Sliding bearing

Abstract

To provide a slide bearing which is advantageous for damping large seismic energy while reducing an occupied space and costs.SOLUTION: When a large horizontal force is exerted on a building by an earthquake, a control unit 28 causes a magnetic force generation part 26 to generate a magnetic force according to a magnitude of the vibration quantity detected by a sensor 38. The magnetic force acts as a force which attracts a downward-facing slide surface 20 to an upward-facing slide surface 18, and thus the downward-facing slide surface 20 receives a resistance from an outer periphery part 1804. Further, the magnetic force is applied to a magnetic viscous fluid 24 to increase the viscosity of the magnetic viscous fluid 24 and cause a leg part 30 to receive a resistance caused by the magnetic viscous fluid 24. When a large horizontal force is exerted on a building, two kinds of resistances occur to inhibit swinging of the building with larger damping force.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sliding bearing. [Background technology]

[0002] A sliding bearing has been proposed in which multiple sliding bearings are provided between the upper structure, which is a building, and the lower structure, which forms the foundation of the building, and one of the sliding surfaces of each sliding bearing is formed from a magnetic material that is attracted to a magnet, and the other sliding surface is provided with a magnetic force generating unit that generates magnetic force toward the magnetic material; when the building vibrates due to an earthquake or the like, magnetic force is generated from the magnetic force generating unit, generating a force in a direction that attracts one of the sliding surfaces toward the other, thereby providing resistance to one of the sliding surfaces and attenuating the earthquake energy acting on the building (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-153501 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above-mentioned conventional technology, the greater the earthquake energy acting on a building, the larger the magnetic force generated by the magnetic force generating unit and the larger the area of ​​the sliding surface must be secured, raising concerns about the increased space occupied by the sliding bearing and increased costs, and some kind of improvement is required. The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a sliding bearing which is advantageous in attenuating large earthquake energy while suppressing the space occupied and costs. [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, one embodiment of the present invention includes an upward sliding surface provided on a lower structure, and a downward sliding surface provided on an upper structure, the downward sliding surface being smaller than the contour of the upward sliding surface and in slidable contact with a central portion of the upward sliding surface, the upward sliding surface being formed of a material that transmits magnetic force and has a small coefficient of friction, the upward sliding surface being provided with a first magnetic force generating unit that generates a magnetic force against the downward sliding surface, the downward sliding surface being formed of a magnetic material that is attracted to a magnet and has a small coefficient of friction, and a control unit that controls the magnetic force generated by the first magnetic force generating unit being provided. a side wall extending along the contour of the upward sliding surface is provided, a magnetorheological fluid is contained in an upwardly open storage space formed by the upward sliding surface and the side wall, the downward sliding surface is provided at the lower end of a leg protruding from the lower part of the upper structure, at least the lower part of the leg is immersed in the magnetorheological fluid with the downward sliding surface in contact with the upward sliding surface, a second magnetic force generating unit is provided which generates a magnetic force with respect to the magnetorheological fluid, and the magnetic force generated by the second magnetic force generating unit is controlled by the control unit. Moreover, one embodiment of the present invention is characterized in that the first magnetic force generating portion also serves as the second magnetic force generating portion. In addition, one embodiment of the present invention is characterized in that a sliding member constituting the upward sliding surface is provided on the lower structure, and the side wall is provided integrally with the sliding member. In addition, one embodiment of the present invention is characterized in that the second magnetic force generation portion is provided on the side wall. In addition, one embodiment of the present invention is characterized in that the upward sliding surface has a central portion that is larger than the contour of the downward sliding surface, and the first magnetic force generating portion is provided on the outer periphery of the upward sliding surface around the central portion. In addition, one embodiment of the present invention is characterized in that the first magnetic force generating portion is composed of an annular coil array consisting of a plurality of coils arranged at intervals in the circumferential direction on a virtual circumference centered on the center of the central portion. In one embodiment of the present invention, the annular coil array is provided on a plurality of imaginary circumferences having different radii from the center of the central portion. In addition, one embodiment of the present invention is characterized in that the control of the first magnetic force generating unit by the control unit in the outer circumferential portion is performed so that the magnetic force becomes larger the greater the distance from the center of the central portion. In addition, one embodiment of the present invention is characterized in that the control of the first magnetic force generating unit and the second magnetic force generating unit by the control unit is performed such that the magnetic force is increased as the vibration amount of the upper structure or the lower structure increases. Effect of the Invention

[0006] According to one embodiment of the present invention, when a large horizontal force acts on the upper structure or the lower structure, a magnetic force is generated from the first magnetic force generating unit, which acts as a force that attracts the downward sliding surface toward the upward sliding surface, so that the downward sliding surface experiences resistance from the upward sliding surface, and a magnetic force is generated from the second magnetic force generating unit, which increases the viscosity of the magnetorheological fluid, so that the legs experience resistance from the magnetorheological fluid. Therefore, when a large horizontal force acts on the building, two types of resistance are generated, allowing the building's swaying to be suppressed with a greater damping force. Therefore, there is no need to secure a large magnetic force generated by the magnetic force generating unit or a large area for the sliding surface as in the conventional technology, which is advantageous in attenuating large earthquake energy while reducing the space and costs required for the sliding bearing. Furthermore, if the first magnetic force generating unit, which is provided on the upward sliding surface and generates magnetic force toward the downward sliding surface, also serves as the second magnetic force generating unit that generates magnetic force toward the magnetorheological fluid, this is advantageous in terms of simplifying the configuration and reducing costs. Furthermore, providing the side wall integrally with the sliding member is advantageous in terms of simplifying the structure and reducing costs. Furthermore, by providing the second magnetic force generating unit on the side wall, the first magnetic force generating unit and the second magnetic force generating unit can be controlled independently, which is advantageous for finely controlling the attenuation of earthquake energy. Furthermore, if the contour of the central part of the upward sliding surface is formed larger than the contour of the downward sliding surface, when a small horizontal force acts on the upper structure or lower structure, the downward sliding surface will move smoothly and quickly within the contour of the central part of the upward sliding surface, just like a conventional sliding bearing. Furthermore, if the first magnetic force generating section is constructed from an annular coil array consisting of a plurality of coils arranged at intervals circumferentially on a virtual circle centered on the center of the central section, a magnetic force can be applied stably from the outer periphery of the upward sliding surface to the downward sliding surface regardless of the direction of the horizontal force acting on the upper structure or the lower structure, so that the downward sliding surface receives more stable resistance from the outer periphery of the upward sliding surface, which is advantageous for dissipating energy by the sliding support. Furthermore, by arranging the coil annular array on multiple virtual circumferences with different radii from the center of the central portion, it is possible to reliably apply a magnetic force from the outer periphery of the upward sliding surface to the downward sliding surface in a stable manner even if the horizontal displacement of the upper structure or lower structure becomes large, so that the downward sliding surface receives more stable resistance from the outer periphery of the upward sliding surface, which is advantageous for dissipating energy by the sliding bearing. Furthermore, if the first magnetic force generating unit is controlled so that the magnetic force generated by the first magnetic force generating unit increases the greater the distance from the center of the central part at the outer periphery of the upward sliding surface, the greater the horizontal displacement of the upper structure or lower structure, the greater the resistance that the downward sliding surface will experience from the outer periphery of the upward sliding surface, which is advantageous for greatly attenuating energy through the sliding support. Furthermore, if the first magnetic force generating unit is controlled so that the magnetic force generated by the first magnetic force generating unit and the second magnetic force generating unit increases as the vibration amount of the upper structure or lower structure increases, the resistance that the downward sliding surface receives from the upward sliding surface and the resistance that the legs receive from the magnetorheological fluid increase as the vibration amount of the upper structure or lower structure increases, which is advantageous for greatly attenuating energy through the sliding bearings. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2A is a side view of the sliding bearing of the first embodiment, showing in cross section the lower structure provided with the sliding member, and FIG. 2B is a plan view of the lower structure provided with the sliding member. [Diagram 2] 1A is a side view of a sliding bearing according to a second embodiment, showing in cross section a lower structure provided with a sliding member, and FIG. 1B is a plan view of the lower structure provided with the sliding member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the seismic isolation device 10 includes, for example, a plurality of sliding bearings 16 arranged between an upper structure 12, which is a building, and a lower structure 14, which forms the foundation of the building, a plurality of laminated rubber members (not shown), and an energy damping means (not shown). The sliding support 16 is composed of an upward sliding surface 18 provided on the lower structure 14, a side wall 22, a downward sliding surface 20 provided on the upper structure 12 and supported by the upward sliding surface 18, a magnetorheological fluid 24, a magnetic force generating unit 26, and a control unit 28. The plurality of sliding bearings 16 support the load of the upper structure 12 via their sliding surfaces 18, 20, and also support the upper structure 12 movably on the lower structure 14. The downward sliding surface 20 is smaller in profile than the upward sliding surface 18, and the downward sliding surface 20 is located at the central portion 1802 of the upward sliding surface 18, and when a horizontal force acts on the upper structure 12 or the lower structure 14, the downward sliding surface 20 slides from the central portion 1802 of the upward sliding surface 18 toward its surrounding outer periphery 1804.

[0009] The downward sliding surface 20 is provided at the lower end of the leg 30 protruding from the lower part of the upper structure 12, and in this embodiment, the leg 30 is attached to the lower surface 1202 of the upper structure 12. In addition, the leg 30 is made of a magnetic material that is attracted to a magnet, and the downward sliding surface 20 is formed to have a small coefficient of friction. As such a magnetic material, various conventionally known metal materials that are attracted to a magnet, such as iron or nickel alloys, can be used. The leg 30 includes a flange 3002 that is attached to the underside 1202 of the upper structure 12 with bolts, and a cylindrical column portion 3004 that protrudes from the center of the flange 3002. The circular lower end surface of the column portion 3004 is formed into a flat, smooth, downward-facing sliding surface 20 . Furthermore, with the downward-facing sliding surface 20 in contact with the upward-facing sliding surface 18, at least the lower portion of the leg 30, i.e., at least the outer peripheral surface 3006 of the lower portion of the column portion 3004, is immersed in the magnetorheological fluid 24 as described below.

[0010] The upwardly facing slide surface 18 is provided on the upper surface 1402 of the lower structure 14. The lower structure 14 is made of concrete, and a circular recess 1404 is provided in the upper surface 1402 of the lower structure 14 when viewed from above. The upward sliding surface 18 is formed by the upper surface of the sliding member 32 attached to this recess 1404, and the upward sliding surface 18 is formed with a small coefficient of friction. The sliding member 32 is formed from a low-friction material that is permeable to magnetic force. As such a low-friction material that is permeable to magnetic force, various synthetic resin materials that are conventionally known, such as a synthetic resin material whose main component is polytetrafluoroethylene, can be used. The upward sliding surface 18 is composed of a circular central portion 1802 and an annular outer peripheral portion 1804 located on its outer periphery, and the central portion 1802 of the upward sliding surface 18 is formed with a diameter larger than the diameter of the downward sliding surface 20. Therefore, the contour of the central portion 1802 of the upward sliding surface 18 is larger than the contour of the downward sliding surface 20.

[0011] The side wall 22 extends along the contour of the upwardly facing sliding surface 18 . In this embodiment, the side wall 22 is formed integrally with the sliding member 32 , and the side wall 22 is formed in an annular shape along the outer periphery of the sliding member 32 . In addition, the height of the side wall 22 is set to a dimension such that the upper end of the side wall 22 does not interfere with the upper structure 12, and in this embodiment, the height of the side wall 22 is approximately half the height of the leg 30.

[0012] As shown in Fig. 1(A), the magnetorheological fluid 24 is contained in an upwardly open containing space S formed by the upwardly facing slide surface 18 and the inner peripheral surface 2202 of the side wall 22. Note that the magnetorheological fluid 24 is omitted in Fig. 1(B). With the downward sliding surface 20 in contact with the upward sliding surface 18 , at least the lower portion of the leg portion 30 (the outer peripheral surface 3006 of the column portion 30 ) is immersed in the magnetorheological fluid 24 . A magnetorheological fluid 24 (MR fluid) is a fluid in which magnetic particles such as iron (Fe) are dispersed in a solvent such as oil, and is a functional fluid whose viscosity changes significantly when a magnetic force (magnetic field) is applied; the greater the magnetic force applied, the higher the viscosity.

[0013] The magnetic force generating unit 26 is provided on the upward sliding surface 18, and functions as a first magnetic force generating unit 26A that generates a magnetic force on the downward sliding surface 20. In this embodiment, the magnetic force generating unit 26 also functions as a second magnetic force generating unit 26B that generates a magnetic force on the magnetorheological fluid 24, in other words, the first magnetic force generating unit 26A doubles as the second magnetic force generating unit 26B. In this embodiment, the magnetic force generating unit 26 is provided on the outer periphery 1804 of the upward sliding surface 18 . When a magnetic force is generated by the magnetic force generating unit 26, the downward sliding surface 20 is attracted toward the upward sliding surface 18 by the magnetic force. The magnetic force generating unit 26 is configured with an annular coil array 36 made up of a plurality of coils 34 arranged at equal intervals in the circumferential direction on a virtual circle centered on the center of the central unit 1802 in the outer circumferential portion 1804. Each coil 34 is an electromagnet that generates a magnetic force when a current is supplied from the control unit 28, which will be described later. The plurality of coils 34 are arranged by being embedded in the sliding member 32. In this embodiment, the coil annular rows 36 are arranged on multiple virtual circumferences having different radii from the center of the central portion 1802, and there are two coil annular rows 36: a first coil annular row 36A and a second coil annular row 36B having a larger radius from the center of the central portion 1802 than the first coil annular row 36A. The number of coil annular rows 36 constituting the magnetic force generating unit 26 is not limited to two rows, but may be one row or three or more rows.

[0014] In this embodiment, the magnetic force generating unit 26 is composed of an annular coil array 36 consisting of a plurality of coils 34 arranged at equal intervals circumferentially on a virtual circle centered on the center of the central portion 1802 on the outer periphery 1804 of the upward sliding surface 18. Therefore, regardless of the direction of the horizontal force acting on the building, a magnetic force can be applied stably from the outer periphery 1804 to the downward sliding surface 20, so that the downward sliding surface 20 receives more stable resistance from the outer periphery 1804 of the upward sliding surface 18, which is advantageous for attenuating earthquake energy by the sliding bearing 16 and suppressing shaking of the building due to earthquakes. Furthermore, in this embodiment, the magnetic force generating unit 26 has a plurality of first coil annular arrays 36A and second coil annular arrays 36B arranged on two virtual circumferences having different radii from the central portion 1802, so that even if the horizontal displacement of the building increases, a magnetic force can be reliably applied from the outer periphery 1804 to the downward sliding surface 20 in a stable manner. As a result, the downward sliding surface 20 receives more stable resistance from the outer periphery 1804 of the upward sliding surface 18, which is advantageous in attenuating earthquake energy through the sliding bearings 16 and suppressing shaking of the building due to earthquakes.

[0015] Furthermore, the magnetic force generated by the magnetic force generating unit 26 acts on the magnetorheological fluid 24 contained in the containing space S, so that the viscosity of the magnetorheological fluid 24 changes, and the greater the magnetic force, the higher the viscosity. Therefore, when a building shakes due to an earthquake or the like and the leg 30 immersed in the magnetorheological fluid 24 moves horizontally, the leg 30 experiences resistance from the magnetorheological fluid 24, and this resistance is controlled by the magnitude of the magnetic force applied to the magnetorheological fluid 24. Therefore, in addition to the resistance that the downward sliding surface 20, which is generated by the magnetic force generated by the magnetic force generating unit 26, receives from the outer periphery 1804 of the upward sliding surface 18, resistance acting on the leg 30 is generated by the magnetorheological fluid 24, so that the sliding bearing 16 can attenuate earthquake energy, which is even more advantageous in suppressing the shaking of the building due to earthquakes.

[0016] The control unit 28 controls the magnetic force generated by the magnetic force generating unit 26 . The control unit 28 includes a microcomputer including a CPU, a storage unit, an interface circuit, and the like. The storage unit stores a control program executed by the CPU. In addition, a plurality of coils 34 and sensors 38 are connected via an interface circuit. The sensor 38 detects the amount of vibration (for example, acceleration) of the building in which the sliding bearing 16 is installed, that is, the upper structure 12 or the lower structure 14. The CPU executes a control program to control the amount of electricity (current) passed through the coil 34 based on the detection results of the sensor 38, thereby controlling the magnetic force generated on the downward sliding surface 20 and the magnetic force applied to the magnetorheological fluid 24. More specifically, vibrations of different magnitudes are divided into stages, and a table that associates the magnitude of vibration of each stage with the amount of current passed through the multiple coils 34 in each coil annular row 36 is stored in advance in a memory unit. The CPU refers to the table based on the amount of vibration detected by the sensor 38, and energizes the coil 34 with an amount of electricity that corresponds to the magnitude of the vibration.

[0017] In this embodiment, the control unit 28 controls the magnetic force generation unit 26 so that the magnetic force generated by the magnetic force generation unit 26 gradually increases with increasing distance from the center of the central portion 1802 in the outer circumferential portion 1804. In other words, the control unit 28 controls the magnetic force generation unit 26 so that the magnetic force generated by the multiple coils 34 for each annular coil array 36 gradually increases with increasing distance from the center of the central portion 1802. In other words, the control unit 28 controls the magnetic force generation unit 26 so that the magnetic force of the second annular coil array 36B is greater than the magnetic force of the first annular coil array 36A. In addition, in this embodiment, the magnetic force generating unit 26 is controlled so that the magnetic force generated by the magnetic force generating unit 26 gradually increases as the amount of vibration of the upper structure 12 or the lower structure 14 detected by the sensor 38 increases. In other words, the magnetic force generating unit 26 is controlled so that the magnetic force generated from each annular coil array 36 gradually increases as the distance from the center of the central portion 1802 increases in the outer circumferential portion 1804, and so that the magnetic force generated from each annular coil array 36 gradually increases as the vibration amount of the upper structure 12 or the lower structure 14 increases.

[0018] Next, the effects of this embodiment will be described. When a small horizontal force due to wind or the like acts on the building, the laminated rubber (not shown) undergoes shear deformation and the downward sliding surface 20 moves within the contour of the central portion 1802 of the upward sliding surface 18. Therefore, when a small horizontal force acts on the building, the shaking of the building due to the small horizontal force is suppressed. In this case, the control unit 28 does not yet cause the magnetic force generating unit 26 to generate a magnetic force because the amount of vibration detected by the sensor 38 is small.

[0019] In addition, when a large horizontal force such as an earthquake acts on the building, the laminated rubber (not shown) undergoes shear deformation, and the downward sliding surface 20 moves from the center 1802 of the upward sliding surface 18 to the outer periphery 1804, and at that time, the energy is damped by the energy damping means (not shown). Furthermore, the control unit 28 generates magnetic force from the magnetic force generating unit 26, i.e., the multiple coils 34 of each coil annular row 36 provided on the outer periphery 1804 of the upward sliding surface 18, depending on the magnitude of the vibration detected by the sensor 38. This magnetic force acts as a force attracting the downward-facing slide surface 20 towards the upward-facing slide surface 18 , so that the downward-facing slide surface 20 encounters resistance from the outer periphery 1804 of the upward-facing slide surface 18 . Furthermore, when this magnetic force is applied to the magnetorheological fluid 24 , the viscosity of the magnetorheological fluid 24 increases, and the legs 30 experience resistance from the magnetorheological fluid 24 . Therefore, when a large horizontal force acts on the building, two types of resistance are generated, allowing the building's swaying to be suppressed with a greater damping force. Therefore, there is no need to secure a large magnetic force generated by the magnetic force generating unit 26 or a large area for the sliding surfaces 18, 20 as in the conventional technology, which is advantageous in attenuating large earthquake energy while reducing the space and costs occupied by the sliding bearing 16. In addition, earthquake energy is also attenuated by the sliding bearings 16, and since part of the damping force of the seismic isolation device 10 is borne by the sliding bearings 16, energy attenuation means such as lead plugs and oil dampers can be made smaller without changing the damping force required of the seismic isolation device 10, which is advantageous in reducing the size of the seismic isolation device 10.

[0020] Furthermore, in this embodiment, the first magnetic force generating unit 26A, which is provided on the upward sliding surface 18 and generates a magnetic force toward the downward sliding surface 20, also serves as the second magnetic force generating unit 26B, which generates a magnetic force toward the magnetorheological fluid 24, which is advantageous in terms of simplifying the configuration and reducing costs.

[0021] Further, the side wall 22 may be provided separately from the sliding member 32. However, providing the side wall 22 integrally with the sliding member 32 as in this embodiment is advantageous in terms of simplifying the structure and reducing costs.

[0022] The contour of the central portion 1802 of the upward slide surface 18 and the contour of the downward slide surface 20 may be formed to be the same, but as in this embodiment, the central portion 1802 of the upward slide surface 18 is formed with a diameter larger than the diameter of the downward slide surface 20, in other words, the contour of the central portion 1802 of the upward slide surface 18 is formed larger than the contour of the downward slide surface 20, so that when a small horizontal force due to wind or the like acts on the building, the downward slide surface 20 will move smoothly and quickly within the contour of the central portion 1802 of the upward slide surface 18, as in the conventional case. Therefore, when a small horizontal force due to wind or the like acts on the building, this is advantageous in quickly and efficiently suppressing the swaying of the building.

[0023] Furthermore, in this embodiment, the magnetic force generating unit 26 is composed of an annular coil array 36 consisting of a plurality of coils 34 arranged at equal intervals circumferentially on a virtual circle centered on the center of the central portion 1802 at the outer periphery 1804. Therefore, regardless of the direction of the horizontal force acting on the building, a magnetic force can be stably applied from the outer periphery 1804 to the downward sliding surface 20. As a result, the downward sliding surface 20 receives more stable resistance from the outer periphery 1804, which is advantageous in attenuating seismic energy by the sliding bearings 16 and suppressing shaking of the building due to earthquakes. In addition, in this embodiment, the multiple first coil annular arrays 36A and the second coil annular arrays 36B are arranged on multiple virtual circumferences with different radii from the center of the central portion 1802, so that even if the horizontal displacement of the building becomes large, a magnetic force can be reliably applied to the downward sliding surface 20 from the outer periphery 1804 in a stable manner, and the downward sliding surface 20 receives more stable resistance from the outer periphery 1804, which is advantageous in attenuating earthquake energy by the sliding bearings 16 and suppressing shaking of the building due to earthquakes.

[0024] In addition, the control unit 28 may control the magnetic force generating unit 26 so that the magnetic force generated by the magnetic force generating unit 26 is the same regardless of the distance from the center of the central portion 1802 of the upward sliding surface 18. However, if, as in this embodiment, the control unit 28 controls the magnetic force generating unit 26 so that the magnetic force increases the farther the outer periphery 1804 is from the center of the central portion 1802 of the upward sliding surface 18, when a large horizontal force acts on the building due to an earthquake or the like, the further the downward sliding surface 20 is from the central portion 1802 of the upward sliding surface 18, in other words, the greater the horizontal displacement of the building, the greater the resistance that the upward sliding surface 18 will receive from the outer periphery 18, which is advantageous for significantly attenuating earthquake energy by the sliding bearing 16. Therefore, when a large horizontal force acts on the building, it is more advantageous to suppress the swaying of the building through a larger damping force.

[0025] In addition, the control unit 28 may control the magnetic force generating unit 26 so that the magnetic force generated by the magnetic force generating unit 26 remains constant regardless of the amount of vibration of the building detected by the sensor 38. However, if, as in this embodiment, the control unit 28 controls the magnetic force generating unit 26 so that the magnetic force generated by the magnetic force generating unit 26 gradually increases as the amount of vibration of the building detected by the sensor 38 increases, when a large horizontal force acts on the building due to an earthquake or the like, the greater the force acting on the building and the greater the amount of vibration detected by the sensor 38, the greater the resistance that the downward-facing sliding surface 20 receives from the outer periphery 1804 of the upward-facing sliding surface 18 and the resistance that the leg 30 receives from the magnetorheological fluid 24 will be, which is advantageous for significantly attenuating earthquake energy by the sliding bearing 16. Therefore, when a large horizontal force acts on the building, it is more advantageous to suppress the swaying of the building through a larger damping force.

[0026] (Second embodiment) Next, a second embodiment will be described with reference to FIG. In the sliding bearing 16A of the second embodiment, a first magnetic force generating portion 26A and a second magnetic force generating portion 26B are provided separately. The first magnetic force generating portion 26A is provided on the outer periphery 1804 of the upward sliding surface 18, similarly to the first embodiment. The second magnetic force generating portion 26B is configured by a coil 40 that is wound in a spiral shape so as to surround the side wall 22, and the coil 40 is attached to the outer circumferential surface of the side wall 22 with an adhesive or the like. The coil 40 is an electromagnet that generates a magnetic force on the magnetorheological fluid 24 when a current flows through it, and the current supplied to the coil 40 is controlled by the control unit . Alternatively, the coil 40 may be wound in a spiral shape along the inner circumferential surface 2202 of the side wall 22 and attached to the inner circumferential surface 2202 so that the coil 40 and the magnetorheological fluid 24 come into contact with each other. Furthermore, if the side wall 22 is made of a material (sliding member 32) that transmits magnetic force, the helically wound coil 40 may be embedded inside the side wall 22.

[0027] The CPU of the control unit 28 executes a control program to control the amount of electricity (current) flowing through the coil 34 based on the detection results of the sensor 38, thereby controlling the magnetic force generated on the downward sliding surface 20, and also controls the amount of electricity (current) flowing through the coil 40 to control the magnetic force acting on the magnetorheological fluid 24. As in the first embodiment, vibrations of different magnitudes are divided into stages, and a table in which the magnitude of vibration at each stage corresponds to the amount of current to be passed through the multiple coils 34 in each coil annular row 36 is stored in advance in the storage unit. In addition, vibrations of different magnitudes are divided into stages, and a table in which the magnitude of vibration at each stage corresponds to the amount of current to be passed through the coils 40 is stored in advance in the storage unit. The CPU refers to the two tables based on the amount of vibration detected by the sensor 38, and energizes the coils 34 and 40 with an amount of electricity corresponding to the magnitude of the vibration.

[0028] According to the second embodiment, the control unit 28 can independently control the magnetic force generated by the first magnetic force generating unit 26A and the magnetic force generated by the second magnetic force generating unit 26B, thereby enabling fine control of the resistance that the downward sliding surface 20 receives from the outer periphery 1804 of the upward sliding surface 18 and the resistance that the leg 30 receives from the magnetorheological fluid 24, which is advantageous in finely controlling the attenuation of earthquake energy. Furthermore, the control unit 28 can of course operate both the first magnetic force generating unit 26A and the second magnetic force generating unit 26B to attenuate earthquake energy, but it can also operate one of the first magnetic force generating unit 26A and the second magnetic force generating unit 26B and stop the functioning of the other to attenuate earthquake energy. Therefore, selectively controlling the magnetic forces generated by the first magnetic force generating unit 26A and the second magnetic force generating unit 26B depending on the magnitude of the vibrations acting on the building is advantageous in appropriately attenuating earthquake energy. [Explanation of symbols]

[0029] 10 Seismic isolation device 12 Superstructure 1202 Bottom surface 14 Undercarriage 1402 Top surface 1404 Recess 16, 16A Sliding bearing 18 Upward sliding surface 1802 Central part 1804 Outer periphery 20 Downward sliding surface 22 Side wall 2202 Inner surface 24 Magnetorheological fluid 26 Magnetic force generating unit 28 Control Unit 30 Legs 3002 flange 3004 Pillar section 3006 Outer surface 32 Sliding member 34 Coil 36 coil annular array 36A First coil ring 36B Second coil ring array 38 Sensors 40 Coil S Storage space

Claims

1. an upwardly facing slide surface provided on the lower structure; a downward sliding surface provided on the upper structure and smaller than the contour of the upward sliding surface and in slidable contact with a central portion of the upward sliding surface; The upward sliding surface is made of a material that is permeable to magnetic force and has a small coefficient of friction; A first magnetic force generating unit is provided on the upward sliding surface to generate a magnetic force against the downward sliding surface, The downward sliding surface is made of a magnetic material that is attracted to a magnet and has a small coefficient of friction. A sliding bearing provided with a control unit that controls the magnetic force generated by the first magnetic force generating unit, a side wall extending along a contour of the upwardly facing slide surface; A magnetorheological fluid is contained in an upwardly open storage space formed by the upwardly facing sliding surface and the side wall, The downward sliding surface is provided at the lower end of a leg protruding from the lower part of the upper structure, at least a lower portion of the leg is immersed in the magnetorheological fluid with the downward sliding surface in contact with the upward sliding surface; a second magnetic force generating unit that generates a magnetic force on the magnetorheological fluid; The magnetic force generated by the second magnetic force generating unit is controlled by the control unit, The first magnetic force generating unit doubles as the second magnetic force generating unit, A sliding bearing characterized by:

2. A sliding member constituting the upward sliding surface is provided on the lower structure, The side wall is integral with the sliding member.

2. The sliding bearing according to claim 1.

3. the upwardly facing slideway has a central portion that is larger than the contour of the downwardly facing slideway; The first magnetic force generating portion is provided on an outer periphery of the central portion of the upward sliding surface.

3. The sliding bearing according to claim 1 or 2.

4. The first magnetic force generating portion is configured by an annular coil array including a plurality of coils arranged at intervals in the circumferential direction on a virtual circumference centered on the center of the central portion.

4. The sliding bearing according to claim 3.

5. The coil annular array is provided on a plurality of imaginary circumferences having different radii from the center of the central portion.

5. The sliding bearing according to claim 4.

6. The control of the first magnetic force generating unit by the control unit in the outer circumferential portion is performed so that the magnetic force is increased as the distance from the center of the central portion increases.

6. A sliding bearing according to claim 3, characterized in that the sliding bearing is a rotatable member.

7. The control of the first magnetic force generating unit and the second magnetic force generating unit by the control unit is performed so that the magnetic force is increased as the vibration amount of the upper structure or the lower structure increases.

7. A sliding bearing according to claim 1, characterized in that it is arranged so as to be in a position parallel to the sliding surface.

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