JPH0533528A - Vibration damping device - Google Patents

Abstract

PURPOSE:To make compact in a vertical direction a vibration damping device comprising an additional mass suspended by a spring. CONSTITUTION:A plurality of springs 3 are provided in parallel so that these springs 3 are connected in series through wires 23 with respect to fixed blocks 15, 19; 17, 21 which are fixed to an upper chord 11 and a lower chord 13 respectively. An additional mass 5 is attached to the end of the wire 23.

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 damping vertical vibration of a building beam or the like.

[0002]

2. Description of the Related Art A beam having a long span is likely to vertically vibrate due to an earthquake or wind pressure. In order to perform such vibration damping of the beam, conventionally, as shown in FIG. 4, the additional mass body 5 is hung through the spring 3 at the substantially center of the beam 1, and the spring 3
Of the so-called TMD (TunedM) by controlling the elastic coefficient and length of the
There is a passive damping device of an ass Damper (adjusted mass damper) type.

[0003]

However, since the beam 1 having a long span has a small natural frequency and a long cycle, it is necessary to secure a predetermined amplitude, and the length of the spring 3 becomes long. . Therefore, the space under the beam 1 cannot be effectively used. That is, if the spring 3 and the additional mass body 5 are hidden by the decorative material 7 or the like to make the ceiling flat, the effective space 9 under the beam 1 becomes extremely narrow as shown by the alternate long and short dash line in FIG.

Since the length of the spring 3 becomes long because it is necessary to secure a predetermined amplitude of the additional mass body 5 as described above, the vertical vibration of a large span structure such as a large beam on a large space roof or a bridge girder on a suspension bridge. There is a problem that the device for damping the vibration cannot be made compact and the space for installing the device cannot be saved.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a vibration damping device capable of saving space in the vertical direction.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and is a vibration damping system for damping vibration generated in a beam by an additional mass body attached to the beam via a spring. In the device, between the upper and lower chord members of the beam,
It is characterized in that the spring groups are connected by pulleys.

The pulley is a fixed pulley supported by the beam, the spring group is connected in series through the fixed pulley, and the base end is connected to the beam and the additional mass body is attached to the tip. Is provided.

Further, the pulley is a moving pulley supported on the beam via the spring group, and the additional mass body has a base end coupled to the beam and hung around the moving pulley. Is provided at the tip of the.

[0009]

The pulley eliminates the need for linearly arranging the springs in the vertical direction as in the conventional case, so that even in the case of springs having the same length, the vertical space, that is, the vertical space can be saved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an enlarged view of the main part of FIG. Beam 1 has a long span, and upper chord member 11 and lower chord member 1
3 and 3. Two fixed pulleys 15, 17, 19, 21 are fixed to the upper chord member 11 and the lower chord member 13, respectively.
The fixed pulleys 15, 17, 19 and 21 do not overlap each other in the left-right direction, and are provided every other upper and lower chord members 11 and 13, and are arranged in a zigzag manner. 5 springs 3
Are connected in series via a wire 23 that is sequentially wound around these fixed pulleys 15, 17, 19, and 21, and the wire 23
The base end 25 is fixed to the upper chord member 11, and the additional mass body 5 is attached to the tip. Spring 3 coupled in this way
Are arranged in parallel between the upper chord member 11 and the lower chord member 13 of the beam 1, but are connected in series by the constant pulleys 15, 17, 19, and 21. As a result, the springs 3 are housed in series inside the beam 1, so to speak.

The operation of the above embodiment will be described. The beam 1 having a long span has a long natural period, and in the case of performing the TMD type passive vibration suppression, it is necessary to secure a sufficient amplitude 27 in the additional mass body 5. This amplitude 27 is ensured by the fact that the entire five springs 3 act as one spring. That is, with the five springs 3 connected in series, it is possible to obtain the same amplitude as in the case of hanging linearly in the vertical direction as in the conventional case, and it is possible to obtain the same vibration damping effect. Further, since the springs 3 are arranged in parallel, so to speak, the space required in the vertical direction is sufficient for the length of one spring 3, and the installation space in the vertical direction is sufficiently smaller than in the conventional device. Can be made compact.

In the above embodiments, the fixed pulleys 15 and 1
Two pieces of 7, 19, 21 are provided on the upper chord member 11 and two pieces of the lower chord member 13, but it is possible to provide more than seven pieces in other embodiments. By increasing the number of fixed pulleys, a larger number of springs can be arranged in parallel, and the vertical space can be further saved.

Further, in the above embodiments, each spring 3 is
Are arranged in the vertical direction, but in other embodiments, the springs may be arranged to be inclined at a certain angle with respect to the vertical direction by decreasing or increasing the distance between the fixed pulleys in the left-right direction. It is possible.

In the above embodiment, the pulleys are fixed pulleys 15, 17,
However, in another embodiment, as shown in FIG. 3, for example, the movable pulleys 29, 31, 33,
It is also possible to use 35, 37, 39. That is, the additional mass body 5 is attached to the tip of one wire 41,
The base end 43 is fixed to the upper chord member 11. Further, three moving pulleys 29, 33, 37 are suspended on the upper chord member 11 via a spring 3. The lower chord member 13 has three movable pulleys 31 and 3
5, 39 are supported upward via the spring 3. These six movable pulleys 29, 31, 33, 35, 37, 39 are arranged so that the left and right positions do not overlap each other, and the upper and lower movable pulleys 2
Every other 9, 31, 33, 35, 37, 39 are arranged in a zigzag manner. The movable pulleys 29, 31, 33, 35, 37, arranged in this zigzag,
The wire 41 is wound around 39.

Also in the above embodiment, the predetermined amplitude 45
Since a plurality of springs 3 required to secure the above are arranged in parallel, so to speak, the installation space in the vertical direction is determined by the length of the two springs 3. Therefore, the installation space in the vertical direction can be made smaller and the apparatus can be made sufficiently compact as compared with the case where the springs are arranged in a row in the vertical direction as in the prior art.

Also in this embodiment, the movable pulleys 29, 31,
The number of 33, 35, 37, 39 can be changed. If the number of moving pulleys is increased, the number of springs 3 can be increased, and the device can be made more compact. Further, the angle of the wire 41 can also be inclined at a predetermined angle with respect to the vertical direction.

In the above embodiments, the fixed pulleys 15 and 1
7, 19, 21 only or moving pulleys 29, 31, 3
Only 3,35,37,39 were used, but in other embodiments it is also possible to use a combination of a fixed pulley and a moving pulley. Further, in the above two embodiments, the wires 41 and 23 are wound around the fixed pulley or the moving pulley only once, but in other embodiments, the wires 41 and 23 are wound a plurality of times to be provided in parallel. It is also possible to reduce the number of pulleys relative to the number of springs used.

In the above two embodiments, the structure for carrying out the passive type vibration damping is explained, but in the other embodiments, it is also possible to carry out the active type vibration damping by the TMD method. For example, it is possible to wind the base ends of the wires 41 and 23 around a drum and control the drum by a driving device such as an AC servomotor to positively suppress the vibration. Further, it is also possible to combine the active type vibration damping configuration and the passive type vibration damping configuration to form a hybrid type vibration damping device that saves the power of the drive unit.

[0019]

As described above, according to the vibration damping device of the present invention, a plurality of springs can be arranged in parallel in a so-called parallel manner at the installation place where the vertical space is limited by the pulley. Since it is not necessary to dispose the springs linearly in the vertical direction as in the above, the installation space in the vertical direction can be saved and the device can be made compact.

[Brief description of drawings]

FIG. 1 is an enlarged view of an essential part showing an embodiment of the present invention.

FIG. 2 is a front view of the entire beam which is a structure provided with the device of FIG.

FIG. 3 is an enlarged view of a main part showing another embodiment of the present invention.

FIG. 4 is a front view of an entire beam including a conventional vibration damping device.

[Explanation of symbols]

3 springs 5 Additional mass 15,17,19,21 Fixed pulley 29, 31, 33, 35, 37, 39 Moving pulley 11 upper chord material 13 Lower chord material

Claims (3)

[Claims] 1. A vibration damping device for damping a vibration generated in a beam by an additional mass body attached to the beam via a spring, wherein a spring group is provided between an upper chord member and a lower chord member of the beam. A vibration damping device characterized by being connected by. 2. The pulley is a constant pulley supported by the beam, the spring group is connected in series through the constant pulley, and the base end is coupled to the beam and the additional mass body is attached to the tip. The vibration damping device according to claim 1, further comprising: 3. The moving pulley, wherein the pulley is supported by the beam via the spring group, and the additional mass body has a base end coupled to the beam and wound around the moving pulley. The vibration damping device according to claim 1, wherein the vibration damping device is provided at the tip of the.