JPH08334148A - Damping device - Google Patents

Abstract

PURPOSE: To provide a damping device constituted to damp vibration of a structure by making characteristic frequency of an added mass coincide with characteristic frequency of the structure. CONSTITUTION: A damping device is constituted of an added mass 13 in size corresponding to a mass of a structure, laminated rubber 14 supporting this added mass 13 free to oscillate, a spring mechanism 15 to energize the laminated rubber 14 and a characteristic cycle regulating mechanism 16 to regulate a characteristic cycle of the spring mechanism 15. The characteristic cycle regulating mechanism 16 is constituted of an engagement member 21 with which the other end of a coil spring 20 is engaged, a support 22 to support the engagement member 21 and a bolt 23 to connect the engagement member 21 to the support 22. As the number of turns of the coil spring 20 engaged with a spiral groove 21a of the engagement member 21 is regulated in a non-expandable and contractible state and the number of turns to function as a material spring is changed, the coil spring 20 is installed so that spring constant can be changed in accordance with the number of engagement turns.

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, and more particularly to a vibration damping device configured to damp the vibration of a structure by matching the natural frequency of an additional mass with the natural frequency of the structure.

[0002]

2. Description of the Related Art For example, a structure such as a building is provided with a vibration damping device for damping vibrations caused by an earthquake or wind pressure. One of the vibration damping devices of this type is a passive vibration damping device configured to support an additional mass by laminated rubber.

As shown in FIG. 13, the vibration damping device 1 has a structure in which the additional mass 2 is supported by the laminated rubber 3. The laminated rubber 3 is formed by alternately laminating disc-shaped rubber plates 4 and metal plates 5. Since the rubber plate 4 has viscoelasticity, when the vibration is input from the outside, the rubber plate 4 of each layer is elastically deformed to swing the additional mass 2. Therefore,
In the laminated rubber 3, the weight of the additional mass 2 is set to a size according to the total weight of the structure, and the number of laminated rubbers according to the natural frequency of the structure is laminated to effectively vibrate the structure. Can be controlled by.

When the mass of the additional mass 2 is M, the mass of the metal plate 5 of each layer of the n-layer laminated rubber 3 is m _r, and the spring constant of the rubber plate 4 is modeled as K _{r1 to} K _rn , FIG. As shown in. Then, assuming that the mass m _r of the metal plate 5 of each layer is zero, the spring constant K _{r of the} whole laminated rubber 3 is 1 / K _r = 1 / K _r1 + 1 / K _r2 + ... + 1 / K _rn (1) ). Further, the natural frequency f of the additional mass 2 is obtained by the following equation.

F = 1 / 2π × √ (K / M) (2) Therefore, the natural frequency of the vibration damping device 1 is added so as to match the natural frequency of the structure in the A direction (horizontal direction). By setting the mass of the mass 2 and the spring constant K _r of the laminated rubber 3 as a whole, the primary vibration of the structure can be suppressed.

[0006]

In order to suppress the vibration of the structure by using the laminated rubber 3 as described above, it is necessary to manufacture the laminated rubber 3 that matches the natural frequency of the structure.
However, in the case of structures such as buildings, the strength of the ground may change, the strength of the steel frame may decrease compared to the time of construction, or air conditioning equipment may be added.
After several years have passed since the construction, the natural frequency of the structure itself changes, and the laminated rubber 3 and the structure become out of synchronization. Also,
Since the viscoelasticity of the rubber plate 4 itself of the laminated rubber 3 also changes over time, the difference in natural frequency between the laminated rubber 3 and the structure tends to gradually increase.

Therefore, in the case of the vibration damping device using the laminated rubber 3 as described above, when the laminated rubber 3 and the structure become out of synchronization, the mass of the additional mass 2 is changed or the spring constant is changed. Since different laminated rubbers are attached, it is necessary to lift the additional mass 2 with a jack or the like to replace the laminated rubbers, which causes a problem that the adjustment work becomes large. In addition, when the additional mass 2 is increased, there is no installation space for the additional mass 2, which causes a problem that the mass of the additional mass 2 cannot be changed.

Therefore, a dedicated additional mass 2 for each structure
Therefore, it takes a lot of time to match the natural frequency of the additional mass 2 with the natural frequency of the structure, and the additional mass 2 is calculated by measuring the natural frequency of the structure. The mass of is calculated, but when it is actually installed, an error from the theoretical value may occur, making it difficult to accurately match the natural frequencies.

Therefore, an object of the present invention is to provide a vibration damping device that solves the above problems.

[0010]

The invention according to claim 1 is
A vibration damping device configured to oscillate an additional mass by a laminated rubber formed by alternately laminating a plurality of metal plates and rubber plates, and a biasing member that biases the laminated rubber, and the biasing member. And a natural period adjusting mechanism for adjusting a natural period of the biasing member.

According to a second aspect of the present invention, there is provided a vibration damping device having a support for suspending an additional mass so as to be vertically movable, and a damper for damping vertical vibration of the additional mass. A biasing member that is provided between the biasing member and the additional mass and biases the additional mass upward, and a natural period adjusting mechanism that adjusts the natural period of the biasing member. Is.

The invention according to claim 3 is characterized in that the biasing member comprises a coil spring, and the natural period adjusting mechanism is configured to change the effective number of turns of the coil spring. .

[0013]

According to the first aspect of the present invention, since the natural period of the urging member for urging the laminated rubber can be adjusted by the natural period adjusting mechanism, the natural frequency of the structure itself or the natural frequency of the laminated rubber can be adjusted. Even if is changed, the natural frequency of the laminated rubber can be matched with the structure by adjusting the natural period of the biasing member, and the laminated rubber can be tuned to the structure.

Further, according to claim 2, since the natural period of the urging member that hangs the additional mass so as to be movable in the vertical direction and urges the additional mass upward, the structure itself can be adjusted. Even if the natural frequency of the additional mass or the natural frequency of the additional mass changes, the natural frequency of the additional mass can be made to match the structure and the additional mass can be tuned to the structure by adjusting the natural period of the biasing member. it can.

According to the third aspect, since the effective period of the coil spring is changed by the natural period adjusting mechanism, the natural period of the biasing member can be easily adjusted, and the natural frequency of the laminated rubber is increased. It can be adjusted in a short time adjustment work so as to match the natural frequency of the structure.

[0016]

1 to 3 show a first vibration damping device according to the present invention.
An example will be described. 1 is a front view of the vibration damping device 11, FIG.
3 is an enlarged view showing a laminated rubber 14 and a spring mechanism 15 that swingably support the additional mass 13, and FIG.
It is a perspective view which shows the structure of FIG.

The damping device 11 is a building 12 as a structure.
Is a passive-type device installed on the rooftop of the vehicle, and has an additional mass 13 having a size substantially corresponding to the mass of the structure, a laminated rubber 14 that swingably supports the additional mass 13, and a laminated rubber 14. It comprises a spring mechanism 15 for urging and a natural period adjusting mechanism 16 for adjusting the natural period of the spring mechanism 15. Therefore, when the building 12 vibrates due to an earthquake or the like, the vibration damping device 11 is configured to damp the vibration of the building 12 by bending the laminated rubber 14 and swinging the additional mass 13.

Below the additional mass 13, for example, four laminated rubbers 14 (two laminated rubbers are hidden and invisible in FIG. 1) are provided. Laminated rubber 14, a plurality of rubber plates 17 formed in a disk shape and (17 ₁ to 17 _n), a plurality of metal plates _{18 (18 1 ~18 n-1} ) and becomes a structure in which stacked alternately There is. That is, since the laminated rubber 14 swingably supports the additional mass 13 having a considerable weight,
Alone rubber plate 17 having a viscoelastic (17 ₁ to 17 _n) not fully supported, rubber plate 17 (17 ₁ to 17 _n) iron of the metal plate 18 between (18 ₁ ~18 _n-1) that is interposed The strength is secured by.

The laminated rubber 14 has a structure in which a natural frequency main portion 14a formed on the upper portion and a natural frequency adjusting portion 14b for adjusting the natural frequency are stacked, and the natural frequency main portion is formed. A large-diameter metal plate 19 is provided between 14a and the natural frequency adjusting unit 14b. Further, the outer circumferences of the rubber plate 17 and the metal plate 18 are covered with a rubber coating 14c (indicated by a chain line in FIG. 5).
Also, the metal plates 18 are integrally connected while being in close contact with each other. Therefore, the laminated rubber 14 can be elastically deformed as if it were one elastic body when the vibration in the A direction is input.

The spring mechanism 15 has four coil springs 20 (biasing members) extending in the horizontal direction. The four coil springs 20 are arranged radially in four directions which are orthogonal to each other when viewed from above. In FIGS. 1 and 2, two coil springs 20 extend in a direction parallel to the paper surface. Only the spring 20 is shown. In addition, each coil spring 20 has an end coupled to a metal plate 19 provided at an intermediate portion of the laminated rubber 14.

The spring constants of the coil springs 20 are evenly adjusted by the natural period adjusting mechanism 16 so that the tensile forces are balanced, and the natural period is adjusted to be constant. Therefore, when the additional mass 13 swings to perform the vibration damping operation, the laminated rubber 14 is moved by the four coil springs 20 to
Since the laminated rubber 14 is evenly biased in the direction, the laminated rubber 14 returns to the vertically laminated state before the operation when the vibration damping operation ends.

The vibration damping device 11 having the above structure is represented by a mathematical model as shown in the schematic diagram of FIG. This damping device 1
The spring constant of 1 can be expressed as: 1 / K = 1 / (k ₂ + k ₃ ) + 1 / k ₁ (3) where K is the total value of the spring constants, k ₁ is the natural frequency of the main part 14a, and k ₂ is the natural frequency. Adjustment unit 14b
Is the spring constant of the coil spring 20, and k ₃ is the spring constant of the coil spring 20.
The magnitude of each spring constant is as follows.

K ₁ > k ₂ > k ₃ (4) FIG. 5 is a vertical sectional view showing the structure of the natural period adjusting mechanism 16. The natural period adjusting mechanism 16 includes an engaging member 21 with which the other end of the coil spring 20 engages, a support 22 for supporting the engaging member 21, and a bolt 23 for connecting the engaging member 21 to the support 22. Consists of. The engaging member 21 is provided with a spiral groove 21a for engaging the coil spring 20 on the outer circumference, and an internal thread 21 for engaging a bolt 23 therein.
b is provided in the axial direction.

Therefore, the coil spring 20 has the engaging member 21.
The number of turns engaged with the spiral groove 21a is restricted to a state in which expansion and contraction is impossible, and the number of turns functioning as a substantial spring is changed. Therefore, the spring constant is changed by the number of turns engaged. There is. Further, the lower end portion of the column 22 is fixed to the building 12, and has a strength sufficient to withstand the biasing force of the coil spring 20. And the support 22
A hole 22a for inserting the bolt 23 in the upper end portion of the
Is provided. The columns 22 provided so as to be located in the four directions of the laminated rubber 14 are erected at positions with a uniform distance from the laminated rubber 14, and the spring force of each coil spring 20 varies depending on the arrangement position. It is supposed not to.

Here, an adjusting operation for adjusting the natural period by adjusting the spring constant of each coil spring 20 by the natural period adjusting mechanism 16 will be described. In the vibration damping device 11 for damping the vibration of the structure using the laminated rubber 14 as described above, it is necessary to manufacture the laminated rubber 14 that matches the natural frequency of the building 12.

Therefore, when the natural frequencies of the laminated rubber 14 and the building 12 become out of synchronization with each other, the bolt 23 is removed from the engaging member 21 to separate the engaging member 21 from the support 22, and then the engaging member 21. 21 or the coil spring 20 is rotated around the axis to change the number of engagement turns of the coil spring 20 that engages with the spiral groove 21a of the engaging member 21. As a result, the effective number of turns functioning as a spring is adjusted out of the total number of turns of the coil spring 20.

In the case of this embodiment, the cycle can be adjusted to be shorter by increasing the number of engaging turns of the coil spring 20 which engages with the spiral groove 21a, or the relationship of the coil spring 20 which engages with the spiral groove 21a. The cycle can be adjusted to be longer by reducing the number of windings. Therefore, when the natural frequencies of the laminated rubber 14 and the building 12 are deviated from each other, adjustment work is performed so as to increase or decrease the number of engagement turns of the coil spring 20 according to the magnitude relationship of the natural frequencies of both members.

As a result, the spring constant of the coil spring 20 that biases the laminated rubber 14 is adjusted, and the natural period of the laminated rubber 14 is adjusted. Then, install the bolt 23 into the hole 2 of the column 22.
It is inserted through 2a and screwed into the female screw 21b of the engaging member 21 to be tightened. At that time, the spring force of the coil spring 20 (biasing force for urging the laminated rubber 14) is set to be the same as that before the adjustment by the tightening amount of the bolt 23.

For example, the strength of the ground may be changed, the strength of the steel frame may be lower than that at the time of construction, or air conditioning equipment may be added. The natural frequency of itself changes and the laminated rubber 14 and the building 12 become out of synchronization. Further, since the viscoelasticity of the rubber plate 17 itself of the laminated rubber 14 also changes with time,
The difference in natural frequency between the laminated rubber 14 and the building 12 tends to gradually increase.

However, in the case of this embodiment, since the natural period can be adjusted by adjusting the spring constant of each coil spring 20 by the natural period adjusting mechanism 16, the laminated rubber 14 and the building 12 are not synchronized with each other. In such a case, the cycle of the laminated rubber 14 is changed by adjusting the spring constant of each coil spring 20, and the natural frequency of the laminated rubber 14 can be matched with the natural frequency of the building 12. Thereby, the additional mass 13 can oscillate at the same frequency as the natural frequency of the building 12, and a sufficient damping effect can be obtained.

Further, when the spring constant of each coil spring 20 is adjusted, the adjustment work is performed so that the spring force does not change, so that the vibration characteristics of the laminated rubber 14 are prevented from changing and the vibration of the building 12 is prevented. It becomes possible to effectively suppress the vibration. When the spring force of the coil spring 20 is reduced, the amount of screwing of the bolt 23 is changed to adjust the spring force of the coil spring 20 to an initial set value, thereby keeping the vibration characteristics of the laminated rubber 14 constant. You can also

Moreover, the spring constant of the coil spring 20 can be easily changed only by adjusting the number of turns in which the coil spring 20 engages with the spiral groove 21a of the engaging member 21. The natural period of the laminated rubber 14 can be adjusted in a short time so that and are synchronized.

FIG. 6 is a vertical sectional view showing a modification of the natural period adjusting mechanism. The engaging member 21 of the natural period adjusting mechanism 24 has a male screw 21c extending axially from the end,
The 2 is provided with a female screw 22b into which a male screw 21c is screwed. Therefore, when the engaging member 21 is rotated around the axis, the male screw 21c is screwed into the female screw 22b, and thus moves in the X direction.

As a result, the spiral groove 21a of the engaging member 21 is formed.
It is possible to change the number of turns of engagement of the coil spring 20 that engages with the coil spring 20, and the effective number of turns functioning as a spring out of the total number of turns of the coil spring 20 is adjusted. Further, the engaging member 21
By matching the pitch of the spiral groove 21a and the pitch of the male screw 21c, the coil spring 20 does not move in the same direction even when the engaging member 21 moves in the X direction, and the coil spring 20
The spring constant of the coil spring 20 can be changed without changing the spring force of.

Therefore, when the laminated rubber 14 and the building 12 are out of synchronization with each other, the engaging member 21 is rotated to change the number of turns engaged with the spiral groove 21a of the engaging member 21.
In this way, the cycle of the laminated rubber 14 is changed by changing the engaging winding number of each coil spring 20 and adjusting the spring constant, and the natural frequency of the laminated rubber 14 is made to match the natural frequency of the building 12. be able to. Thereby, the additional mass 13 can oscillate at the same frequency as the natural frequency of the building 12, and a sufficient damping effect can be obtained.

FIG. 7 is a vertical sectional view showing another modification of the natural period adjusting mechanism. The natural period adjusting mechanism 25 attaches the spring connecting members 26 and 27 for adjusting the effective number of turns functioning as a spring out of the total number of turns of the coil spring 20 to the bolt 28.
It is fixed integrally by. This spring connecting member 26,
The groove 27a, 27a having the same pitch as the coil spring 20 and a semicircular cross section is provided in the groove 27. Grooves 26a and 27
By facing a, a circular hole through which the coil spring 20 is inserted is formed.

When the spring connecting members 26 and 27 are attached to the coil spring 20, the springs are inserted into the grooves 26a and 27a at three positions out of the total number of turns of the coil spring 20 as shown in FIG. The connecting members 26 and 27 are fixed with bolts 28. As a result, the number of turns connected by the spring connecting members 26 and 27 does not function as a spring, so that the spring constant of the coil spring 20 is changed.

Therefore, when the laminated rubber 14 and the building 12 are out of synchronization, the number of turns connected to the spring connecting members 26 and 27 is changed. In this way, each coil spring 2
The cycle of the laminated rubber 14 is changed by changing the connection winding number of 0 to adjust the spring constant, and the natural frequency of the laminated rubber 14 can be matched with the natural frequency of the building 12. Thereby, the additional mass 13 can oscillate at the same frequency as the natural frequency of the building 12, and a sufficient damping effect can be obtained.

8 to 11 show a second embodiment of the present invention. 8 is a view showing a mounting state of the second embodiment, FIG. 9 is a vertical sectional view showing a natural period adjusting mechanism of the second embodiment, FIG. 10 is a vertical sectional view showing a mounting state of an attenuator, and FIG. [FIG. 6] is a plan view of a second embodiment. The vibration damping device 31 has a staircase 32.
Is a suspension type vibration damping device configured to be hung from a base 33 attached to the lower surface of the above and to damp vertical vibrations. The base 33 is supported by legs 33 a fixed to the lower surface of the stairs 32, and is provided at a position separated from the lower surface of the stairs 32 by a predetermined distance.

The vibration damping device 31 has four pillars 34 extending downward with the male screw of the upper end 34a screwed into the screw hole 33b of the base 33, and a cylinder into which the pillar 34 is inserted. -Shaped spring guide member 35, a coil spring (biasing member) 36 interposed inside the spring guide member 35 to urge the upper end portion 35a of the spring guide member 35 upward, and a lower end flange portion 35b of the guide member 35. An additional mass 37 in which a plurality of iron plates 37 _{1 to} 37 _n are stacked, an attenuator 38 that is inserted into a central hole 37 a of the additional mass 37 to attenuate vertical vibration of the additional mass 37, and a coil spring 36. And a natural period adjusting mechanism 39 for adjusting the natural period of.

The attenuator 38 is composed of a hydraulic damper and has an upper end 3
8a is screwed and fixed to the base 33, and the other end 38b is fixed to the contact plate 40 that contacts the lower surface of the additional mass 37. Further, the lock nut 41 prevents loosening of the upper end 38a of the attenuator 38 and the upper end 34a of the support column 34.

The vibration damping device 31 damps the vibration of the stairs 32 by vibrating the additional mass 37 at the natural frequency of the stairs 32 when the stairs 32 vibrate in the vertical direction. Therefore, the mass of the stairs 32, which is a structure, and the stairs 32
The natural period determined by the spring constant of itself and the vibration damping device 31
It is necessary to set the mass of the additional mass 37 of the vibration damping device 31 and the spring constant so that the natural period of the same becomes the same.

Here, assuming that the natural period of the stairs 32 is ω, the spring constant K can be obtained from ω = √ (K / M) (5). Therefore, in the vibration damping device 31, the spring constant K of the coil spring 36 is set to the above (5).
The value is made smaller than the value obtained by the above, so that the spring constant K can be adjusted later.

The vibration damping device 31 is attached in such a state that the spring constant K can be adjusted, and is set so that the natural period of the additional mass 37 is synchronized with the natural period of the stairs 32. In addition, when the vibration damping device 31 was installed,
Since the spring constant K is small, it is necessary to gradually increase the spring constant K after mounting. That is, by adjusting the natural period adjusting mechanism 39, the number of effective turns of the coil spring 36 is reduced and the overall spring constant K is set to be high.

In the natural period adjusting mechanism 39, the lower end 34b of the column 34 is integrally provided with an engaging member 42 with which the coil spring 36 is engaged. The engaging member 42 has a spiral groove 42a on the outer circumference for engaging the coil spring 36. Therefore, in the coil spring 36, the number of windings engaged with the spiral groove 42a of the engaging member 42 is restricted to a state in which the expansion and contraction operation is not possible,
Since the number of turns functioning as a substantial spring is changed, the spring constant is changed by the number of turns of engagement.

In the natural period adjusting mechanism 39, the support 3
Since the male screw of the upper end 34a of No. 4 is screwed into the screw hole 33b of the base 33, the support 34 and the engaging member 42 can be rotated around the axis by loosening the lock nut 41. Then, when the engaging member 42 is rotated around the axis,
Coil spring 36 engaging with spiral groove 42a of engaging member 42
The number of engaging windings is adjusted to adjust the spring constant.

Here, the adjustment work for adjusting the natural period by adjusting the spring constant of each coil spring 36 by the natural period adjusting mechanism 39 will be described. When the additional mass 37 and the natural frequency of the coil spring 36 become out of synchronization with each other, the lock nut 41 is loosened and the support column 34 and the engaging member 42 are loosened.
Is rotated about the axis to change the position of the engaging member 42 to a position lower than the original mounting position. Thereby, the engaging member 42
The number of turns of engagement of the coil spring 36 that engages with the spiral groove 42a can be reduced, and the spring constant K can be increased.

If the pitch of the external thread of the upper end 34a of the column 34 and the pitch of the spiral groove 42a are set to be the same,
The number of engagement turns can be adjusted without changing the spring force of the coil spring 36. In this way, by changing the number of turns of engagement of the coil spring 36 that engages with the spiral groove 42a of the engagement member 42, the effective number of turns functioning as a spring out of the total number of turns of the coil spring 36 is adjusted. . As a result, the spring constant of the coil spring 36 that biases the additional mass 37 upward is adjusted, and the natural period of the additional mass 37 is adjusted. Then, after the adjustment, the nut 41 is tightened.

The period of the additional mass 37 is changed by adjusting the spring constant of the coil spring 36, and the natural frequency of the additional mass 37 can be made to match the natural frequency of the stairs 32. Thereby, the vertical vibration of the additional mass 37 can vibrate at the same frequency as the natural frequency of the stairs 32, and a sufficient vibration damping effect can be obtained.

FIG. 12 shows a modification of the second embodiment. The natural period adjusting mechanism 44 is configured such that the lower end 34b of the support column 34 is inserted into the through hole 42b of the engaging member 42, and the nut 45 screwed to the male screw of the lower end 34b contacts the lower end of the engaging member 42. ing. The engaging member 42 has a spiral groove 42a on the outer periphery for engaging the coil spring 36.

Therefore, the coil spring 36 has the engaging member 42.
The number of turns engaged with the spiral groove 42a is restricted to a state in which expansion and contraction is not possible, and since the number of turns functioning substantially as a spring is changed, the spring constant is changed by the number of turns engaged. There is. Here, an adjusting operation for adjusting the natural period by adjusting the spring constant of each coil spring 36 by the natural period adjusting mechanism 44 will be described.

When the natural frequencies of the additional mass 37 and the coil spring 36 become out of synchronization with each other, the nut 45 is removed from the lower end 34b of the column 34 and the coil spring 36 is rotated around the axis to spiral the engaging member 42. The number of turns engaged with the groove 42a is changed. Then, the height position of the engaging member 42 is adjusted by the tightening position of the nut 45 so that the spring force of the coil spring 36 becomes constant. In addition, the upper end 34a of the column 34
Are fixed to the base 33 by welding or the like.

In this way, the spiral groove 42 of the engaging member 42 is
By changing the number of turns of engagement of the coil spring 36 that engages with a, the effective number of turns functioning as a spring among the total number of turns of the coil spring 36 is adjusted. As a result, the spring constant of the coil spring 36 that biases the additional mass 37 upward is adjusted, and the natural period of the additional mass 37 is adjusted.

When the natural frequency of the staircase 32 changes and the additional mass 37 and the staircase 32 become out of synchronization with each other, the cycle of the additional mass 37 is changed by adjusting the spring constant of the coil spring 36. The natural frequency of the additional mass 37 can be matched with the natural frequency of the stairs 32.
As a result, the vertical vibration of the additional mass 37 causes the stairs 32 to move.
It can oscillate at the same frequency as the natural frequency of, and a sufficient damping effect can be obtained.

In the second embodiment described above, the vibration damping device 31 is installed on the lower surface side of the stairs 32, but the invention is not limited to this, and the vibration of the structure may be hung from another structure. May be controlled. In each of the above embodiments,
Although an example in which the coil spring is used as the biasing member has been described, the present invention is not limited to this, and it is also applicable to a configuration using a gas spring filled with compressed gas instead of the coil spring. Of course.

In the structure in which the additional mass is urged by the spring force of the gas spring, the cycle is adjusted by adjusting the gas pressure by supplying and discharging the gas filled in the gas spring by the operation of the gas supply and discharge device. can do. In this case, the cycle can be adjusted to be shorter by increasing the pressure of the gas charged in the gas spring, or the cycle can be adjusted to be longer by reducing the pressure of the gas charged in the gas spring. .

[0057]

As described above, according to claim 1, the natural period of the structure itself can be adjusted because the natural period of the biasing member for biasing the laminated rubber can be adjusted by the natural period adjusting mechanism. Even if the natural frequency of the rubber changes, the natural frequency of the laminated rubber can be matched with the structure by adjusting the natural period of the biasing member, and the laminated rubber can be tuned to the structure. Therefore, even if the viscoelasticity of the laminated rubber changes over time or the strength of the ground of the structure changes and the laminated rubber and the structure become out of synchronization, the additional mass is increased or the laminated rubber is replaced. It is possible to obtain the initial vibration damping effect by adjusting the natural period of the biasing member by a simple operation without performing such troublesome work.

Further, according to claim 2, since the natural period of the urging member that hangs the additional mass so as to be movable in the vertical direction and urges the additional mass upward, the structure itself can be adjusted. Even if the natural frequency of the additional mass or the natural frequency of the additional mass changes, the natural frequency of the additional mass can be made to match the structure and the additional mass can be tuned to the structure by adjusting the natural period of the biasing member. It is possible to obtain the same effect as that of the first aspect.

According to the third aspect, since the effective period of the coil spring is changed by the natural period adjusting mechanism, the natural period of the biasing member can be easily adjusted, and the natural frequency of the laminated rubber is increased. It becomes possible to easily adjust to match the natural frequency of the structure, and the adjustment work can be completed in a short time.

[Brief description of drawings]

FIG. 1 is a front view of a first embodiment of a vibration damping device according to the present invention.

FIG. 2 is an enlarged view showing an enlarged laminated rubber and a spring mechanism for swingably supporting an additional mass.

FIG. 3 is a perspective view showing the structure of laminated rubber.

FIG. 4 is a schematic diagram of a first embodiment of the vibration damping device.

FIG. 5 is a vertical cross-sectional view showing the structure of a natural period adjusting mechanism.

FIG. 6 is a vertical cross-sectional view showing a modified example of the natural period adjusting mechanism.

FIG. 7 is a vertical cross-sectional view showing another modification of the natural period adjusting mechanism.

FIG. 8 is a view showing a mounting state of the second embodiment of the present invention.

FIG. 9 is a vertical sectional view showing a natural period adjusting mechanism of a second embodiment.

FIG. 10 is a vertical cross-sectional view showing a mounted state of an attenuator.

FIG. 11 is a plan view of the second embodiment.

FIG. 12 is a vertical sectional view showing a natural period adjusting mechanism of a modified example of the second embodiment.

FIG. 13 is a perspective view for explaining a conventional vibration damping device.

FIG. 14 is a diagram modeling a conventional vibration damping device.

[Explanation of symbols]

 11, 31 Vibration control device 12 Building 13, 37 Additional mass 14 Laminated rubber 15 Spring mechanism 16, 24, 25, 39, 44 Natural period adjusting mechanism 20, 36 Coil spring 21, 42 Engaging member 22 Strut 23 Bolt 26, 27 Spring connecting member 32 Stairs 33 Base 34 Strut 35 Spring guide member 38 Damper

Claims (3)

[Claims] 1. A vibration damping device having a structure in which a laminated rubber formed by alternately laminating a plurality of metal plates and rubber plates supports an additional mass in a swingable manner. A vibration damping device, comprising: a member; and a natural period adjusting mechanism that adjusts a natural period of the biasing member. 2. A vibration damping device, comprising: a column that suspends an additional mass so that it can move in the vertical direction; and a damper that damps the vertical vibration of the additional mass. And a natural period adjusting mechanism that adjusts a natural period of the biasing member, and a vibration damping device. 3. The control unit according to claim 1, wherein the biasing member is a coil spring, and the natural period adjusting mechanism is configured to change the effective number of turns of the coil spring. Shaking device.