 5 or a roller, slide and rolling movement is performed between the ball or the roller and the plates in a travel effective scope determined in advance of the ball or the roller by making radius of curvature of the spherical face of the upper and lower plates or the cylindrical face different, and generated slide friction force acts as damper force. Coefficient of friction of slide friction force is 0.02 or more and 0.08 or less. A ratio A of radius of curvature R<SB>2</SB>/R<SB>1</SB>is 3≥A≥1.5. A device for applying constant friction force in addition to friction damper force action of the base isolation device is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  With regard to seismic isolation devices such as base isolation tables and base isolation floors that protect acceleration-sensitive devices such as building seismic isolation devices or computer servers from earthquakes, especially balls or rollers between the upper and lower spherical surfaces or cylindrical surfaces. It is related with the improvement of the rolling type seismic isolation device which can move horizontally and automatically.

  The seismic isolation device in which the balls can roll between the upper and lower plates has the same curvature radius between the upper plate and the lower plate, one of the upper and lower plates is a flat surface, as shown in Patent Document 1, Various things, such as a thing with a different curvature radius with a lower plate, can be considered. However, the seismic isolation device adapted to move horizontally between the upper and lower pans having the upper and lower spherical surfaces or the cylindrical surface via a ball or roller has a function of supporting the building or the load weight as a component thereof, and in the event of an earthquake. Therefore, a so-called damper is required. Examples of the damper include a friction damper that applies a predetermined pressing force to the friction members that are in contact with each other between the upper and lower pans, and a hydraulic cylinder that uses the viscous resistance of the fluid. Such a damper is provided separately from the upper and lower pans and balls, but the frictional force and viscous resistance generally used as a damper do not increase or decrease according to the magnitude of the external force, so when the loading load changes The damper force needs to be changed accordingly. Therefore, in the case of a building house with a large loading load, the seismic isolation device including the house, especially the foundation, is individually designed each time. However, in the case of seismic isolation floors and bases for loading small and medium-sized items such as works of art, computer servers, exhibits, etc., friction dampers are generally used because oil is disliked. It is complicated to design each time, and we want to obtain a friction damper force that increases and decreases according to the load. For this purpose, the friction damper force is preferably a value obtained by multiplying the constant friction coefficient by the loading load, and a friction damper having a so-called constant friction coefficient is ideal. I want to simplify the structure.

Therefore, in Patent Document 2, the upper surface of the lower plate is a concave spherical surface and the lower surface of the upper plate is a concave spherical surface, but the curvature radius of the spherical surface of the upper plate is substantially the same as the curvature radius of the ball. The plate and the ball are integrated, so that almost no sliding or rolling occurs, and the lower plate and the ball are almost in a sliding state. As a result, a slip resistance of about 0.10, that is, a friction damper force with a constant friction coefficient can be obtained. Moreover, in the thing of patent document 3, the concave surface is provided in the upper surface of the rail corresponded to a lower pan, and the wheel (rolling body) rotatably attached to the axis | shaft attached to the upper support body corresponded to an upper plate. ) Rolls on the rail. The shaft and the shaft hole of the wheel constitute a sliding bearing so that a sliding frictional force can be obtained. Since the sliding friction coefficient between the shaft and the wheel hole of the wheel is substantially constant, a friction damper force having a constant friction coefficient is obtained.
Japanese Utility Model Publication No. 55-041608 FIG. 4 JP-A-10-008571 Japanese Patent Publication No. 06-074609

  However, in Patent Documents 2 and 3, since the ball or wheel does not move relative to the upper plate and cannot move relative to the upper plate, the length of the lower plate or rail is required by the size of the moving distance of the response displacement to the earthquake. Therefore, there is a problem that the width size becomes large. This is a big problem when the upper and lower pans are moved relative to each other in a typical single-ball type rolling bearing because the ball has almost half the stroke with respect to the response displacement travel distance and the size of the upper and lower pans is almost half. . In addition, since the friction coefficient is constant, when the friction coefficient is set to a small value, the frictional force becomes small when the loaded load is small, and there is a problem in that it may move carelessly due to an external force by a person or the like. Furthermore, the thing of patent document 3 had the problem that a structure became complicated compared with a ball | bowl. Moreover, the thing of patent document 1 has no description regarding a curvature radius and a friction damper except the figure seen that the curvature radius of an upper and lower plate differs.

  An object of the present invention is to provide a friction damper function in which the structure is simple and the friction coefficient is constant without increasing the length of the tray or rail while providing the friction damper function to the upper and lower dishes or the ball itself. Is to provide a seismic isolation device. Furthermore, it is to eliminate the wobbling at the center position.

  In the present invention, an upper plate having a concave spherical surface or cylindrical surface formed on the lower surface, a lower plate having a concave spherical surface or cylindrical surface formed on the upper surface, and a ball that can roll between the upper and lower plates. Alternatively, in the seismic isolation device having the roller, the curvature radius of the spherical surface or the cylindrical surface of the one dish is made different from the curvature radius of the spherical surface or the cylindrical surface of the other dish, so that the movement is made between the upper and lower dishes. A sliding and rolling motion is caused between the ball or roller and the one or the other or both of the plates within a predetermined effective range of movement of the ball or roller, and the generated sliding frictional force is acted as a damper brake. The above-mentioned problem was solved by providing a seismic isolation device.

  In other words, if the curvature radius of the upper and lower plates is the same, a pure rolling motion will occur unless plastic deformation occurs due to contact force, so the friction coefficient generated between the upper and lower plates and the ball or roller is the rolling friction coefficient. There is a unit of 0.001. On the other hand, if the curvature radii of the upper and lower plates are consciously different, slip occurs between the upper and lower plates and the balls or rollers. This slip rate varies depending on the difference in curvature radius between the upper and lower dishes. For example, in the above-mentioned Patent Document 2, when the curvature radius value of the upper plate is made very close to the curvature radius value of the ball, the ball hardly rolls and is close to a pure slip, and the friction coefficient is about 0.1 to 0.2. Become. In this case, the upper plate is not rolling. Therefore, by making the radius of curvature of one of the upper and lower plates smaller than the radius of curvature of the other plate, the ball or roller and one or the other or both plates are within the predetermined effective range of movement of the ball or roller. It is possible to adjust the slip rate by manipulating these radius of curvature values, and the desired constant friction coefficient can be obtained. Force can be generated.

The occurrence of this slip will be described. As shown in FIG. 1, the load vector Q is not balanced mechanically unless the center position O ′ of the ball 5 ′ moved from the center is positioned on the line connecting the curvature centers Oi ′ and Oe of the upper and lower plates. In other words, no matter how the upper and lower pans move, the center of the ball must come on the center line of curvature of the upper and lower pans. When the ball is set at such a position, the rolling lengths of the ball and the upper and lower pans are not equal, and slippage must be generated. Specifically, it is assumed that the upper plate 2 moves relative to the lower plate 1 by S, and as a result, the ball 5 moves T. The ball load Q cannot be balanced unless the ball center O 'is on the line connecting the curvature centers Oe and Oi' of the moved plate. If the angle formed by the line connecting the center of curvature Oi ′ after the movement of the upper plate 2 and the center of curvature Oe of the lower plate is Oe and Oi is θ,
S = OeOi ′ · sin θ = (Re + Ri−2r) · sin θ
T = OeO ′ · sin θ = (Re−r) · sin θ
It is.
Here, Re and Ri are the radii of curvature of the lower plate and the upper plate, and r is the radius of the ball.
T / S = (Re−r) / (Re + Ri−2r). When Re and Ri are not equal, T / S = 0.5 as in the rolling motion is not constant, and slipping occurs.

  Since there is no pure rolling, the amount of slippage can be calculated as follows. In FIG. 1, the rolling lengths of the upper and lower dishes are examined. A and B are points of contact with the lower plate 1 and the upper plate 2 of the ball 5 before movement. It is assumed that the ball contacts the lower plate and the upper plate with H and K after moving. Assuming that the same location of the upper plate 2 after the movement of B is B ′, the arc AH = OeA · θ = Re · θ and the arc B′K = Oi′K · θ = Ri · θ. Since Re and Ri are not equal, arc AH and arc B'K are not equal. Next, when the rolling length of the ball is calculated, it is assumed that the position after movement of the point A of the ball is A ′, and the 180 ° symmetrical position of A ′ with respect to the ball center is A ″. The ball 5 is assumed to be a rigid body. If the ball rolls by arc A ″ K, it should also roll by arc A′H (A ″ and A ′ are symmetrical positions). If the pan 2 ′ and the ball 5 ′ are pure If rolling, arc A ″ K and arc B′K should be equal. Also, since the arc A′H and the arc A ″ K are equal, the arc A′H and the arc AH are not equal. Here, if Re> Ri, the arc AH> the arc A′H.

Thus, the rolling trajectory length at the point A is different between the ball 5 and the lower plate 1, and the ball revolves more than the rolling length. In other words, you are slipping. Assuming that the sliding amount of the upper plate 2 and the ball 5 rolls purely,
Slip rate = (arc AH−arc A′H) / arc AH
Slip rate = (Re · θ−Ri · θ) / Re · θ
Slip rate = 1−Ri / Re. If Re = Ri, the slip rate is 0, but if Re = 2 · RI, 50% of the ball trajectory of the dish is slipping and the remaining 50% is pure rolling.

  Thus, it can be seen that by varying the curvature of the spherical surfaces of the upper and lower dishes, the ball can slide and roll, and if the ratio of the curvature radii of the upper and lower dishes is changed, the slip ratio can be adjusted and the generated friction coefficient can be adjusted. Note that the friction coefficient is appropriately selected because it varies depending on factors such as the material of the balls and upper and lower dishes, hardness, and curvature.

  According to a second aspect of the present invention, the sliding friction force is preferably 0.02 or more and 0.08 or less in terms of a friction coefficient.

In order to ensure the effective movement range of the ball or roller, the outer diameter dimension of the spherical surface of the upper plate and the lower plate or the circumferential direction length of the cylindrical surface may be in a range where they are substantially the same value. Therefore, in the invention described in claim 3, the radius of curvature of the spherical surface or cylindrical surface of the one dish R _1, when the radius of curvature of the spherical or cylindrical surface of the other dish was R ₂ R ₂ / The ratio A of R ₁ was set such that 3 ≧ A ≧ 1.5. More preferably, A = 2 when the material of the upper and lower pans is mild steel and the ball is bearing steel.

If the curvature radius of either one of the upper and lower pans is close to the curvature radius of the ball, the outer diameter of the upper and lower pans cannot be made the same in terms of geometry, so there is a limit to providing a difference in curvature. Therefore, in the invention described in claim 4, the radius of curvature of the spherical surface or cylindrical surface of the one dish is R ₁ , the radius of curvature of the spherical surface or cylindrical surface of the other dish is R ₂ , and When the radius is r and the predetermined effective moving length of the ball or roller moving between the upper and lower dishes is D,
2r> R ₁ − (R ₁ ² − (D / 2) ² ) ^1/2 + R ₂ − (R ₂ ² − (D / 2) ² ) ^1/2 (1)
And R ₂ > R ₁ > r (2)
The seismic isolation device satisfies the requirements.

  In the seismic isolation device using the friction damper function by the sliding rolling between the upper and lower pans and the balls, the friction coefficient is constant. Therefore, when the loaded load is small, the frictional force is small and the external force by a person or the like easily moves. . Accordingly, the invention according to claim 5 provides a seismic isolation device provided with a device for applying a predetermined constant friction force in addition to the friction damper force action of the seismic isolation device. Since the frictional force is constant, the frictional force does not change even when the loaded load changes, but the relative movement of the upper and lower pans with respect to an external force below a certain value at the center position is prevented. If the ball slide or rolling surface of the upper and lower pan is spherical, the ball can move in all horizontal directions, but if the slide or rolling surface of the rollers of the upper and lower pan is cylindrical, the upper and lower pans are moved in all horizontal directions. Needless to say, in order to enable relative movement, at least one set in the direction perpendicular to the axis and two sets in total are required.

  In the present invention, the radius of curvature of the spherical surface or cylindrical surface of one plate is different from the radius of curvature of the spherical surface or cylindrical surface of the other plate, and the ball or roller falls within a predetermined effective movement range of the ball or roller. And one or the other or both of the dishes are made to slide and roll, and the generated sliding frictional force is used, so that the upper and lower dishes and the balls themselves have a friction damper function, The present invention provides a seismic isolation device having a damper function with a simple structure and a constant friction coefficient without increasing the length of the rail. Moreover, the seismic isolation device which can respond to various loading loads and can load a wide range of small and medium-sized articles is provided. Further, as described in claim 2, since the sliding friction coefficient is set to 0.02 or more and 0.08 or less, good friction damper performance and damping performance are obtained, and the operation is effective for earthquakes. became.

In the invention according to claim 3, since the ratio of the curvature radii of the upper and lower dishes is 1.5 to 3 times, it is possible to secure an effective movement range of balls and the like, and against a lateral movement range caused by various earthquakes. Provide effective seismic isolation devices. In a more detailed design, in the invention of claim 4, the radius of curvature of _one dish is R ₁ , the radius of curvature of the other dish is R ₂ , the radius of a ball or the like is r, the moving ball or the like is When the predetermined effective movement length is D, the seismic isolation device satisfies the above-described calculation formula, and the outer diameter of the upper and lower pans is almost the same. Even with a simple and narrow plate relative motion type seismic isolation device with a narrow width direction, a bearing with a friction damper function having a constant friction coefficient can be realized.

  Further, in the invention described in claim 5, in addition to the friction damper function having a constant friction coefficient, a friction force adding device having a constant friction force is provided, and the upper and lower plates are relatively moved with respect to an external force less than a fixed value at the center position. Because it prevents it, there is no wobbling around the center, even if the loading load is small, even if a person leans on it, it can not move easily, and a wider loading load is possible Provided a seismic isolation device.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a plan view excluding the upper plate, upper plate, and upper stopper of the seismic isolation device according to the embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2 shows a state in which the ball position is moved and the upper plate and the lower plate are relatively displaced, and FIG. 3 is a cross-section when the ball is in the original position in FIG. This generates a friction damper with a constant friction coefficient in a seismic isolation device having a rectangular horizontal holding guide and damping device (brake device) of Japanese Patent Application No. 2003-285497 (not disclosed) previously filed by the present inventor. This is an application of support. In each drawing, four support bodies 14 each including a ball 5 for supporting the upper plate 2 with respect to the lower plate 1 are disposed between the upper plate 2 and the lower plate 1 opposed thereto. Has been. The upper plate 2 of each support body 4 is fixed to the upper plate 12 and the lower plate 1 is fixed to the lower plate 11. When the upper plate 12 moves relative to the lower plate 11, each support body responds to the movement. The ball 5 also moves.

  Although not explicitly shown in FIGS. 2 and 3, in the present embodiment, as shown in FIG. 1, the lower surface 4 of the upper plate 2 and the upper surface 3 of the lower plate 1 are spherical concave surfaces, The curvature radius of the lower plate spherical seat is 2000 mm, and the curvature radius of the upper plate spherical seat is 1000 mm, which is half the radius of curvature of the lower plate spherical seat. Further, the diameter of the upper and lower dish spherical seats 3 and 4 is D = 210 mm, which is the effective moving length of the ball 5. Since the upper and lower pans move relative to each other around the ball 5, the base 11 and the support 12 move relative to each other within a maximum range of 200 mm. The diameter of the ball 5 is 2 inches (50.8 mm). When the ball 5 moves between the upper and lower pans having a difference in the radius of curvature, as shown in FIG. 1 described above, rolling slip occurs, and a frictional force having a constant friction coefficient can be obtained. Further, when the horizontal force due to an earthquake or the like disappears, the ball 5 works to return to the center position of the spherical surface of the upper and lower dishes, and has an origin return function.

  The upper and lower plates 12 and 11 are each divided into two pieces, and are composed of a pair of left and right seismic isolation members 16. The seismic isolation member 16 has a pair of upper and lower plates 12, 11 each having two support bodies 14 arranged and fixed. Between the upper plate 12 and the lower plate 11 that form a pair, a guide mechanism having a rectangular guide rod 9 composed of two pairs of a longitudinal guide rod 9y and a lateral guide rod 9x that are formed in a rectangular shape orthogonal to each other. 7 is interposed and is movable in the horizontal direction. On the upper plate 12, one guide guide 10x for the horizontal direction is arranged and fixed on each side of the support body 14 along the vertical guide rod 9y. Further, a lateral guide guide 10x is arranged and fixed on the lower plate 11 along the lateral guide rod 9x, one on each of the upper and lower sides of the support body 14 in the figure.

  In FIG. 2, two vertical guide rods 9y and horizontal guide rods 9x each overlap end portions 9a so as to be orthogonal to each other, and at the intersection (end portion), as shown in FIG. The bolts 23 are tightened through 22 and are connected to a rectangle. Each guide bar is guided by one guide 10y, 10x. The guide 10 and the rectangular guide rod 9 form the guide mechanism 7 and are arranged outside the support body so as to surround the two support bodies 14 in a set. Each guide bar 9 is slidably guided by a spring 20 and a slidable contact pad 21 mounted on the guide 10 to constitute a brake device 15 having a constant frictional force. The guide 10 (lateral guide rod guide 10x) is substantially U-shaped in cross section, fixed on the opening side 10a on the upper and lower plates 12 and 11, and formed with a guide hole 10b. A direction guide rod 9x) is inserted. A gap 10c is provided in the vertical direction between the guide hole 10b and the guide rod 9, and can be moved slightly in the vertical direction so as to follow the vertical movement by the support body 14. Moreover, although the upper and lower plates are accompanied by movement in a minute range in the vertical direction, they do not fall apart. The number of guides 10x and 10y may be further increased.

  Further, two seismic isolation members 16 comprising a pair of upper and lower plates and members attached to them are connected by a connecting rod 25 to form a set of seismic isolation devices. Further, since the guide mechanism 7 is disposed on the outside so as to surround the support body 14, it does not interfere with the upper and lower dishes 2, 1 of the support body. In addition, although the guide mechanism 7 is arrange | positioned on the outer side of a support body, when the movement distance of a guide mechanism is short, it cannot be overemphasized that what is necessary is just the outer side of a support body within the movement distance. Further, ring-shaped stoppers 24 are provided on the outer edges of the upper and lower dishes 2 and 1 of each support body 14 so as to prevent the balls from jumping out of the dishes.

  In such a configuration, when the upper plate 12 moves laterally with respect to the lower plate 11 in a plan view, the vertical guide rods 9y of the guide rods 9 integrated perpendicularly to each other are arranged and fixed to the lower plate 11. The two guides 10x arranged on the upper plate 12 slide on the lateral guide rod 9x along with the movement of the upper plate 12. On the other hand, when the upper plate 12 moves in the vertical direction with respect to the lower plate 11, the vertical guide rods 9 y that are orthogonal and integrated with each other follow the guides 10 y that are arranged and fixed to the upper plate 12. The upper plate 12 and the upper plate 12 move in the vertical direction. In both the vertical and horizontal movements, the upper plate 12 is blocked by the guide rods 9x and 9y and the guides 10x and 10y fixed to the upper and lower plates 12 and 11 even if the upper plate 12 tries to rotate with respect to the lower plate 11. The upper plate 12 can move without changing its posture in plan view with respect to the lower plate 11. When the upper plate 12 moves in the vertical direction and the horizontal direction simultaneously with respect to the lower plate 11, each member moves in the above-described manner only by the vertical movement component and the horizontal movement component of the movement. As a result, as indicated by a two-dot chain line in FIG. 2, the upper plate 12 can move horizontally without changing the posture of the lower plate 11 in plan view, and one independent seismic isolation member 16 is formed. become.

  Since the distance 18 of the seismic isolation member 16 in FIG. 5 can be freely set by the connecting rod 25 or the like, even a large installation space can be loaded. In addition, even if multiple seismic isolation members are connected, each seismic isolation member moves as a single unit as a seismic isolation device, so that the motion of the seismic isolation device as a whole is smooth and the damping performance is always constant. Needless to say, it is kept constant. The same applies to the case where a plurality of support bodies are provided in a set of seismic isolation members. In addition to the method using the guide rod and the sliding contact pad as in the present embodiment, the brake device 15 with a constant frictional force is provided with a sliding bearing on the outer periphery of the ball as disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-295054. A brake device is obtained by providing a rotational frictional force of the balls by being arranged between the dishes. Alternatively, it is needless to say that various devices such as a brake device in which a ball cage is slidably contacted with a cross-shaped retainer via a frictional resistor as disclosed in Japanese Patent Application Laid-Open No. 2000-240721 can be applied.

  The result of measuring the friction coefficient in the seismic isolation device will be described. 4, 5, and 6 are graphs showing movement amount-moving load obtained by measuring the horizontal load when the load of 100 kg, 300 kg, and 500 kg is loaded on the seismic isolation device of the present invention and moved in the horizontal direction. Yes, the horizontal axis shows the amount of movement, and the vertical axis shows the horizontal load. In addition, only the sliding and rolling resistance between the ball and the upper and lower dishes is used. As shown in FIGS. 4, 5, and 6, as the ball moves from the center of the ball 5, the ball goes up the lower plate spherical surface, and thus a force toward the center always acts. Therefore, for example, a force F that tries to roll down to the center when moved to the right from the center and a friction force (resistance) f obtained by multiplying the load by a friction coefficient due to sliding are applied in the direction opposite to the movement direction. Appears as a locus shown in FIG. On the other hand, when returning from the right end, the direction of the force F is the same, but the direction of the frictional force f is reversed, so the value of F−f appears as a locus shown in FIG. Therefore, when a loop of these trajectories is drawn, a rectangular friction hysteresis appears as a size in which the width in the P direction is 2f.

  Accordingly, the movement amount δ-movement load P is a parallelogram having hysteresis as shown in FIGS. The hysteresis is the frictional force (f) that is ½ of the width in the load direction (vertical axis). The coefficient of friction is μ = f / w. As shown in FIG. 4, when the load is 100 kg, the frictional force is 6 kg, so that μ = 6/2/100 = 0.03. On the other hand, in FIG. 5, since the friction force is 15 kg with respect to the load of 300 kg, the friction coefficient is μ = 15/2/300 = 0.025. Similarly, in the case of 500 kg in FIG. 6, μ = 24/2/500 = 0.024. Thus, it can be seen that the friction coefficient is substantially the same even when the load is changed to be substantially constant 0.025.

  In this way, by making the ratio of the radius of curvature of the spherical seats of the upper and lower plates different from 1/2, by generating slip in addition to rolling between the ball and the spherical seat, the friction coefficient due to sliding friction is almost constant. It was confirmed by experiments that it could be used as a device. Accordingly, since a constant coefficient of friction can be obtained according to the loaded load, it is possible to provide a seismic isolation device that can respond to an earthquake regardless of the magnitude of the loaded load.

In the embodiment, the friction generating device having a constant frictional force is opened (so that the sliding contact pad does not touch the guide rod 9) to eliminate the influence. Therefore, if a resistance of about 5 kg, for example, is given as a constant frictional force, even at a load of 100 kg at the neutral point (center position).
6/2 + 5 = 8 kgf. In addition, when it is 500 kg, it becomes 24/2 + 5 = 17 kg, and there is no wobbling at the neutral time. At the same time, it becomes a practically appropriate frictional force when an earthquake occurs. Can be obtained.

  In the embodiment, the case where the upper and lower pans are spherical has been described, but the same applies to the combination of the upper and lower pans having a cylindrical surface. However, in the case of a cylindrical surface, it goes without saying that it is arranged so as to be movable in at least two directions of the XY (right angle) direction.

It is a schematic diagram of the seismic isolation apparatus which shows the generation | occurrence | production mechanism of the slip of this invention. It is a top view of the seismic isolation apparatus which shows embodiment of this invention. It is the sectional view on the AA line of FIG. It is a graph which shows the moving amount-moving load which measured the horizontal load at the time of carrying the load of 100 kg on the seismic isolation apparatus of this invention, and moving to a horizontal direction. It is a graph which shows the movement amount-movement load which measured the horizontal load at the time of mounting the load of a weight of 300 kg on the seismic isolation apparatus of this invention, and moving to a horizontal direction. It is a graph which shows the movement amount-movement load which measured the horizontal load at the time of carrying the load of 500 kg on the seismic isolation apparatus of this invention, and moving to a horizontal direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower plate 2 Upper plate 3 Spherical surface or cylindrical surface of lower plate 4 Spherical surface or cylindrical surface of upper plate 5 Ball or roller 10 Seismic isolation device D Predetermined effective moving length (effective diameter)
Radius of curvature of R ₁ , R ₂ spherical surface or cylindrical surface r radius of ball or roller μ friction coefficient

Claims (5)

  An upper plate having a concave spherical surface or cylindrical surface formed on the lower surface, a lower plate having a concave spherical surface or cylindrical surface formed on the upper surface, and a ball or a roller that can roll between the upper and lower plates. In the seismic isolation device, the curvature radius of the spherical surface or the cylindrical surface of the one dish is different from the curvature radius of the spherical surface or the cylindrical surface of the other dish, so that the ball or roller moving between the upper and lower dishes A sliding and rolling motion is caused between the ball or roller and the one or the other or both of the plates within a predetermined effective moving range so that the generated sliding frictional force acts as a friction damper. A seismic isolation device characterized by that.   The seismic isolation device according to claim 1, wherein the sliding frictional force is 0.02 or more and 0.08 or less in terms of a friction coefficient. The ratio A of R ₂ / R ₁ when the radius of curvature of the spherical surface or cylindrical surface of the one dish is R ₁ and the radius of curvature of the spherical surface or cylindrical surface of the other dish is R ₂ is 3 ≧ A ≧ 1 The seismic isolation device according to claim 2, wherein the seismic isolation device is. The radius of curvature of the spherical surface or cylindrical surface of the one plate is R ₁ , the radius of curvature of the spherical surface or cylindrical surface of the other plate is R ₂ , the radius of the ball or roller is r, and the ball moves between the upper and lower plates. Or, when D is the predetermined effective movement length of the roller,
2r> R ₁ − (R ₁ ² − (D / 2) ² ) ^1/2 + R ₂ − (R ₂ ² − (D / 2) ² ) ^1/2 (1)
And R ₂ > R ₁ > r (2)
The seismic isolation device according to claim 2 or 3, characterized in that: The seismic isolation device according to any one of claims 1 to 5, further comprising a device that applies a certain frictional force in addition to the friction damper function of the seismic isolation device.

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