JP2021025576A - Seismic isolation device - Google Patents

Abstract

To provide a seismic isolation device which can suppress displacement of a base isolation layer generated by wind and which can achieve base isolation of a building by maintaining base isolation performance without inhibiting the movement of the base isolation layer when an earthquake occurs, with a simple structure.SOLUTION: A seismic isolation device 100 includes: an outer cylinder 10 which is fixed to a first structure A1, in which a hollow part S is formed inside and which extends in an axial direction; a screw shaft 15 which is fixed to a second structure A2, which is arranged coaxially with the outer cylinder 10 on one side in the axial direction of the hollow part S, and in which a screw groove 16 is formed on an outer peripheral surface; a nut 20 screwed with the screw shaft 15, and for converting an axial direction motion of the screw shaft 15 into a rotary motion; an inner cylinder 25 arranged on the other side in the axial direction of the hollow part S, and joined to the nut 20; a viscous body 26 arranged between the outer cylinder 10 and the inner cylinder 25; and a lock mechanism 3 having a friction material 55, and capable of restraining the rotation of the nut 20 with respect to the outer cylinder 10 by pressing the friction material 55 to the nut 20.SELECTED DRAWING: Figure 1

Description

The present invention relates to a seismic isolation device.

Conventionally, in order to reduce shaking during an earthquake, seismic isolation buildings equipped with a device having a damping function as shown in Patent Document 1 below in the seismic isolation layer are increasing.

In addition, in order to suppress the displacement of the seismic isolation layer caused by wind power while maintaining the seismic isolation performance against earthquakes, a locking mechanism that locks the seismic isolation layer and suppresses the displacement of the seismic isolation layer when the wind speed exceeds a predetermined level is installed. A building equipped is proposed. With this lock mechanism, seismic isolation performance is maintained without hindering the movement of the seismic isolation layer during an earthquake, and the controller outputs a signal to the solenoid valve only when the wind speed is above a predetermined level, and the oil connecting the orifice and tank. The solenoid valve is switched so as to block the path to lock the piston entry / exit operation in the cylinder (see Patent Document 2 below).

Japanese Unexamined Patent Publication No. 2012-37005 Japanese Unexamined Patent Publication No. 9-291721

However, the lock mechanism described in Patent Document 2 has a problem that the configuration becomes complicated because it is necessary to switch the solenoid valve or the like as compared with the case of using a normal seismic isolation device.

Therefore, the present invention has been made in view of the above circumstances, and can suppress the displacement of the seismic isolation layer generated by the wind with a simple configuration, and does not hinder the movement of the seismic isolation layer during an earthquake. To provide a seismic isolation device that can maintain seismic isolation performance.

In order to achieve the above object, the present invention employs the following means.
That is, the seismic isolation device according to the present invention is fixed to the first structure and has an outer cylinder extending in the axial direction in which a hollow portion is formed, and is fixed to the second structure and inside the hollow portion. A screw shaft is arranged coaxially with the outer cylinder on one side in the axial direction of the screw shaft and has a thread groove formed on the outer peripheral surface, and is screwed onto the screw shaft to convert the axial movement of the screw shaft into a rotational movement. It has a nut, an inner cylinder arranged on the other side of the hollow portion in the axial direction and joined to the nut, a viscous body arranged between the outer cylinder and the inner cylinder, and a friction material. However, the friction material is pressed against the nut, and a locking mechanism capable of restraining the rotation of the nut with respect to the outer cylinder is provided.

In the seismic isolation device configured in this way, when an external force is generated due to the wind, the friction material is pressed against the nut to restrain the rotation of the nut with respect to the outer cylinder, and the movement of the seismic isolation layer is locked. be able to. Therefore, the displacement of the seismic isolation layer caused by the wind can be suppressed by a simple configuration in which the friction material is pressed against the nut without requiring a complicated control system.
In addition, when an external force is generated due to an earthquake, the lock mechanism is released, and the nut and screw shaft convert axial motion into rotary motion, and the viscous body between the outer cylinder and the inner cylinder. Due to the viscous resistance of the building, it exerts a damping force, seismic isolation of the building, and damping can be applied.

Further, the seismic isolation device according to the present invention is a signal that restrains the rotation of the nut with respect to the lock mechanism when the measurement result is equal to or more than a threshold value based on the anemometer and the measurement result of the anemometer. It is preferable to include a control unit for transmitting the above.

In the seismic isolation device configured in this way, when the measurement result of the anemometer is equal to or higher than the threshold value, the control unit sends a signal to the lock mechanism to restrain the rotation of the nut, thereby moving the seismic isolation layer. Can be locked. Therefore, it can be controlled without the need for an operator to lock.
Alternatively, it is also possible for the operator to judge based on the measurement result of the anemometer and manually transmit a signal for restraining the rotation of the nut. The work in this case is only the turning on of the signal transmission switch, and no complicated work is required.

Further, in the seismic isolation device according to the present invention, the lock mechanism includes a pressing portion provided with the friction material at the tip portion, a hydraulic jack for applying a compressive force so as to bring the friction material close to the nut. It may have an urging portion that urges the friction material in a direction away from the nut.

In the seismic isolation device configured in this way, when an external force is generated due to the wind, the friction material provided in the pressing portion presses the nut by the compressive force of the hydraulic jack and restrains the rotation of the nut. The movement of the seismic isolation layer can be locked. Since the urging portion urges the friction material in the direction of separating it from the nut, when the external force caused by the wind is less than the predetermined wind speed, the friction material separates from the nut and the lock mechanism is released. To.

According to the seismic isolation device according to the present invention, it is possible to suppress the displacement of the seismic isolation layer generated by the wind with a simple configuration, and maintain the seismic isolation performance without hindering the movement of the seismic isolation layer in the event of an earthquake. Then, the building can be seismically isolated.

It is a figure which shows the seismic isolation device which concerns on one Embodiment of this invention. It is sectional drawing which shows the lock mechanism of the seismic isolation device which concerns on one Embodiment of this invention. It is sectional drawing which shows the lock mechanism of the seismic isolation device which concerns on one Embodiment of this invention. It is sectional drawing which shows the lock mechanism of the seismic isolation device which concerns on one Embodiment of this invention, and shows the time of unlocking. It is sectional drawing which shows the lock mechanism of the seismic isolation device which concerns on one Embodiment of this invention, and shows the time of locking.

The seismic isolation device according to the embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a seismic isolation device according to an embodiment of the present invention. In FIG. 1, a part of the seismic isolation device is shown as a cross section.
As shown in FIG. 1, the seismic isolation device 100 according to the present embodiment has a first member (first structure) A1 and a second member (second structure) A2 such as columns and beams that are relatively displaceable. It is provided between the first member A1 and the second member A2 so as to reduce the relative displacement.

The seismic isolation device 100 includes a seismic isolation mechanism 1 and a lock mechanism 3. The seismic isolation device 100 is arranged with the axis O as the central axis. The direction along the axis O is the X direction, one side of the X direction is the + X side, and the other side is the −X side. The seismic isolation device 100 is divided into regions of amplification unit B1, transmission unit B2, and damping unit B3 along the + side to the-side in the X direction.

The seismic isolation mechanism 1 has a fixed outer cylinder (outer cylinder) 10, a screw shaft 15, a nut 20, and a rotating inner cylinder 25. The fixed outer cylinder 10, the screw shaft 15, the nut 20, and the rotating inner cylinder 25 are arranged so that the axis O is coaxial.

The fixed outer cylinder 10 has an outer cylinder main body 11 and end plates 12a and 12b. The outer cylinder main body 11 is formed in a tubular shape with the axis O as the axis direction. The end plates 12a and 12b are provided at both ends of the outer cylinder body 11 in the X direction. The end plate (end plate arranged on the −X side) 12b is provided with a second mounting portion 13 fixed to the second member A2. A hollow portion S is formed inside the fixed outer cylinder 10.

The screw shaft 15 is inserted into the hollow portion S from the + X side end of the fixed outer cylinder 10. The screw shaft 15 is arranged in the amplification unit B1.

The screw shaft 15 is a rod-shaped member, and is arranged with the axis O as the axis direction. At the end of the screw shaft 15 on the + X side, a first mounting portion 17 fixed to the first member A1 is provided.

FIG. 2 shows the lock mechanism 3 and is a cross-sectional view taken along the axis O.
As shown in FIG. 2, a screw groove 16 is formed on the outer peripheral surface of the screw shaft 15. A ball bearing 18 (see FIG. 2; the same applies hereinafter) capable of rolling the thread groove 16 is arranged in the thread groove 16.

The nut 20 is a cylindrical member having an insertion hole 21 through which the screw shaft 15 is inserted. The nut 20 is screwed onto the screw shaft 15 via a ball bearing 18. As shown in FIG. 1, the nut 20 is arranged in the amplification unit B1. The nut 20 is rotatably joined to the outer cylinder body 11 via the thrust bearing 23. The nut 20 and the screw shaft 15 form a screw movement mechanism that converts a translational motion (axial motion) into a rotational motion or a rotational motion into a translational motion.

The rotating inner cylinder 25 is arranged inside the fixed outer cylinder 10. The rotating inner cylinder 25 is joined to the nut 20. The rotating inner cylinder 25 is arranged in the damping portion B3. The rotating inner cylinder 25 is made rotatable together with the nut 20 in the fixed outer cylinder 10.

In the damping portion B3, a viscous body 26 is arranged between the fixed outer cylinder 10 and the rotating inner cylinder 25. O-rings 27 are provided on both sides in the X direction between the fixed outer cylinder 10 and the rotating inner cylinder 25.

The lock mechanism 3 is configured to be able to restrain the rotation of the nut 20 with respect to the fixed outer cylinder 10. The lock mechanism 3 includes a control panel 30, a hydraulic pump 35, a hydraulic jack (hydraulic cylinder) 40, and a lock device 50.

The control panel 30 is electrically connected to the hydraulic pump 35. The control panel 30 has a pressure display unit 31 and a switch 32. The pressure of the hydraulic pump 35 is displayed on the pressure display unit 31. The hydraulic pump 35 can be operated and stopped by turning the switch 32 on and off.

The hydraulic pump 35 is connected to the hydraulic jack 40 by a hydraulic pipe 36. The hydraulic pump 35 includes a motor 37 and a pressure gauge 38. The motor 37 is a drive source for operating the hydraulic jack 40. The pressure gauge 38 measures the pressure of the hydraulic jack 40. The hydraulic pump 35 is small and can be installed in the fixed outer cylinder 10. The hydraulic pipe 36 may be a member made of inflexible steel.

FIG. 3 shows a lock mechanism 3 and is a cross-sectional view orthogonal to the axis O.
As shown in FIG. 3, a plurality of hydraulic jacks 40 are installed along the circumferential direction of the outer cylinder main body 11 of the fixed outer cylinder 10. In the present embodiment, the hydraulic jacks 40 are installed at four locations, but they may be installed at one or more locations.

FIG. 4 shows the lock mechanism 3, which is a cross-sectional view taken along the axis O and shows the time when the lock is released.
As shown in FIG. 4, a reaction force jig 41 is provided on the outside of the outer cylinder main body 11 of the fixed outer cylinder 10. The hydraulic jack 40 is supported by the reaction force jig 41. In the hydraulic jack 40, when the hydraulic pump 35 (see FIG. 1; the same applies hereinafter) is operated, the push rod 51 described later is moved inward in the radial direction by utilizing the reaction force from the reaction force jig 41. Then, a compressive force is applied so as to press the friction material 55, which will be described later, against the nut 20.

As shown in FIG. 2, the lock device 50 includes a push rod (pressing portion) 51, a friction member 55, and an urging portion 60.

The push rod 51 has a jack fixing portion 52, a rod main body 53, and a friction material support portion 54.

The jack fixing portion 52 is fixed to the hydraulic jack 40. The jack fixing portion 52 is arranged outside the outer cylinder main body 11.

The outer cylinder body 11 of the fixed outer cylinder 10 is formed with a mounting hole 14 penetrating in the radial direction. The rod body 53 extends inward in the radial direction from the jack fixing portion 52. The rod body 53 is inserted into the mounting hole 14 of the outer cylinder body 11. The friction material support portion 54 is provided at the tip end portion (diameter inner end portion) of the rod main body 53.

The friction material 55 is provided on the surface of the friction material support portion 54 that faces inward in the radial direction. The friction material 55 can come into contact with the outer peripheral surface of the nut 20. In a state where the friction material 55 shown in FIG. 2 is in contact with the outer peripheral surface of the nut 20 (locked state), the mounting hole 14 of the outer cylinder body 11 of the fixed outer cylinder 10 is radially larger than the friction material support portion 54. A space is formed on the outside. As a result, when the rod body 53 is displaced outward in the radial direction, the friction material support portion 54 enters the space so that the friction material 55 can be separated from the outer peripheral surface of the nut 20.

The urging portion 60 is provided between the jack fixing portion 52 and the outer cylinder main body 11. The urging portion 60 urges the friction material 55 in the direction away from the nut 20, that is, outward in the radial direction. In this embodiment, the urging portion 60 is composed of a disc spring.

Next, the operation of the seismic isolation device 100 will be described.
Normally, the switch 32 of the control panel 30 is turned off, the hydraulic pump 35 is not operating, and the friction material 55 is separated from the nut 20 in the unlocked state shown in FIG.
When an interlayer displacement occurs between the first member A1 and the second member A2 at the time of an earthquake, the nut 20 and the screw shaft 15 convert the translational motion into a rotary motion, and the damping portion B3 fixes the outer cylinder. A damping force is exerted by the viscous resistance of the viscous body 26 between the 10 and the rotating inner cylinder 25. That is, it functions as a viscous damper.

FIG. 5 shows the locking mechanism 3, which is a cross-sectional view taken along the axis O and shows the locked state.
When the wind speed exceeds the threshold value, the operator automatically or automatically turns on the switch 32 of the control panel 30 to operate the hydraulic pump 35, and the compressive force of the hydraulic jack 40 causes as shown in FIG. , The push rod 51 is moved inward in the radial direction, and the nut 20 is pressed by the friction material 55. As shown in FIG. 3, a frictional resistance force P is generated between the friction material 55 and the nut 20 by the jack axial force N. As a result, the nut 20 and the screw shaft 15 are locked, the translational motion of the nut 20 and the screw shaft 15 is stopped, and the displacement of the seismic isolation layer is suppressed.

The operator turns off the switch 32 of the control panel 30. Alternatively, the switch is automatically turned off by setting the switch to be turned off several hours after the locked state. As a result, the hydraulic pump 35 stops, the compressive force from the hydraulic jack 40 disappears, and the push rod 51 moves to the original position (outside in the radial direction) due to the urging force of the urging portion 60. The friction material 55 is separated from the nut 20, and the frictional resistance force P disappears.

It should be noted that the friction material 55 may slide on the nut 20 and the lock may be released when a large earthquake or a larger wind force is generated at the time of locking and a load exceeding the installed lock load is applied. ..

For example, Table 1 shows various numerical values when four hydraulic cylinders with a guaranteed load of 100 kN and a stroke of 25 mm are installed using a damping frame with a maximum shaft damping force of 1400 kN.

The calculation of the torque T, the required frictional force P, and the required jack axial force N is as shown in mathematical formulas (1) to (3).

In the seismic isolation device 100 configured in this way, when an external force due to wind is generated, the friction material 55 is pressed against the nut 20 to restrain the rotation of the nut 20 with respect to the fixed outer cylinder 10 to seismically isolate the device 100. The movement of the layers can be locked. Therefore, the displacement of the seismic isolation layer caused by the wind can be suppressed by a simple configuration in which the friction material 55 is pressed against the nut 20 without requiring a complicated control system.

Further, when an external force is generated due to an earthquake, the lock mechanism 3 is released, and the nut 20 and the screw shaft 15 convert the translational motion into a rotary motion, so that the fixed outer cylinder 10 and the rotary inner cylinder 25 are released. Due to the viscous resistance of the viscous body 26 between and, a damping force is exerted, the building can be seismically isolated, and damping can be imparted.

Further, when an external force is generated due to the wind, the friction material 55 provided on the push rod 51 presses the nut 20 by the compressive force of the hydraulic jack 40 to restrain the rotation of the nut 20 and seismic isolation. The movement of the layers can be locked. Since the urging portion 60 urges the friction material 55 in the direction of separating it from the nut 20, when the external force caused by the wind is equal to or less than a predetermined wind speed, the friction material 55 is separated from the nut 20. The lock mechanism 3 is released.

Also, unlike the windproof lock mechanism that uses shear pins and steel dampers, it can be automatically released without the need to replace members even after locking. In addition, since the rigidity of the seismic isolation layer is not constantly increased, the original seismic isolation performance can be exhibited even in the event of a small or medium-sized earthquake.

Further, since the structure is such that the lock mechanism 3 is only added to the seismic isolation mechanism (viscous damper) 1, the function can be added at low cost. That is, it is a device that locks the seismic isolation layer during a storm while functioning as a normal viscous damper at all times and during an earthquake. However, since the sum of the frictional resistance force P and the viscous resistance force of the lock mechanism 3 becomes the damper reaction force, the length of the damping portion B3 may be reduced, or the damping portion B3 may be omitted and only the locking mechanism 3 may be used. You can also do it. Further, when an earthquake is encountered while the lock mechanism 3 is operating, a method of releasing the lock mechanism 3 to eliminate the frictional resistance force P can be taken.

Further, since the ball screw mechanism is used, the frictional resistance force P between the nut (ball nut) 20 and the outer cylinder main body 11 of the fixed outer cylinder 10 can be orders of magnitude smaller than the lock load. As shown in Table 1, the frictional resistance force P between the nut 20 and the outer cylinder body 11 of the fixed outer cylinder 10 is 18.6 × 4 units = 74 for a lock load (axial force of the device) of 1000 kN. It is extremely small at 0.4 kN. Therefore, the jack reaction force that presses the friction material 55 against the nut 20 may be small. Moreover, the jack stroke for generating frictional resistance is also small. Therefore, the hydraulic jack to be used may be a small, lightweight and inexpensive device, and the hydraulic pump 35 may be a device having a small amount of oil, so that the device can be realized at low cost.

Further, since the hydraulic jack 40 and the hydraulic pump 35 have a compact structure, the hydraulic jack 40 and the hydraulic pump 35 can be mounted on the seismic isolation mechanism 1. Therefore, since there is no relative displacement between the hydraulic jack 40 and the hydraulic pump 35, it is possible to connect with an inexpensive steel hydraulic pipe 36 that is not flexible, and to construct a high-pressure and highly reliable hydraulic system at low cost. Can be done.

It should be noted that the various shapes and combinations of the constituent members shown in the above-described embodiment are examples, and various changes can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the embodiment shown above, the switch 32 is turned on and off by a person such as an operator, but the present invention is not limited to this. The seismic isolation device 100 includes an anemometer and a control unit, and is a signal that restrains the rotation of the nut 20 with respect to the lock mechanism 3 when the measurement result is equal to or higher than the threshold value based on the measurement result of the anemometer. May be configured to transmit. In this case, when the measurement result of the anemometer is equal to or higher than the threshold value, the control unit locks the movement of the seismic isolation layer by transmitting a signal for restraining the rotation of the nut 20 to the lock mechanism 3. Can be done. Therefore, it can be controlled without the need for an operator to lock.

1 ... Seismic isolation mechanism 3 ... Lock mechanism 10 ... Fixed outer cylinder (outer cylinder)
15 ... Screw shaft 16 ... Thread groove 18 ... Ball bearing 20 ... Nut 25 ... Rotating inner cylinder (inner cylinder)
26 ... Viscous body 30 ... Control panel 35 ... Hydraulic pump 40 ... Hydraulic jack 50 ... Locking device 51 ... Push rod (pressing part)
55 ... Friction material 60 ... Biasing part 100 ... Seismic isolation device A1 ... First member (first structure)
A2 ... Second member (first structure)
B1 ... Amplification part B2 ... Transmission part B3 ... Attenuation part S ... Hollow part

Claims (3)

An outer cylinder that is fixed to the first structure and has a hollow portion formed inside and extends in the axial direction.
A screw shaft fixed to the second structure and coaxially arranged with the outer cylinder on one side in the axial direction in the hollow portion and having a thread groove formed on the outer peripheral surface.
A nut that is screwed onto the screw shaft and converts the axial movement of the screw shaft into rotational movement.
An inner cylinder arranged on the other side in the hollow portion in the axial direction and joined to the nut,
A viscous body arranged between the outer cylinder and the inner cylinder,
A seismic isolation device having a friction material, comprising a lock mechanism capable of pressing the friction material against the nut and restraining the rotation of the nut with respect to the outer cylinder. Anemometer and
A claim comprising a control unit that transmits a signal for restraining the rotation of the nut to the lock mechanism when the measurement result is equal to or greater than a threshold value based on the measurement result of the anemometer. Item 1. The seismic isolation device according to item 1. The lock mechanism is
A pressing portion provided with the friction material at the tip portion and
A hydraulic jack that applies a compressive force so that the friction material is brought close to the nut,
The seismic isolation device according to claim 1 or 2, further comprising an urging portion for urging the friction material in a direction away from the nut.

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