JPH0658363A - Active vibration control device - Google Patents

Abstract

PURPOSE:To dampen micro-vibration, vibration in the case where the number of oscillation changes, with a static displacement permitted. CONSTITUTION:This vibration control device is provided with a easing 2 which is connected to a fixed system 9 as necessary, and has a roughly-sealed compartment chamber 1 in it, an ER fluid 3 with which the compartment chamber 1 is filled, and where viscosity changes in proportion to voltage, and a rod 4 which passes through the compartment chamber 1 and is inserted in the casing 2 so as to slide, and whose one end side is installed to piping 7. Moreover, this oscillating device is also provided with electrode plates 5 which are mounted in parallel with a narrow clearance S and where voltage is applied to the ER fluid, a piston 6 which is installed to either of the rod 4 or the easing 2 and makes an ER fluid 3 flow in the compartment chamber 1 with the above sliding, and a voltage control means 8 which detects the vibration of piping 7 and changes the voltage of the electrode plates 5 to dampen vibration based on the detected value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active vibration damping device for damping vibrations generated in pipes and the like.

[0002]

2. Description of the Related Art In general, a plant equipped with pipes and equipment is provided with a device for appropriately absorbing and supporting vibrations generated therein. For example, in a nuclear power plant, a cooling water circulation pump and its piping system are supported by a fixed system such as a building by a plurality of supporting devices such as pedestals and straddles, and a known mechanical snapper for damping vibration is provided. ing. This mechanical snapper receives damage to dynamic displacements such as earthquakes and pump vibrations to prevent it from damaging the object to be supported, and also causes it to heat up due to rising cooling water. This is allowed for static displacement such as thermal expansion.

[0003]

However, since the mechanical snapper has some mechanical play, it cannot act on a slight vibration of about 0.1 to 1.0 mm. Therefore, there is a problem that abnormal noise is generated due to this slight vibration and metal fatigue is given to the connecting portion of the machinery. It is also possible to use an oil damper or the like instead of the mechanical snapper, but these are effective only for a certain specific frequency, and a cooling water circulation pump whose rotation speed changes according to the circulating cooling water amount. It was not effective for those whose frequency changed, such as nuclear power piping whose load and load fluctuate.

On the other hand, a fluid damper using an ER fluid (electrorheological fluid) has been proposed as a means for actively damping vibrations (Japanese Patent Laid-Open No. 1-295040). E
The R fluid is made of a substance whose viscosity changes according to the applied voltage, and can detect the vibration and control the applied voltage to effectively act on static displacement and various vibrations. However, in this proposal, the damper casing is filled with the ER fluid, and the electrode is provided at the orifice of the piston that reciprocates inside the damper casing. Therefore, there is a problem that the damping force due to the viscosity of the ER fluid is not sufficiently exerted. .

In view of the above circumstances, the present invention provides an active vibration damping device which allows static displacement such as thermal expansion and can effectively dampen microvibrations or vibrations whose frequency changes. It was designed to be provided.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a casing having a substantially hermetically-sealed compartment which is appropriately connected to a fixed system, and the viscosity of which is filled in the compartment and changes in proportion to voltage.
An R fluid, a rod penetrating through the compartment and slidably inserted in the casing, one end of which is attached to a support object such as a pipe, and an electrode which is arranged in parallel in the compartment with a narrow gap and applies a voltage to the ER fluid. A plate, a piston that is attached to either the rod or the casing and that causes the ER fluid to flow in the compartment as it slides, and the vibration of the support target is detected, and the vibration is damped based on this detection value. And a voltage control means for changing the voltage of the electrode plate.

[0007]

With the above structure, the viscosity of the ER fluid is always fixedly connected to the casing and the rod, and the sliding of the rod is not restricted by static displacement such as thermal expansion. Tolerate. When vibration occurs,
The piston pushes the ER fluid as the rod and the casing slide, causing it to flow in the compartment while passing through the gap between the electrode plates. At the same time, the voltage control means detects the vibration, calculates an optimum voltage corresponding to the vibration, and applies the voltage between the electrode plates. The ER fluid changes its viscosity by this voltage and generates a predetermined frictional force between the ER fluid and the electrode plate to damp the vibration.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of an active vibration damping device according to the present invention. This active vibration damping device 21
A casing 2 having a substantially sealed compartment 1 therein, an ER fluid 3 filled in the compartment 1, a rod 4 penetrating the compartment 1 and slidably inserted into the casing 2.
Voltage control for changing the voltage V of the electrode plate 5 by detecting the vibration of the electrode plate 5 arranged in parallel in the compartment 1 with a narrow gap S, the piston 6 attached to the rod 4, and the pipe 7 which is the object to be supported. It is mainly configured by the means 8.

The casing 2 is formed in a cylindrical shape with a bottom,
A bracket 10 for connecting to the fixed system 9 is attached to the peripheral side surface, and insertion holes 11 for inserting the rod 4 are formed at the axial center positions of both end surfaces. In the present embodiment, the rod 7 is arranged so that the axial center of the rod 4 intersects the pipe 7 extending in the vertical direction in the radial direction.
The compartment 1 is formed in a cylindrical shape similar to the outer shape of the casing 2.

The ER fluid 3 is a liquid dispersion medium (electrically insulating fluid such as mineral oil) in which a powder dispersed phase (porous solid particles such as silica gel) and a dispersant (sulfonates or the like).
And the like, which is a publicly known one to which an applied voltage V
The viscosity changes in proportion to.
That is, a high frictional force (shearing force) can be exerted on an object that moves in contact with the liquid surface.

One end of the rod 4 is attached to the outer surface of the pipe 7 via a bracket 12 so that the rod 4 reciprocates along the axis of the casing 2 when the pipe 7 is displaced (vibrated) in the radial direction. It has become. Also, at the other end on the opposite side, in order not to pull out the rod 4 from the casing 2,
A flange-shaped stopper 13 that is sufficiently larger than the insertion hole 11 is attached.

The electrode plate 5 has a cylindrical shape having a length L _i that is appropriately shorter than the axial length L ₀ of the compartment 1, and a plurality of electrode plates 5 are arranged so that adjacent electrodes have different polarities (positive electrode and negative electrode). The number of sheets (two in the illustrated example, a total of four) is provided. Then, as also shown in FIG. 2, the insulator support 1 is arranged concentrically with the rod 4 and the casing 2 and extends in the radial direction.
Casing 2 so that they are at substantially equal intervals S with each other.
It is attached to the inner wall of the. Therefore, the ER fluid 3 filled in the compartment 1 is applied with the voltage V by these electrode plates 5. Further, the insulator support 17 plays a role of transmitting the axial force acting on the electrode plate 5 to the casing 2.

The piston 6 is an annular member attached to the outer peripheral surface of the rod 4 at an appropriate position in the longitudinal direction, so that the piston 6 is brought into close contact with and slides on the inner wall of the cylinder plate 18 attached to the innermost electrode plate 5a. It has become. Ie rod 4
Is moved in the axial direction (arrow b in the figure), the ER fluid 3 between the rod 4 and the cylinder plate 18 is pushed to force the entire ER fluid 3 to pass between the electrode plates 5, As indicated by an arrow c in the figure, the fluid is circulated in the compartment 1. Although not shown in the figure, when the rod 4 moves in the opposite direction, E
The flow direction of the R fluid 3 is opposite to the arrow c in the figure. Further, in the present embodiment, the outer peripheral surface of the rod 4 and the inner wall of the cylinder plate 18 are set so that the cross-sectional area between the rod 4 and the cylinder plate 18 is larger than the total cross-sectional area between the electrode plates 5. Is formed sufficiently larger than the distance S between the electrode plates.

The voltage control means 8 sets a vibration sensor (accelerometer or the like) 14 attached to the outer surface of the pipe 7 and an optimum voltage value V ₁ for damping the vibration based on the value detected by the vibration sensor 14. It is composed of a controller 15 which calculates and outputs in the form of an electric signal, and a power amplifier 16 which applies an optimum voltage V ₁ to the electrode plate 5 by the output signal of the controller 15. The controller 15 uses the detected value to determine the vibration level (strength, frequency, amplitude, etc.).
The program (or control map) for calculating the electric power value V ₁ corresponding to is incorporated. That is, by applying the optimum voltage V ₁ to the ER fluid 3, the vibration can be most quickly attenuated.
It should be noted that the electric wire 19 connecting the power amplifier 16 and the electrode plate 5 has a portion inside the compartment 1 where an absorbing portion 20 capable of absorbing the movement displacement.
Is provided. The absorbing portion 20 is the electric wire 2 on the cathode side.
It is also provided in 1.

Next, the operation of this embodiment will be described.

When vibration occurs in the pipe 7, the vibration sensor 14 detects it. The controller 15 compares this detected value with a preset allowable vibration level, and if it is a harmless extremely small vibration, it leaves it. If the detected value exceeds the permissible vibration level, the controller 15 calculates the optimum voltage value V ₁ that can most quickly attenuate the vibration based on the vibration intensity and the like, and outputs the control signal to the electric power. Output to the amplifier 16. At this time, the rod 4 directly connected to the pipe 7 reciprocates at the axial center position of the casing 2, and the piston 6 pushes the ER fluid 3 to make it flow inside the compartment 1 and between the electrodes 5. It is in.

The power amplifier 16 applies an optimum voltage V ₁ between the electrodes 5 according to the output signal from the controller 15. Due to this voltage V ₁ , the viscosity of the ER fluid 3 flowing in the compartment 1 changes, and a predetermined frictional force is generated between the ER fluid 3 and the surface of the electrode plate 5 rubbing against each other. With this, the vibration damping force F corresponding to the flow velocity and the applied voltage (V ₁ ) acts as a resistance force to the piston 6, and the movement of the rod 4 is suppressed,
The vibration of the pipe 7 is damped. That is, the vibration sensor 1
The controller 4 and the controller 15 control the applied voltage so that the vibration is always below the allowable level. And at all times, like a normal damper,
The viscosity of the ER fluid 3 fixedly supports the rod 4 and the pipe 7, and allows static displacement of the pipe 7 due to thermal expansion or the like.

As described above, the rod 4 having the piston 6 is inserted into the casing 2 containing the ER fluid 3,
Since the voltage V to the electrode plate 5 is changed according to the vibration level of the pipe 7, the pipe 7 can be held while permitting static displacement such as thermal expansion, and at the same time, in any of the various modes. Vibration can be damped. Since the ER fluid 3 is made to pass through the narrow gaps S between the many electrode plates 5, the effective area related to the frictional force can be increased, and the ER fluid 3 can be used regardless of the stroke of the ER.
The damping force F due to the viscosity of the fluid 3 can be effectively applied to the rod 4. Therefore, it is possible to appropriately dampen minute vibrations, vibrations that change in frequency, etc., and it is possible to prevent abnormal noise, prevent metallic fatigue of the connecting portion, and prevent destruction of the piping system.

Further, according to the present invention, the portion to be attached to the pipe 7 has an extremely compact structure, can be easily applied to a narrow pipe place, and is extremely versatile.

The dimensions of the compartment 1 of the casing 2, the rod 4 and the electrode plate 5 are such that the stroke of the piston 6 can be taken even when static displacement including thermal deformation and vibration displacement occur. In consideration of the above, the axial length L _{i of} the electrode plate 5 and the axial length L ₀ of the compartment 1 are appropriately selected. Further, by appropriately selecting the outer diameter of the rod 4, the inner diameter D _i of the cylinder plate 18, the inner diameter D _{0 of the} compartment 1 and the electrode gap S, the ER obtained in proportion to the voltage V can be obtained.
The damping force gradient (damping coefficient) of the fluid can be freely changed. The number and shape of the electrode plates 5 should also be selected according to design conditions and the like.

Further, in the above embodiment, the case where the vertically extending pipe 7 of the nuclear power plant or the like is supported horizontally is shown, but the supporting structure and the object to be supported are not limited to this. As shown in FIG. 3, it is of course possible to hold the devices 22 so as to be suspended at two points by the two active vibration damping devices 21 extending in the oblique direction.

Next, another embodiment of the present invention will be described with reference to FIG. In this embodiment, the piston 31 is attached to the inner wall of the casing 2, and the electrode plate 5 is concentrically supported by the rod 4 via an insulator support 32. A cylinder plate 33 that slides on the piston 31 is attached to the outer wall of the outermost electrode plate 5d. Further, the cross-sectional area between the casing 2 and the cylinder plate 33 is formed to be larger than the total cross-sectional area between the electrode plates 5.

Therefore, when a disturbance such as an earthquake propagates from the fixed system 9 to the casing 2 (arrow e), the piston 31 moves relative to the rod 4 and the electrode plate 5, and E
The R fluid is pushed from the outside of the cylinder plate 33 into the space between the electrode plates 5 to forcefully flow (arrow f), and the controller (not shown)
Viscosity is displayed according to voltage control. Further, the vibration from the supporting object such as the pipe is caused by the rod 4 and the electrode plate 5.
However, since the ER fluid is relatively moved with respect to the casing 2 and the piston 31, the ER fluid is forcedly passed between the electrode plates 5 and a vibration damping action is exerted. The other structure, function and effect are the same as those of the above-mentioned embodiment, and therefore omitted.

[0025]

In summary, according to the present invention, the following excellent effects are exhibited.

A casing having a compartment, an ER fluid filled in the compartment, a rod slidably inserted in the casing, an electrode plate for applying a voltage to the ER fluid, and a rod and a casing for sliding. Since a piston that causes the ER fluid to flow along with it and voltage control means that detects the vibration of the support target and changes the voltage of the electrode plate are provided, static displacement such as thermal expansion is allowed, and slight vibration or vibration is allowed. Vibrations of which the number changes can be appropriately damped, and the damping action of the ER fluid can be effectively exerted, so that a sufficient damping force can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of an active vibration damping device according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a side view showing a specific example of FIG.

FIG. 4 is a cross-sectional view of essential parts showing another embodiment of the present invention.

[Explanation of symbols]

 1 Compartment 2 Casing 3 ER fluid 4 Rod 5 Electrode plate 6 Piston 7 Piping (supporting object) 8 Voltage control means 9 Fixed system

Claims (1)

[Claims] 1. A casing which is appropriately connected to a fixed system and has a substantially sealed compartment therein, an ER fluid which is filled in the compartment and whose viscosity changes in proportion to a voltage, and penetrates the compartment. Rod which is slidably inserted into the casing and one end of which is attached to a support object such as a pipe, an electrode plate which is arranged in parallel in the compartment with a narrow gap and applies a voltage to the ER fluid, the rod or It is attached to either one of the above casings and the ER
A piston for causing a fluid to flow in the compartment, and a voltage control means for detecting the vibration of the support target and changing the voltage of the electrode plate based on the detected value to attenuate the vibration are provided. Characteristic active vibration control device.