JPH0443630Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention [Field of industrial application] This invention absorbs seismic forces and wind loads acting on structures such as cable-stayed bridges and suspension bridges, and The present invention relates to a damper for a bridge structure that performs vibration damping, and more particularly to an oil damper that obtains damping force by utilizing the fluid resistance of oil flowing through an orifice hole.

[Conventional technology and its problems]

Oil dampers are commonly used as vibration damping devices for structures such as bridges. This device consists of a cylindrical cylinder, a piston that moves in the axial direction within this cylinder, a piston rod connected to this piston, and oil sealed in the cylinder, and the cylinder side is the pier or lower structure side. The piston rod side is fixed to the bridge girder, that is, the superstructure side, and converts the relative displacement of the upper and lower structures into movement of the piston.The orifice hole provided in this piston generates hydraulic pressure and generates vibration energy. It is something to absorb.

According to this oil damper, if the orifice hole is properly defined, it is possible to obtain a fluid resistance that is uniquely determined in proportion to the square of the speed, and it is possible to obtain a large damping force in accordance with the pressure receiving area of the piston. It has features such as:

However, with this conventional oil damper, as the bridge becomes longer and the length of the superstructure becomes longer, that is, the span becomes longer, it is necessary to take a longer travel distance or stroke of the piston, and in order to obtain a larger pressure-receiving area, the cylinder is enlarged. This results in an increase in the size of the device itself, making it difficult to install it at a predetermined position between the upper structure and the lower structure. Furthermore, in order to seal the oil sealed in the cylinder, a sealing mechanism consisting of a gasket is required at the sliding portion between the piston rod and the cylinder, and damage and deterioration of this gasket also poses a problem.

[Technical issues of invention]

This invention was made in view of the above circumstances,
While taking advantage of the characteristics of oil dampers, it can easily cope with large displacements in the superstructure of long spans without increasing the size of the device.It also eliminates the need for a sealing mechanism using a gasket and overcomes the drawbacks of conventional oil dampers. The purpose (technical problem) is to provide a structural damper with

B. Structure of the invention [Means for solving the problems] The swinging damper for bridge structures of the present invention adopts the following structure (technical means) in order to achieve the above object. That is, it is a swing damper for a bridge structure that is placed between an upper structure such as a bridge girder and a lower structure such as a bridge pier, and absorbs long-period vibrations that predominantly act on the upper structure. In this case, an upper mounting body integrally provided with clevises arranged opposite to each other at a predetermined interval on the lower surface is fixed with the clevises facing downward, and a hollow cylinder portion with a bottom is provided between both clevises of the upper mounting body. A swing cylinder having a hollow cylinder portion is inserted into a circular hole provided in the clevis, and is attached to a rotating shaft rotatably supported by the clevis with the opening of the hollow cylinder portion facing downward. The hollow cylinder part of the swing cylinder is fitted and fixed in a swingable manner, and the hollow cylinder part of the swing cylinder has a right cylindrical sliding piston part; a rotating shaft extending integrally over substantially the same length; integrally protruding along the axial direction of the rotating shaft at opposing positions across the sliding piston portion of the rotating shaft; A rocking arm having two rotary blades provided therein; and a journal portion formed at both ends of the rotating shaft portion is disposed so as to be slidably inserted into the sliding piston portion, The structure includes: a mounting plate; a lower cylinder body integrally formed with the mounting plate and having a cylindrical inner circumferential wall on the inner surface; side covers closing openings at both ends of the lower cylinder body; a partition wall having an orifice hole provided along the longitudinal direction of the lower cylinder body at the bottom of the inner circumferential wall of the cylinder; a fixed cylinder is fixed via the mounting plate part;
A cylinder chamber is formed on the inner surface of the lower cylinder body, and a groove is formed at the top of the partition wall of the lower cylinder body in the longitudinal direction, and a valve body is inserted into the groove. A swinging arm is disposed under pressure from a spring disposed between the valve body and is disposed within the lower cylinder body of the fixed cylinder, with a sliding piston part inserted through the hollow cylinder part of the swinging cylinder. A rotating shaft portion is rotatably supported on the side cover at journal portions at both ends, and the rotary blade is brought into sliding contact with the cylindrical inner circumferential wall of the lower cylinder body, and the bottom of the rotating shaft portion is connected to the partition wall. The cylinder chamber of the lower cylinder body is divided into a first and second sealed space having an orifice hole formed in the partition wall as a communicating hole, and The second sealed space is characterized by being filled with oil.

[Effect]

When a forced vibration force such as an earthquake force or a wind load acts on the upper and lower structures and a relative displacement occurs between the upper and lower structures, the upper and lower structures are pivoted to be able to swing relative to the upper structure. The swing cylinder swings in the direction of this relative displacement.

The swinging of this swinging cylinder is achieved by inserting a sliding piston part into the hollow cylinder part of the swinging cylinder, and making it possible to rotate the rotating shaft part formed integrally with the sliding piston part to the side cover of the fixed cylinder. The signal is transmitted to the swinging arm that is pivotally supported by the oscillating arm.

Due to the swinging of the swinging arm, a rotor blade formed integrally with the rotating shaft portion of the swinging arm rotates while slidingly contacting the cylindrical inner circumferential wall of the inner surface of the lower cylinder body of the fixed cylinder.

The rotation of the rotor causes the cylinder chamber of the lower cylinder body to have an inner circumferential wall of the cylinder, a rotor blade that is in sliding contact with the inner circumferential wall of the cylinder, and a valve body of a partition formed at the bottom of the lower cylinder body that slides with the valve body. Oil sealed in first and second sealed spaces defined by the bottom surface of the rotating shaft section is provided in the partition wall and flows through an orifice hole that acts as a communication hole between the first and second sealed spaces. do. Due to the flow resistance of this oil flowing through the orifice hole, the swinging arm and thus the swinging cylinder receive a resistance force in a direction opposite to the direction of rotation, and the relative displacement between the upper and lower structures is braked.

〔Example〕

An embodiment of the swing damper for bridge structures according to the present invention will be described based on the drawings.

FIGS. 1 to 3 show one embodiment thereof.

In the figure, G is an upper structure such as a bridge girder, and B is a lower structure such as a bridge pier.

The swinging damper for bridge structures (hereinafter simply referred to as "damper") D of this embodiment has an upper structure G and a lower structure B.
It is interposed between the upper structure G and has the main function of absorbing vibrations acting on the upper structure G, and does not have the function of supporting the load of the upper structure G.

This damper D includes an upper mounting body 1 attached to an upper structure G, and a swing cylinder 3 swingably attached to the upper mounting body 1 via a rotating shaft 2.
, a swinging arm 4 that interlocks with the swinging cylinder 3, and a fixed cylinder 5 that rotatably supports the swinging arm 4, has a cylinder chamber inside, and is attached to the lower structure B. , oil L is sealed in the cylinder chamber of the fixed cylinder 5.

The detailed structure of each part will be explained below.

The upper mounting body 1 consists of a flat mounting plate 10 and clevises 11, 11 disposed in parallel with each other on the lower surface of the mounting plate 10. A boss 1a protrudes from the center of the upper surface of the mounting plate 10 for fixing it to the upper structure G, and anchor insertion holes 1b are bored at the four corners of the boss 1a. The clevis 11 is provided with a circular hole 12 for receiving a rotating shaft to be described later.

A swing cylinder 3 is swingably mounted between the opposing clevises 11, 11 via a rotating shaft 2. That is, the rotating shaft 2 has a cylindrical shape, and both ends thereof are inserted into a sliding bearing material 14 fitted into a circular hole 12 of a clevis 11, and a flange material 15 is fixed on both end surfaces with a fixing bolt 16. It is set up. The rotating shaft 2 further includes a swing cylinder 3
The rotary shaft fitting hole 18 of the rotary shaft fitting hole 18 is integrally fitted and attached.

The lower part of the swing cylinder 3 is formed into a hollow cylinder part, and a sliding bearing 20 is installed on the inner surface of this cylinder part.
is fitted and fixed.

The swinging arm 4 includes a sliding piston portion 4A and a rotating shaft portion 4B.
It consists of.

The swing piston portion 4A is formed in the shape of a right cylinder, and its upper half is slidably inserted into the cylinder portion of the swing cylinder 3 via the slide bearing 20.

The rotating shaft portion 4B has a main body extending in the shape of a horizontally long right cylinder, and is formed perpendicularly to the lower end of the sliding piston portion 4A. The axis of the right circular cylinder is the center of rotation. Rotary blades 22 are formed on both sides of the main body portion to protrude in the longitudinal direction, and both ends thereof form journal portions 24.

The fixed cylinder 5 includes a lower cylinder body 6, an upper cover 7, and a side cover 8, and a cylindrical cylinder chamber 9 is defined therein. In other words, the lower cylinder body 6, the upper cover 7, and the side cover 8 are assembled to form the cylinder chamber 9, and the rotating shaft portion 4B of the swing arm 4 is fitted into the cylinder chamber 9.

The lower cylinder body 6 has a lower mounting plate portion 25.
It is fixed to the substructure B via. Mounting plate part 2
A boss 5a protrudes from the center of the lower surface of 5 for fixing to the lower structure B, and anchor insertion holes 5b are bored at the four corners of the boss 5a.

The upper cover 7 has windows on both sides of the upper part of the lower cylinder body 6, and is mounted and fixed with fixing bolts.

The side cover 8 is connected to the upper cover 7 and the lower cylinder body 6 so that the upper cover 7 is fitted therein and the journal portion 24 of the rotating shaft portion 4B is fitted via a sliding bearing 26.
It is firmly fixed with a large number of fixing bolts. The side cover 8 serves as a bearing for the rotating shaft portion 4B.

The inner peripheral wall 9A of the cylinder chamber 9 is in contact with the tip of the rotor blade 22 of the rotary shaft portion 4B, and when the rotary shaft portion 4B rotates about its rotation center axis, the rotor blade 22
It is formed in accordance with the trajectory drawn by the tip of. In other words, it becomes concentric with the rotating shaft portion 4B. Therefore, the inner circumferential wall of the cylinder chamber 9 that is not included in the rotation locus does not need to be formed into a cylindrical wall surface.

A partition wall 28 is formed in the cylinder chamber 9 and interposed between the two rotary blades 22 to protrude in the longitudinal direction. The top of the partition wall 28 follows the rotation of the rotating shaft portion 4B and is always in contact with the rotation shaft portion 4B.

The cylinder chamber 9 is filled with oil L. This oil L
Silicone oil is preferably used.

In this way, the rotor blade 22
First and second sealed spaces, that is, hydraulic chambers A and B, filled with oil L are defined between the two.

The bulkhead 28 has one or at most two locations;
An orifice hole 30 is provided so that the first hydraulic chamber A and the second hydraulic chamber B communicate with each other. Recesses 29 are provided on both sides of the partition wall 28 facing the orifice hole 30. In other words, the orifice hole 30 is bored between the recesses 29. Thereby, the orifice hole 30 can be made as short as possible and effective turbulence characteristics can be obtained.

This orifice hole 30 may be provided at any location in the longitudinal direction of the partition wall 28, but when the regulating valve 32 is interposed as in this embodiment, the regulating valve 32
2, the location near the end of the partition wall 28 is appropriate.

More specifically, a valve body insertion hole 31 is bored from the side of the partition wall 28 so as to be orthogonal to the orifice hole 30 . The diameter of the valve body insertion hole 31 is larger than the diameter of the orifice hole 30.

The regulating valve 32 has a round rod shape, and a valve hole 33 approximately equal in diameter to the orifice hole 30 is provided at the tip.
A collar body 34 is provided in the middle, and a rotating head (spanner) 35 is formed at the other end. A concave portion 36 for receiving the head of the regulating valve 32 is provided in the side cover 8, and the regulating valve 32 is fixed via a collar body presser 37. The adjustment valve 32 is inserted into the valve body insertion hole 31 in a tight-fitting state, and the head is fitted with a spanner 3.
By turning 5 with strong force, the valve hole 33 at the tip is inclined to the orifice holes 30 on both sides, making the cross section of the flow path variable.

The sliding contact portion between the partition wall 28 and the rotating shaft portion 4B has a sealed structure.

FIG. 3 shows an example of a sealing structure of the sliding contact portion between the partition wall 28 and the rotating shaft portion 4B. That is, a groove 40 is formed in the top of the partition wall 28 in the longitudinal direction, and a valve body 41 is housed in the groove 40 so as to be biased outward by a spring 42 .

The sliding contact portion between the rotary blade 22 and the cylinder inner wall surface 9A may also have a similar sealed structure.

In this embodiment, the partition wall 28 is integrally formed to protrude from the fixed cylinder 6, but it is normally manufactured separately from the viewpoint of formability, and is shrink-fitted into a fitting groove in the fixed cylinder 6. It is designed to be firmly attached.

The mounting positional relationship between the swing damper D of this embodiment configured as described above, the upper structure G and the lower structure B is as follows.

In response to earthquake motion, the bridge girder vibrates with its natural period, but displacement in the direction of the bridge axis is predominant, so the direction created by the clevis 11 (clevis surface), that is, the direction of swing, is directed in the direction of the bridge axis. Therefore, the rotation axis of the rotary piston portion 4B is oriented in a direction perpendicular to the bridge axis.

In suspension bridge systems including cable-stayed bridges, wind loads cause vibrations in the direction perpendicular to the bridge axis. Therefore, the clevis surface is oriented in the direction perpendicular to the bridge axis, and the rotation axis of the rotating piston part 4B is oriented in the direction of the bridge axis. directed towards.

The swing damper D of this embodiment operates as follows.

When the upper structure G shakes due to forced vibration force such as an earthquake or wind load, this vibration is caused by the swing cylinder 3.
This appears as the rotation of the rotating shaft portion 4B of the swinging arm 4 via.

Now, if the upper structure G is displaced parallel to the right direction in FIG. 1, the swing cylinder 3 is free to rotate about the rotating shaft 2, so it rotates clockwise. Since the swing arm 4 is linked to the swing cylinder 3, it is rotated and displaced in accordance with the rotation of the swing cylinder 3, but the center of rotation of the swing cylinder 3 is the rotation shaft portion 4.
B, the swing arm 4 rotates clockwise around the rotation axis of the rotation shaft portion 4B. Although the arm length r changes with the horizontal displacement, it is absorbed by the sliding displacement between the swing cylinder 3 and the sliding piston portion 4A of the swing arm 4.

During this rotation, the oil L flows from the hydraulic chamber B to the hydraulic chamber A through the orifice hole 30, and the rotor blade 22 receives resistance due to the flow resistance caused by this, and as a reaction, the oil L flows toward the right side of the upper structure G. acts in the direction of preventing displacement.

When the upper structure G is displaced to the left in FIG. 1, the rotational displacement is opposite to that described above, and the oil L flows from the hydraulic chamber A to the hydraulic chamber B.

At this time, the flow resistance generated in the orifice hole 30 occurs in a turbulent region.

In order to more effectively obtain a turbulent region, the length l of the orifice hole 30 is set to a predetermined length (2.5 to 3.5 times, at least 5 times or more, the hole diameter), and the opening edge of the orifice hole 30 is formed to be rounded. be done. Furthermore, the oil used has the lowest possible viscosity.

By utilizing the flow resistance in the turbulent region, a unique pressure drop proportional to the square of the speed can be obtained without being affected by changes in oil viscosity, that is, changes in temperature. Therefore, when designing the seismic resistance of a bridge, the amount of attenuation can be kept within a predetermined accuracy, and an ideal damper can be obtained.

Also, as is clear in this operation,
The relative displacement amount x between the lower structures G and B is converted into the rotation angle θ of the rotor blade 22 by the distance between the axis of the rotary shaft 2 and the rotation axis of the rotary shaft portion 4B, that is, the arm length r. Therefore, if x, r, and θ are set appropriately,
Even if the displacement amount x is large, the rotation angle θ can be made small by making the arm length r correspondingly long.

Since the damping force is proportional to the pressure receiving area of the rotor blade 22, the diameter of the cylinder chamber 9 can be increased by appropriately increasing the length b of the rotor blade 22 (therefore, the length of the cylinder chamber 9). It is possible to obtain a large damping force without

The present invention is not limited to the above-mentioned embodiments, and various design changes can be made within the scope of the basic technical ideal of the present invention. That is, the following aspects are included within the technical scope of the present invention.

The main body of the rotating shaft portion 4B of the swinging arm 4 does not necessarily have to be formed into a cylindrical body, but the point is that the central axis of rotation is held, and the outer surface that contacts the inner wall 9A of the cylinder chamber 9 is formed at an equal distance from this central axis of rotation. As long as it can be done.

There is no need to provide a special regulating valve 32 in the orifice hole 30.

Two orifice holes 30 are provided, one with a regulating valve 32 and the other without a regulating valve.

The sliding contact portion between the rotary blade 22 and the cylinder inner wall surface 9A, and the sliding contact portion between the partition wall 28 and the rotating shaft portion 4B do not require a sealing structure using a valve body as long as the mating portions of both can be formed with high precision.

C. Effects of the invention The swinging damper for structures of the present invention has the above-mentioned configuration and functions, so even if the upper structure has a long span and requires a large stroke, the arm length can be adjusted to an appropriate length. By setting the length of the cylinder chamber (that is, the length of the rotating shaft portion) appropriately, it is possible to easily secure a pressure-receiving area suitable for this large stroke. Therefore, the cylinder chamber, that is, the damping force generating portion of this damper need only maintain a small diameter, and the damper can be made smaller. Further, unlike conventional oil dampers, there is no need for a gasket on the sliding part with the piston rod, and therefore, the effort of maintaining the gasket can be saved.

[Brief explanation of the drawing]

The drawings show an embodiment of the rocking damper for structures according to the present invention, and FIG. 1 is a longitudinal cross-sectional view of one embodiment (cross-sectional view taken along the - line in FIG. 2), and FIG. 2 is a cross-sectional view taken along the - line in FIG. 1. The cross-sectional view and FIG. 3 are partially enlarged views. G... Upper structure, B... Lower structure, 1... Upper mounting body, 2... Rotating shaft, 3... Swinging cylinder,
4... Swinging arm, 4A... Sliding piston part, 4B...
... Rotating shaft portion, 5 ... Rotating cylinder, 6 ... Lower cylinder body, 7 ... Upper cover, 8 ... Side cover, 9 ... Cylinder chamber, 9A ... Inner peripheral wall, 11 ... Clevis, 2
2... Rotating blade, 28... Partition wall, 30... Orifice hole, A, B... Sealed space, L... Oil.

Claims (1)

[Claims for Utility Model Registration] (1) A rocking damper for a bridge structure that is arranged between an upper structure such as a bridge girder and a lower structure such as a bridge pier, and absorbs vibrations acting on the upper structure, An upper mounting body integrally provided with clevises facing each other at a predetermined interval on the lower surface is fixed to the upper structure with the clevises facing downward, and a bottomed bottom is provided between the clevises of the upper mounting body. A swing cylinder having a hollow cylinder portion is inserted into a circular hole provided in the clevis, and the opening of the hollow cylinder portion is directed downward to a rotating shaft rotatably supported by the clevis. The swing cylinder is fitted and fixed in a swingable manner with respect to the clevis, and the hollow cylinder portion of the swing cylinder includes a right cylindrical sliding piston portion; the lower end of the sliding piston portion has an axis line of the sliding piston portion; A rotary shaft portion integrally extending substantially the same length in both orthogonal directions; and two rotary blades that protrude integrally;
A rocking arm having a journal portion formed at both ends of the rotating shaft portion is arranged to slidably fit the sliding piston portion, and the lower structure includes a mounting plate portion; a lower cylinder body integrally formed with the mounting plate and having a cylindrical inner circumferential wall on the inner surface; a side cover closing both end openings of the lower cylinder body; and a lower cylinder body at the bottom of the cylindrical inner circumferential wall of the lower cylinder body. a partition wall having an orifice hole provided along the longitudinal direction of the fixed cylinder is fixed via the mounting plate, a cylinder chamber is formed in the inner surface of the lower cylinder body, and A concave groove is formed in the top of the partition wall in the longitudinal direction thereof, and a valve body is disposed in the concave groove while being pressed by a spring disposed between the concave groove and the valve body, Inside the lower cylinder body of the fixed cylinder,
A rotating shaft portion of a swinging arm, which has a sliding piston inserted through the hollow cylinder portion of the swinging cylinder, is rotatably supported by the side cover at journal portions at both ends, and the rotary blade is placed in sliding contact with the cylindrical inner circumferential wall of the lower cylinder body, and the bottom of the rotating shaft portion is arranged in sliding contact with the valve body of the partition wall, and the cylinder chamber of the lower cylinder body is formed in the partition wall. The first hole has an orifice hole as a communicating hole.
and a second sealed space, wherein the first and second sealed spaces are filled with oil. (2) Utility model registration claim No. 1 in which a regulating valve is installed in the orifice hole formed in the partition wall.
A rocking damper for bridge structures as described in .