JPH11153183A - Damping device for structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damping device in simple constitution capable of removing restriction of the pendulum damping device and carrying out highly sensitive damping by providing a spring regulation means to regulate characteristic frequency to match it with characteristic frequency of a structure and a means to properly set a damping factor. SOLUTION: This damping device supports a base plate 5 by a support roller 4 travelling on a horizontal support frame 3 free to oscillate in a machine frame 1, and a variable heavy bob 6 is placed on it. A spring 9 and a damper 12 are installed on the base plate 5, a spring constant and a damping factor are regulated by a spring regulation means 10 and a flow rate control valve, characteristic frequency of vibration of the heavy bob 6 is vibrated so as to synchronize with a structure, and it is devised to apply damping work on swinging due to wind and traffic at high sensitivity by properly setting the damping factor.

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 a structure for attenuating vibration of a structure such as a bridge main tower or a high-rise building.

[0002]

2. Description of the Related Art Structures such as the main tower of a cable-stayed bridge and high-rise buildings (buildings) are provided with vibration damping devices to suppress vibrations caused by wind, traffic, earthquakes, etc. to minimize the vibrations of the structures. May be damped. As one type of a vibration damping device for such a structure, a weight, a spring, and an attenuator (damper) are generally housed in a machine frame of a predetermined size to form one unit, and the unit is placed on the top of the structure. There is a thing which seems to exert a vibration damping effect by installing near.

[0003] In particular, for the main tower of a cable-stayed bridge, if it is necessary to suppress the vibration outside the tower of the main tower generated during the installation in addition to the vibration in the tower surface after the completion of the cable-stayed bridge, The unitized vibration damper is suitable for vibration suppression.

[0004] As one example of such a vibration damping device for a structure, for example, a device disclosed in Japanese Patent Application Laid-Open No. 7-197991 is known. The vibration damping device disclosed in this publication,
A weight is horizontally movably disposed on the machine frame attached to the structure, and the upper end is pivotally supported on the machine frame via a pivot shaft,
A lower end portion is connected to the weight, and a swing lever that swings about a pivot shaft in conjunction with the horizontal movement of the weight is provided, and a spring, a damper, and the like are provided between the swing lever and the machine frame. Is provided so that the position in the vertical direction can be changed, and a driving device with a clutch for horizontally moving the weight is provided.

The vibration damping device having the above construction is of a pendulum type. The natural frequency of the structure is calculated or measured in advance, and the damper and the spring are adjusted so that the natural frequency of the weight is synchronized with the value. Is freely changeable in the vertical direction. Since the setting positions of the damper and the spring can be changed freely, the natural frequency of the weight can be easily changed over a wide range.

As another example of the conventional vibration damping device, one disclosed in Japanese Patent Application Laid-Open No. 8-334148 is also known. This gazette proposes two types of vibration damping devices.
First, an urging member for urging the laminated rubber in a vibration damping device configured to swingably support the added mass by a laminated rubber formed by alternately laminating a plurality of metal plates and rubber plates,
And a natural period adjusting mechanism for adjusting a natural period of the urging member.

Another one is a vibration damping device including a column for suspending an additional mass so as to be movable in a vertical direction and an attenuator for attenuating vertical vibration of the additional mass. The vibration damping device includes an urging member provided between the urging members to urge the additional mass upward, and a natural period adjusting mechanism for adjusting a natural period of the urging member.

In the first vibration damping device according to this publication, the natural frequency of the additional mass (weight) supported on the laminated rubber is tuned to the natural frequency of the structure. The natural period of the urging member is adjusted by the adjusting mechanism for adjusting the vibration, and the vibration is suppressed.

In the second vibration damping device, the additional mass is attached to a column suspended from the horizontal overhang of the structure so that the additional mass can be moved in the vertical direction, and the vertical vibration of the additional mass is attenuated by the attenuator. The natural period of the urging member between the and the additional mass is adjusted by the natural period adjusting mechanism to perform vibration suppression.

[0010]

By the way, as described above, in the vibration damping device according to the first publication, the natural frequency of the weight is changed by moving the horizontal mounting level of the damper or the spring to the swing lever in the vertical direction. Can be changed if
Since it is a pendulum type, a rocking lever is required, and the frame of the unit extends in the height direction, so that the whole unit becomes large in space, and when connecting a plurality of springs to the rocking lever, these Since the spring box formed by providing the spring in the cylinder is not directly connected to the weight, there is a problem that the mechanism and the structure are complicated.

Further, as a mechanism for moving the weight horizontally, in an actual apparatus, the weight is moved on the rail by a guide device called a linear guide. The friction resistance against the movement of the weight is large because of the use of the bearings, and therefore, even if it operates for vibrations with large amplitude, it does not respond well to vibrations with relatively small amplitude, At the early stage of occurrence, the effect of suppressing vibration cannot be expected so much.

On the other hand, in the first vibration damping device of the second publication, a weight is placed on a laminated rubber, and the length of a spring means connected to the laminated rubber is adjusted to change the spring constant. Since it is of the type that allows the top of the laminated rubber to move in the horizontal direction, the vibration can be absorbed.

However, the range of the change in the spring constant of the laminated rubber due to the adjustment of the number of turns of the spring means is limited, and a large difference occurs between the frequency assumed when setting the laminated rubber and the frequency of the actual vibration behavior. In such a case, adjustment cannot be made, and a sufficient damping effect cannot be obtained. Further, in this type, since no damper is provided, the laminated rubber itself has a damper function, so that the damping effect cannot be adjusted.

In the second type, a weight formed by stacking iron plates is suspended from a structure by a column with a spring and supported by a damper, and the vibration is absorbed by changing the length of engagement of the spring with the column. The strut is fixedly attached to a mounting plate for a structure.

[0015] For this reason, a vibration damping action can be exerted on the vertical vibration of the structure, but the horizontal vibration cannot be absorbed by this vibration damping device. Further, if the second vibration damping device is to be used to absorb horizontal vibrations, it is necessary to provide a structure for supporting at least the weight in a horizontally movable manner. It cannot be a damping device that absorbs.

The present invention adopts a horizontal movement system instead of a pendulum system and is sensitive to any of vibrations having a large amplitude and a small amplitude in consideration of various problems of the conventional vibration damping device. An object of the present invention is to provide a vibration damping device for a structure capable of suppressing vibration in response to vibration.

Another object of the present invention is to provide a vibration damping device which can be used as an active type vibration damping device and can also be applied as a vibration exciter.

[0018]

According to the present invention, as a means for solving the above-mentioned problems, a weight is provided in a machine frame so as to be horizontally movable by a supporting roller, and a horizontal weight is provided between the weight and the machine frame. A spring provided to absorb the vibration in the direction and a damper, and a spring adjusting means for adjusting a spring constant at one end of the spring so that the natural frequency can be adjusted freely. This is a vibration damping device for a structure in which an adjusting means is provided so that the damping constant can be adjusted.

[0019] The vibration damping device of the present invention having the above-described structure includes:
An extremely simple configuration that faithfully represents a one-degree-of-freedom vibration system suppresses vibration over a wide range from large to small amplitude vibrations. The spring constant and the damper are adjusted in advance by calculation or actual measurement so that the frequency is synchronized with the natural frequency of the structure by the spring adjusting means, and the damping rate is set to a predetermined value by the damping constant adjusting means of the damper. Keep it.

When the structure vibrates due to wind or the like, the weight moves with a delay from the movement of the structure due to the vibration at the point where the vibration damping device is installed. At this time, the spring constant is adjusted as described above. The weight will move with a phase shift of about 90 ° from the movement of the structure, and if the vibration of this device is approximately synchronized with the natural frequency of the structure, it will be most effective. Even if the vibration is not synchronized, the apparatus can be adjusted in accordance with the vibration characteristics of the structure by appropriately setting the spring constant and the damping rate to suppress the vibration.

In addition, even if the vibration has a small amplitude, the weight is supported by the supporting rollers so as to be horizontally movable. Therefore, the coefficient of friction in the horizontal direction is small, and the weight is small even when the structure is small. It moves sensitively and suppresses the vibration of the structure.

The passive type vibration damping device is provided with an active type by providing a gear mechanism to be able to freely contact with and separate from the weight, and driving the gear mechanism by a rotation drive unit to swing the weight. Can function as things. In addition, if the rotation drive unit is activated other than during vibration, it can be used as a vibration exciter.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. 1 is an external perspective view of the vibration damping device according to the embodiment, FIG. 2 is a plan view, and FIG. 3 is a side view. As shown, the vibration damping device includes a variable weight 6 on a base plate 5 having a support roller 4 running on a horizontal support frame 3 in a machine frame 1.
The spring 9 and the damper 12 are provided on the lower surface of the base plate 5.
Is attached. The variable weight 6 is provided so that a plurality of thick steel plates are stacked and fixed by the fixing member 6a, and the weight (mass) can be changed by increasing or decreasing the number of the thick steel plates.

The machine frame 1 connects a vertical frame 2a and a horizontal frame 3b to a vertical frame 2 erected at four corners to form a cubic space inside, and a space below the vertical and horizontal frame 3a. A parallel horizontal support frame 3 is provided to support and guide the traveling of the support roller 4. The base plate 5 is doubled with a bottom plate 5a provided below the base plate 5, and the vibration absorbing means is provided through the double space.

The variable damper 12 of the vibration absorbing means is mounted so that the damper head 12a is located on the longitudinal center line of the bottom plate 5a (see the mounting method described later), and the piston rod 12 protrudes from the variable damper 12 to both sides.
The terminal b is fitted and attached to the cut in the end plate 8 with a nut that engages a screw engraved on the terminal. The variable damper 12 is provided with an attenuation rate adjusting means, which will be described later.

As shown in the figure, four springs 9 are provided in parallel on both sides of the variable damper 12 with one end of each spring 9 provided at the end of the bottom plate 5a. 7 is attached by a terminal engaging member, and the other end is fitted and attached to a cut of the end plate 8 via a spring adjusting means 10 for adjusting a spring constant. The springs 9 are rationally arranged such that two inner springs are engaged with the left end plate 8 and two outer springs are engaged with the right end plate 8 in FIG. .

The spring adjusting means 10, as shown in FIG.
The threaded rod 11 is fitted into the cut of the end plate 8 with its head 11 a facing outward, and the number of turns (length) of the spring 9 engaged with the threaded portion of the threaded rod 11 is reduced. The spring constant is adjusted by rotating and adjusting the head of the screw rod 11. Reference numeral 9a denotes a retaining collar. The opposite end of the spring 9 is
The screw end member 13 is attached to the inside of the end plate 7 with a screw bolt 14 attached to the end plate 7, and a predetermined length of a spring is engaged with the screw end member 13 and set.

FIG. 7 is an overall model diagram including the variable damper 12 and the spring 9. As shown in the figure, the variable damper 12 has a piston 12c provided at the center and piston rods 12b, 12b of the same length on the left and right, and pipes 15, 15 using pressure-resistant hoses connected to the left and right damper heads 12a, 12a. Are connected to each other via two flow control valves 16, 16 which are damping rate adjusting means of the damper 12 at the center. When the adjustment knob 16a is manually rotated, the flow rate of the flow control valve 16 changes from one to the other, thereby adjusting the damping force of the damper. 17 is an oil replenishing unit.

As shown in FIG. 5, guide rollers 18 are provided at four ends of the bottom plate 5a of the base plate 5 to prevent horizontal deflection of the base plate 5. The guide roller 18 is guided in the horizontal direction using the vertical flange of the horizontal support frame 3 as a guide member. Guide rollers 19 are also provided at the four corners of the upper surface of the base plate 5 to prevent the base plate 5 from vibrating in the vertical direction. The vertical and horizontal frames 3a serve as guide members.

As shown in FIG. 4, when the base plate 5 has moved the maximum distance (the moving stroke is shown by a two-dot chain line in the figure), a buffer 21 for stopping further movement is provided as a stop buffering member. ing. Reference numeral 22 denotes a rod of a linear sensor, and a position detection sensor 23 is provided on a bracket provided at the center of the length of the base plate 5 in the vertical direction. The position detecting sensor 23 is a magnetostrictive position detector, and measures the moving distance by utilizing the fact that when the linear sensor rod 22 moves, magnetostriction occurs.

Reference numeral 24 shown in FIG. 4 is a limit switch for detecting a limit position of movement to both ends of the base plate. FIG.
Reference numeral 25 denotes a proximity switch for forcibly stopping the movement of the base plate 5 when the motor 40 runs away, and reference numeral 25a denotes a magnetic piece.
Reference numeral 26 shown in FIG. 4 denotes a damping force detection sensor, one end of which is fixed to the back surface of the base plate 5, and the other end of which is attached to a mounting plate 27. Both ends and the center of the damper 12 are fixed to the mounting plate 27. Therefore, the damper 12 is mounted on the base plate 5 via the damping force detection sensor. When the weight 6 and the base plate 5 move, the damper 12 also moves. At this time, the piston 12c in the damper 12 moves relatively to the cylinder and the flow control valve 1
6 acts and the cylinder internal pressure acts. The movement of the cylinder due to this internal pressure slightly acts on the movement of the base plate 5 to act on the damper 12, and the force acting on the damper 12 is detected by the damping force detection sensor 26.

Next, a drive mechanism for horizontally moving the weight 6 is provided below the base plate 5. This drive mechanism is for causing the weight 6 to vibrate horizontally to act as an active vibration damping device or to act as a vibrator. The drive mechanism includes a rack 31 attached to the lower surface of the bottom plate of the base plate 5, a gear group engaged with the rack 31, a motor for driving the gear, and a gear group composed of the rack 3
1 comprises a switch mechanism for engaging and disengaging.

The gear group includes a pinion 32 and a gear 33, and the pinion 32 is mounted on a gear stand 34. The gear stand 34 is rotatably supported at one end by a support base 36 around a rotation shaft 35. The other end is supported by an electromagnetic holder 38 via a connecting plate 37. Electromagnetic holder 38
When the power is cut off, the suction force by the electromagnetic force is cut off, and the connecting plate 37 moves to the position indicated by the two-dot chain line (see FIG. 4).

Therefore, when the pinion 32 is disengaged from the rack 31 and power is supplied to the electromagnetic holder 38, the connecting plate 37 is attracted to the solid line and the pinion 32 is engaged with the rack 31. 39 is a support arm of the electromagnetic holder 38. As shown in FIG. 5, the rotational force of the motor 40 is transmitted to the gear 33 via the rotational shaft 35, and the rotational force causes the rack 31 to reciprocate, so that the weight 6 vibrates. The drive mechanism is provided on a motor base plate 41 and provided on a common base plate 42.

The vibration damping device of this embodiment configured as described above is of a passive (passive) type or an active (active) type.
It acts as a vibration damper of the form or as a shaker as follows. When the electromagnetic force of the electromagnetic holder 38 is cut off, the pinion 32 of the drive mechanism is separated from the rack 31,
Acts as a passive damping device. When structures such as the main tower and high-rise buildings of the cable-stayed bridge equipped with this damping device vibrate due to wind, traffic, or an earthquake, the weight 6 swings to cancel the vibration and the vibration is controlled. Will be

In order to obtain the above-described vibration damping action, the spring constant of the spring 9 is adjusted to the natural frequency of the structure, and the damping force of the damper 12 is set to the target damping rate of the vibration of the structure. The adjustment is made in advance by the respective adjusting means of the spring 9 and the damper 12, and the vibration is suppressed so as to be most effective.

The adjustment by the adjusting means is performed, for example, as one of the most effective methods, by connecting a drive mechanism to the vibration damping device so that the vibration damping device acts as a vibration generator, and the vibration of the structure by the vibration generator is used. Measure the natural frequency and damping rate from
The spring constant is adjusted by the spring adjusting means 10 of the spring 9 and the damping rate is adjusted by the flow control valve 16 of the damper 12 so as to conform to the respective measured values.

When the above-mentioned vibration damping device is operated as a vibration exciter, the power of the motor 40 can be transmitted by supplying power to the electromagnetic holder 38 in advance, adsorbing the connecting plate 37 and engaging the pinion 32 with the rack 31. So that When the motor 40 is rotated in this state, the base plate 5 is swung, and the weight is shaken to generate a vibrating force, and the structure vibrates due to the vibrating force.

The spring adjusting means 10 and the flow control valve 16
When the spring constant and the damping rate are adjusted and set according to the weight, if the size (weight) of the weight 6 is also necessary, the number of steel sheets stacked as the weight 6 is increased to increase the weight ratio with the structure. Should be fine-tuned.

When the main tower of the cable-stayed bridge is erected, there are scaffolding and erection equipment, and it is difficult to estimate the weight accurately.
In such a case, when the spring constant and the damping rate are determined by the measurement performed by using the vibration damping device as an exciter, the device is designed in advance by considering the error by analysis, and the values are adjusted by actual measurement. It is good to do so.

The passive type vibration damping device in which the spring constant and the damping rate are set as described above vibrates in response to the vibration having a large amplitude as well as the vibration having a small amplitude with high accuracy. In the case of vibration having a small amplitude, in order for the base plate 5 supporting the weight 6 to operate sharply, friction sliding of the base plate 5 with respect to the horizontal support frame 3 must be as small as possible.

In the above-described embodiment, the base plate 5 is slidably supported by the support roller 4 for this reason, and as a frictional sliding type moving means, most different from other types, for example, linear bearings. The one with small friction coefficient is adopted. For this reason, the weight 6 including the base plate 5 responds immediately and promptly even when the vibration is small.

Even if the vibration has a small amplitude, if the natural frequency set for the spring 9 matches the natural frequency of the structure and the damping rate is set appropriately, the set natural vibration can be obtained. Not only when the vibrations are caused by numbers, but also when the vibrations deviate therefrom, the vibration of the weight system is always deviated from the vibration of the structure by approximately 90 ° by setting the damping rate, so that the vibration is effectively damped. At this time, if the friction coefficient of the friction sliding portion is small, it reacts sharply as described above.

It should be noted that the vibration damping device of this embodiment acting as the above passive damping device generally has a TMD (Tune
d Mass Damper)
It operates in an adjusted state corresponding to one vibration mode assumed in advance. Therefore, in a vibration in which various modes of vibration such as an earthquake overlap and act on a structure,
Vibration suppression devices adjusted for each unique vibration mode can be installed at a plurality of predetermined positions to cope with the vibration control.

Next, when the vibration damping device is operated as an active type, as described above, the magnetic holder 38 is operated to engage the pinion 32 with the rack 31, and the motor 40 is driven to drive the weight system. Rocks. At this time, the swing speed is tuned to the natural frequency of the structure described above, or coincides with the actual frequency lower than that, and the movement of the weight is 90 ° out of phase with the movement of the structure. The rotation speed of the motor 40 may be changed according to the set attenuation rate by moving the motor 40 so that

In the above-described embodiment, the spring 9 and the damper 12 are such that the left and right extending members are fixed to the end plate 8 at the ends. However, the spring 9 and the damper 12 are used for both tension and compression. The type provided only on one side of the plate 5 may be used.

[0047]

As described in detail above, the vibration damping device of the present invention supports the weight by the support roller, provides vibration absorbing means comprising a spring and a damper, and adjusts the spring constant by the spring adjusting means.
Since the damping rate is adjusted by the damping constant adjusting means, it has a very simple structure, unlike the pendulum type vibration damping device, and it is easy to adjust the spring constant and damping rate and use a supporting roller with a small friction coefficient. Accordingly, it is possible to obtain a vibration damping device that can respond sensitively to even smaller vibrations.

Further, in the configuration in which the gear mechanism can be freely moved toward and away from the weight, the vibration damping device can be an active type, or the vibration damping device can be driven to drive the vibration damping device. There is. In addition, when the gear mechanism is disconnected, it can be returned to a completely passive vibration damping device (TMD) which is not affected by a motor or the like.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a vibration damping device according to an embodiment.

FIG. 2 is a plan view of the above.

FIG. 3 is a side view of the above.

FIG. 4 is a longitudinal sectional view of the above.

FIG. 5 is a longitudinal sectional side view of the above.

FIG. 6 is a detailed view of a spring adjusting means.

FIG. 7 is a schematic diagram of an attenuation rate adjusting unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Machine frame 2 Vertical frame 3 Horizontal support frame 4 Support roller 5 Base plate 6 Weight 7 End plate 8 End plate 9 Spring 10 Spring adjustment means 15 Piping 16 Flow control valve 16a Knob 18, 19 Guide roller 31 Rack 32 Pinion 38 Electromagnetic Holder 40 motor

Claims (3)

[Claims] 1. A weight provided in a machine frame so as to be horizontally movable by a support roller, and a spring provided between the weight and the machine frame so as to vibrate the weight in a horizontal direction, and to absorb the vibration. A damping device comprising a damper, and a spring adjusting device for adjusting a spring constant at one end of the spring so that the natural frequency can be adjusted. The attenuator includes a damping constant adjusting device so that the damping constant can be adjusted. Vibration control device for structures. 2. The weight is mounted on a base plate as a variable weight, and a support roller attached to the base plate is horizontally movable on a horizontal support frame of a machine frame. The structural vibration damping device according to claim 1, wherein a vessel is attached and the other end is connected to the machine frame. 3. A weight mechanism for horizontally moving a gear mechanism is attached to and separated from the weight, and a rotary drive unit is connected to the gear mechanism to allow the weight to swing horizontally. Item 3. A vibration damping device for a structure according to item 1 or 2.