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 22 to generate a magnetic force according to a magnitude of the vibration quantity detected by a sensor 52. 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, a magnetic force is generated from a coil 34 with respect to a magnetic viscous fluid 50 to deform a shape of the magnetic viscous fluid 50 enclosed in a bag body 48 in a manner that the shape extends along a direction of a magnetic field. The action causes a piston rod 46 to protrude upward to move a friction body 24 to a contact position P1 and place a frictional surface 38 in contact with the downward-facing slide surface 20. As a result, the downward-facing slide surface 20 receives frictional resistance.SELECTED DRAWING: Figure 3

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 reducing 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 is a sliding bearing comprising 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 made of a material permeable to magnetic force and having a small friction coefficient, the downward sliding surface being made of a magnetic material that is attracted to a magnet and having a small friction coefficient, a first magnetic force generating unit that generates a magnetic force from below the downward sliding surface is provided, and a first control unit that controls the magnetic force generated by the first magnetic force generating unit is provided, the sliding bearing comprising: a friction body provided on the upward sliding surface and having a friction surface formed with a larger friction coefficient than the upward sliding surface; an actuator that moves the friction body between a contact position where the friction surface contacts the downward sliding surface and a non-contact position where it is separated from the downward sliding surface; and a second control unit that controls the actuator. Moreover, one embodiment of the present invention is characterized in that a guide hole is provided in the upward sliding surface, the friction body has an outer circumferential surface that contacts with an inner circumferential surface of the guide hole without any gap, and the friction body is moved between the contact position and the non-contact position while the outer circumferential surface is guided by the inner circumferential surface. Moreover, one embodiment of the present invention is characterized in that a flange portion having an outer diameter larger than that of the friction body is provided at the lower part of the friction body, a large diameter hole into which the flange portion is inserted is provided at the lower part of the guide hole, and the flange portion abuts against an upper end surface of the large diameter hole, thereby positioning the friction body at the contact position. Moreover, one embodiment of the present invention is characterized in that the actuator includes a cylindrical cylinder oriented in the vertical direction, a piston that divides a cylinder chamber of the cylinder into upper and lower halves, a piston rod that extends upward from the piston, protrudes above the cylinder and is connected to the friction body, a flexible bag body that is contained in the lower of the two cylinder chambers that are divided into upper and lower halves and in which a magnetorheological fluid is sealed, and a second magnetic force generating unit that generates a magnetic force on the magnetorheological fluid, and the movement of the friction body between the contact position and the non-contact position is achieved by controlling the magnetic force generated by the second magnetic force generating unit with the second control unit to change the shape of the magnetorheological fluid sealed in the bag body, thereby moving the piston in the axial direction of the cylinder. In addition, one embodiment of the present invention is characterized in that the cylinder is formed of a material that transmits magnetic force, and the first magnetic force generating portion also serves as the second magnetic force generating portion. In addition, in one embodiment of the present invention, the second magnetic force generation portion is provided for each of the actuators. In addition, one embodiment of the present invention is characterized in that the control of the first magnetic force generating unit by the first control unit is performed so 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 further, the actuator brings the friction surface of the friction body into contact with the downward sliding surface, so that the downward sliding surface experiences frictional resistance. 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, according to one embodiment of the present invention, regardless of the position of the friction body, no gap is formed between the outer peripheral surface of the friction body and the inner peripheral surface of the guide hole, which is advantageous in preventing dust from entering the guide hole and improving durability. Furthermore, according to one embodiment of the present invention, the gap between the flange portion and the upper end face is blocked at the contact position, which is advantageous in preventing dust from entering the guide hole and improving durability. Furthermore, according to one embodiment of the present invention, an actuator is used in which the shape of the magnetorheological fluid sealed in a bag is changed by controlling magnetic force to move the piston in the axial direction of the cylinder, thereby moving the friction body between a contact position and a non-contact position. This is advantageous in terms of simplifying the configuration and making it more compact than when an actuator using hydraulic or pneumatic pressure is used. Furthermore, according to one embodiment of the present invention, the first magnetic force generating section also serves as the second magnetic force generating section, which is advantageous in terms of simplifying the configuration and reducing costs. Furthermore, according to one embodiment of the present invention, the first magnetic force generation unit and the second magnetic force generation unit can be controlled independently, which is advantageous in finely controlling the attenuation of earthquake energy. Furthermore, according to one embodiment of the present invention, the first magnetic force generating unit is controlled so that the magnetic force generated by the first magnetic force generating unit increases as the vibration amount of the upper structure or the lower structure increases. Therefore, the greater the vibration amount of the upper structure or the lower structure, the greater the resistance that the downward sliding surface receives from the upward sliding surface, which is advantageous for greatly attenuating energy through the sliding bearing. [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] 1 is an enlarged cross-sectional view of the actuator and its periphery in the first embodiment, showing a state in which a friction body is located at a non-contact position P0. FIG. [Diagram 3] 1 is an enlarged cross-sectional view of the actuator and its periphery in the first embodiment, showing a state in which a friction body is located at a contact position P1. [Figure 4] FIG. 11 is an enlarged cross-sectional view of the actuator and its periphery in the second embodiment, showing a state in which the friction body is located at a non-contact position P0. [Diagram 5] FIG. 11 is an enlarged cross-sectional view of the actuator and its periphery in the second embodiment, showing a state in which the friction body is located at contact position P1. 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 bearing 16 includes an upward sliding surface 18 provided on the lower structure 14, a downward sliding surface 20 provided on the upper structure 12 and supported by the upward sliding surface 18, a magnetic force generating unit 22, a plurality of friction bodies 24 (see Figure 2), an actuator 26 (see Figure 2), 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 .

[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 magnetic force generating unit 22 is provided on the upward sliding surface 18, and functions as a first magnetic force generating unit 22A that generates a magnetic force from below on the downward sliding surface 20. In this embodiment, the magnetic force generating unit 22 also functions as a second magnetic force generating unit 22B that generates a magnetic force on the magnetorheological fluid 50 described later, in other words, the first magnetic force generating unit 22A also serves as the second magnetic force generating unit 22B. In this embodiment, the magnetic force generating unit 22 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 22, the downward sliding surface 20 is attracted toward the upward sliding surface 18 by the magnetic force. The magnetic force generating unit 22 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 circumference centered on the center of the central portion 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 22 is not limited to two rows, but may be one row or three or more rows.

[0012] In this embodiment, the magnetic force generating unit 22 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 22 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.

[0013] As shown in FIGS. 2(A) and 2(B), the plurality of friction bodies 24 are provided on the upward sliding surface 18 and have a friction surface 38 formed with a friction coefficient larger than that of the upward sliding surface 18. The friction body 24 is made of, for example, a material having a larger friction coefficient than the sliding member 32, and various conventionally known materials such as synthetic resin materials and elastomers (rubber) can be used as such materials. Furthermore, the friction coefficient of the friction surface 38 may be adjusted by performing a surface treatment (surface processing) on ​​the friction surface 38.

[0014] As shown in FIG. 1(B), in this embodiment, the friction bodies 24 are provided at intervals on the same virtual circumference as the coil annular rows 36 (first and second coil annular rows 36A, 36B), and each friction body 24 is arranged alternately with the coils 34 that constitute the coil annular row 36. As shown in FIG. 2, the friction body 24 includes a friction body main body 2402 formed in a cylindrical shape and having a friction surface 38 formed at the upper end thereof, and a flange portion 2404 provided at the lower portion of the friction body main body 2402 and having a larger radius than the friction body main body 2402. The outer circumferential surface of the friction body main body 2402 is a portion that comes into contact with the inner circumferential surface of the small diameter hole 4002 of the guide hole 40 described below without any gap. In addition, the reference numeral 2406 in the figure indicates a chamfer formed at the corner where the friction surface 38 and the outer circumferential surface of the friction body main body 2402 intersect. By forming the chamfer 2406, damage to the downward sliding surface 20 due to the corner of the friction body 24 located at the contact position P1 is prevented, and durability is improved.

[0015] The sliding member 32 is provided with a guide hole 40 that opens onto the upward sliding surface 18, and the friction body 24 is guided by the guide hole 40 in the vertical direction. The guide hole 40 comprises a small diameter hole 4002 formed with an inner diameter corresponding to the outer diameter of the friction body main body 2402, and a large diameter hole 4004 provided at the lower part of the small diameter hole 4002 and into which the flange portion 2404 is inserted, and at the boundary between the small diameter hole 4002 and the large diameter hole 4004, an annular upper end surface 4006 is formed against which the flange portion 2404 can abut.

[0016] The actuator 26 moves the friction body 24 between a contact position P1 where the friction surface 38 contacts the downward sliding surface 20 and a non-contact position P0 where the friction surface 38 is separated from the downward sliding surface 20, and in this embodiment, is provided for each friction body 24. At this time, the friction body 24 is moved between the contact position P1 and the non-contact position P0 while the outer circumferential surface of the friction body main body 2402 is guided by the inner circumferential surface of the small diameter hole 4002. That is, as shown in FIG. 2(B), the actuator 26 moves the friction body 24 upward, and the flange portion 2404 abuts against the upper end surface 4006, thereby positioning the friction body 24 at the contact position P1, and as shown in FIG. 2(A), the actuator 26 moves the friction body 24 downward, thereby moving the friction body 24 from the contact position P1 to the non-contact position P0.

[0017] In the present embodiment, the actuator 26 includes a cylinder 42, a piston 44, a piston rod 46, a bag body 48, a magnetorheological fluid 50, and a second magnetic force generation unit 22B. The cylinder 42 is cylindrical in shape and has a bottom wall 4202, a peripheral wall 4204 rising from the periphery of the bottom wall 4202, and an upper wall 4206 closing the upper end of the peripheral wall 4204. The cylinder 42 is embedded in the sliding member 32 at the lower part of the guide hole 40 with its axis aligned with the axis of the guide hole 40. The cylinder 42, like the sliding member 32, is made of a material that transmits magnetic force, such as a synthetic resin material. The piston 44 divides the cylinder chamber formed by the cylinder into an upper cylinder chamber 42A and a lower cylinder chamber 42B, and is provided movably along the axis of the cylinder . The piston rod 46 extends upward from the piston 44 , protrudes upward from the upper wall 4206 of the cylinder 42 , and is connected to the friction body 24 . The bag body 48 is housed in the lower cylinder chamber 42B, has a magnetorheological fluid 50 sealed therein, and has flexibility and stretchability. The bag 48 is made of a material such as a rubber membrane. The magnetorheological fluid 50 (Magneto Rheological Fluid: 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 shape changes so as to extend along the direction of the magnetic field when a magnetic force is generated in the magnetorheological fluid 50 (in other words, when a magnetic field is applied). The magnetorheological fluid 50 is also a functional fluid whose viscosity changes significantly when a magnetic force is generated. The greater the generated magnetic force (in other words, the stronger the applied magnetic field), the greater the change in shape and the higher the change in viscosity.

[0018] The second magnetic force generating section 22B generates a magnetic force with respect to the magnetorheological fluid 50 (in other words, applies a magnetic field). In this embodiment, the above-mentioned magnetic force generating section 22 also serves as a second magnetic force generating section 22B that generates a magnetic force on the magnetorheological fluid 50. The movement of the friction body 24 between the contact position P1 and the non-contact position P0 is achieved by the control unit 28 controlling the magnetic force generated by the second magnetic force generating unit 22B (in other words, by controlling the magnetic field applied to the magnetorheological fluid 50) to change the shape of the magnetorheological fluid 50 sealed in the bag body 48 along the magnetic field (a magnetic field oriented vertically in this embodiment). That is, as shown in FIG. 3, when a magnetic field is applied, the magnetorheological fluid 50 changes shape so as to extend along the magnetic field, and the magnetorheological fluid 50 presses the piston 44 upward through the bag body 48, whereby the friction body 24 moves upward together with the piston rod 46 to the contact position P1. Furthermore, as shown in FIG. 2, when the application of the magnetic field is removed, the magnetorheological fluid 50 returns to its original shape, causing the piston 44 to move downward via the bag body 48, and the friction body 24 moves downward together with the piston rod 46 to the non-contact position P0. In addition, the magnetorheological fluid 50 returns to its original shape when the weight applied to the bag body 48 from the friction body 24, the piston rod 46, and the piston 44, and the gravity acting on the magnetorheological fluid 50 itself, and the elasticity of the bag body 48 when contained in the lower cylinder chamber 42B are balanced.

[0019] The control unit 28 constitutes a first control unit that controls the magnetic force generated by the magnetic force generating unit 22. 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 a sensor 52 are connected via an interface circuit. The sensor 52 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 result of the sensor 52, thereby controlling the magnetic force generated on the downward sliding surface 20 and the magnetic force applied to the magnetorheological fluid 50. 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 52, and energizes the coil 34 with an amount of electricity that corresponds to the magnitude of the vibration.

[0020] In this embodiment, the control unit 28 controls the magnetic force generation unit 22 so that the magnetic force generated by the magnetic force generation unit 22 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 22 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 ... of the second annular coil array 36B to be greater than the magnetic force of the first annular coil array 36A. In addition, in this embodiment, the magnetic force generating unit 22 is controlled so that the magnetic force generated by the magnetic force generating unit 22 gradually increases as the amount of vibration of the upper structure 12 or the lower structure 14 detected by the sensor 52 increases. In other words, the magnetic force generating unit 22 is controlled so that the magnetic force generated from each annular coil array 36 in the outer circumferential portion 1804 gradually increases as the distance from the center of the central portion 1802 increases, 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.

[0021] In this embodiment, the control unit 28 (first control unit) also serves as a second control unit that controls the actuator 26, and controls the magnetic force generated by the magnetic force generating unit 22 on the magnetorheological fluid 50 (in other words, controls the magnetic field applied to the magnetorheological fluid 50). In this embodiment, the magnetic force generated by the magnetic force generating unit 22 is set to a value sufficient to move the friction body 24 to the contact position P1 when the actuator 26 is operated. Therefore, when magnetic force is generated from the magnetic force generating unit 22, the friction body 24 is moved to the contact position P1, and when magnetic force is not generated from the magnetic force generating unit 22, the friction body 24 is moved to the non-contact position P0.

[0022] 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 22 to generate a magnetic force because the amount of vibration detected by the sensor 52 is small.

[0023] 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 22, 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 52. 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 .

[0024] Furthermore, as a magnetic force is generated from the coil 34 on the magnetorheological fluid 50, the shape of the magnetorheological fluid 50 sealed in the bag body 48 is deformed so as to extend along the direction of the magnetic field (vertical direction), whereby the piston rod 46 protrudes upward and the friction body 24 moves to the contact position P1, causing the friction surface 38 to come into contact with the downward sliding surface 20, resulting in the downward sliding surface 20 being subjected to frictional resistance. 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 22 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.

[0025] Furthermore, in this embodiment, the first magnetic force generating unit 22A, which generates magnetic force from below on the downward-facing slide surface 20, also serves as the second magnetic force generating unit 22B, which generates magnetic force on the magnetorheological fluid 50, which is advantageous in terms of simplifying the configuration and reducing costs.

[0026] 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.

[0027] Furthermore, in this embodiment, the magnetic force generating unit 22 is composed of an annular coil array 36 consisting of a plurality of coils 3434 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.

[0028] In addition, the control unit 28 may control the magnetic force generating unit 22 so that the magnetic force generated by the magnetic force generating unit 22 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 22 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.

[0029] In addition, the control unit 28 may control the magnetic force generating unit 22 so that the magnetic force generated from the magnetic force generating unit 22 remains constant regardless of the amount of vibration of the building detected by the sensor 52. However, as in this embodiment, if the control unit 28 controls the magnetic force generating unit 22 so that the magnetic force generated by the magnetic force generating unit 22 gradually increases as the amount of vibration of the building detected by the sensor 52 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 52, the greater the resistance that the downward-facing sliding surface 20 will receive from the outer periphery 1804 of the upward-facing sliding surface 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.

[0030] In this embodiment, the friction body 24 has an outer peripheral surface that comes into contact with the inner peripheral surface of the guide hole 40 that opens into the upward sliding surface 18 without any gap, and the friction body 24 is moved between the contact position P1 and the non-contact position P0 while the outer peripheral surface is guided by the inner peripheral surface. Therefore, regardless of the position of the friction body 24, no gap is formed between the outer peripheral surface of the friction body 24 and the inner peripheral surface of the guide hole 40, which is advantageous in preventing dust from entering the guide hole 40 and improving durability.

[0031] In addition, in this embodiment, the flange portion 2404 of the friction body 24 abuts against the upper end surface 4006 of the large diameter hole 4004 of the guide hole 40, thereby positioning the friction body 24 at the contact position P1. Therefore, the gap between the flange portion 2404 and the upper end surface 4006 at the contact position P1 is blocked, which is advantageous in preventing dust from entering the guide hole 40 and improving durability.

[0032] As the actuator, various types of actuators known in the art, such as a hydraulic actuator or a pneumatic actuator, can be used. However, as in the present embodiment, when an actuator 26 is used that moves the piston 44 in the axial direction of the cylinder 42 by changing the shape of the magnetorheological fluid 50 sealed in the bag body 48 by controlling the magnetic force, thereby moving the friction body 24 between the contact position P1 and the non-contact position P0, this is advantageous in terms of simplifying the configuration and making it more compact than when an actuator using hydraulic or pneumatic pressure is used.

[0033] Furthermore, in this embodiment, the cylinder 42 of the actuator 26 is formed from a material that is permeable to magnetic force, and the first magnetic force generating unit 22A also serves as the second magnetic force generating unit 22B that generates magnetic force on the magnetorheological fluid 50 sealed in the bag body 48, which is advantageous in terms of simplifying the configuration and reducing costs.

[0034] In the present embodiment, the case has been described where the multiple friction bodies 24 are arranged at equal intervals on the same virtual circumference as the coil annular array 36 (on a virtual circumference centered on the center of the central portion 1802 at the outer circumferential portion 1804). However, the plurality of friction bodies 24 may be arranged at equal intervals on a virtual circumference different from that of the annular coil array 36, or the plurality of friction bodies 24 may be arranged at equal intervals on the same virtual circumference as that of the annular coil array 36 and also arranged at equal intervals on a virtual circumference different from that of the annular coil array 36. Although multiple friction bodies 24 may be arranged at locations other than on the virtual circumference, arranging multiple friction bodies 24 at equal intervals on the virtual circumference as described above ensures friction between the friction surface 38 and the downward sliding surface 20 regardless of the direction of vibration of the upper structure 12 or the lower structure 14, which is advantageous in stably attenuating earthquake energy.

[0035] (Second embodiment) Next, a second embodiment will be described with reference to FIGS. In the following embodiment, the same parts and members as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted, and the description will focus on the differences. In the sliding bearing 16A of the second embodiment, a second magnetic force generating portion 22B is provided in addition to a first magnetic force generating portion 22A (not shown in Figs. 4 and 5). Explaining this with reference to FIG. 1(B), similarly to the first embodiment, the first magnetic force generating portion 22A (coil 34) is provided on the outer periphery 1804 of the upward sliding surface 18.

[0036] The second magnetic force generating unit 22B is composed of a coil 54 wound in a spiral shape so as to surround the peripheral wall 4204 of the cylinder 42 of the actuator 26A, and the coil 54 is attached to the outer circumferential surface of the peripheral wall 4204 with an adhesive or the like. The coil 54 is an electromagnet that generates a magnetic force on the magnetorheological fluid 50 sealed in the bag body 48 when a current flows through it, and the current supplied to the coil 54 is controlled by the control unit 28. If peripheral wall 4204 is made of a material that transmits magnetic force, spirally wound coil 54 may be embedded inside peripheral wall 4204 . In addition, a coil 54 wound in a spiral shape along the inner surface of peripheral wall 4204 may be attached to the inner surface of peripheral wall 4204 so that the magnetic force of coil 54 is applied directly to magnetorheological fluid 50. In this case, cylinder 42 may be made of a material that is not permeable to magnetic force.

[0037] The CPU of the control unit 28 executes a control program to control the amount of electricity (current) passed through the coil 34 based on the detection results of the sensor 52, thereby controlling the magnetic force generated on the downward sliding surface 20, and also controls the amount of electricity (current) passed through the coil 54 to generate a magnetic force on the magnetorheological fluid 50 sealed in the bag body 48. As in the first embodiment, the magnitude of the magnetic force generated in the magnetorheological fluid 50 from the coil 54 (the strength of the magnetic field applied to the magnetorheological fluid 50) need only be large enough to move the friction body 24 from the non-contact position P0 to the contact position P1.

[0038] As in the first embodiment, vibrations of different magnitudes are divided into stages, and a table correlating 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 52, and energizes the coil 34 with an amount of electricity that corresponds to the magnitude of the vibration.

[0039] According to the second embodiment, not only can the same effects as those of the first embodiment be achieved, but the control unit 28 can independently control the magnetic force generated by the first magnetic force generating unit 22A and the magnetic force generated by the second magnetic force generating unit 22B, so that not only can earthquake energy be attenuated by causing both the first magnetic force generating unit 22A and the second magnetic force generating unit 22B to function, but earthquake energy can also be attenuated by causing one of the first magnetic force generating unit 22A and the second magnetic force generating unit 22B to function and stopping the function of the other. Therefore, selectively controlling the magnetic forces generated by the first magnetic force generating unit 22A and the second magnetic force generating unit 22B depending on the magnitude of the vibrations acting on the building is advantageous in appropriately attenuating earthquake energy. [Explanation of symbols]

[0040] 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 Magnetic force generating unit 22A First magnetic force generating unit 22B Second magnetic force generating unit 24 Friction body 2402 Friction body 2404 Flange 2406 Chamfering 26, 26A Actuator 28 Control section (first control section, second control section) 30 Legs 3002 flange 3004 Pillar section 32 Sliding member 34 Coil 36 coil annular array 36A First coil ring row 36B Second coil ring array 38 Friction surface 3802 Chamfering 40 Guide hole 4002 Small diameter hole 4004 Large diameter hole 4006 Top surface 42 cylinders 4202 Bottom wall 4204 Peripheral wall 4206 Upper wall 42A Upper Cylinder Chamber 42B Lower cylinder chamber 44 Piston 46 Piston rod 48 Bag body 50 Magnetorheological Fluid 52 Sensors 54 Coil

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; The downward sliding surface is made of a magnetic material that is attracted to a magnet and has a small coefficient of friction. A first magnetic force generating unit is provided to generate a magnetic force from below on the downward sliding surface, A sliding bearing provided with a first control unit that controls a magnetic force generated by the first magnetic force generating unit, a friction body provided on the upward sliding surface and having a friction surface formed with a friction coefficient larger than that of the upward sliding surface; an actuator that moves the friction body between a contact position where the friction surface is in contact with the downward sliding surface and a non-contact position where the friction surface is separated from the downward sliding surface; a second control unit that controls the actuator, The actuator comprises: A vertically oriented cylindrical cylinder; A piston that divides the cylinder chamber of the cylinder into upper and lower halves; a piston rod extending upward from the piston, protruding above the cylinder, and connected to the friction body; a flexible bag body that is accommodated in the lower cylinder chamber of the cylinder chamber divided into upper and lower halves and in which a magnetorheological fluid is sealed; a second magnetic force generating unit that generates a magnetic force on the magnetorheological fluid, the movement of the friction body between the contact position and the non-contact position is achieved by changing the shape of the magnetorheological fluid sealed in the bag by controlling the magnetic force generated by the second magnetic force generating unit using the second control unit, thereby moving the piston in the axial direction of the cylinder. A sliding bearing characterized by:

2. A guide hole is provided on the upward sliding surface, the friction body has an outer circumferential surface that comes into contact with the inner circumferential surface of the guide hole without any gap; The friction body is moved between the contact position and the non-contact position while the outer circumferential surface is guided by the inner circumferential surface.

2. The sliding bearing according to claim 1.

3. A flange portion having an outer diameter larger than that of the friction body is provided at a lower portion of the friction body, a large diameter hole into which the flange portion is inserted is provided at a lower portion of the guide hole; The flange portion abuts against an upper end surface of the large diameter hole, thereby positioning the friction body at the contact position.

3. The sliding bearing according to claim 2.

4. The cylinder is made of a material that is permeable to magnetic force; The first magnetic force generating unit doubles as the second magnetic force generating unit, 4. A sliding bearing according to claim 1, wherein the sliding bearing is a bearing having a first end and a second end.

5. The second magnetic force generating unit is provided for each of the actuators.

4. A sliding bearing according to claim 1, wherein the sliding bearing is a bearing having a first end and a second end.

6. The control of the first magnetic force generation unit by the first control unit is performed so that the magnetic force is increased as the vibration amount of the upper structure or the lower structure increases.

6. A sliding bearing according to claim 1, characterized in that it is

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