JPH0444775B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration control device for controlling low frequency vibrations occurring in structures such as elevated roads.

Generally, as shown in Figure 1, in an elevated road, a bridge section 1 consisting of a beam section 2 and a leg section 3 is fixed on a foundation (not shown) buried deep underground. A bridge 5 is supported on the beam portion 2 via a main girder 4. Conventionally, in an elevated road having such a configuration, when a car or the like runs on the bridge 5, vibrations as shown by dotted lines in FIG. 1 occur in the piers 1 and the bridge 5. Since this vibration is a low-frequency vibration, it passes through the ground and resonates with surrounding buildings, causing so-called low-frequency pollution, which has become a major social problem. Conventionally, elevated roads were reinforced as a countermeasure, but this only slightly changed the vibration system and was not a fundamental countermeasure.

Therefore, as a solution to this problem, a tendon-type vibration control device shown in FIG. 2 has been proposed. That is, FIG. 2 shows the structure of a vibration control device that uses the so-called tendon method for a beam. In the figure, 6 is a beam, and both ends of the beam are supported by support stands 7.

A pair of arms 8 are attached near both ends of the beam 6, and a moment can be generated in the beam 6 by a force applied to the tip of the arm 8 in the longitudinal direction of the beam 6.

9 is a tendon, 10 is a hydraulic actuator, 1
1 is a sensor, 12 is a filter, 13 is a control device, and 14 is a hydraulic drive device.

Now, suppose that the beam 6 is vibrating and is about to move downward in FIG. , after converting it into a necessary signal, sends it to the control device 13. The control device 13 issues necessary commands to the hydraulic drive device 14 that drives the hydraulic actuator 10, and the hydraulic actuator 10 eventually generates a control force P in the tensile direction corresponding to the amount of vibration in the direction of the arrow shown in FIG. This control force P is given by the following equation.

P (t) = -G It is a gain matrix. The generated control force P is applied to the arm 8 via the tendon 9, and the second
In the figure, a moment M is generated. In this way, the vibrations generated in the beam 6 are controlled by the moment M which tends to stop the beam 6 from moving downwards. Exactly the same principle applies at the moment when the beam 6 attempts to move upwards, but in this case it is controlled by a moment -M in the opposite direction.

Therefore, in order to increase this effect, the moment M applied to the beam 6 must be increased, but in order to increase the moment M, the length of the arm 8 must be increased, or the tensile force P must be increased. must not. However, increasing the length of the arm 8 is difficult due to the problem of space under the bridge, especially on elevated roads, where the bridge is often used as a road, and it is difficult to increase the tensile force P due to the capacity of the device. It was difficult.

This invention eliminates the above drawbacks,
The present invention provides a vibration control device for use in elevated roads, etc., which uses screws for minute fluctuations to obtain a large control force.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a diagram showing an embodiment of the present invention.
In the figure, 6, 7, 8, 9, 11, 12, and 13 are the same as those shown in FIG. 2, but the difference from FIG. A power amplification device 15 is provided in place of the device 14, and a pair of screw mechanisms 18 are provided between the pair of arms 8 to move in the axial direction by fitting a male screw 16 and a female screw 17. Also, in this screw mechanism, the female screw 17 is attached to one end of the tendon 9, and the male screw 16 is attached to the rotating machine 19.
is connected to the rotating shaft.

FIG. 4 is a diagram showing the operating principle of the screw mechanism according to the present invention. The magnitude of the force P that controls vibration is
Although it varies depending on the structure and scale of the elevated road, on a normal elevated road, the distance between piers 1 and 1 shown in Figure 1 is several tens of meters, and the combined weight of the main girder 4 and bridge 5 is several tens of meters. For objects weighing about 100 tons, a force of several tens of tons must be applied. However, if the screw mechanism shown in Fig. 4 is used, and if the pitch angle of the screw is α and the average diameter of the screw surface is d, then the torque T required to generate the control force P, ignoring friction, is , T=Ptanα×d/2 −(2). Therefore, if the pitch angle α of the screw is appropriately selected, a large control force P can be obtained with a small torque T. In addition, when using a screw, although it is possible to generate a large axial force, one rotation of the screw only advances the pitch distance a, but the stroke required for the control force P is within a range of several mm. can be,
By appropriately designing the pitch a of the screw, the rotation angle can be selected to be an angle that is likely to occur in the rotating machine 18.

In this embodiment, a rod that can withstand tension and compression is used as the tendon 9, but instead, a wire may be used to maintain tension at all times and vibrations may be controlled by changing the tension. Needless to say, the control force can be doubled by using the screw mechanism in some cases.

In this way, when trying to control the vibrations of elevated roads, etc., the force that must be applied to the tendons 9 is very large, but the stroke is small, so if the vibration control device of the present invention is used, the screw mechanism shown in FIG. By appropriately selecting the pitch distance a and the pitch angle α, it is possible to convert the torque T generated by the rotary machine 19 into a large control force P. It is possible to install it in places where it cannot be removed.

[Brief explanation of drawings]

Figure 1 is a perspective view of an elevated road, Figure 2 is a diagram showing a known example of using the tendon method for beams, Figure 3 is a diagram showing an embodiment of this invention, and Figure 4 is the operating principle in the embodiment. 1 is a pier, 2 is a beam part, 3 is a leg part, 4 is a main girder, 5 is a bridge, 6 is a beam, 7
is a support stand, 8 is an arm, 9 is a tendon, 10 is a hydraulic actuator, 11 is a sensor, 12 is a filter, 13 is a control device, 14 is a hydraulic drive device,
15 is a power amplifier, 16 is a male screw, 17 is a female screw, 18 is a screw mechanism, and 19 is a rotating machine. Note that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1. A vibration control device for a structure that generates vibrations in response to an external force, including a pair of arms coupled to the structure at a predetermined distance, and a pair of arms each having one end connected to the pair of arms in the longitudinal direction. a coupling member, a detector for detecting the vibration, a rotating machine fixed to the structure and having a pair of rotating shafts between the other ends of the pair of coupling members, and an output signal of the detector; control means for driving and controlling the rotating machine so that the rotating machine generates a rotational torque corresponding to the control force for reducing the vibration based on the control means; the other end of the pair of coupling members and the pair of rotating shafts; and a pair of screw mechanisms coupled between the pair of rotating shafts and converting the rotational torque of the pair of rotating shafts into the control force along the longitudinal direction of the pair of coupling members.