JP2682774B2 - Structure damping device - Google Patents

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 attenuating vertical vibrations of a structure such as a bridge under construction or after completion or a building under construction.

[0002]

2. Description of the Related Art For example, as shown in FIG. 4, when constructing a cable-stayed bridge, bridge towers 1 and 1 are erected at predetermined intervals, and then bridge girders 2 are connected from the respective bridge towers 1 and 1. , 2 are gradually extended in the horizontal direction, and a cable 3 is stretched between each bridge girder 2, 2 and each bridge tower 1, 1 to maintain the horizontal state of each bridge girder 2, 2. Finally, the bridge girders 2 and 2 facing each other are connected to each other, but during this erection work, the bridge girders 2 and 2 are easily vibrated by a working machine or wind pressure that moves on the bridge girders 2, 2 and the vibration thereof is generated. If the condition is left as it is, there is a danger of causing a resonance phenomenon, which is very dangerous. Therefore, the vibration damping devices 4 and 4 are arranged on the bridge girders 2 and 2.

Conventionally, as the vibration damping devices 4 and 4, there is a pendulum type vibration damping device, for example, in which a weight is shaken in the horizontal direction to cancel the vibration, and only the horizontal vibration is damped. I can't.

There is also a passive type vibration damping device for damping vertical vibrations, which is designed to maximize the damping effect for a preset single frequency, Since the damping effect is extremely small for vibrations of different frequencies, as mentioned above, it is effective for those that change the frequency of the bridge girders 2, 2 as the erection work progresses. Cannot be attenuated.

[0005]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the present invention effectively damps the vibration even when the structure vibrates in the vertical direction and its frequency changes. It is an object of the present invention to provide a vibration damping device that can

[0006]

In order to achieve the above object, the present invention provides a base mounted on a structure and a structure above the base.
Between the vibrating tables to be placed, the vibrating table can be vertically vibrated.
The lower end of the link mechanism
It is rotatably connected and the upper end is rotatably connected to the connecting rod.
The connected parallel link and the upper end are rotatably connected to the vibrating table.
And the lower end is rotatably connected to the connecting rod.
Parallel links and connected to the vibrating table
Length of the connecting rod via an interlocking rod that is rotatably connected to the rod
Drive device that pushes and pulls in one direction to vertically vibrate the vibrating table
Is provided .

[0007]

In the above structure, the base is attached to the structure, and the drive mechanism is activated to push and pull the connecting rod in the longitudinal direction to make the upper and lower parallel links bend and extend, thereby causing the vibrating table. Vibrate up and down. As a result, vertical vibrations are positively applied to the structure, and the vibrations of the vibrating table and the vertical vibrations of the structure are canceled each other, so that the vibrations of the structure can be damped.

Further, in particular, when the frequency of the structure changes, the change in the frequency is determined by calculation at the design stage or by actual measurement at the site, and based on the determined set value or measured value. The vibration of the structure can be continuously dampened by controlling the drive mechanism by the above.

[0009]

An embodiment of the present invention will be described below. 1 and 2 show a vibration damping device 4 attached to a structure such as the above-mentioned bridge girder 2 being built or a building under construction, above a base 5 attached to the structure. A vibrating table 7 is disposed on the base 5 via a link mechanism 6 so as to be vertically vibrated.

The link mechanism 6 is composed of four parallel links 6a to 6d, which are respectively arranged in front and back of the opposite ends of both the bases 5 and 7, and each parallel link 6a.
6d, one end is pivotally attached to both the bases 5 and 7 through pivot pins 8, 8, 9 and 9, and the other end portions facing each other are rotated via connecting pins 10 and 10. It is composed of four link members 11a to 11d that are movably connected, and a horizontal connecting rod 12 that connects the connecting pins 10 and 10 together, and pushes each connecting rod 12 in the longitudinal direction. The parallel links 6a-6d are loaded by pulling.
The vibrating table 7 can be moved up and down directly or in parallel
Drive smaller than directly driving the links 6a to 6d
The parallel links 6a to 6d are flexed and extended by force, and the vibration table 7
Can be vibrated up and down.

A central portion of the vibrating table 7 is bent downward in a U-shape, and a driven shaft 16 rotatably supported by a motor 14 and a bearing 15 is provided in a recess 13 formed on the central portion. And the drive gears 17, 17 fitted to the rotary drive shafts 14a, 14a projecting on both sides of the motor 14, and the driven gears 18, 18 fitted on both ends of the driven shaft 16 mesh with each other. Both ends of the interlocking rod 19 are connected to the outer peripheral portions of the gears 17, 17, 18, 18 and one end of the connecting rod 12 of the parallel links 6a to 6d via interlocking pins 20, 20. By operating the motor 14, the parallel links 6a to 6d can be bent and extended through the gears 17, 17, 18, 18 and the interlocking rod 19.

A shock absorber 21 composed of a damper 21a and a spring 21b fitted onto each damper 21a is arranged between the opposite ends of the both tables 5 and 7, and the vibrating table 7 has a shock absorber 21a. Vertical vibration is performed smoothly. The shock absorber 21 may be omitted. Further, in FIG. 1, reference numeral 22 is an additional weight for adjusting the weight of the movable portion.

The operation principle of the vibration damping device 4 will be described below.
First, the state shown in FIG. 1 shows the state where the vibrating table 7 is at the lowest position. When the motor 14 is operated from this state, the gears 17, 17, 18, 18 rotate in the directions of the arrows, and the interlocking rod 19 Each of the parallel links 6a to 6d moves in the extension direction via the, and the vibrating table 7 rises as shown in FIG.
Each of the parallel links 6a to 6d moves in the refraction direction and the vibrating table 7 descends (see FIG. 1). By repeating this action, the structure is vertically vibrated. You can

According to the above configuration, the motor 14, the bearing 15,
The weight of the drive mechanism such as the driven shaft 16 and the gears 17, 17, 18, 18 contributes to the generated force as an inertial mass, and the drive mechanism is installed on the base 5 to try to obtain an equivalent generated force. Compared with the case, it is possible to reduce the weight of the drive mechanism by twice as much, which is economical.

An example of specific dimensions will be described. The vibrating table 7
In the descending state, the device height H is 2.5 m, the vertical vibration stroke S of the vibrating table 7 is about 1 m, and the weight of the vibrating table 7 and the motor 14 mounted thereon is several tons. The vibration mode of No. 7 is several hertz or less.

Here, for example, as shown in FIG. 4, when damping the vibration of the bridge girder 2 during erection, the change in the frequency of the bridge girder 2 is determined by calculation at the design stage or by actual measurement at the site. A control device (not shown) controls the rotation speed of the motor 14 based on the calculated set value or measured value, and changes the vertical vibration frequency of the vibration table 7 in accordance with the vibration frequency of the bridge girder 2. Just do it. As a result, no matter how the vibration of the bridge girder 2 changes, it can be reliably damped by the vibration of the vibrating table 7.

In the above embodiment, the motor 23 is used as a drive source for vertically vibrating the vibrating table, but other than this, for example, a cylinder device may be used. Also, each gear 17,1
Although the link mechanism 6 is bent and extended by the combination of 7, 18, 18 and the interlocking rod 19, the link mechanism 6 may be bent and extended by, for example, a rack and pinion mechanism or a cam mechanism.

Further, the motor 14 is provided with a brake, and the brake is operated to stop the vibrating table 7 at an intermediate height position of vertical vibration, and the stopped state is set between the damper 21a of the shock absorber 21 and the spring 21b. After being held by interaction, the operation of the brake may be released so that the vibrating table 7 can freely vibrate vertically. As a result, the vibration damping device of the present invention can be changed from an active type in which the motor 14 positively vibrates to a passive type in which the structure 14 vibrates passively.

[0019]

According to the present invention, even when a structure vibrates in the vertical direction and the frequency of the structure changes, the change in the frequency can be determined by calculation at the design stage or actual measurement at the site. By controlling the drive mechanism based on the calculated set value or measured value, it is possible to change the vertical frequency of the vibrating table to correspond to the change in the vibration of the structure. No matter how it changes, it can be surely attenuated.

Further, it is a lightweight and simple type that does not require any sliding mechanism for vertical movement, and the movable part performs pure vertical movement, so that it is a disturbance other than vertical movement when compared with a pendulum type vibration control device or the like. Since it does not generate various forces and does not induce complicated out-of-plane vibration, vibration can be performed smoothly. Also, shake it on the vibration table.
Since a drive unit that vibrates the moving table up and down is provided,
Can be used as the weight of the vibration table, and
The weight of the moving table can be reduced, and the installation space for the drive unit can be reduced.
It is unnecessary and can be compactly constructed. Further drive
The connecting rod with parallel links connected by the device
Push-pull drive to vibrate the vibrating table up and down, so parallel
Up and down the vibration table with a large mass on the link with a smaller driving force
Can be vibrated.

Further, by making the drive mechanism free, it can be made to function as a passive type vibration damping device, and the applicable range is wide.

[Brief description of the drawings]

FIG. 1 is a front view of a vibration damping device that is an embodiment of the present invention in a state where a vibrating table is lowered.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view of the vibrating table in a raised state.

FIG. 4 is a schematic explanatory view showing an example of a mounted state of the vibration damping device.

[Explanation of symbols]

 2 bridge girder (structure) 5 base 6 link mechanism 6a parallel link 6b parallel link 6c parallel link 6d parallel link 7 vibrating table 14 motor (driving mechanism) 17 drive gear 18 driven gear 19 interlocking rod

Front page continuation (72) Inventor Hiroshi Tanaka 5-3-3 Nishi-Kujo, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (56) Reference JP-A-4-34188 (JP, A) JP-A-58 -144221 (JP, A) Actually open 61-112024 (JP, U)

Claims (1)

(57) [Claims] 1. A base to be attached to a structure and a base installed above the base.
Link that can vibrate the vibrating table vertically between the vibrating tables to be placed
A mechanism is interposed , and the lower end of this link mechanism is rotatably connected to the base.
And a parallel ring whose upper end is rotatably connected to the connecting rod.
And the upper end is rotatably connected to the vibrating table and the lower end
Is a parallel link rotatably connected to the connecting rod.
Ri configured, the vibrating table, which is pivotally connected to said connecting rod linkage
Push and pull the connecting rod in the length direction through the rod to drive the vibrating table.
A vibration damping device for a structure, comprising a drive device for vertically vibrating .