JPH0526287A - Variable damping device using magnetic fluid - Google Patents

Abstract

PURPOSE:To simplify constitution, to perform reliable operation, to improve reliability, to facilitate maintenance, and to vary a damping constant at the initial stage of a damper using magnetic fluid. CONSTITUTION:A force sensor 5 and a speed sensor 6 are mounted to a piston 3 of a magnetic fluid cylinder 1, and an electromagnet 8 is disposed in a magnetic fluid passage 7 communicated to the cylinder 1. A control signal is outputted by a computer 10 receiving detecting signals from the sensors 5 and 6, the magnetic force of the electromagnet 8 is changed, and viscosity of magnetic fluid 2 of a fluid passage 7 is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable damping device for damping a structure or preventing relative displacement when the structure vibrates due to an earthquake, wind or the like.

[0002]

2. Description of the Related Art Conventionally, as a damping device of this kind, as shown in FIG. 6, a piston b is slidably fitted in a viscous fluid cylinder a, and when the piston b moves left and right in a cylinder a. A fluid d flows in a gap c between the two and a device configured so that a damping force is obtained by its viscosity, or as shown in FIG. 7, as the piston b moves left and right in the cylinder a, the piston c There is a device configured such that the fluid d flows through the hole e provided in the and the damping force is obtained by its viscosity.

[0003]

In the conventional damping device described above, the damping force changes depending on the speed of the piston. Thus, the damping force is proportional to the velocity at low speeds, but proportional to the square of the velocity at high speeds, and if the damping force characteristics change in this way, the structural equations change when substituting with a physical model, and response calculation becomes difficult. .. Further, as described above, if the characteristics of the damping force change depending on the speed, the range of application as a damper is narrowed.

The present invention has been proposed in view of the above-mentioned problems of the prior art. The object of the present invention is to provide a magnetic fluid which is simple in construction, reliable in operation, highly reliable and easy to maintain. The point is to provide a variable damping device used.

[0005]

In order to achieve the above object, the variable damping device using magnetic fluid according to the present invention is mounted on a piston fitted in a magnetic fluid cylinder so as to be movable back and forth. A force sensor and a speed sensor, and an electromagnet arranged in a magnetic fluid passage communicating with the cylinder,
The control device receives the detection signals of the force sensor and the velocity sensor and changes the magnetic force of the electromagnet to change the viscosity of the magnetic fluid.

[0006]

Since the present invention is constructed as described above,
A velocity sensor mounted on a piston fitted in a magnetic fluid cylinder and a force sensor measure the relative velocity and damping force between the piston and the cylinder. When the relationship between speed and force is stored in the control device in advance, the magnetic force of the electromagnet arranged in the flow path communicating with the cylinder does not change.

However, when the relationship between the speed and the force measured by each of the sensors is different from the state stored in the control device, the electromagnet is instructed by the control device receiving an input signal from each of the sensors. The magnetic force of is changed to change the viscosity of the magnetic hydrodynamic force so that a preset speed-force relationship is obtained.

[0008]

The present invention will be described below with reference to the illustrated embodiments. In FIG. 1, 1 is a cylinder filled with a magnetic fluid 2, 3 is a piston slidably fitted in the cylinder 2, 4 is a rod of the piston, and the rod 4 includes a speed sensor 5 and a load cell. The force sensor 6 is mounted.

A pipe-shaped fluid passage 7 is connected between both ends of the cylinder 1, and an electromagnet 8 facing the passage 7 is disposed across the passage. An orifice 9 is formed between the electromagnets 8. Has been done. Further, the cylinder 1 is provided with a computer 10 which receives signals from the speed sensor 5 and the force sensor 6 and sends a control signal to the electromagnet 8. The computer 10 constitutes a control device of the electromagnet 8. is there. In the figure, 11 is an amplifier. In the illustrated embodiment, the cylinder 1 has a speed sensor 5
Is arranged so that the relative speed between the piston rod 3 and the cylinder 1 can be measured.

Since the illustrated embodiment is constructed as described above, the speed sensor 5 measures the relative speed between the piston 3 and the cylinder 1, and the force sensor 6
Measure the deceleration force by. Since the illustrated embodiment is configured as described above, the relative speed between the piston 3 and the cylinder 1 is controlled by the speed sensor 5 and the force sensor 6,
The damping force is measured in parallel, a measurement signal is sent to the computer 10, and a control signal is sent from the computer 10 to the electromagnet 8.

At this time, if the relationship between speed and force is stored in the microcomputer 10 in advance, the electromagnet 8
Does not change its magnetic force. However, each of the sensors 5, 6
When the relationship between the velocity and the force measured by the computer is different from the state stored in the micro computer 10, the instruction from the computer 10 is sent to the amplifier 11 to change the magnetic force of the electromagnet 8 to change the viscosity of the magnetic fluid 2. Is changed to establish a preset speed-force relationship.

As described above, according to the above-described embodiment, the magnetic fluid 2 operates effectively only by applying an external magnetic field to the fluid passage through which the magnetic fluid 2 passes. Therefore, an expensive electromagnetic valve or the like is unnecessary, and the valve or the like is unnecessary. There is no fear that clogging will occur due to dust and the like when using. Further, when controlling the flow rate of the magnetic fluid, since there is no mechanical moving part, there is no failure, reliability is high, and a maintenance-free variable damping device is configured.

FIG. 2 shows an embodiment in which the present invention is applied to a structure damping structure. Between the ground 11 and the structure 12, a laminated rubber or a sliding bearing 13 is used together with the magnetic fluid shown in the above embodiment. The variable damping damper 14 that has been used is interposed. In the vibration control structure, when a damper having a constant damping constant as shown in FIGS. 6 and 7 is used together with a conventional laminated rubber or a sliding bearing, a resonance phenomenon is generated with respect to long-period ground motion and the amplitude becomes extremely large. growing.

According to the illustrated embodiment, a variable damping damper 1
By using 4, the damping constant is h = 0.3.
The initial setting is about this level, and damping effect is aimed at by the small and medium earthquakes. However, when there is an outstanding input of a component corresponding to the long period of the structure-laminated rubber or slip bearing-damper due to a large earthquake, the initial damping constant h = 0.3 of the variable damping damper 14 is set to 0.0 to Change to 1.0 and the natural period T of the structure 12

[0015]

[Equation 1]

By changing to, the resonance phenomenon is prevented and the damping effect is enhanced. As described above, according to the above-described embodiment, the damping period of the variable damping damper 14 can be changed with a small amount of energy to change the natural period of the structure 12, so that the vibration damping energy efficiency is good. 3, 4 and 5, the variable damping damper 14 is attached to the seismic wall 15 and the braces 16 and 17 of the structure 12, respectively.
When the vibration oscillates to cause a resonance phenomenon, the damping constant h of the damper 14 is changed to change the structure 1
The period of 2 is changed in the same manner as in the above-described embodiment to prevent the resonance phenomenon and to suppress the structure 12.

[0017]

As described above, the variable damping device according to the present invention mounts the force sensor and the velocity sensor on the piston of the magnetic fluid cylinder, and arranges the electromagnet in the magnetic fluid passage communicating with the cylinder. The control signal is generated in response to the detection signals of the respective sensors, and the control device changes the magnetic force of the electromagnet to change the viscosity of the magnetic fluid in the magnetic fluid passage. Since it operates effectively only by giving an appropriate external magnetic field, an expensive valve or the like becomes unnecessary. Further, since the valve is unnecessary in this way, there is no fear that clogging will occur due to dust and the like generated when the valve or the like is used.

Furthermore, according to the present invention, when controlling the flow rate of the magnetic fluid in the flow path, there is no mechanical moving part, so that the reliability is high and the maintenance is free.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a variable damping device using a magnetic fluid according to the present invention.

FIG. 2 is a front view showing an embodiment in which the variable damping device of the present invention is applied to a structure vibration damping device.

FIG. 3 is a vertical sectional view showing an embodiment in which the variable damping device of the present invention is attached to a seismic wall of a structure.

FIG. 4 is a vertical sectional view showing an embodiment in which the variable damping device of the present invention is attached to a brace of a structure.

FIG. 5 is a vertical sectional view showing another embodiment in which the variable damping device of the present invention is attached to a brace of a structure.

FIG. 6 is a vertical sectional view showing an example of a conventional damper.

FIG. 7 is a vertical sectional view showing another embodiment of the conventional damper.

[Explanation of symbols]

 1 Cylinder 2 Magnetic Fluid 3 Piston 4 Rod 5 Speed Sensor 6 Force Sensor 7 Fluid Passage 8 Electromagnet 9 Orifice 10 Computer 11 Amplifier

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[Procedure amendment]

[Submission date] November 26, 1991

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (1)

Claim: What is claimed is: 1. A force sensor and a speed sensor mounted on a piston fitted in a magnetic fluid cylinder so as to be movable back and forth, and a magnetic fluid passage communicating with the cylinder. A variable damping device using a magnetic fluid, comprising an electromagnet and a control device which receives detection signals from the force sensor and the velocity sensor and changes the magnetic force of the electromagnet to change the viscosity of the magnetic fluid.