JPH08128499A - Hydraulic actuator for vibration damping device - Google Patents

Abstract

PURPOSE: To achieve the reduction of dimension of a device, surely detect the extension/contraction quantity of a rod and improve the durability in use on the sea, by pressurizing a supporting oil chamber for accommodating the end part of the rod which projects from the second oil chamber, in correspondence with a vibration control mass. CONSTITUTION: A frame 10 is successively extended through the advance of execution, and after being shifted to the end part of a main girder by a wheel 7, the frame 10 is fixed by a supporting leg 8, and the pressurized oil is supplied into a hydraulic cylinder 2 from a hydraulic unit 6 according to the speed detected by a speedometer 11, and the vibration applied to the main girder 50 is attenuated by the reaction force for driving a vibration control mass 1 in the vertical direction. In this case, when the vibration control mass 1 is brought into stop or driven, the vibration control mass 1 can be supported by the hydraulic pressure in a supporting oil chamber 24 which is applied at the lower end 20B of a rod 20, i.e., the pressure in the gas chamber 31 of an accumulator 3, and since the pressurized oil supplied into the hydraulic cylinder 2 is enough to drive the vibration control mass 1, the necessary power for the hydraulic unit 6 is reduced, and the reduction of dimension can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic actuator for a vibration damping device for reducing vertical vibrations generated by wind force in a structure such as a cable-stayed bridge being installed.

[0002]

2. Description of the Related Art As shown in FIG. 7, a main tower 51 and a main girder 50 are simultaneously installed and a cable 52 is stretched during the construction of a PC cable-stayed bridge among cable-stayed bridges. The construction wagon 53 installed at the end portion of the main girder 50 moves as the construction progresses, and the overall length of the main girder 50 increases. As the total length of the main girder 50 increases, the natural frequency of the entire bridge decreases and its amplitude also increases.

This frequency is, for example, a low frequency vibration of 0.3 Hz or less, so that a worker who works at the end of the main girder 50 may suffer from sea sickness. The amplitude of the digit 50 may be excessive.

In order to suppress such vibration, the applicant of the present application has proposed a vibration damping device as shown in FIG. 8 as Japanese Patent Application No. 6-221336.

Explaining this, the damping mass 1 is supported in the frame 10 via the linear guides 4 and 4 arranged in the vertical direction so as to be freely displaceable in the vertical direction.
Is driven up and down by a hydraulic cylinder 70, and springs 80, 80 are interposed between the damping mass 1 and the frame 10 to reduce the load of the damping mass 1 applied to the hydraulic cylinder 70.

The hydraulic actuator for a vibration damping device used in this vibration damping device is generally used, as shown in FIG.

The rod 73 of the hydraulic cylinder 70 is connected to the oil chamber 7
The rod 73 is formed of a double rod type penetrating through the first and the second portions 72 and protrudes to the outside. A magnetic portion (not shown) is formed at a predetermined interval on the outer periphery of the rod 73 protruding upward in the drawing on the damping mass 1 side. The stroke sensor 12 that detects a magnetic field that changes according to the expansion and contraction of the rod 73 is provided in the oil chamber 71, and the displacement amount of the rod 73 is detected from the fluctuation of the magnetic field.

The stroke sensor 12 is composed of, for example, a non-contact type magnetic sensor proposed by the applicant of the present application as Japanese Patent Laid-Open No. 4-136713, and a main girder 50 of a cable-stayed bridge.
The vibration applied to the vehicle is detected by a speed sensor (not shown) or the like, and a controller (not shown) calculates the amount of displacement of the damping mass 1 based on this vibration, while the amount of expansion / contraction of the rod 73 from the stroke sensor 12, that is, the damping mass 1 is calculated. Feedback control is performed at the position of, and the damping mass 1 moves to the hydraulic cylinder 7
Driven by 0, it is displaced in the vertical direction and is displaced by the damping mass 1
The vibration of the main girder 50 is attenuated by the reaction force of.

[0009]

However, in the above-mentioned conventional example, a part of the self-weight of the damping mass 1 is supported by the spring 80 to reduce the driving force of the hydraulic cylinder 70. The weight of the vibration damping mass 1 is accordingly increased, and accordingly, the weight of the damping mass 1 needs to be large, for example, about 10 t. Therefore, even when the apparatus is stopped, the hydraulic cylinder 70 needs pressure oil to support most of the load of the vibration damping mass 1, and when the hydraulic oil leaks, the neutral position of the rod 73 changes. In some cases, the maximum stroke of the vibration damping operation cannot be secured, and the damping mass 1 is supported by the hydraulic cylinder 7
Since it depends on 0, it is inevitable that the hydraulic unit for supplying the pressure oil becomes large in size, and further, a space for interposing the spring 80 is required in the lower part of the vibration damping mass 1, and it is difficult to downsize the frame 10. Alternatively, in a vibration damping device that damps low-frequency vibrations of 0.3 Hz or less, the natural frequency of the spring is about 0.5 Hz, and the spring may be too soft and buckle during compression.

In addition, it is necessary to form the magnetic portion detected by the stroke sensor 12 also on the outer periphery of the rod 73 projecting to the outside, and nickel plating having magnetism cannot be adopted for rust prevention. Only the hard chrome plating, which has little effect on the rod 7 when used at sea, etc.
Not only does rust occur on 3 and hinder the detection of displacement,
In some cases, durability cannot be ensured.

Therefore, the present invention has been made in view of the above problems, and promotes miniaturization of the device, and can reliably detect the expansion and contraction amount of the rod, while ensuring durability even when used at sea. An object of the present invention is to provide a hydraulic actuator for a vibration damping device that can be secured.

[0012]

According to a first aspect of the present invention, a vibration damping mass constituting a vibration damping device for damping vertical vibrations of a main girder when a cable-stayed bridge is erected corresponds to vibration of the cable-stayed bridge. In a hydraulic actuator for a vibration damping device that is vertically driven by a vertical direction, a vibration damping mass is driven by first and second oil chambers defined inside the hydraulic actuator and one end penetrating the first oil chamber. On the other hand, the rod penetrating the second oil chamber at the other end, and the second
A support oil chamber for accommodating the end of the rod protruding from the oil chamber, and means for pressurizing the support oil chamber in correspondence with the damping mass.

In a second aspect based on the first aspect, the pressurizing means comprises an accumulator which pressurizes the hydraulic oil with a pressurized gas.

A third invention is the first or second invention.
In the invention described above, in the supporting oil chamber, means for detecting the displacement amount of the rod for feedback controlling the hydraulic actuator is housed.

In a fourth aspect based on the third aspect, the displacement amount detecting means changes in accordance with the expansion and contraction of the rod and the magnetic portion formed on the outer periphery of the rod projecting into the supporting oil chamber. And a means for detecting magnetism.

[0016]

Therefore, according to the first aspect of the present invention, when the damping mass is stopped, the rod is supported by the pressure applied to the end portion of the rod, the power for supporting the damping mass is unnecessary, and the driving of the hydraulic actuator is controlled by the damping force. All that is necessary is to provide the power necessary for displacement of the mass, and it is possible to promote the miniaturization of the driving power source.

According to a second aspect of the present invention, the neutral position of the rod is such that the pressure receiving area of the rod end that receives the pressure of the accumulator, which is proportional to the displacement volume of the supporting oil chamber with the projecting end,
The rod is displaced to the neutral position without any special control if it is set at a position in equilibrium with the sum of the weight of the damping mass and the rod, and after the damping operation is completed, the hydraulic pressure in the second oil chamber is removed. However, the position can be held, and the damping mass is supported by the gas pressure of the accumulator, so that the miniaturization of the device can be promoted.

Further, according to the third aspect of the invention, since the displacement amount detecting means of the rod is housed in the supporting oil chamber, the displacement amount detecting means is protected from salt damage and deposits to suppress deterioration such as rust and durability. It is possible to reliably detect the displacement amount while improving.

Further, according to the fourth aspect of the invention, since the magnetic portion is formed on the outer periphery of the rod projecting into the supporting oil chamber, the magnetic portion is prevented from coming into contact with the outside, preventing rust due to salt damage, and improving durability. Can be improved.

[0020]

1 to 5 show an embodiment of the present invention.

1 to 3, a frame 10 for accommodating a vibration damping device is formed in a substantially box shape, and a main girder 5 is provided at a lower portion thereof.
0 is provided with wheels 7 for moving in the horizontal direction and support legs 8 for fixing the frame 10 to the main girder 50 at an arbitrary position, and the support legs 8 are configured to be extendable and retractable by a jack (not shown). It

Inside the frame 10, vertically fixed linear guides 4 and 4 are arranged at predetermined intervals, and between the linear guides 4 and 4, a rectangular cylindrical damping mass 1 is vertically arranged. It is guided so as to be freely displaceable in the vertical direction with respect to the upper surface of the main girder 50.

From the upper surface of the damping mass 1, the arms 40, 40
Is projected upward, and the upper end of the arm 40 is connected to the upper end 20A of the rod 20 protruding from the hydraulic cylinder 2 inserted into the hole 1A on the inner circumference of the damping mass 1.

A lower end of the hydraulic cylinder 2 is supported by a column 5 and is vertically arranged. The lower end of the column 5 is a frame 1.
The hydraulic cylinder 2 is pivotally supported by the bottom portion 10A of 0, and can swing about the lower end of the column 5 as an axis to allow horizontal displacement due to distortion of the linear guide 4 or the like.

The load of the vibration damping mass 1 is applied to the rod 20 via the arm 40, and is supported by the hydraulic cylinder 2 and the column 5. An oil buffer 9 is provided on the bottom portion 10A to prevent the damping mass 1 from colliding with the bottom portion 10A due to excessive displacement.

Here, the hydraulic cylinder 2 is of a double rod type as shown in FIG. 3, and the oil chambers 22 and 23 are defined by the piston 21 in the inner circumference of the cylinder tube 2A, and the oil chamber 23 is formed. The partition wall 25 is provided below the support oil chamber 2
4 is defined.

The upper end 20A of the rod 20 projects above the cylinder tube 2A from the oil chamber 22, while the rod 20
The lower end 20B of the above penetrates the partition wall 25 from the oil chamber 23 and projects into the supporting oil chamber 24. The supporting oil chamber 24 is formed so that the lower end 20B does not project to the outside at the most contracted position of the rod 20.

The oil chambers 22 and 23 are connected to the hydraulic unit 6 formed separately from the frame 10 for driving the rod 20 to expand and contract, while the supporting oil chamber 24 is fixed to the bottom portion 10A of the frame 10. It is connected to the accumulator 3.

The inside of the accumulator 3 is divided into a gas chamber 31 and an oil chamber 32 by a free piston 30, and a gas having a predetermined pressure is sealed in the gas chamber 31 while the oil chamber 3
2 communicates with the support oil chamber 24 of the cylinder tube 2A, supports the lower end 20B of the rod 20 by the hydraulic pressure according to the pressure applied via the free piston 30, and the load of the damping mass 1 applied to the hydraulic cylinder 2 is the rod 20. It is supported by the hydraulic pressure of the accumulator 3 applied to the lower end 20B of the above, and it is not necessary to apply the hydraulic pressure for supporting the damping mass 1 to the oil chamber 23.

Here, in the hydraulic unit 6, as shown in FIG. 4, the hydraulic pressure generated in the hydraulic unit 6 is transmitted from the servo valve 61 responsive to the current from the controller (not shown) to the oil chambers 22 and 23 via the stop valve 62. The hydraulic pressure is applied to the rod 20 to drive the rod 20 to expand and contract, and the rod 20 receives an excessive load, for example,
If excessive fluctuations of the damping target are applied, the brake valve 63
Is activated to relieve the hydraulic pressure applied to the hydraulic cylinder 2.

On the other hand, as shown in FIG. 3, a magnetic portion (not shown) is formed on the outer periphery of the rod 20 between the piston 21 and the lower end 20B as in the conventional example, while the supporting oil chamber 2 is provided.
4, a stroke sensor 12 fixed to the cylinder tube 2A for detecting the displacement amount of the rod 20 projects at one end thereof, and a non-contact type stroke sensor 12 composed of a magnetic sensor is formed in the same manner as the conventional example. One end is rod 20
It confronts the outer circumference at a predetermined interval. Then, the displacement amount detected by the stroke sensor 12 is sent to the controller described later and fed back as the displacement amount of the vibration damping mass 1.

As shown in FIG. 5, this controller has a speedometer 11 at the end of the main girder 50 for detecting the vertical speed.
Is provided, the output of the speedometer 11 is input to the drive circuit 16 of the hydraulic cylinder 2 via the filter 13 and the amplification circuit 14 that remove high-frequency vibration components, and the drive circuit 16 multiplies the command by a predetermined control gain. While the value is sent to the hydraulic unit 6, the output from the stroke sensor 12 is fed back to the drive circuit 16 via the amplification circuit 15, and the vibration damping mass 1 is accurately displaced according to the vibration of the end portion of the main girder 50.

With the above construction, the operation will be described.

The frame 10 is moved by the wheels 7 to the end of the main girder 50 which is sequentially extended as the construction progresses, and is fixed by the support legs 8 so that the hydraulic unit can be adjusted according to the speed detected by the speedometer 11. 6 supplies pressure oil to the hydraulic cylinder 2 to damp the vibration applied to the main girder 50 by the reaction force that drives the damping mass 1 in the vertical direction. This damping action is the same as in the conventional example. Therefore, detailed description thereof will be omitted.

The supporting oil chamber 2 added to the lower end 20B of the rod 20 when the damping mass 1 is stopped or not driven.
4 hydraulic pressure, that is, the gas chamber 31 of the accumulator 3
It is possible to support the damping mass 1 by the pressure of 1., and it is not necessary to supply or hold the pressure oil to the oil chamber 23 of the hydraulic cylinder 2 to support the damping mass 1 as in the above-mentioned conventional example. Since the pressure oil to be applied to the cylinder 2 may be any one capable of driving the vibration damping mass 1, the required power of the hydraulic unit 6 can be reduced and the miniaturization of the hydraulic unit 6 can be promoted.

The rod 20 is supported by the pressure of the gas chamber 31 because the sum of the load of the damping mass 1 and the weight of the rod 20 is proportional to the pressure receiving area of the lower end 20B of the rod 20 and the displacement of the lower end 20B of the gas chamber 31. A position where the product of pressure is in equilibrium is reached, and in this equilibrium position, the amount of protrusion of the rod 20 into the support oil chamber 24, that is, the support oil chamber 24, is set so that the piston 21 is located in the approximate center of the stroke of the hydraulic cylinder 2.
The displacement volume, gas pressure, etc. may be appropriately set.

After the damping operation is completed or when the oil pressure in the oil chamber 23 is released, the rod 20 contracts according to the load of the damping mass 1 and its own weight, and the lower end 20B is supported by the supporting oil chamber 24.
To a predetermined amount to stand still at the equilibrium position,
The control for driving the piston 21 to the neutral position is not necessary, the configuration of the control device can be simplified, and the increase in manufacturing cost can be suppressed.

In the above-mentioned conventional example, the support spring is provided between the vibration damping mass 1 and the frame 10. However, since the rod 20 is supported by the gas chamber 31, the space for storing the support spring is unnecessary. Can promote the miniaturization of the device,
When the weight of the damping mass 1 is changed according to the scale of the main girder 50, it can be dealt with by changing the pressure of the gas chamber 31, and the handling of the device can be facilitated and the efficiency of the work can be promoted. .

Since the stroke sensor 12 is provided in the support oil chamber 24, and the lower end 20B of the rod 20 is housed in the support oil chamber 24 so as not to project from the cylinder tube 2A to the outside, the lower end 20B side of the piston 21 is located. The outer periphery of the rod 20 does not need to be subjected to rust prevention treatment, and it is possible to suppress an increase in manufacturing cost, and it is not necessary to consider the occurrence of rust in the magnetic portion formed on the rod 20 even when it is used on the sea, The durability performance and detection accuracy can be ensured, and the amount of displacement of the rod 20 can be reliably detected while preventing adhesion of foreign matter and improving reliability.

FIG. 6 shows a second embodiment of the piston 21.
To the upper end 20A of the rod 20, a nickel-chromium plated layer 26 having high corrosion resistance is formed on the outer periphery of the rod 20, while the outer periphery of the rod 20 from the piston 21 to the lower end 20B of the rod 20 is formed with a chromium plated layer 27 that has little effect on magnetism. In addition, a predetermined magnetic portion is formed, and the other structure is the same as that of the first embodiment.

Since the nickel chrome plating layer 26 is formed on the upper end 20A side protruding outward from the cylinder tube 2A, deterioration of the rod 20 due to rust or the like can be prevented, while the chrome plating layer 27 formed on the lower end 20B side. Has little effect on the magnetic part (not shown),
It is possible to reliably detect the displacement amount of the rod 20 and reduce the sliding resistance in the partition wall 25.

[0042]

As described above, according to the first aspect of the present invention, the damping mass which constitutes the damping device for damping the vertical vibration of the main girder when the cable-stayed bridge is erected is applied to the vibration of the cable-stayed bridge. Correspondingly, in the hydraulic actuator for the vibration control device that is driven in the vertical direction,
A first and a second oil chamber defined inside the hydraulic actuator, and a rod penetrating the second oil chamber while driving the damping mass at one end penetrating the first oil chamber. And a support oil chamber for accommodating the end portion of the rod protruding from the second oil chamber, and a means for pressurizing the support oil chamber in correspondence with the damping mass, when the damping mass is stopped. The rod is supported by the pressure applied to the lower end of the rod, the power for supporting the damping mass becomes unnecessary, and the hydraulic cylinder need only be driven with the power required for displacement of the damping mass. As described above, the spring supporting the vibration damping mass is not required, and the miniaturization of the entire device can be promoted.

In a second aspect of the present invention, the pressurizing means comprises an accumulator which pressurizes the hydraulic oil with a pressurized gas, and the neutral position of the rod is proportional to the displacement of the support oil chamber whose lower end protrudes from the accumulator. The pressure and the pressure receiving area at the lower end of the rod are set at a position where the damping mass and the weight of the rod are in equilibrium, and the rod can be held in the neutral position without requiring special control, which simplifies the structure of the control means. Thus, the increase in manufacturing cost is suppressed, and the damping mass is supported by the gas pressure of the accumulator, so that the device can be downsized as compared with the conventional example.

A third aspect of the invention is that the support oil chamber has
A means for detecting the displacement amount of the rod for feedback control of the hydraulic actuator is housed, the displacement amount detecting means is protected from salt damage and deposits to suppress deterioration such as rust, and durability is improved, Promote improvement of reliability by maintaining detection accuracy of rod displacement.

According to a fourth aspect of the present invention, the displacement amount detecting means comprises a magnetic portion formed on the outer periphery of the rod protruding into the supporting oil chamber, and a means for detecting magnetism which changes according to expansion and contraction of the rod. The magnetic part does not come into contact with the outside, prevents rust on the rod due to salt damage, etc. to improve durability, and reliably detects the displacement amount of the rod to promote reliability improvement. be able to.

[Brief description of drawings]

FIG. 1 is a front view of a vibration damping device showing an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a schematic diagram of a hydraulic actuator for a vibration damping device.

FIG. 4 is a hydraulic circuit diagram of the same.

FIG. 5 is a block diagram showing a vibration damping system.

FIG. 6 is a schematic diagram of a hydraulic actuator for a vibration damping device.

FIG. 7 is a schematic side view showing a cable-stayed bridge under construction.

FIG. 8 is a front view showing a conventional vibration damping device.

FIG. 9 is a schematic view of a conventional hydraulic actuator for a vibration damping device.

[Explanation of symbols]

 1 Damping Mass 2 Hydraulic Cylinder 3 Accumulator 4 Linear Guide 6 Hydraulic Unit 10 Frame 12 Stroke Sensor 20 Rods 22, 23 Oil Chamber 24 Support Oil Chamber 50 Main Girder

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Yasuno Kenichi Yasuno 2-1-1, Tobita-cho, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (72) Inventor Shin Oshio 2-1-1-1, Tobita-cho, Chofu-shi, Tokyo No. Kashima Construction Co., Ltd. Technical Research Laboratory (72) Inventor Tatsuko Nakano No. 19-1 Tobita, Chofu City, Tokyo Kashima Construction Co., Ltd. Technical Research Institute

Claims (4)

[Claims] 1. A vibration damping device for driving a damping mass, which constitutes a vibration damping device for damping the vertical vibration of a main girder when a cable-stayed bridge is installed, in a vertical direction in response to the vibration of the cable-stayed bridge. In the hydraulic actuator, the first and second oil chambers defined inside the hydraulic actuator and one end penetrating the first oil chamber drive the damping mass, and the other end drives the second oil chamber. A rod that penetrates the second oil chamber, a support oil chamber that accommodates the end of the rod that protrudes from the second oil chamber, and a means that pressurizes the support oil chamber in correspondence with the damping mass. A characteristic hydraulic actuator for vibration control devices. 2. The hydraulic actuator for a vibration damping device according to claim 1, wherein the pressurizing means is composed of an accumulator that pressurizes the hydraulic oil with pressurized gas. 3. The vibration damping device according to claim 1, wherein the support oil chamber is provided with means for detecting a displacement amount of a rod for feedback controlling the hydraulic actuator. Hydraulic actuator for equipment. 4. The displacement amount detecting means comprises a magnetic portion formed on the outer circumference of the rod protruding into the support oil chamber, and means for detecting magnetism that changes according to expansion and contraction of the rod. The hydraulic actuator for a vibration damping device according to claim 3.