JPH04237707A - Cable vibration damping device - Google Patents

Abstract

PURPOSE:To provide a cable vibration isolating device which is favorable for suppressing vibrations of a cable of a cable stayed bridge or a power transmission cable. CONSTITUTION:To a fixing member 5 a cable 4 is installed in penetrating a cable protection pipe 1 as the body of a vibration isolating device filled with a viscous fluid 2 being mounted on the fixing member 5. A flexible film 3 is stretched over the open end of this cable protection pipe 1, and now vibrations in all directions can be suppressed without requiring any wide space for installation of the device.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable vibration damping device suitable for use as a damping device for cables of cable-stayed bridges, power transmission cables, and the like.

0002

2. Description of the Related Art Generally, as shown in FIG. 14, a cable-stayed bridge has a structure in which the bridge girder 5 is supported by cables 4 stretched diagonally between the main tower 6 of the cable-stayed bridge and the bridge girder 5. . This diagonally stretched cable 4 undergoes various vibrations as shown in FIG. 15 due to external forces such as wind or earthquakes. In order to suppress this vibration, conventional methods include connecting the cables 4 with vibration damping wires 7 as shown in FIG.
As shown in FIGS. 17 and 18, an oil damper 8 is attached between the cable 4 and the bridge girder 5.

[Problems to be Solved by the Invention] By the way, the method of suppressing cable vibration by connecting the cables 4 of different lengths with the damping wire 7 described above has a great effect of suppressing in-plane vibration, but The problem with vibration is that it has little effect.

Furthermore, the method of installing the oil damper 8 described above between the cable 4 and the bridge girder 5 is a method of damping vibration by the damping force of the oil damper 8, and by installing two oil dampers 8, the surface Although it is possible to suppress in-plane and out-of-plane cable vibrations, there is a problem in that a large space is required for installing the oil damper 8.

[0004] The present invention aims to solve these problems, and is aimed at solving the problems described above.
A cable control system is a cable control system in which the main body of the vibration damping device, in which the cable or a vibration damping member integrated with the cable is disposed inside, is filled with viscous fluid, and the vibration of the cable is suppressed by the viscous resistance of the viscous fluid. The purpose is to provide a shaking device.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the cable vibration damping device of the present invention is a vibration damping device for a cable stretched between fixed members. A vibration damping device body filled with viscous fluid is provided, and the cable or a vibration damping member integrated with the cable is disposed inside the vibration damping device body, and a vibration damping device is provided at the open end of the vibration damping device body. It is characterized in that a flexible membrane is attached that prevents leakage of the viscous fluid and has an insertion hole for the cable or a damping member integrated with the cable.

[0006]

[Operation] In the cable vibration damping device of the present invention, the inside of the vibration damping device body is filled with viscous fluid, and when the cable or the vibration damping member integrated with the cable vibrates, there is a gap between the vibration damping device and the viscous fluid in contact with the vibration damping device. A viscous resistance is generated, and this viscous resistance has the effect of suppressing vibration.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cable vibration damping device as an embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show a cable vibration damping device as a first embodiment of the present invention, FIG. 1 is a side sectional view thereof, and FIGS. 2 and 3 are side sectional views of the operating state. It is.

Note that in FIGS. 1 to 3, the same reference numerals as in FIGS. 14 to 18 indicate substantially the same reference numerals.

In FIG. 1, the cable 4 is attached to the bridge girder 5 on the bridge girder side by passing through the inside of a hollow cable protection tube 1, which serves as a vibration damping device body attached to the bridge girder 5. A viscous fluid 2 is filled inside the cable protection tube 1 and is in contact with the surface of the cable 4. In addition, in order to prevent leakage of the viscous fluid 2, an insertion hole for the cable 4 is provided at the open end of the cable protection tube 1, and a flexible membrane 3 is provided.
is provided.

As shown in FIGS. 2 and 3, the cable 4
When the cable 4 vibrates, the viscous fluid 2 displaced by the cable 4 moves in the direction shown by the arrow, and at this time the cable 4
A viscous drag force is generated between the This viscous resistance force acts in the opposite direction to the direction in which the cable 4 vibrates and is displaced, and acts as a vibration damping effect. In this embodiment, the entire inside of the cable protection tube 1 is filled with the viscous fluid 2, but a structure may be adopted in which a part of the cable protection tube 1 is filled with the viscous fluid 2.

According to the cable vibration damping device of this embodiment, the following effects can be obtained. (1) Since the cable protection tube itself, which is installed on the bridge girder side to protect the cables, is used as the main body of the vibration damping device, there is no need to install special accessory equipment, and there is no need for a large space for installation. (2) Since only the cables and cable protection tubes are visible from the exterior, the beauty of the bridge will not be compromised. (3) Since the viscous force generated by the viscous fluid filled inside the cable protection tube is used for vibration damping, maintenance is simple as only the leakage of the viscous fluid needs to be checked. (4) The cable can move in any direction inside the cable protection tube, and since the cable is in contact with the viscous fluid in all circumferential directions, it exhibits a damping effect in response to vibrations in any direction. be able to.

Next, a cable vibration damping device as a second embodiment of the present invention will be explained with reference to FIGS. 4 to 8.

FIG. 4 is a side sectional view thereof, FIG. 5 is a schematic side sectional view of the attachment portion thereof, FIGS. 6 and 7 are side sectional views in operating conditions, and FIG. 8 is a viscous resistance characteristic diagram.

[0015] In Figs. 4 to 8, Figs. 1 to 3 and Fig. 1
The same reference numerals as in FIGS. 4 to 18 indicate substantially the same members.

The cable vibration damping device of this embodiment includes a vibration damping device main body 10 attached to the tip of the cable protection tube 1.
Inside the vibration damping device 10, a plurality of disc-shaped sliding plates 11 with the same diameter are installed on the cable 4, and a vibration damping device main body 10 with the same diameter as the cable protection tube 1 is provided. A plurality of donut-shaped base plates 12 installed inside and protruding to face the sliding plate 11, and a vibration damping device main body 10.
a viscous fluid 2 filled in the interior of the slide plate 11 and the base plate 12 to generate a viscous resistance force between the sliding plate 11 and the base plate 12; a flexible membrane 3a provided to prevent leakage of the viscous fluid 2 from the vibration damping device main body 10; It is composed of 3b. Note that an insertion hole for the boss 11a of the sliding plate 11 is formed in the center of the flexible membranes 3a, 3b.

The vibration damping device main body 10 is attached to the tip of the cable protection tube 1. Therefore, a large installation space is not required, and the beauty of the bridge will not be affected. Further, the sliding plate 11 is attached to the cable 4 and vibrates together with the cable 4, and can vibrate in any direction in the circumferential direction.

On the other hand, the base plate 12 is arranged in a protruding manner so as to face the sliding plate 11 at a constant distance. are individually changed (d1<d2). Note that depending on the damping vibration mode, the lengths may be the same (d1=d2).

When the cable 4 vibrates, the relationship between the sliding plate 11 and the base plate 12 in the vibration damping device changes from the state shown in FIG. 4 to that shown in FIG. 6 or 7. FIG. 6 shows the situation when the displacement is relatively small, and FIG. 7 shows the situation when the displacement is relatively large.

The viscous resistance force F generated between the sliding plate 11 and the base plate 12 is determined by equation (1).

[Equation 1] Here, F: viscous drag force, μ: viscosity coefficient s of viscous fluid 2:
Area of one side in contact with fluid V: Moving speed of sliding plate 11 h: Distance between sliding plate 11 and base plate 12 Now, assuming that velocity V and interval h are constant, viscous resistance force F
will change depending on the area s in contact with the fluid. Figure 6
When the displacement is relatively small (y1) as shown in FIG.
The sheets are facing each other (overlapping each other). On the other hand, when the displacement is relatively large (y2) as shown in FIG. 7, all the sliding plates 11 and base plates 12 overlap. Therefore, in the state of FIG. 6, the contact area is small, so the viscous resistance force is small, and in the state of FIG. 7, the contact area is large, and the viscous resistance force is also large. In other words, there is a relationship between displacement and viscous resistance as shown in Figure 8. When the displacement is small, the viscous resistance is small, and when the displacement is large, the viscous resistance is large. In the vibration device, a damping force corresponding to the vibration amplitude can be obtained.

[0021] With the above-described configuration, since the cable vibration damping device main body is attached to the tip of the cable protection tube 1,
The structure is compact and the installation space can be reduced without compromising the aesthetics. Further, the sliding plate 11 attached to the cable 4 has a plurality of disc shapes, and can arbitrarily move between the base plate 12 and the base plate 12 in the circumferential direction. Therefore, it is possible to exert a damping effect on vibrations in any direction.

Since the base plate 12 is made up of a plurality of donut-shaped discs with different protruding lengths, if the deformation of the cable 4 becomes large, the sliding plate 11
The overlapping area increases, resulting in an increase in viscous resistance and a greater vibration damping effect.

[0023] The cable vibration is damped by the viscous fluid 2 filled inside the vibration damping device, which generates a viscous resistance force between the sliding plate 11 and the base plate 12. is the same as in the first embodiment described above.

According to the cable vibration damping device of this embodiment, the following effects can be obtained. (1) The sliding plate 11 can move along with the cable 4 in the circumferential direction of the cable 4, and can cope with cable vibration in any direction. (2) Since it is attached to the tip of the cable protection tube 1, it has a compact structure and does not require a large installation space. Also, it does not spoil the beauty of the bridge. (3) When the vibration displacement of the cable 4 increases, the contact area with the viscous fluid 2 increases, the viscous resistance force increases, and as a result, the vibration damping effect increases.

Next, referring to FIGS. 9 to 13, the third embodiment of the present invention will be described.
To explain the cable vibration damping device as an example,
9 is a side sectional view, FIGS. 10 and 11 are sectional views taken along the lines AA and BB in FIG. 9, respectively, FIG. 12 is a side sectional view of the attachment part, and FIG. 13 is an enlarged sectional view of the main part . Note that in FIGS. 9 to 13, the same reference numerals as in FIGS. 1 to 8 and FIGS. 14 to 18 indicate substantially the same members.

The cable vibration damping device of this embodiment is also located on the bridge girder 5 side of the cable 4 connecting the main tower and the bridge girder 5, and is installed at the tip of the cable protection pipe 1 that protects the cable 4. Therefore, the damping device main body 10 is not visible from the outside, and the aesthetic appearance of the bridge is not impaired. Also,
The vibration damping device main body 10 is also small and compact. That is, the cable vibration damping device of this embodiment has the cable 4
Circular sliding plate 1 attached to
3, and a base plate 15 as a vibration damping device main body 10 which is attached inside the cable protection tube 1, has a U-shaped cross section, and is attached to cover the sliding plate 13. A bearing 14 is arranged between the sliding plate 13 and the base plate 15 in order to keep the distance constant and to not hinder the movement of the sliding plate 13. With this bearing 14, the distance between the sliding plate 13 and the base plate 15 can be kept constant,
The sliding plate 13 can move smoothly in the circumferential direction.

A viscous fluid 2 is filled between the sliding plate 13 and the base plate 15, and in order to prevent the viscous fluid 2 from leaking, the sliding plate 1
3 on the cable fixing side and the boss 15a on the base plate 15
A flexible membrane 3 is provided between the two. In addition, in order to accommodate the expansion and contraction of the cable 4 in the length direction,
A bearing 14a is disposed between the cable protection tube 1 and the base plate 15, and the damping device main body 10 is structured to be movable together with the cable 4 in the length direction of the cable.

Cable vibration is suppressed by the viscous resistance force generated between the sliding plate 13 and the base plate 15, and this viscous resistance force F can be easily determined by equation 2.

[0029]

[Equation 2] Here, F: viscous drag force, μ: viscosity coefficient s of viscous fluid 2:
Area of one side in contact with fluid V: sliding plate 13
Moving speed h: distance between sliding plate 13 and base plate 15 Also, the cable vibration damping device of this embodiment can move arbitrarily in the circumferential direction of the cable 4, and damps vibrations in any direction. be able to. In this embodiment, bearings 14 and 14a are used between the sliding plate 13 and the base plate 15 and between the base plate 15 and the cable protection tube 1, but these are made of a material with low friction, such as Teflon (registered trademark). ) can also be substituted.

With the above-described configuration, the damping device main body 10 is attached between the cable 4 and the cable protection tube 1, so it is compact and small and does not spoil the aesthetic appearance. Also, a circular sliding plate 13 attached to the cable 4 is attached to a base plate 1 having a U-shaped cross section together with the cable 4.
5 in the circumferential direction, vibrations in any direction can be suppressed. The cable vibration is damped by the viscous resistance force generated between the sliding plate 13 and the base plate 15 by the viscous fluid 2 filled inside the vibration damping device main body 10 as described in each of the above embodiments. The same is true for .

According to the cable vibration damping device of this embodiment, the following effects can be obtained. (1) The sliding plate 13 can move arbitrarily along with the cable in the circumferential direction of the cable 4,
Cable vibrations in any direction caused by wind or earthquakes can be suppressed. (2) Since the damping device main body 10 is installed between the cable 4 and the cable protection tube 1, the structure is compact, and the damping device is not visible from the outside, which may detract from the beauty of the bridge. There is no. (3) Since the distance between the sliding plate 13 and the base plate 15, which affects the damping effect, can be kept constant, the damping effect can be easily studied. (4) It can accommodate the expansion and contraction of the cable 4 in the length direction, and since it moves along with the cable in the length direction, no unreasonable force is applied to the cable and the vibration damping device body.

As described in detail above, the cable vibration damping device of the present invention provides the following effects and advantages. (1) Since the main body of the vibration damping device is the cable protection tube itself or is connected to the tip of the cable protection tube, a large space is not required for installation. (2) The appearance will not be damaged due to the reason mentioned in (1) above. (3) Since the damping action is performed by the viscous resistance force of the viscous fluid filled inside the vibration damping device main body, maintenance is simple and only requires checking for leakage of the viscous fluid. (4) Since the cable or the vibration damping member integrated with the cable can move in any direction inside the vibration damping device main body, it is possible to damp vibrations in any direction.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a cable vibration damping device as a first embodiment of the present invention.

[Figure 2],

FIG. 3 is a side sectional view of the same operating state.

FIG. 4 is a side sectional view of a cable vibration damping device as a second embodiment of the present invention.

FIG. 5 is a schematic side sectional view of the attachment portion.

[Figure 6],

FIG. 7 is a side sectional view of the same operating state.

FIG. 8 is a viscous resistance characteristic diagram.

FIG. 9 is a side sectional view of a cable vibration damping device as a third embodiment of the present invention.

FIG. 10 is a sectional view taken along the line A-A in FIG. 9;

FIG. 11 is a sectional view taken along the line BB in FIG. 9;

FIG. 12 is a side sectional view of the attachment portion.

FIG. 13 is an enlarged side sectional view of the same main part.

FIG. 14 is a side view of a conventional cable-stayed bridge.

FIG. 15 is a vibration mode diagram of the same cable.

FIG. 16 is an enlarged side view of the main part when the damping wire is stretched.

FIG. 17 is a schematic side view when the same oil damper is provided.

18 is a front view of the main part of FIG. 17. FIG.

[Explanation of symbols]

1 Cable protection tube 2 Viscous fluid 3, 3a, 3b Flexible membrane 4 Cable 5 Bridge girder 6 Main tower 10 Vibration damping device main body 11, 13 Sliding plate 12, 15
Base plate 14, 14a bearing

Claims (1)

[Claims] Claim 1: A vibration damping device for a cable stretched between fixed members, comprising a vibration damping device main body attached to the fixed member and filled with viscous fluid, the inside of the vibration damping device main body being The above-mentioned cable or a vibration damping member integrated with the cable is disposed at the opening end of the vibration damping device main body to prevent leakage of the viscous fluid, and a vibration damping member integrated with the cable or the same cable is provided. A cable vibration damping device characterized by being equipped with a flexible membrane having a member insertion hole.