JPH08270726A - Low frequency vibration control device - Google Patents

Abstract

PURPOSE: To provide a low frequency vibration control device for absorbing low frequency vibration. CONSTITUTION: A device comprises permanent magnets 5, 6 fixed on a frame 1, an object to be supported above the permanent magnets 5, 6 and a conductive line 7 mounted under the object to be supported and disposed across a magnetic field of the permanent magnets 5, 6 and supporting weight of the object to be supported 3 accepting force of upward direction by electrifying and an elastic member 9 fit between the frame 1 and the object to be supported, and the conductive line 7 support, weight of the object to be supported by accepting up ward force. The weight of the object to be supported is not loaded to the elastic member 9 fit between the frame 1 and the object to be supported, so that the elastic member 9 is formed with soft one to absorb low frequency vibration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low frequency vibration isolator capable of absorbing low frequency vibration generated in a support.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional vibration isolator supports a supported object 3 such as a mechanical device on a pedestal 1 by an elastic body 2 such as a vibration isolating rubber and a spring. Elastic body 2
In general, the vibration is absorbed to prevent the supported object 3 from vibrating.

[0003]

However, when the weight of the supported object 3 is heavy, the elastic body 2 must also bear the heavy weight, so that it cannot be made too soft and the frequency is 10 Hz or less. There was a problem that the low frequency vibration of could not be absorbed.

An object of the present invention is to solve the above problems and to provide a low frequency vibration isolator capable of absorbing low frequency vibrations.

[0005]

According to the present invention, a permanent magnet fixed on a pedestal and a supported object above the permanent magnet are provided.
A lead wire which is attached below the object to be supported and which is arranged across the magnetic field of the permanent magnet to support the weight of the object to be supported by an upward force due to energization; and the pedestal and the object to be supported. A low-frequency vibration isolator, comprising: an elastic body attached between the control element and the pedestal and the supported object for controlling the value of the current flowing through the conductor according to the weight of the supported object. It is also possible to provide an element that detects a relative speed and relative displacement between the control element and the control element and changes the current value controlled by the control element.

[0006]

When the conductor is energized, the conductor receives the upward force to support the weight of the supported object, and the weight of the supported object is not loaded on the elastic body mounted between the pedestal and the supported object. Therefore, the elastic body can be made soft to absorb low-frequency vibration.

According to the second aspect of the present invention, the relative speed and relative displacement between the gantry and the supported object are detected to adjust the value of the current flowing through the conductor, and the upward force acting on the conductor is supported by the supported object. The elastic body can be made to have a size suitable for, and the elastic body can exhibit optimum damping performance.

[0008]

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

FIG. 1 is a vertical sectional front view of an embodiment of the present invention, and FIG. 2 is an enlarged sectional view taken along the line II--II of FIG. 1. In the present invention, as shown in FIG. A circular permanent magnet 5 having an N pole on the outer peripheral side and a ring-shaped permanent magnet 6 having an S pole on the inner peripheral side are concentrically mounted on the yoke 4 as shown in FIG. The permanent magnets 5 and 6 are fixed to each other so that a strong magnetic field is generated.

A conductor 7 wound in a circular coil shape is arranged between the permanent magnets 5 and 6, and the conductor 7 is the permanent magnets 5 and 6.
It crosses the magnetic field between them.

The conductor 7 is adapted to be energized as will be described later. The upper portion of the coiled conductive wire 7 is attached to the lower surface of the supported object 3 such as a mechanical device via a mounting plate 8 as shown in FIG. The coil-shaped conductor 7 can receive the load of the supported object 3,
It has a strength structure integrally solidified with a non-magnetic material.

FIG. 3 is a vertical sectional front view showing an embodiment in which the polarities of the permanent magnets 5 and 6 are opposite to those of FIG. 1, and FIGS. 4 and 5 show two yokes 4 having an upward U-shape. And the permanent magnets 5 and 6 are respectively fixed to the inside of the upper part of the shape, and the conducting wire 7 wound in a rectangular coil shape is arranged so as to cross the magnetic field between the permanent magnets 5 and 6. FIG. 2 is a view and a cross-sectional plan view thereof, showing a conductor 7
Is attached to the lower surface of a supported object such as a mechanical device (not shown) via a mounting plate 8.

As shown in FIG. 1, an elastic body 9 such as a soft anti-vibration rubber or a spring is attached between the upper surface of the gantry 1 and the lower surface of the supported object 3, and the gantry 1 has an accelerometer. 1
0, a displacement gauge 11 is attached, and a rod for detection 12 is attached to the supported object 3 so that the relative speed and relative displacement generated between the gantry 1 and the supported object 3 can be detected.

FIG. 6 is a wiring diagram of an embodiment of a circuit for energizing the above-mentioned conducting wire 7, in which a self-weight cancel command 13 of a size corresponding to the self-weight of the supported object 3 measured in advance is a control element. It is constantly input to the control circuit 14, and the control element 14 controls the output voltage of the power amplifier 15 according to this command to energize the conducting wire 7.

The conducting wire 7 wound into a coil by this energization receives an upward force from the magnetic field between the permanent magnets 5 and 6, and the upward force is exactly the same as the weight of the supported object 3. The electric wire 7 that crosses the magnetic field supports the entire weight of the supported object 3, and the elastic body 9 is not loaded with the own weight of the supported object 3 at all.

As described above, since the elastic body 9 does not bear the weight of the supported object 3 at all, it is possible to use a soft elastic body as the elastic body 9.

Therefore, since the weight of the supported object 3 does not act on the elastic body 9, only the dynamic spring characteristic is borne, and the soft elasticity thereof causes a low frequency vibration in the vertical direction with a frequency of about 10 Hz or less. Can be absorbed to prevent the vibration of the supported object 3.

When a relative speed or relative displacement occurs between the gantry 1 and the supported object 3 due to vibration or the like, the accelerometer 1
0, the displacement meter 11 detects them and inputs them to the elements 16 and 17, and the elements 16 and 17 respectively add the relative velocity corresponding instruction 18 and the relative displacement corresponding instruction 19 to the control element 14,
The power amplifier 15 receives a command from the control element 14 so as to generate a force that cancels the generated relative speed and relative displacement.
Is controlled to increase or decrease the current value to.

As a result, an optimum damping force can be given to the relative speed and relative displacement generated between the gantry 1 and the supported object 3.

[0020]

The inventions of claims 1 and 2 have the effect of absorbing the vertical low-frequency vibration generated in the supported object and preventing the vibration of the supported object.

Further, the invention of claim 2 has an effect that an optimum damping force can be applied to the relative speed and relative displacement generated between the gantry and the supported object.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is a vertical cross-sectional front view showing a main part of another embodiment of the present invention.

FIG. 4 is a vertical sectional front view showing a main part of still another embodiment of the present invention.

5 is a cross-sectional plan view of FIG.

FIG. 6 is a wiring diagram of an embodiment of the invention of claim 2;

FIG. 7 is a front view showing an example of a conventional vibration damping device.

[Explanation of symbols]

 1 cradle 3 supported object 5 permanent magnet 6 permanent magnet 7 conducting wire 9 elastic body 14 control element 16 element 17 element

Claims (2)

[Claims] 1. A permanent magnet fixed on a pedestal, an object to be supported above the permanent magnet, an object to be supported below the object to be supported, which is disposed across the magnetic field of the permanent magnet and which is energized by an electric current. A low-frequency vibration damping device comprising: a conductor wire that receives a force in a directional direction to support the weight of the supported object; and an elastic body that is attached between the gantry and the supported object. 2. A control element for controlling a value of a current flowing through a conductor according to the weight of a supported object, and a current controlled by the control element by detecting a relative speed and a relative displacement between a pedestal and the supported object. The low frequency vibration isolation device according to claim 1, further comprising: an element that changes a value.