JPH0941720A - Vibration mitigator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently transfer vibration displacement of a structure to a rotational drum of a damper through cables and to make it possible to convert vibration energy of the structure into reciprocation turning motion of the rotational drum without letting the vibration energy escape. SOLUTION: Two system cables 3a.3b symmetrically arranged to a structure are connected with a common damper, and when the structure makes vibration displacement, one cable is tensioned to loosen the other cable. A rotational drum 51 is provided to the damper, both cables 3a.3b are wound on the drum 51, and the ends are fixed to the drum 51. When one cable is tensioned, the cable is drawn out while rotating the drum with the tensile force and, at the same time, the other loose cable is wound on the drum. Both cables 3a.3b are divided into first cables 31 and 33 and second cables 32 and 34, and the first cables and second cables are drawn out in the opposite direction from the drum each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping device for suppressing the vibration (sway) of a structure such as a building or a warehouse rack due to an earthquake or wind, and particularly to a structure for a structure that is fixed by a cable fixed to the upper part of the structure. The present invention relates to a vibration control device that transmits vibration displacement to a damper installed on the ground.

[0002]

2. Description of the Related Art Conventionally, as this type of vibration damping device, there is one disclosed in JP-A-4-176974 (E04H 9/02, E04B 1/34). Regarding vibrations of structures such as high-rise buildings that shake horizontally due to an earthquake or wind, a cable is fixed near the top of the structure where the vibration displacement in the primary mode is the largest, and the cable is guided in a polygonal line by a pulley to the ground. Connect to the damper installed in. At that time, two systems of cables are symmetrically arranged in the structure to create a mechanically complementary relationship in which both cables are alternately tensioned when the structure is displaced back and forth due to vibration. In addition, a laminated rubber damper that absorbs kinetic energy by shear deformation is installed on the ground directly under the structure, the ends of both cables are connected to both ends of the damper, and the damper is sheared by the tension of the cable. Configure. That is, the vibration displacement of the structure is reciprocally transmitted to the damper via both cables, and the vibration energy of the structure is absorbed by the damper.

In order to improve the performance of this type of vibration damping device, the present inventors have previously developed the following improved technique. It includes a mechanism in which a rotary drum is provided at the input stage of the damper and a vibration displacement of a structure is converted into a reciprocating rotary displacement of the drum. That is, as described above, the cable for transmitting the vibration displacement of the structure is wound around the rotating drum, and the drum is rotated by the tension of the cable to give an appropriate damper action to the rotational movement.

[0004]

Since the object is to suppress the vibration of a high-rise building or the like, a tension of several thousand tons is generated in the cable for transmitting the vibration displacement of the structure to the damper. A mechanism for shearing and deforming a laminated rubber damper with this tension can be easily realized, but the tension of the cable is converted into the rotational displacement of the drum, and the reciprocating displacement of the vibration of the structure is reciprocating the drum. Converting to dynamic displacement is not easy. In the configuration in which the cable is simply wound around the drum and both sides of the cable are pulled out from the drum and guided to the structure, the cable and the drum may slip, and the tensile displacement of the cable may not be linked to the rotational displacement of the drum. Therefore, the vibration energy of the structure cannot be efficiently transmitted to the damper, and the damping effect is significantly reduced. Further, since an extremely large force (cable tension) is applied to the rotary drum itself and its bearing support mechanism, the drum itself or its support mechanism may be damaged unless the force is properly dispersed.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to efficiently transmit a vibration displacement of a structure to a rotary drum of a damper via a cable without releasing the vibration energy of the structure. It is an object of the present invention to provide a vibration damping device which can be converted into a reciprocating rotary motion of a rotary drum, and which can appropriately receive a huge force applied to the rotary drum by a cable.

[0006]

The vibration damping device of the present invention has the following requirements. A cable fixed to the upper part of the structure is guided in a polygonal line by a pulley and is connected to a damper installed on the ground,
The vibration displacement of the structure is transmitted to the damper via the cable, and the vibration energy of the structure is absorbed by the damper. The two systems of the cables symmetrically arranged on the structure are coupled to the common damper, and when the structure vibrates, one cable is tensioned and the other cable is relaxed mechanically complementary. Relationship. The damper has a rotating drum, the both cables are wound around the rotating drum, and the ends of the both cables are fixed to the rotating drum. When one of the cables is strained, the tension causes the cable to be pulled out from the rotary drum while rotating the rotary drum, and at the same time, the relaxed other cable is wound around the rotary drum. At least the side of each of the cables wound around the rotary drum is divided into a first cable and a second cable, and the first cable and the second cable are pulled out from the rotary drum in opposite directions.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall schematic configuration of a vibration damping device according to an embodiment of the present invention. A high-rise / super-high-rise structure 2 is built on the ground 1. In the first-order mode of vibration, the vibration displacement is most noticeable.
Is fixed at one end. This pair of cables 3a and 3
b is a structure 2 which crosses diagonally downward and crosses
Is guided to the center of the base of the structure 2 and is connected to a damper 5 described next. ing.

The damper 5 has a rotary drum 51 rotatably supported on the ground 1. The ends of the pair of cables 3a and 3b are respectively wound around the rotary drum 51 as shown in FIG. When the structure 2 vibrates to the left and right due to an earthquake or wind, the pair of cables 3a and 3b have a mechanically complementary relationship so that they are alternately tensioned and relaxed. That is, in FIG. 1, when the structure 2 swings to the right, the cable 3a is tensioned and the cable 3b relaxes, and when the structure 2 swings to the left, the cable 3b.
Strains and the cable 3a relaxes.

The winding form of the rotary drum 51 and both cables 3a and 3b is shown in detail in FIG. Cable 3a
Consists of a first cable 31 and a second cable 32. Similarly, the cable 3b is also composed of two cables, a first cable 33 and a second cable 34. The rotary drum 51 is supported by bearings 6a and 6b at both ends, and a bearing 6c is also provided in the center. Double cable 3a
(31 and 32) are wound around the area of the rotary drum 51 between the bearing portions 6a and 6c, and the double cable 3b (3
3 and 34) are bearings 6b and 6c in the rotary drum 51.
Wrapped in the area between.

The first cable 31 of the double cable 3a
Is directly connected to the rotary drum 51 from the pulley 4 and its end is fixed to the drum 51, and
Is wrapped around. The second cable 32 is connected from the pulley 4 to the rotary drum 51 via another pulley 4a,
The end portion is fixed to the drum 51 and is wound around the drum 51. That is, when viewed around the rotary drum 51, the first cable 31 and the second cable 32 are drawn out in opposite directions. The first cable 31 and the second cable 32 are wound around the rotating drum 51 so as to give a rotating torque in the same direction (X direction) when a large tension acts on the double cable 3a to make it tense. At the time of this tension, the tensions of the first cable 31 and the second cable 32 act in directions opposite to each other with respect to the axis of the rotary drum 51, so that both forces cancel each other out and the shearing force on the axis becomes almost zero. . The rotary drum 51
In the area between the bearing portions 6a and 6b of the cable 31
The fixing points A1 and A2 of the cable 32 are on both ends, and both cables are wound from there toward the center.

Similarly, the first cable 33 of the double cables 3b is directly connected from the pulley 4 to the rotary drum 51, the end of which is fixed to the drum 51 and is wound around the drum 51. . The second cable 34 is connected from the pulley 4 through the other pulley 4b to the rotary drum 51, the end of which is fixed to the drum 51, and the drum 5
It is wrapped around 1. That is, when viewed around the rotary drum 51, the first cable 33 and the second cable 34 are pulled out in opposite directions. Double cable 3
When a large tension acts on b, the first cable 3
3 and the second cable 34 are wound around the rotating drum 51 so as to give a rotating torque in the same direction (Y direction opposite to the X direction). In this tension, the first
The tension of the cable 33 and the second cable 34 is set to the rotary drum 5
Since they act in directions opposite to each other with respect to one axis, both forces cancel each other out and the shearing force with respect to the axis becomes almost zero. In the area between the bearings 6b and 6c of the rotary drum 51, the fixing point B1 of the cables 33 and 34 is fixed.
And B2 are on both ends, and both cables are wound from there toward the center.

As is apparent from the above construction, when one of the cables 3a (31 and 32) is strained, the tension causes the cable 3a to be pulled out from the rotary drum 51 while rotating the rotary drum 51 in the arrow X direction. At the same time, the other relaxed cable 3b (33 and 34) is wound around the rotary drum 51. And vice versa, cable 3b (33 and 34)
Is strained, the tension of the cable 3b causes the rotating drum 5
1 rotates in the opposite direction (arrow Y), the cable 3b is pulled out from the rotary drum 51, and at the same time, the other relaxed cable 3a (31 and 32) is wound around the rotary drum 51.

In this way, the left and right reciprocating displacement due to the vibration of the structure 2 is transmitted to the rotary drum 51 via the cables 3a and 3b, and is converted into the reciprocating rotational displacement of the drum 51.
Four support shafts 52 are radially arranged in a rotary system that is rotationally displaced integrally with the rotary drum 51, and a weight 53 is attached to a tip portion of the support shaft 52. Further, the weight 53 and the ground 1 are connected via a hydraulic damper 54. The weight 53 is added to appropriately adjust the natural vibration frequency of the entire vibration damping device, and the hydraulic damper 54 absorbs the kinetic energy of the weight 53 that reciprocally rotates together with the rotary drum 51. As a result, the vibration energy of the structure 2 is absorbed and the vibration damping effect is exhibited.

In the present invention, since the shearing force acting on the rotary drum 51 can be made almost zero by the above-mentioned structure, the rotary drum 51 is formed with an outer diameter that can withstand the twisting shearing force. do it. This means that the diameter of the rotating drum 51 can be reduced. Therefore, for example, in the device of FIG. 1, even if the mounting radius of the weight 53 via the support shaft 52 is set to be small, the cable 3a.
It is possible to secure a large ratio of the outer diameter of the rotating drum 51 around which 3b is wound, that is, the ratio of the winding radius of the cables 3a and 3b to the radius of rotation of the weight 53. For example, in the device of FIG. 1, the radius ratio is set to 1:
When it is desired to set to 10, the radius of the rotary drum 51 can be set to 25 cm by the configuration of the present invention, and when it is set to 50 cm.
In comparison with the case where the weight must be set to 5, the mounting radius of the weight 53 is 2.5 m in the former case, but it is 5 m in the latter case.
In contrast, the latter has a diameter of 10 m, while the latter has a diameter of 10 m. Thus, according to the present invention, the device can be made compact.

[0015]

According to the vibration damping device of the present invention, when one cable is strained by the vibration displacement of the structure, the other cable is relaxed so that the other cable is relaxed. The vibration displacement of is transmitted to the rotating drum of the damper. The ends of both cables are fixed to a rotating drum and wound around the drum. Then, when one of the cables is strained, the tension causes the cable to be pulled out from the rotary drum while rotating the rotary drum, and at the same time, the relaxed other cable is wound around the rotary drum. In this way, the vibrational displacement of the structure is converted into the rotational displacement of the rotary drum, and the kinetic energy thereof is absorbed.

Although the cable is subjected to extremely large tension of several thousand tons, since the end of the cable is fixed to the rotating drum, the slip between the drum and the cable does not occur. Further, at least the side of each of the two cables wound around the rotary drum is divided into a first cable and a second cable, and the first cable and the second cable are pulled out from the rotary drum in mutually opposite directions. Therefore, both tensions are canceled out, and the shearing force on the axis of the rotating drum becomes almost zero, smooth rotation of the drum is compensated, and damage to the drum can be prevented. Therefore, the vibration displacement of the structure can be efficiently transmitted to the rotary drum of the damper via the cable, and the vibration energy of the structure can be converted into the reciprocating rotary motion of the rotary drum without being released. As a result, a good vibration damping effect can be obtained.

Further, since the shearing force acting on the rotary drum can be made substantially zero, the rotary drum may be formed with an outer diameter that can withstand the twisting shearing force. This means that the diameter of the rotary drum can be reduced, and the device can be made compact.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of a vibration damping device according to an embodiment of the present invention.

FIG. 2 is a detailed view showing a relationship between a rotary drum and a cable in the above embodiment.

[Explanation of symbols]

 1 Ground 2 Structure 3a / 3b Cable 31 First Cable 32 Second Cable 33 First Cable 34 Second Cable 4 Pulley 4a Pulley 4b Pulley 5 Damper 51 Rotating Drum 52 Support Shaft 53 Weight 54 Hydraulic Damper 6a / 6b / 6c Bearing Department

Claims (1)

[Claims] 1. A vibration damping device having the following requirements. A cable fixed to the upper part of the structure is guided in a polygonal line by a pulley and is connected to a damper installed on the ground,
The vibration displacement of the structure is transmitted to the damper via the cable, and the vibration energy of the structure is absorbed by the damper. The two systems of the cables symmetrically arranged on the structure are coupled to the common damper, and when the structure vibrates, one cable is tensioned and the other cable is relaxed mechanically complementary. Relationship. The damper has a rotating drum, the both cables are wound around the rotating drum, and the ends of the both cables are fixed to the rotating drum. When one of the cables is strained, the tension causes the cable to be pulled out from the rotary drum while rotating the rotary drum, and at the same time, the relaxed other cable is wound around the rotary drum. At least the side of each of the two cables wound around the rotary drum is divided into a first cable and a second cable, and the first cable and the second cable are pulled out from the rotary drum in opposite directions.