JP5574337B2 - Vertical motion isolation system - Google Patents

Description

  The present invention relates to a vertical motion seismic isolation mechanism that can significantly suppress vibration during an earthquake by increasing the natural period.

  Conventionally, an air spring corresponding to vertical movement is known as a seismic isolation device used for a seismic isolation structure. In such an air spring, since the allowable load per area is small, it is difficult to apply to high-rise buildings. On the other hand, there is a seismic isolation device in which a coil spring, not an air spring, is provided between a building and a foundation, for example, with its expansion / contraction direction facing up and down, and corresponding to the up and down movement of both (for example, patent document) 1).

Japanese Patent No. 3749931

However, the conventional seismic isolation device has the following problems.
In other words, in a seismic isolation device equipped with a coil spring that expands and contracts in the vertical direction, it is difficult to control to increase the natural period effectively because it directly receives a large force due to the vertical movement generated between the vertical structures. There was room for.
Further, when the seismic isolation device is the above-described air spring, it is necessary to manage the air compressor so that it can always operate satisfactorily, and much labor is required for maintenance.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a vertical motion seismic isolation mechanism that can significantly suppress vibration during an earthquake by increasing the natural period.
Another object of the present invention is to provide a vertical motion seismic isolation mechanism that can reduce the labor required for maintenance.

In order to achieve the above object, the vertical motion isolation mechanism according to the present invention is a vertical motion isolation mechanism interposed between an upper structure and a lower structure that are close to and away from each other in the vertical direction. A screw shaft in which one end of the screw shaft direction is fixed to any one of the structures, and a screw shaft that is screwed to the screw shaft, and rotates according to displacement of the screw shaft in the screw shaft direction. It includes a nut which is rotatably held relative to the other structure of the lower structure, and a spring member restoring force is applied to the rotated nut returns to the predetermined initial position, the spring member, the outer peripheral side of the nut And a torsion coil spring having one end fixed to the nut and the other end fixed to the other structure .

In the present invention, when a displacement that is close to and away from each other in the vertical direction occurs between the upper structure and the lower structure due to vibration during an earthquake, the screw shaft fixed to either the upper structure or the lower structure is While reciprocating in the screw shaft direction (vertical direction) with respect to the nut held in the other structure, the nut screwed to the screw shaft rotates in proportion to the amount of displacement in the screw shaft direction. As the nut rotates, the spring member operates, and a restoring force acts so that the rotated nut returns to a predetermined initial position. For this reason, the screw shaft that is screwed onto the nut also suppresses the displacement caused by the vertical movement and also provides a damping effect.
In addition, the configuration in which the linear motion of the screw shaft is converted into the rotational motion of the nut, that is, the vibration acting between the upper structure and the lower structure acting in the vertical direction is converted into rotational motion, and the rotation is controlled by the spring member. Thus, the natural period of vertical vibration can be increased, and vertical seismic isolation can be realized.
Furthermore, in this vertical motion seismic isolation mechanism, the rotation of the nut can be controlled with a smaller force in the spring member than when the vertical vibration is directly controlled by the vertical spring.
Also, when a vertical displacement occurs between the upper structure and the lower structure, a torsional moment about the coil axis acts on the torsion coil spring member provided coaxially with the rotation of the nut, and the nut that rotates The restoring force works so that the nut returns to a predetermined initial position. For this reason, the screw shaft that is screwed onto the nut also suppresses the displacement caused by the vertical movement and also provides a damping effect.

Moreover, in the vertical motion seismic isolation mechanism according to the present invention, it is more preferable that two or more spring members are provided for the nut.
In the present invention, it is possible to distribute the force by providing a plurality of spring members, and more effectively by arranging the spring members on the expansion side and the contraction side with respect to the rotation of the nut in one direction. The rotation of the nut can be controlled.

Moreover, in the vertical motion seismic isolation mechanism according to the present invention, it is preferable that a plurality of combinations of screw shafts and nuts are provided and connected by a connecting member so that the rotations of the plurality of nuts are synchronized.
In the present invention, by synchronizing the rotation of a plurality of nuts, it is possible to synchronize the vertical movement of the screw shaft, and the vertical movement of the entire building equipped with this vertical movement seismic isolation mechanism is aligned. Rocking vibration can be prevented.

According to the vertical motion seismic isolation mechanism of the present invention, the natural period of the vertical vibration is obtained by converting the linear motion of the vertical motion generated between the upper structure and the lower structure into a rotational motion and controlling the rotation by the spring member. The vibration during an earthquake can be greatly suppressed. And since it is the structure which controls rotation of a nut with a spring member, it can respond effectively with a small force compared with the case where the vibration of an up-down direction is directly controlled by an up-down direction spring.
In addition, since stable performance can be maintained over a long period of time as compared with an air spring, there is an advantage that labor for maintenance can be reduced.

It is an elevation sectional view showing the whole seismic isolation device composition by a 1st embodiment of the present invention. It is the sectional view on the AA line shown in FIG. It is a partially broken side view of the seismic isolation apparatus shown in FIG. (A), (b) is a horizontal sectional view for demonstrating the effect | action of a seismic isolation apparatus, Comprising: It is a figure corresponding to FIG. It is a horizontal sectional view which shows the whole structure of the seismic isolation apparatus by the 2nd Embodiment of this invention, Comprising: It is a figure corresponding to FIG. FIG. 5 is an elevational sectional view showing an overall configuration of a seismic isolation device according to a third embodiment of the present invention, corresponding to FIG. 1.

Hereinafter, a vertical motion seismic isolation mechanism according to a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, a seismic isolation device 1 as a vertical motion isolation system according to the first embodiment is interposed between an upper structure 2 and a lower structure 3 that supports the upper structure 2. The seismic isolation effect is obtained with respect to the vibration in the vertical direction (arrow Y direction) generated between 2 and the lower structure 3.
As shown in FIGS. 1 and 2, the seismic isolation device 1 includes a screw shaft 11 in which one end (fixed end 11b) in the screw shaft direction is fixed to the upper structure 2, and a screw shaft 11 and a lower portion. A nut 12 that is rotatably held with respect to the structure 3 and a pair of spring members 13 (13A, 13B) that suppress the rotation of the nut 12 are schematically configured.

  The screw shaft 11 has a screw 11a formed on the outer peripheral surface over the entire length in the screw shaft direction, and the fixed end 11b is fixed to the base 21 of the upper structure 2 with the screw shaft direction directed in the vertical direction Y.

The nut 12 has a female screw formed on the inner peripheral surface 12 c, is screwed coaxially with the screw shaft 11, and is rotatably held in a cylindrical portion 31 provided in the lower structure 3.
As shown in FIG. 3, specifically, the nut 12 includes a wall portion 12a and a peripheral edge portion 12b projecting radially outward along the entire periphery of the upper end edge of the wall portion 12a. The tube portion 31 is inserted. A locking rod 13b of a spring member 13, which will be described later, is fixed to the peripheral portion 12b at two points (fixed points P1, P2) that are opposed in the radial direction.

In each of the pair of spring members 13A and 13B, a spring main body 13a made of a coil spring is fixed to a base 32 on the lower structure 3, and a fixing point P (which connects the spring main body 13a and the peripheral portion 12b of the nut 12). P1 and P2) are connected to each other by a rod-shaped locking bar 13b. At this time, the spring members 13A and 13B are arranged in a state in which the expansion and contraction direction of the spring is directed in a direction (X direction) parallel to the tangential direction of the nut 12 in a plan view shown in FIG.
The spring members 13A and 13B are not expanded or contracted when the relative position between the upper structure 2 and the lower structure 3 is in the initial state, that is, when the screw shaft 11 is in the initial position in the vertical direction with respect to the nut 12. It is in a state of length L0 (see FIG. 2).

Next, the effect | action of the seismic isolation apparatus 1 mentioned above is demonstrated in detail based on drawing.
As shown in FIG. 1, when the upper structure 2 and the lower structure 3 are displaced in the vertical direction by the vibration at the time of an earthquake, the screw shaft 11 fixed to the upper structure 2 is held by the lower structure 3. While reciprocating in the screw shaft direction (vertical direction Y) with respect to the nut 12, the nut 12 screwed into the screw shaft 11 rotates in proportion to the amount of displacement in the screw shaft direction. At the same time, the fixing points P1 and P2 to which the respective locking rods 13b of the spring members 13A and 13B are fixed also rotate around the central axis.

Then, as shown in FIG. 4A, the screw shaft 11 is displaced downward, the nut 12 rotates in the direction of the arrow W1 in the cylindrical portion 31, and the fixing points P1 and P2 are counterclockwise in the figure from the initial position. When one of the first spring members 13A (here, the upper spring in the drawing) is extended in the direction of the arrow X1 and the spring body 13a is biased, the other second spring member 13B (below the drawing) Side spring) is compressed in the direction of the arrow X2, and the respective spring members 13A and 13B act to return to the original initial state L0 (see FIG. 2).
On the other hand, as shown in FIG. 4B, the screw shaft 11 is displaced upward, the nut 12 rotates in the direction of the arrow W2 in the cylindrical portion 31, and the fixing points P1 and P2 are clockwise from the initial position in the drawing. When moved, the second spring member 13B extends in the arrow X1 direction and the spring body 13a is biased, and the first spring member 13A is compressed in the arrow X2 direction, and each spring member 13A, 13B works to return to the original initial state L0 (see FIG. 2).

  In this way, the spring members 13A and 13B are operated in accordance with the rotation of the nut 12, and thereby a restoring force is exerted so that the rotated nut 12 returns to a predetermined initial position. In addition, displacement due to vertical movement is suppressed and a damping effect is also obtained.

Further, as shown in FIG. 1, in the seismic isolation device 1, the linear motion of the screw shaft 11 is converted into the rotational motion of the nut, that is, the vertical motion generated between the upper structure 2 and the lower structure 3. By converting the vibration to be turned into a rotational motion and controlling the rotation by the spring member 13, the natural period of the vertical vibration can be increased, and the vertical seismic isolation can be realized.
Furthermore, in the spring member 13, the rotation of the nut 12 can be controlled with a smaller force than when the vertical vibration is directly controlled by the vertical spring.

  Further, since the spring member 13 is fixed to the lower structure 3 on which the nut 12 is held via the base 32, even if a displacement occurs between the upper structure 2 and the lower structure 3, the nut 12 and the spring Since there is no relative change in the vertical height with respect to the member 13, the spring member 13 can always give a damping action to the rotation of the nut 12 under the same conditions.

  Further, since the spring member 13 is provided in a state in which the expansion / contraction direction of the spring is directed in a direction parallel to the tangential direction of the nut 12, the spring member 13 is effectively expanded / contracted with respect to the rotation direction of the nut 12. Therefore, the rotation control of the nut 12 can be performed more reliably and with high accuracy.

  In the present embodiment, by providing a plurality (two) of spring members 13A and 13B, the force can be distributed, and the expansion side and the contraction side with respect to the rotation of the nut 12 in one direction. By disposing the spring members 13A and 13B, the rotation of the nut 12 can be controlled more effectively.

As described above, in the vertical motion isolation system according to the present embodiment, the vertical motion linear motion generated between the upper structure 2 and the lower structure 3 is converted into rotational motion, and the rotation is controlled by the spring member 13. Thus, the natural period of vertical vibration can be increased, and vibration during an earthquake can be significantly suppressed. And since it is the structure which controls rotation of the nut 12 with the spring member 13, it can respond effectively with a small force compared with the case where the vibration of an up-down direction is directly controlled with an up-down direction spring.
In addition, since stable performance can be maintained over a long period of time as compared with an air spring, there is an advantage that labor for maintenance can be reduced.

Next, another embodiment of the vertical motion seismic isolation mechanism of the present invention will be described with reference to the accompanying drawings. The same or similar members and parts as those of the above-described embodiment will be described using the same reference numerals. A configuration different from that of the embodiment will be described.
In the seismic isolation device 1A according to the second embodiment shown in FIG. 5, a plurality (two pairs in FIG. 5) of the screw shaft 11 and the nut 12 (motion conversion mechanisms T1 and T2) are provided, and each nut 12A. , 12B are connected by a pair of connecting members 14 (14A, 14B) so as to synchronize with each other. Here, in FIG. 5, the upper first motion conversion mechanism is denoted by reference numeral T1, and the lower second motion conversion mechanism is denoted by reference numeral T2.

One connecting member 14A connects the fixing points P3 and P5 of the nuts 12A and 12B of the motion conversion mechanisms T1 and T2, respectively. The other connecting member 14B connects the fixing points P4 and P6 of the nuts 12A and 12B of the motion conversion mechanisms T1 and T2, respectively.
And spring member 13A, 13B fixed to the base 32 on the lower structure 3 is being fixed to the nut 12A of 1st motion conversion mechanism T1 similarly to 1st Embodiment mentioned above. That is, the action of the spring members 13A and 13B is transmitted to the second motion conversion mechanism T2 via the first motion conversion mechanism T1.

  In the seismic isolation device 1A of the second embodiment, the same functions and effects as those of the first embodiment described above can be obtained, and a pair of motion conversion mechanisms T1, which are connected by the connecting members 14A and 14B, Since the rotation of the nuts 12A and 12B of T2 can be synchronized, and the vertical movement of the screw shafts 11A and 11B can be synchronized, the vertical direction of the entire building equipped with the seismic isolation device 1A The movements of these are aligned, and rocking vibration can be prevented.

Next, as shown in FIG. 6, the seismic isolation device 1 </ b> B according to the third embodiment replaces the spring member 13 (see FIG. 1) of the first embodiment described above with the nut 12 and the lower structure 3. And a torsion coil spring member 15 (spring member).
That is, the torsion coil spring member 15 is coaxially disposed on the outer peripheral side of the cylindrical portion 31 through which the nut 12 is inserted, one end 15a of this spring is fixed to the peripheral portion 12b of the nut 12, and the other end 15b is a lower structure. 3 (the other structure). As the torsion coil spring member 15, a known member is used.

  In the seismic isolation device 1B of the third embodiment, when a displacement in the vertical direction Y occurs between the upper structure 2 and the lower structure 3, the torsion coil spring provided coaxially with the rotation of the nut 12 A torsional moment about the coil axis (symbol C shown in FIG. 6) acts on the member 15, which acts as a resistance of the rotating nut 12, and a restoring force acts so that the nut 12 returns to a predetermined initial position. Therefore, also in the screw shaft 11 screwed into the nut 12, the displacement due to the vertical movement is suppressed, and a damping effect is also obtained.

As mentioned above, although embodiment of the vertical motion seismic isolation mechanism by this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, although a coil spring is used as the spring member in the present embodiment, the present invention is not limited to this, and for example, a damper may be employed.
In the present embodiment, the two spring members 13A and 13B are provided for the nut 12. However, the number of the spring members 13 is not limited, and may be, for example, one spring member or three or more. It doesn't matter.

Moreover, in this Embodiment, although the screw part 11 is fixed to the upper structure 2 side and the nut 12 is hold | maintained at the lower structure 3, arrangement | positioning can also be made upside down. In other words, the nut 12 may be held on the upper structure 2 side and the screw shaft 11 may be fixed on the lower structure 3 side.
Furthermore, in the second embodiment described above, two sets of motion conversion mechanisms T1 and T2 are provided. However, the nuts 12 of three or more sets of motion conversion mechanisms T are connected by connecting members 14 as appropriate. And may be tuned.
Furthermore, the dimensions of the screw shaft 11 and the nut 12, the performance of the spring member, and the like can be appropriately changed according to the conditions for applying the vertical motion seismic isolation mechanism.
In addition, it is possible to appropriately replace the constituent elements in the above-described embodiments with well-known constituent elements without departing from the spirit of the present invention, and the above-described embodiments may be appropriately combined.

1, 1A, 1B Seismic isolation device (vertical motion isolation system)
2 Upper structure 3 Lower structure 11, 11A, 11B Screw shaft 12, 12A, 12B Nut 13, 13A, 13B Spring member 13a Spring body 13b Locking rod 14, 14A, 14B Connecting member 15 Torsion coil spring member (spring member)
P, P1-P6 Fixed point T, T1, T2 Motion conversion mechanism

Claims (3)

A vertical motion seismic isolation mechanism interposed between an upper structure and a lower structure that are closely spaced apart in the vertical direction,
A screw shaft in which one end of the screw shaft direction is fixed to one of the upper structure and the lower structure;
A nut that is screwed to the screw of the screw shaft and rotates in accordance with the displacement of the screw shaft in the screw shaft direction, and is held rotatably with respect to the other structure of the upper structure and the lower structure;
A spring member in which a restoring force works to return the rotated nut to a predetermined initial position;
Equipped with a,
The spring member is a torsion coil spring that is coaxially disposed on the outer peripheral side of the nut, has one end fixed to the nut, and the other end fixed to the other structure. Seismic mechanism. It said spring member is vertically movable seismic isolation mechanism according to claim 1, characterized in that are two or more provided et al with respect to the nut. 3. The vertical motion isolation device according to claim 1 , wherein a plurality of combinations of the screw shafts and nuts are provided and connected by a connecting member so that rotations of the plurality of nuts are synchronized with each other. mechanism.

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