JP7551567B2 - Damping Addition Device - Google Patents

Description

Embodiments of the present invention relate to a damping device, and in particular to vibration control technology that suppresses response displacement in response to vibration inputs such as earthquake waves and shock waves.

It is desirable that various equipment installed in nuclear power plants and other facilities be constructed so that it can maintain its functionality against various external forces, such as earthquake loads and collision loads from flying objects. In recent years, the standard earthquake motion has been revised, and the expected earthquake load has been estimated to be large. In some cases, it is difficult to ensure earthquake resistance by simply using rigid reinforcement measures to withstand conventional earthquake shaking. For this reason, measures that incorporate the concept of seismic isolation, which prevents earthquake input from the building from being directly transmitted to the equipment, have been proposed. Methods of incorporating seismic isolation include installing seismic isolation devices such as laminated rubber or sliding bearings between various equipment and the floor of the building. In addition, for spent nuclear fuel storage racks, there is a free-standing installation method in which the spent nuclear fuel storage rack is placed on the bottom of the fuel pool without being fixed with anchor bolts. In general seismic isolation devices, the natural frequency is set to a value lower than the frequency range that includes the main component of earthquake motion, so the response displacement to vibration input is large. To address this issue, a technology has been proposed that provides a mechanism for adjusting the restoring force and frictional force in the support member that supports the bottom end of the equipment, and suppresses vibration input to the equipment by allowing the bottom end of the equipment to slide slightly when an external force such as an earthquake load acts on it.

Figure 5 of Patent Document 2 shows that it is possible to add significant damping to the object to be vibration-controlled.

Patent No. 6591310 JP 2020-85158 A

Conventional damping adding devices have a problem in that when an acceleration exceeding the input acceleration at which optimal damping is added is input, the damping added gradually decreases.
SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a damping device capable of damping vibrations of an object to be damped for a wide range of input accelerations.

In order to solve the above problem, the damping addition device in an embodiment is arranged between the bottom of a vibration-damping object and a mounting portion on which the vibration-damping object is placed, and when the relative position of the lower surface of the vibration-damping object relative to the upper surface of the mounting portion changes from a default position to a second position due to the vibration of the vibration-damping object, the damping addition device comprises: a restoring force generating unit that generates a restoring force that restores the relative position to the default position; a pressing force generating unit that generates a pressing force that presses the lower surface of the vibration-damping object against the upper surface of the mounting portion; and a frictional force adjustment unit that changes the frictional force that the vibration-damping object receives directly or indirectly from the upper surface of the mounting portion depending on the distance from the default position to the second position, and is characterized in that the frictional force adjustment unit changes the total area of the sliding surface that slides against the upper surface of the mounting portion depending on the distance from the default position to the second position .

Embodiments of the present invention provide a damping device that can dampen the vibration of an object to be damped over a wide range of input accelerations.

FIG. 1 is a schematic front view showing a damping device according to a first or second embodiment attached to an object to be damped. FIG. 2 is a schematic cross-sectional view illustrating an example of a restoring force generating portion. FIG. 3 is a schematic cross-sectional view showing an example of a pressing force generating portion. FIG. 4 is a schematic cross-sectional view showing an example of a frictional force adjusting portion. FIG. 5 is a schematic cross-sectional view showing an example of a frictional force adjusting portion. FIG. 6 is a schematic cross-sectional view showing a first modified example of a frictional force adjusting portion. FIG. 7 is a schematic cross-sectional view showing a second modified example of the frictional force adjusting portion. FIG. 8 is a schematic diagram showing a vibration model of an object to be damped to which a conventional damping device is attached. FIG. 9 is a schematic diagram showing a vibration model of an object to be damped to which the damping device according to the first embodiment is attached. FIG. 10 is a graph showing the relationship between the input acceleration and the damping ratio. FIG. 11 is a graph showing the relationship between the natural frequency ratio and the damping ratio. FIG. 12 is a schematic cross-sectional view showing an example of a frictional force adjusting portion of the damping adding device in the second embodiment.

The damping device 1 according to the embodiment will be described below with reference to the attached drawings. In the following description, the same reference numerals are used for components and parts having the same functions, and repeated description of the components and parts with the same reference numerals will be omitted.

First Embodiment
The damping device 1A in the first embodiment will be described with reference to Figs. 1 to 11. Fig. 1 is a schematic front view showing the damping device 1A in the first embodiment attached to the vibration-damping target B. In Fig. 1, in order to easily grasp the arrangement of the damping device 1A, a cross-sectional view is shown instead of a front view for the parts other than the equipment 2. Fig. 2 is a schematic cross-sectional view showing an example of the restoring force generating unit 6. Fig. 3 is a schematic cross-sectional view showing an example of the pressing force generating unit 7. Figs. 4 and 5 are schematic cross-sectional views showing an example of the frictional force adjusting unit 8. Fig. 6 is a schematic cross-sectional view showing a first modified example of the frictional force adjusting unit 8. Fig. 7 is a schematic cross-sectional view showing a second modified example of the frictional force adjusting unit 8. Fig. 8 is a schematic diagram showing a vibration model of the vibration-damping target B to which the conventional damping device 100 is attached. Fig. 9 is a schematic diagram showing a vibration model of the vibration-damping target B to which the damping device 1A in the first embodiment is attached. Fig. 10 is a graph showing the relationship between the input acceleration and the damping ratio. Fig. 11 is a graph showing the relationship between the natural frequency ratio and the damping ratio.

(Composition and Function)
The damping device 1A in the first embodiment is disposed between an object B to be damped and a mounting portion C such as a sliding plate 4. The damping device 1A is used to damp vibrations that occur in the object B to be damped when an external force such as an earthquake load or an impact load acts on the mounting portion C. Examples of the object B to be damped include spent nuclear fuel storage racks, electrical panels, pumps, heat exchangers, transformers, and the like used in nuclear power plants.

In the example shown in FIG. 1, a sliding plate 4 is placed on the floor surface 3 of a building. The sliding plate 4 is fixed to the floor surface 3 by a fixing member 91 such as a bolt. In the example shown in FIG. 1, the placement part C on which the vibration control target B is placed is the sliding plate 4, but the placement part C may be the floor surface 3 itself.

In the example shown in FIG. 1, the vibration control object B includes equipment 2 (e.g., storage equipment such as a spent nuclear fuel storage rack, electrical equipment such as an electrical panel or a transformer, thermal equipment such as a heat exchanger, or fluid equipment such as a pump) and a base member 5. The base member 5 is fixed to the underside of the equipment 2 by welding, bolts, etc. Alternatively, the equipment 2 may be placed directly on the placement portion C, and the base member 5 may be omitted.

In the example shown in FIG. 1, the base member 5 is provided with a restoring force generating unit 6, a pressing force generating unit 7, and a friction force adjusting unit 8, which will be described later. The base member 5 may have a housing structure capable of housing at least a portion of the restoring force generating unit 6, the pressing force generating unit 7, and the friction force adjusting unit 8. In the example shown in FIG. 1, the base member 5 has multiple side plates 5A, a lower plate 5B, and an upper plate 5C. The lower portions of the multiple side plates 5A are fixed to the lower plate 5B by welding or the like, and the upper portions of the multiple side plates 5A are fixed to the upper plate 5C by welding or the like.

The damping device 1A in the first embodiment includes a restoring force generating unit 6, a pressing force generating unit 7, and a friction force adjusting unit 8.

The restoring force generating unit 6 is disposed between the bottom of the vibration-damping object B (e.g., the base member 5) and the support C (e.g., the sliding plate 4) on which the vibration-damping object B is placed. In the example shown in FIG. 2(a), the vibration of the vibration-damping object B due to an external force acting on the support C causes the relative position of the lower surface B1 of the vibration-damping object B with respect to the upper surface C1 of the support C to change from the default position P1 (in other words, the first position) to a second position P2 (see FIG. 2(b)) different from the default position P1.

When the relative position of the lower surface B1 of the vibration-damping object B with respect to the upper surface C1 of the mounting portion C changes from the default position P1 to the second position P2 due to vibration of the vibration-damping object B, the restoring force generating unit 6 generates a restoring force that restores the relative position to the default position P1 (see FIG. 2(a)).

3(a), the pressing force generating unit 7 generates a pressing force that presses the lower surface B1 of the vibration-damping object B against the upper surface C1 of the mounting part C. When the lower surface B1 of the vibration-damping object B slides against the upper surface C1 of the mounting part C, the pressing force generates a frictional force between the lower surface B1 and the upper surface C1. For example, when the relative position of the lower surface B1 of the vibration-damping object B with respect to the upper surface C1 of the mounting part C changes from the default position P1 to the second position P2 due to the vibration of the vibration-damping object B, the pressing force generating unit 7 applies a frictional force F1 to the lower surface B1 of the vibration-damping object B in the direction from the second position P2 to the default position P1. The frictional force F1 absorbs the vibration energy of the vibration-damping object B, and the vibration of the vibration-damping object B is damped.

In the example shown in Figures 4 and 5, the frictional force adjustment unit 8 changes the frictional force that the vibration damping object B receives directly or indirectly from the upper surface C1 of the mounting part C depending on the distance from the default position P1 to the second position P2.

4 and 5, it is assumed that the relative position of the lower surface B1 of the vibration-damping object B with respect to the upper surface C1 of the placement portion C changes from the default position P1 (see FIG. 4(a) or FIG. 5(a)) to the second position P2 (see FIG. 4(b) or FIG. 5(b)). In the example shown in FIG. 4(b), the distance from the default position P1 to the second position P2 is relatively small. In this case, the frictional force adjustment unit 8 adjusts the magnitude (F1) of the frictional force that the vibration-damping object B receives directly or indirectly from the upper surface C1 of the placement portion C to a relatively small value. In the example shown in FIG. 5(b), the distance from the default position P1 to the second position P2 is relatively large. In this case, the frictional force adjustment unit 8 adjusts the magnitude (F1+F2) of the frictional force that the vibration-damping object B receives directly or indirectly from the upper surface C1 of the placement portion C to a relatively large value.

(effect)
In the first embodiment, the damping device 1A includes a frictional force adjusting unit 8 that changes the frictional force that the vibration-damping object B receives directly or indirectly from the upper surface C1 of the mounting portion C depending on the distance from the default position P1 to the second position P2. The magnitude of the frictional force that functions as a damping force acting on the vibration-damping object B is changed depending on the distance from the default position P1 to the second position P2, in other words, the magnitude of the change in the relative position of the lower surface B1 of the vibration-damping object B with respect to the upper surface C1 of the mounting portion C, so that the vibration of the vibration-damping object B can be effectively damped for a wide range of input acceleration. For example, when the input acceleration input to the vibration-damping object B is large and the amplitude of the vibration-damping object B is large, a larger damping force acts. As a result, the vibration of the vibration-damping object B can be effectively damped.

(Optional additional configuration)
Next, optional additional configurations that can be adopted in the damping device 1A in the first embodiment will be described with reference to FIGS.

(Frictional force adjustment unit 8)
In the example shown in Figures 4 and 5, the frictional force adjustment unit 8 changes the total area of the sliding surface that slides against the upper surface C1 of the mounting portion C depending on the distance from the default position P1 to the second position P2.

In the example shown in FIG. 4(b), the distance from the default position P1 to the second position P2 is relatively small. In the example shown in FIG. 4(b), the sliding surface that slides against the upper surface C1 of the mounting portion C is the lower surface B1 of the vibration damping object B (more specifically, the lower surface B1 of the base member 5).

In the example shown in FIG. 5(b), the distance from the default position P1 to the second position P2 is relatively large, and the vibration-damping object B is in contact with the sliding block 17. In the example shown in FIG. 5(b), the vibration-damping object B and the sliding block 17 slide against the mounting part C. In this case, the sliding surfaces that slide against the upper surface C1 of the mounting part C are both the lower surface B1 of the vibration-damping object B (more specifically, the lower surface B1 of the base member 5) and the lower surface 17w of the sliding block 17. Therefore, in the example shown in FIG. 5(b), the total area of the sliding surfaces that slide against the upper surface C1 of the mounting part C is larger than that of the example shown in FIG. 4(b). Due to the large total area of the sliding surfaces, the magnitude of the frictional force that the vibration-damping object B receives directly or indirectly from the upper surface C1 of the mounting part C becomes relatively large. In the example shown in FIG. 5(b), the vibration damping object B receives a friction force F1 directly from the upper surface C1 of the mounting part C, and receives a friction force F2 indirectly from the upper surface C1 of the mounting part C via the sliding block 17.

(Sliding block 17)
4(a), the frictional force adjusting section 8 has a sliding block 17 provided independently of the base member 5 constituting the bottom of the vibration damping object B. The sliding block 17 is placed on the sliding plate 4 constituting the mounting section C such that a gap 16 is formed between the sliding block 17 and the base member 5.

Let us assume that the input acceleration input to the mounting part C is small, and the vibration response of the vibration-damping object B is small. When the vibration response of the vibration-damping object B is small, as illustrated in FIG. 4(b), the distance from the default position P1 to the second position P2 is smaller than the size e of the gap 16 (see FIG. 4(a)). In this case, the base member 5 does not contact the sliding block 17, and only the base member 5 slides against the mounting part C. Therefore, the presence of the sliding block 17 does not contribute to an increase in the frictional force that the vibration-damping object B receives from the upper surface C1 of the mounting part C.

Next, assume that the input acceleration input to the mounting portion C is large, and the vibration response of the vibration-damping object B becomes larger. When the vibration response of the vibration-damping object B is large, as illustrated in FIG. 5(b), the distance from the default position P1 to the second position P2 becomes larger than the size e of the gap 16 (see FIG. 5(a)). In this case, the base member 5 comes into contact with the sliding block 17, and the frictional force that the vibration-damping object B receives directly or indirectly from the upper surface C1 of the mounting portion C is increased. More specifically, the base member 5 comes into contact with the sliding block 17, and both the base member 5 and the sliding block 17 slide against the mounting portion C. As a result, the frictional force that the vibration-damping object B receives from the upper surface C1 of the mounting portion C increases by the amount of the additional frictional force F2 that the vibration-damping object B receives indirectly from the upper surface C1 of the mounting portion C via the sliding block 17.

In the example shown in FIG. 5(b), when the relative displacement between the base member 5 and the sliding plate 4 exceeds the threshold value e (more specifically, the size e of the gap 16 between the sliding block 17 and the base member 5), an additional frictional force F2 is generated in the sliding block 17 of the frictional force adjustment unit 8, and the vibrational energy of the vibration-damping target B is absorbed by the frictional force F1 between the base member 5 and the upper surface C1 of the sliding plate 4 and the additional frictional force F2. In the example shown in FIG. 5, the threshold value e can be easily adjusted by setting the size of the gap 16 between the sliding block 17 and the base member 5 according to the expected magnitude of the relative displacement.

In the example shown in FIG. 4(a), a first through hole portion 511h is formed in the base member 5 (more specifically, the lower plate 5B of the base member 5), and the sliding block 17 is disposed inside the first through hole portion 511h. A gap 16 is formed between the outer surface 17t of the sliding block 17 and the inner surface of the first through hole portion 511h. When the relative position of the lower surface B1 of the vibration damping object B with respect to the upper surface C1 of the mounting portion C is in the default position P1, the distance (e) between the outer surface 17t of the sliding block 17 and the inner surface of the first through hole portion 511h corresponds to the size of the gap 16.

The sliding block 17 may have a ring shape in plan view, or may have other shapes. The outer surface 17t of the sliding block 17 may have a circular shape in plan view, and the inner surface of the first through hole portion 511h may have a circular shape in plan view. In the example shown in FIG. 4(a), when the relative position of the lower surface B1 of the vibration damping object B with respect to the upper surface C1 of the mounting portion C is the default position P1, the center of the sliding block 17 in plan view and the center of the first through hole portion 511h in plan view coincide with each other. Alternatively, when the relative position of the lower surface B1 of the vibration damping object B is the default position P1, the center of the sliding block 17 in plan view may be offset from the center of the first through hole portion 511h in plan view.

For example, when the relative position of the lower surface B1 of the vibration-damping object B with respect to the upper surface C1 of the mounting portion C returns from the second position P2 to the default position P1, the center of the sliding block 17 in a planar view may be offset from the center of the first through-hole portion 511h in a planar view. When the vibration-damping object B returns to the default position P1, and the center of the sliding block 17 in a planar view is offset from the center of the first through-hole portion 511h in a planar view, the size of the above-mentioned gap 16 means the minimum distance between the outer surface 17t of the sliding block 17 and the inner surface of the first through-hole portion 511h.

(Other configurations of frictional force adjustment unit 8)
4A, the frictional force adjustment unit 8 has a first shaft 18, a first biasing force adjustment member 19, and a first elastic member 21. The frictional force adjustment unit 8 may have washers 20 such as a first washer 20a and a second washer 20b.

In the example shown in FIG. 4(a), the first shaft 18 is fixed to the mounting part C (more specifically, the sliding plate 4). The first shaft 18 is fixed to the mounting part C by screwing or the like. In the example shown in FIG. 4(a), a through hole part 17h is formed in the sliding block 17, and the first shaft 18 is inserted into the through hole part 17h. In addition, the lower end part 18b of the first shaft 18 is fixed to the sliding plate 4 by screwing or the like.

The first biasing force adjustment member 19 can be repositioned along the longitudinal axis AX1 of the first shaft 18. The first biasing force of the first elastic member 21 is adjusted by changing the position of the first biasing force adjustment member 19 along the longitudinal axis AX1 of the first shaft 18. The first biasing force adjustment member 19 may be any member as long as it can be repositioned along the longitudinal axis AX1 of the first shaft 18. The first biasing force adjustment member 19 may be a first nut 190 that screws into the first shaft 18, or a cam member that moves along a cam groove formed in the first shaft 18. In addition, when the first shaft 18 is a bolt, the first biasing force adjustment member 19 may be the head of the bolt.

In the example shown in FIG. 4(a), the first biasing force adjustment member 19 is a first nut 190 that screws onto the first shaft 18. In the example shown in FIG. 4(a), a male thread is formed on the upper end 18a of the first shaft 18, and the first nut 190 screws onto the male thread. In this case, the first nut 190 is rotated relative to the first shaft 18 around the longitudinal axis AX1 of the first shaft 18, so that the position of the first nut 190 is changed along the longitudinal axis AX1 of the first shaft. The first nut 190 is rotated, for example, by a known rotating jig (not shown).

The first elastic member 21 is disposed between the first biasing force adjustment member 19 (more specifically, the first nut 190) and the sliding block 17. The first elastic member 21 applies a first biasing force to the sliding block 17 in a direction toward the sliding plate 4 (more specifically, a vertically downward direction). By changing the position of the first biasing force adjustment member 19 along the longitudinal axis AX1 of the first shaft 18, the amount of elastic deformation of the first elastic member 21 is changed, and the magnitude of the first biasing force applied to the sliding block 17 is changed (in other words, the first biasing force is adjusted).

In the example shown in FIG. 4(a), the first elastic member 21 includes a plurality of disc springs stacked along the longitudinal direction of the first shaft 18. Alternatively, the first elastic member 21 may be a spring other than a disc spring, or rubber. In the example shown in FIG. 4(a), the first elastic member 21 is disposed around the first shaft 18.

In the example shown in FIG. 4(a), a first washer 20a is disposed between the first elastic member 21 and the sliding block 17. The first washer 20a smoothly guides the movement of the sliding block 17 when the sliding block 17 slides against the upper surface C1 of the mounting portion C. It is preferable that the static friction coefficient between the lower surface of the first washer 20a and the upper surface of the sliding block 17 is smaller than the static friction coefficient between the lower surface 17w of the sliding block 17 and the upper surface C1 of the mounting portion C. In this case, when the sliding block 17 is pressed by the base member 5, the sliding block 17 is smoothly guided by both the first washer 20a and the mounting portion C, and slides against both the first washer 20a and the mounting portion C.

In the example shown in FIG. 4(a), the first washer 20a functions as a lower spring support that contacts the lower end of the first elastic member 21.

In the example shown in FIG. 4(a), the second washer 20b is disposed between the first biasing force adjustment member 19 (more specifically, the first nut 190) and the first elastic member 21. The second washer 20b functions as an upper spring support that contacts the upper end of the first elastic member 21. In the example shown in FIG. 4(a), the second washer 20b smoothly guides the rotation of the first nut 190 when the first nut 190 is rotated.

In the example shown in FIG. 5(a), when an external force such as an earthquake load or an impact load acts on the placement part C, the base member 5 slides on the upper surface C1 of the sliding plate 4, and the relative position of the lower surface B1 of the base member 5 with respect to the upper surface C1 of the sliding plate 4 changes from the default position P1 to the second position P2. When the distance from the default position P1 to the second position P2 (in other words, the relative displacement of the base member 5 with respect to the sliding plate 4) exceeds the size e of the gap 16, the base member 5 comes into contact with the sliding block 17, and the base member 5 and the sliding block 17 slide against the sliding plate 4 (see FIG. 5(b)). When the base member 5 and the sliding block 17 slide against the sliding plate 4, a friction force F1 is generated from the sliding plate 4 to the base member 5 in the direction from the second position P2 to the default position P1, and an additional friction force F2 is generated from the sliding plate 4 to the sliding block 17 in the direction from the second position P2 to the default position P1. The vibration energy of the vibration damping object B is absorbed by the friction force F1 and the additional friction force F2.

In the example shown in FIG. 5(b) (in other words, when the input acceleration input to the mounting portion C is relatively large), both the friction force F1 acting between the sliding plate 4 and the base member 5 and the additional friction force F2 acting between the sliding plate 4 and the sliding block 17 contribute to the damping of the vibration of the vibration-damping object B. On the other hand, in the example shown in FIG. 4(b) (in other words, when the input acceleration input to the mounting portion C is relatively small), the friction force F1 acting between the sliding plate 4 and the base member 5 contributes to the damping of the vibration of the vibration-damping object B, and the sliding block 17 does not contribute to the damping of the vibration of the vibration-damping object B. In this way, the vibration of the vibration-damping object B can be damped more effectively for a wide range of input accelerations.

When the frictional force adjustment unit 8 has a sliding block 17 and a first biasing force adjustment member 19, the ratio of the magnitude of the additional frictional force F2 to the magnitude of the frictional force F1 can be easily changed or adjusted. Therefore, it is possible to easily add optimal damping in accordance with the vibration characteristics of the vibration-damping object B.

In the example shown in FIG. 5(a), the first elastic member 21 is disposed in a first space SP1 inside the base member 5 (more specifically, the space surrounded by the upper plate 5C, the lower plate 5B, and the multiple side plates 5A). In this case, the first elastic member 21 is protected by the base member 5. As illustrated in FIG. 5(a), the first nut 190 and/or the upper end 18a of the first shaft 18 may be disposed in the first space SP1 inside the base member 5.

In the example shown in FIG. 5(a), a first access hole 511d is formed in the upper plate 5C of the base member 5. The first access hole 511d is preferably formed in a position facing the first biasing force adjustment member 19 (or the first shaft 18). When the first access hole 511d is formed in the upper plate 5C, the user can operate the first biasing force adjustment member 19 (or the first shaft 18) through the first access hole 511d.

In the example shown in FIG. 1, the damping device 1A includes at least two friction adjustment units 8. The number of friction adjustment units 8 included in the damping device 1A is determined according to the size of the vibration-damping object B, etc.

(First Modification)
Fig. 6 shows the frictional force adjustment unit 8 in the first modified example. In the example shown in Fig. 6, the frictional force adjustment unit 8 has an elastic member 22 disposed in the gap 16 between the base member 5 and the sliding block 17. The elastic member 22 reduces the impact when the base member 5 (more specifically, the lower plate 5B) comes into contact with the sliding block 17. The elastic member 22 is, for example, a leaf spring.

(Second Modification)
A frictional force adjusting section 8 in a second modified example is shown in Fig. 7. In the example shown in Fig. 7(a), the sliding block 17 has a plurality of blocks including a first block 17a and a second block 17b.

The first block 17a is placed on the sliding plate 4 so that a first gap 16a is formed between the first block 17a and the base member 5 (more specifically, the lower plate 5B). The second block 17b is placed on the sliding plate 4 so that a second gap 16b larger than the first gap 16a is formed between the second block 17b and the base member 5 (more specifically, the lower plate 5B).

As illustrated in FIG. 7(b), when the distance from the default position P1 to the second position P2 is greater than the size e1 of the first gap 16a (see FIG. 7(a)) and less than the size e2 of the second gap 16b (see FIG. 7(a)), the base member 5 comes into contact with the first block 17a, thereby increasing the frictional force that the vibration-damping object B receives directly or indirectly from the upper surface C1 of the mounting portion C.

Furthermore, as illustrated in FIG. 7(c), when the distance from the default position P1 to the second position P2 is greater than the size e2 of the second gap 16b (see FIG. 7(a)), the base member 5 comes into contact with both the first block 17a and the second block 17b, thereby further increasing the frictional force that the vibration-damping object B receives directly or indirectly from the upper surface C1 of the mounting portion C.

In the example shown in FIG. 7, the number of sliding blocks 17 that contribute to the attenuation of the vibration of the object to be damped B is changed depending on the magnitude of the input acceleration input to the mounting part C. For example, when the magnitude of the input acceleration input to the mounting part C is small, the number of sliding blocks 17 that contribute to the attenuation of the vibration of the object to be damped B is zero, and when the magnitude of the input acceleration input to the mounting part C increases, the number of sliding blocks 17 that contribute to the attenuation of the vibration of the object to be damped B is increased, and when the magnitude of the input acceleration input to the mounting part C increases further, the number of sliding blocks 17 that contribute to the attenuation of the vibration of the object to be damped B is further increased. In this way, in the example shown in FIG. 7, the vibration of the object to be damped B can be more effectively damped for an even wider range of input acceleration.

(Restoring force generating unit 6)
2A, the restoring force generating unit 6 has a rod spring 9 disposed between the base member 5 and the sliding plate 4. The rod spring 9 is supported by both the base member 5 and the sliding plate 4.

When the relative position of the lower surface B1 of the vibration control object B with respect to the upper surface C1 of the mounting portion C changes from the default position P1 to the second position P2, the rod spring 9 uses the bending rigidity of the rod spring 9 to restore the relative position to the default position P1. More specifically, when the base member 5 slides against the upper surface C1 of the sliding plate 4 due to an external force such as an earthquake load or an impact load acting on the mounting portion C, the bending rigidity of the rod spring 9 restores the relative position of the base member 5 with respect to the sliding plate 4 to its original position (in other words, the default position P1).

In the example shown in FIG. 2(a), the lower end 9b of the rod spring 9 is fitted into a first fitting portion 10 (more specifically, a first recess) formed in the sliding plate 4. In this case, the horizontal movement of the lower end 9b of the rod spring 9 relative to the sliding plate 4 is restricted by the first fitting portion 10. In the example shown in FIG. 2(a), the upper end 9a of the rod spring 9 is fitted into a second fitting portion 11 (more specifically, a through hole portion) formed in the upper plate 5C of the base member 5. In this case, the horizontal movement of the upper end 9a of the rod spring 9 relative to the base member 5 is restricted by the second fitting portion 11.

In the example shown in FIG. 2(a), a second through hole portion 512h is formed in the base member 5 (more specifically, the lower plate 5B of the base member 5), and the rod spring 9 is inserted into the second through hole portion 512h. A third gap G3 is formed between the outer surface 9t of the rod spring 9 and the inner surface of the second through hole portion 512h. The distance between the outer surface 9t of the rod spring 9 and the inner surface of the second through hole portion 512h corresponds to the size of the third gap G3. The size of the third gap G3 is preferably larger than the size e of the gap 16 between the sliding block 17 and the base member 5 as illustrated in FIG. 4(a). By making the third gap G3 sufficiently large, interference between the base member 5 and the lower end portion 9b of the rod spring 9 is prevented when the base member 5 vibrates in the horizontal direction.

In the example shown in FIG. 1, the damping device 1A includes at least two restoring force generating units 6. The number of restoring force generating units 6 included in the damping device 1A is determined according to the size of the vibration-damping object B, etc.

(Pressing force generating unit 7)
3A, the pressing force generating unit 7 has a second shaft 12, a second biasing force adjusting member 13, and a second elastic member 15. The pressing force generating unit 7 may have washers 14 such as a third washer 14a and a fourth washer 14b.

In the example shown in FIG. 3(a), the second shaft 12 is fixed to the mounting part C (more specifically, the sliding plate 4). The second shaft 12 is fixed to the mounting part C by screwing or the like. In the example shown in FIG. 3(a), a third through hole part 513h is formed in the base member 5 (more specifically, the lower plate 5B of the base member 5), and the second shaft 12 is inserted into the third through hole part 513h. In addition, the lower end part 12b of the second shaft 12 is fixed to the sliding plate 4 by screwing or the like.

A fourth gap G4 is formed between the outer surface 12t of the second shaft 12 and the inner surface of the third through hole portion 513h. The distance between the outer surface 12t of the second shaft 12 and the inner surface of the third through hole portion 513h corresponds to the size of the fourth gap G4. The size of the fourth gap G4 is preferably larger than the size e of the gap 16 between the sliding block 17 and the base member 5 illustrated in FIG. 4(a). By making the fourth gap G4 sufficiently large, interference between the base member 5 and the second shaft 12 is prevented when the base member 5 vibrates in the horizontal direction.

The second biasing force adjustment member 13 can be repositioned along the longitudinal axis AX2 of the second shaft 12. The second biasing force of the second elastic member 15 is adjusted by changing the position of the second biasing force adjustment member 13 along the longitudinal axis AX2 of the second shaft 12. The second biasing force adjustment member 13 may be any member as long as it can be repositioned along the longitudinal axis AX2 of the second shaft 12. The second biasing force adjustment member 13 may be a second nut 130 that screws into the second shaft 12, or a cam member that moves along a cam groove formed in the second shaft 12. In addition, when the second shaft 12 is a bolt, the second biasing force adjustment member 13 may be the head of the bolt.

In the example shown in FIG. 3(a), the second biasing force adjustment member 13 is a second nut 130 that screws onto the second shaft 12. In the example shown in FIG. 3(a), a male thread is formed on the upper end 12a of the second shaft 12, and the second nut 130 screws onto the male thread. The second nut 130 is rotated relative to the second shaft 12 around the longitudinal axis AX2 of the second shaft 12, whereby the position of the second nut 130 is changed along the longitudinal axis AX2 of the second shaft. The second nut 130 is rotated, for example, by a known rotating jig (not shown).

The second elastic member 15 is disposed between the second biasing force adjustment member 13 (more specifically, the second nut 130) and the base member 5 (more specifically, the lower plate 5B of the base member 5). The second elastic member 15 applies a second biasing force to the base member 5 in a direction toward the sliding plate 4 (more specifically, in a vertically downward direction). The second biasing force presses the base member 5 against the sliding plate 4. By changing the position of the second biasing force adjustment member 13 along the longitudinal axis AX2 of the second shaft 12, the amount of elastic deformation of the second elastic member 15 is changed, and the magnitude of the second biasing force applied to the base member 5 is changed (in other words, the second biasing force is adjusted).

In the example shown in FIG. 3(a), the second elastic member 15 includes a plurality of disc springs stacked along the longitudinal direction of the second shaft 12. Alternatively, the second elastic member 15 may be a spring other than a disc spring, or rubber. In the example shown in FIG. 3(a), the second elastic member 15 is disposed around the second shaft 12.

In the example shown in FIG. 3(a), a third washer 14a is disposed between the second elastic member 15 and the base member 5. The third washer 14a smoothly guides the movement of the base member 5 when the base member 5 slides against the upper surface C1 of the mounting portion C (more specifically, the upper surface of the sliding plate 4). It is preferable that the static friction coefficient between the lower surface of the third washer 14a and the base member 5 is smaller than the static friction coefficient between the lower surface B1 of the base member 5 and the upper surface C1 of the mounting portion C. In this case, when the base member 5 vibrates in the horizontal direction, the base member 5 is smoothly guided by both the third washer 14a and the mounting portion C, and slides against both the third washer 14a and the mounting portion C.

In the example shown in FIG. 3(a), the third washer 14a functions as a lower spring support that contacts the lower end of the second elastic member 15.

In the example shown in FIG. 3(a), a fourth washer 14b is disposed between the second biasing force adjustment member 13 (more specifically, the second nut 130) and the second elastic member 15. The fourth washer 14b functions as an upper spring support that contacts the upper end of the second elastic member 15. In the example shown in FIG. 3(a), the fourth washer 14b smoothly guides the rotation of the second nut 130 when the second nut 130 is rotated.

In the example shown in FIG. 3(a), when an external force such as an earthquake load or an impact load acts on the mounting portion C, the base member 5 slides on the upper surface C1 of the sliding plate 4, and the relative position of the lower surface B1 of the base member 5 with respect to the upper surface C1 of the sliding plate 4 changes from the default position P1 to the second position P2 (see FIG. 3(b)). When the base member 5 slides against the sliding plate 4, a frictional force F1 is generated from the sliding plate 4 to the base member 5 in the direction from the second position P2 toward the default position P1. The frictional force F1 absorbs the vibrational energy of the vibration-damping object B, and the vibration of the vibration-damping object B is damped.

In the example shown in FIG. 3(a), when the second biasing force adjustment member 13 is repositioned along the longitudinal axis AX2 of the second shaft 12, the magnitude of the second biasing force applied to the base member 5 is changed. In addition, by changing the magnitude of the second biasing force, the magnitude of the above-mentioned frictional force F1 is changed (in other words, adjusted).

In the example shown in FIG. 3(a), the second elastic member 15 is disposed in a second space SP2 inside the base member 5 (more specifically, the space surrounded by the upper plate 5C, the lower plate 5B, and the multiple side plates 5A). In this case, the second elastic member 15 is protected by the base member 5. As illustrated in FIG. 3(a), the second nut 130 and/or the upper end 12a of the second shaft 12 may be disposed in the second space SP2 inside the base member 5.

In the example shown in FIG. 3(a), a second access hole 513d is formed in the upper plate 5C of the base member 5. The second access hole 513d is preferably formed in a position facing the second biasing force adjustment member 13 (or the second shaft 12). When the second access hole 513d is formed in the upper plate 5C, the user can operate the second biasing force adjustment member 13 (or the second shaft 12) through the second access hole 513d.

In the example shown in FIG. 1, the damping device 1A includes at least two pressing force generating units 7. The number of pressing force generating units 7 included in the damping device 1A is determined according to the size of the vibration-damping object B, etc.

(Combined Action of the Restoring Force Generator 6, the Pressing Force Generator 7, and the Friction Force Adjuster 8)
In the example shown in FIG. 1, when an external force such as an earthquake load is applied horizontally to the placement portion C, the base member 5 slides on the upper surface C1 of the sliding plate 4.

When the base member 5 slides on the upper surface C1 of the sliding plate 4, the restoring force generating unit 6 illustrated in FIG. 2 generates a restoring force by the rod spring 9, suppressing the vibration displacement of the base member 5 relative to the sliding plate 4. By preparing rod springs 9 with different cross-sectional shapes and/or cross-sectional dimensions, the bending rigidity of the rod springs 9 can be changed, and the support rigidity (natural frequency) of the vibration-damping object B can be adjusted.

When the base member 5 slides on the upper surface C1 of the sliding plate 4, the pressing force generating unit 7 illustrated in FIG. 3 generates a frictional force between the base member 5 and the upper surface C1 of the sliding plate 4. The frictional force absorbs the vibration energy of the vibration damping object B. The second biasing force adjusting member 13 can be used to adjust the amount of deformation of the second elastic member 15, thereby changing the pressing force pressing the base member 5 against the sliding plate 4. In this way, the magnitude of the frictional force F1 generated between the base member 5 and the sliding plate 4 when the base member 5 slides on the upper surface C1 of the sliding plate 4 can be adjusted.

Assume that the input acceleration input to the placement part C is large, and the vibration response of the vibration-damping target B becomes larger. As illustrated in FIG. 5(b), when the relative displacement between the base member 5 and the sliding plate 4 exceeds the threshold value e (more specifically, the size e of the gap 16 between the sliding block 17 and the base member 5), an additional frictional force F2 is generated in the frictional force adjustment part 8, and the vibration energy of the vibration-damping target B is absorbed by the frictional force F1 between the base member 5 and the upper surface C1 of the sliding plate 4 and the additional frictional force F2. The threshold value e can be easily adjusted by setting the size of the gap 16 between the sliding block 17 and the base member 5 according to the expected magnitude of the relative displacement. In addition, the deformation amount of the first elastic member 21 can be adjusted using the first biasing force adjustment member 19, and the pressing force pressing the sliding block 17 against the sliding plate 4 can be changed. In this way, the magnitude of the additional frictional force F2 relative to the magnitude of the frictional force F1 between the base member 5 and the upper surface C1 of the sliding plate 4 can be freely adjusted.

(effect)
Next, with reference to Figs. 8 to 11, an example of the effect achieved by the damping device 1A will be described using a vibration model of an object B to be damped to which the damping device 1A is attached.

Figure 8 shows a vibration model of a vibration-damping object B to which a conventional damping device 100 is attached. "W1" indicates the weight of the vibration-damping object B, "k1" indicates the stiffness (spring constant) of the vibration-damping object B, and "c1" indicates the damping coefficient of the vibration-damping object B. Furthermore, "W2" indicates the weight of the damping device 100, "k2" indicates the stiffness (spring constant) of the damping device 100, and "Fr2" indicates the frictional force generated by the pressing force generating unit 7. Figure 9 shows an example of a vibration model of a vibration-damping object B to which a damping device 1A in the first embodiment is attached. "W1" indicates the weight of the vibration-damping object B, "k1" indicates the stiffness (spring constant) of the vibration-damping object B, "c1" indicates the damping coefficient of the vibration-damping object B, "W2" indicates the weight of the damping addition device 1A, "k2" indicates the stiffness (spring constant) of the damping addition device 1A, "Fr2" indicates the frictional force generated by the pressing force generating unit 7, and "Fr2'" indicates the additional frictional force generated by the frictional force adjusting unit 8.

Figure 10 is a graph showing the relationship between the input acceleration input to the mounting section C and the damping ratio. The damping ratio means the ratio of the damping coefficient to the critical damping coefficient. Figure 10 shows the extent to which the damping ratio increases (in other words, the vibration control performance improves) by attaching the damping device 100 or the damping device 1A to the vibration control target B.

In addition, FIG. 10 shows an example in which the damping ratio of the vibration-damping object B itself, which does not have a damping device attached, is 4%, and a sine sweep wave is input in a frequency range that sufficiently covers the resonant frequency range of the vibration-damping object B. The horizontal axis of FIG. 10 indicates the magnitude of the horizontal input acceleration input to the mounting part C, and the vertical axis of FIG. 10 indicates the damping ratio. In FIG. 10, black circles, black triangles, black squares, white circles, white triangles, and white squares indicate the change in damping ratio with respect to the input acceleration when the damping device 100 (the stiffness ratio k2/k1 and the ratio of the friction force Fr2 to the weight W1 are as shown in the graph) is attached to the vibration-damping object B. In addition, in FIG. 10, the thick solid line indicates the change in damping ratio with respect to the input acceleration when the damping device 1A is attached to the vibration-damping object B.

From FIG. 10, it can be seen that the damping ratio has a significant amplitude dependency (in other words, a characteristic that varies greatly depending on the magnitude of the input acceleration). In the example shown in FIG. 10, the damping ratio increases as the input acceleration increases from 10 Gal. In addition, when the input acceleration exceeds about 100 Gal, the damping ratio becomes maximum, and as the input acceleration increases further, the damping ratio gradually decreases. In the example of FIG. 10, regardless of the input acceleration, a damping ratio that generally exceeds the damping ratio of 4% before the damping device 1 is attached is obtained.

In the example of Figure 10, the maximum value of the damping ratio is not affected by the magnitude of the frictional force Fr2 of the damping device 100, and tends to increase as the stiffness k2 of the damping device 100 decreases. In addition, as the frictional force Fr2 of the damping device 100 increases, the peak of the damping ratio (damping characteristic curve) tends to shift toward the high acceleration side.

In the first embodiment, as the response amplitude of the vibration-damping object B increases (in other words, as the relative displacement of the vibration-damping object B with respect to the mounting portion C increases), the frictional force adjustment portion 8 generates an additional frictional force Fr2'. Thus, in the first embodiment, when the magnitude of the input acceleration increases, the peak of the damping ratio (damping characteristic curve) can be shifted to the high acceleration side during vibration of the vibration-damping object B by generating an additional frictional force Fr2'. In this way, the decrease in damping on the high acceleration side is suppressed. As a result, in the first embodiment, the vibration of the vibration-damping object B can be effectively damped for a wide range of input accelerations.

As shown in FIG. 7, the damping device 1A may have multiple friction adjustment parts 8 with different sizes (e1; e2) of the gap 16. In this case, the friction force can be increased in multiple stages depending on the magnitude of the relative displacement between the base member 5 and the sliding plate 4. This makes it possible to effectively damp the vibration of the vibration-damping object B against an even wider range of input acceleration.

Figure 11 shows a graph in which the graph shown in Figure 10 has been rearranged using the natural frequency ratio as a parameter. Note that the natural frequency ratio refers to the ratio of the natural frequency of the vibration-damping object B after the damping device 1A is attached to the natural frequency of the vibration-damping object B before the damping device 1A is attached.

In the example shown in Figure 9, as the stiffness k2 of the damping device 1A decreases, the natural frequency of the vibration-damping object B decreases. Figure 11 shows that as the stiffness k2 of the damping device 1A decreases and the natural frequency of the vibration-damping object B decreases (shifting to the left on the horizontal axis in Figure 11), the maximum damping ratio tends to increase. Figure 11 shows the result that the damping ratio (4%) before the damping device 1A is installed increases to a maximum of approximately 27%.

For example, it is assumed that the natural frequency of the vibration-damping object B is set to 0.5 to 0.9 times the original natural frequency by attaching the damping device 1A of the first embodiment to the vibration-damping object B. In this case, in the example shown in FIG. 11, the damping ratio of the vibration-damping object B before the damping device 1A is attached (4%) can be increased by approximately 3% to 23% by attaching the damping device 1A, making the damping ratio approximately 7 to 27%. Considering that the damping ratio when the vibration-damping object B is fixed by a normal welding structure is approximately 1%, it can be seen that the damping device 1A of the first embodiment adds a very large damping to the vibration-damping object B.

Conventional vibration suppression technology using sliding-type seismic isolation mechanisms avoids the frequency range of the main components of seismic motion, and sets the natural frequency of the vibration-control target B (generally called the natural frequency of seismic isolation) to a very low frequency, for example, around 0.3 Hz. In this case, long-period seismic motion can cause large displacements of the vibration-control target B.

In contrast, in the first embodiment, the natural frequency of the vibration-damping object B after the damping device 1A is attached to the vibration-damping object B can be set to be 0.5 to 0.9 times the natural frequency of the vibration-damping object B before the damping device 1A is attached to the vibration-damping object B. For example, when the vibration-damping object B includes a structure such as a spent nuclear fuel storage rack or an electrical panel, the natural frequency of the vibration-damping object B before the damping device 1A is attached is about 10 Hz to 30 Hz. In this case, the natural frequency of the vibration-damping object B after the damping device 1 is attached to the vibration-damping object B can be set to 5 Hz or more. In this case, the natural frequency of the vibration-damping object B to which the damping device 1A in the first embodiment is attached can be set to about 16 times or more the natural frequency (0.3 Hz) of the vibration-damping object B to which a general seismic isolation mechanism is attached. If we consider that the response acceleration of both is the same, the ratio of the response displacement between the two is one squared of the ratio of the vibration frequencies between the two, so we can see that the response displacement of the vibration-control object B to which the damping device 1A is attached is extremely small, being one hundredth of the response displacement of the vibration-control object B to which a general seismic isolation mechanism is attached.

When a general seismic isolation mechanism is adopted, the response displacement of the vibration-control object B becomes large, and therefore in order to avoid collisions between the vibration-control object B and surrounding structures, it is necessary to increase the placement area for the vibration-control object B, taking into account the response displacement. In contrast, the vibration-control object B to which the damping device 1A in the first embodiment is attached has an extremely small response displacement compared to a general seismic isolation mechanism, making it easy to design the placement of the vibration-control object B.

Furthermore, in the first embodiment, in the case where the stiffness k2 and/or frictional force Fr2 of the damping device 1A are adjustable according to the vibration characteristics of the object to be damped B and/or the vibration input conditions to the mounting portion C, the damping device 1A can add optimal damping to the object to be damped B.

Furthermore, in the damping adding device 1A in the first embodiment, if the magnitude of the additional friction force Fr2' and/or the size e of the gap 16 are adjustable, by adjusting these parameters, it becomes possible to obtain a high damping effect against a wide range of input acceleration. For example, a high damping effect can be obtained against various vibration inputs such as earthquake inputs and shock wave inputs caused by a flying object colliding with a building. In addition, by making adjustments corresponding to the vibration characteristics of various equipment used in nuclear power plants, such as spent nuclear fuel storage racks, electrical panels, pumps, heat exchangers, and transformers, an optimal damping force can be added to the vibration control target B.

Second Embodiment
A damping device 1B according to the second embodiment will be described with reference to Figures 1 to 3 and 12. Figure 1 is a schematic front view showing a state in which the damping device 1B according to the second embodiment is attached to an object B to be damped. In Figure 1, in order to make it easier to understand the arrangement of the damping device 1B, a cross-sectional view is shown instead of a front view for parts other than the equipment 2. Figure 2 is a schematic cross-sectional view showing an example of a restoring force generating unit 6. Figure 3 is a schematic cross-sectional view showing an example of a pressing force generating unit 7. Figure 12 is a schematic cross-sectional view showing an example of a frictional force adjusting unit 8 of the damping device 1B according to the second embodiment.

In the first embodiment, an example was described in which the frictional force adjustment unit 8 changes the total area of the sliding surface that slides against the upper surface C1 of the mounting part C depending on the distance from the default position P1 to the second position P2, more specifically, an example in which the sliding block 17 slides additionally. In contrast, in the second embodiment, the frictional force adjustment unit 8 differs from the first embodiment in that it generates additional frictional force without changing the total area of the sliding surface that slides against the upper surface C1 of the mounting part C.

In the second embodiment, the differences from the first embodiment will be mainly described. On the other hand, in the second embodiment, repeated explanations of matters already described in the first embodiment will be omitted. Therefore, it goes without saying that matters already described in the first embodiment can be applied to the second embodiment even if they are not explicitly described in the second embodiment.

(Composition and Function)
1 to 3, the damping adding device 1B in the second embodiment includes: (1) a restoring force generating unit 6 that is disposed between the bottom of the vibration-damping object B (more specifically, the base member 5) and a placement unit C (more specifically, the sliding plate 4) on which the vibration-damping object B is placed, and that generates a restoring force for restoring the relative position of the lower surface B1 of the vibration-damping object B to the upper surface C1 of the placement unit C to the default position P1 when the relative position of the lower surface B1 of the vibration-damping object B with respect to the upper surface C1 of the placement unit C changes from the default position P1 to the second position P2 due to the vibration of the vibration-damping object B; and (2) a pressing force generating unit 7 that generates a pressing force for pressing the lower surface B1 of the vibration-damping object B against the upper surface C1 of the placement unit C. Also, as illustrated in FIG. 12, the damping adding device 1B in the second embodiment includes: (3) a friction force adjusting unit 8 that changes the friction force that the vibration-damping object B receives from the upper surface C1 of the placement unit C depending on the magnitude of the distance from the default position P1 to the second position P2.

In the example shown in FIG. 12, the dynamic friction coefficient between the first region AR1 of the upper surface C1 of the mounting portion C and the vibration-damping object B is greater than the dynamic friction coefficient between the second region AR2 of the upper surface C1 of the mounting portion C and the vibration-damping object B. Also, in the example shown in FIG. 12, when the distance from the default position P1 to the second position P2 is smaller than the threshold value e, the lower surface B1 of the vibration-damping object B does not contact the first region AR1, and when the distance from the default position P1 to the second position P2 is equal to or greater than the threshold value e, the lower surface B1 of the vibration-damping object B contacts the first region AR1. When the lower surface B1 of the vibration-damping object B contacts the first region AR1, an additional frictional force is generated.

In the second embodiment, the magnitude of the frictional force acting as a braking force on the vibration-damping object B is changed depending on the distance from the default position P1 to the second position P2, in other words, the magnitude of the change in the relative position of the lower surface B1 of the vibration-damping object B with respect to the upper surface C1 of the mounting portion C. In this way, the vibration of the vibration-damping object B can be effectively damped for a wide range of input accelerations. For example, when the input acceleration input to the vibration-damping object B is large and the amplitude of the vibration-damping object B is large, a larger braking force is applied. As a result, the vibration of the vibration-damping object B can be effectively damped.

Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

1, 1A, 1B...damping addition device, 2...equipment, 3...floor surface, 4...sliding plate, 5...base member, 5A...side plate, 5B...lower plate, 5C...upper plate, 6...restoring force generating portion, 7...pressing force generating portion, 8...friction force adjusting portion, 9...rod spring, 9a...upper end, 9b...lower end, 9t...outer surface, 10...first fitting portion, 11...second fitting portion, 12...second shaft, 12a...upper end, 12b...lower end, 12t...outer surface, 13...second biasing force adjusting member, 14...washer, 14a...third washer, 14b...fourth washer, 15...second elastic member, 16...gap, 16a...first gap, 16b...second gap, 17...sliding block, 17a...first block, 17b...second block, 17h...through hole portion, 1 7t...outer surface, 17w...lower surface, 18...first shaft, 18a...upper end, 18b...lower end, 19...first biasing force adjustment member, 20...washer, 20a...first washer, 20b...second washer, 21...first elastic member, 22...elastic member, 91...fixing member, 100...damping device, 130...second nut, 190...first nut, 511d...first access hole, 511h...first through hole, 512h...second through hole, 513d...second access hole, 513h...third through hole, AR1...first region, AR2...second region, B...vibration damping object, B1...lower surface, C...mounting portion, C1...upper surface, G3...third gap, G4...fourth gap, SP1...first space, SP2...second space

Claims (6)

a restoring force generating unit that is disposed between a bottom of an object to be damped and a mounting portion on which the object to be damped is mounted, and that generates a restoring force that restores a relative position of a lower surface of the object to be damped with respect to an upper surface of the mounting portion to a default position when the relative position changes from a default position to a second position due to vibration of the object to be damped;
a pressing force generating unit configured to generate a pressing force for pressing the lower surface of the object to be vibration-damped against the upper surface of the placement unit;
a friction force adjustment unit that changes a friction force that the vibration damping target receives directly or indirectly from the upper surface of the placement unit depending on a distance from the default position to the second position ,
The friction adjustment unit changes a total area of a sliding surface that slides against the upper surface of the placement unit depending on a distance from the default position to the second position.
Damping addition device. the frictional force adjustment unit has a sliding block provided independently of a base member constituting the bottom of the vibration damping object,
the sliding block is placed on a sliding plate constituting the placement portion such that a gap is formed between the sliding block and the base member;
The damping device according to claim 1 , wherein the frictional force is increased by the base member coming into contact with the sliding block when the distance from the default position to the second position is greater than the gap. The friction force adjustment unit is
A first shaft fixed to the sliding plate;
a first biasing force adjustment member that is changeable in position along a longitudinal axis of the first shaft;
3. The damping adding device according to claim 2 , further comprising: a first elastic member disposed between the first biasing force adjustment member and the sliding block, the first elastic member applying a first biasing force to the sliding block in a direction toward the sliding plate. The damping adding device according to claim 2 or 3 , wherein the frictional force adjusting portion has an elastic member disposed in the gap between the base member and the sliding block. The sliding block has a plurality of blocks including a first block and a second block,
the first block is placed on the sliding plate such that a first gap is formed between the first block and the base member;
the second block is placed on the sliding plate such that a second gap larger than the first gap is formed between the second block and the base member;
When a distance from the default position to the second position is greater than a size of the first gap and smaller than a size of the second gap, the base member comes into contact with the first block, thereby increasing the frictional force;
The damping device according to any one of claims 2 to 4, wherein the frictional force is further increased by the base member contacting both the first block and the second block when the distance from the default position to the second position is greater than the second gap. the restoring force generating unit is disposed between the base member and the sliding plate and includes a rod spring supported by each of the base member and the sliding plate,
The pressing force generating unit includes:
A second shaft fixed to the sliding plate;
a second biasing force adjustment member that is changeable in position along a longitudinal axis of the second shaft;
6. The damping adding device according to claim 2, further comprising: a second elastic member disposed between the second biasing force adjustment member and the base member, the second elastic member applying a second biasing force to the base member in a direction toward the sliding plate.

Images