JPH0310816B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a vibration isolating device using magnetic fluid.

As is well known, when a magnetic field is applied to a magnetic fluid, its apparent specific gravity changes, and it has been considered to utilize this property in vibration isolating devices. Conventional vibration isolators of this type contain a magnetic fluid inside a cylinder mechanism, and an electromagnetic coil is provided at an orifice in the cylinder to apply a magnetic field to the magnetic fluid passing through the orifice, thereby reducing the specific gravity. The damping force is changed by changing the .
Therefore, conventional devices of this type are large and difficult to make thin, and additional elastic members such as coil springs and rubber are required to provide elasticity in addition to damping force. The drawbacks were that it became more difficult to make it thinner and the structure became more complicated.

The present invention was made based on the above circumstances, and its purpose is not only to be able to arbitrarily change the damping force, but also to make the device thinner and simpler in structure, and to provide elasticity. The object of the present invention is to provide a vibration isolating device that can exhibit high damping properties.

That is, the gist of the present invention is to provide a cylinder containing a magnetic fluid, an electromagnetic coil that applies a magnetic field to the magnetic fluid, a movable body movably provided in the cylinder, and an outer peripheral portion of which is locked to the cylinder. In addition, a first disc spring whose inner peripheral part is locked to the movable body and forms a first magnetic fluid storage chamber in the inner part thereof, and an outer peripheral part which is provided at a position opposite to sandwich the electromagnetic coil. A second part is locked to the cylinder, an inner peripheral part is locked to the movable body, and a second
a second disc spring forming a magnetic fluid storage chamber; and an orifice provided so that the magnetic fluid flows when the movable body moves relative to the cylinder. It is.

According to the present invention having the above configuration, by changing the current applied to the electromagnetic coil or turning it on and off, the apparent specific gravity of the magnetic fluid passing through the orifice can be changed, and the damping force accompanying this can be changed. It can be changed arbitrarily. Moreover, since elastic force can be applied to the movable body by the repulsive elasticity of the disc spring, a vibration isolating device having both damping properties and elasticity can be obtained. In addition to the fact that the disc spring itself is thin, it is also possible to use this disc spring as a part of the casing that constitutes the magnetic fluid storage chamber. This is effective and can also contribute to the simplification of the structure.

A first embodiment of the present invention will be described below with reference to FIG. In the figure, reference numeral 1 denotes a cylinder having a short cylindrical shape, and a movable body 2 having a substantially cylindrical shape is provided in the cylinder 1 so as to be movable in the axial direction thereof. Further, a coil case 3 is provided between the movable body 2 and the cylinder 1 so as to surround the movable body 2 in an annular shape, and an electromagnetic coil 4 is disposed in the coil case 3 in an annular shape. is wrapped in. 4a and 4b are conducting wires for power feeding.

A first magnetic fluid storage chamber 5 is formed on the upper side in the drawing, and a second magnetic fluid storage chamber 6 is formed on the lower side in the drawing, with the coil case 3 as a boundary. Both storage chambers 5 and 6 can communicate with each other via an orifice 7 formed between the coil case 3 and the movable body 2 or an orifice 8 formed inside the movable body 2. . The orifice 7 may be formed using the tolerance between the outer diameter of the movable body 2 and the inner diameter of the coil case 3. Further, only one of the orifices 7 and 8 may be provided.

Disc springs 10 and 11 are provided on the upper and lower surfaces of the coil case 3, respectively. Each disc spring 10, 11 has its outer circumferential portion locked to the cylinder 1 using retaining rings 12, 13,
Further, the inner peripheral portion is locked to the movable body 2 using other retaining rings 14 and 15, so that the movable body 2 is urged upward in the figure by the elastic force of the disc springs 10 and 11. . O-rings 16, 17, 18, 19 are attached to the inner surfaces of each disc spring 10, 11 to ensure liquid tightness.
is provided.

The first plate spring 10 described above is located in a portion surrounded by the first disc spring 10 on the upper side of the figure and the upper wall of the coil case 3.
A magnetic fluid storage chamber 5 is formed therein, and a second magnetic fluid storage chamber 6 is formed in a portion surrounded by the second disc spring 11 and the lower wall of the coil case 3 on the lower side in the figure. These storage chambers 5 and 6 are filled with magnetic fluid 20. Note that 21 and 22 are blind plugs that are screwed in after the magnetic fluid is injected.

The first embodiment configured as described above is used, for example, by connecting the cylinder 1 to the support structure side and the movable body 2 to the supported body side, so that a downward load as shown in the figure acts on the movable body 2. The load applied to the movable body 2 is elastically supported by the repulsive force of the disc springs 10 and 11. When the movable body 2 moves up and down relative to the cylinder 1 due to external vibrations, etc., the volume ratio of the first magnetic fluid storage chamber 5 and the second magnetic fluid storage chamber 6 changes depending on the position of the movable body 2. Then, an amount of magnetic fluid corresponding to the change flows through the orifice 7 or 8. As a result, a damping force is exerted, and a vibration damping effect can be obtained.

If you want to change the damping force, you can change the current value flowing through the electromagnetic coil 4, or turn on the current.
If the magnetic field is controlled by turning it off, the specific gravity of the magnetic fluid flowing through the orifices 7 and 8 changes, and the damping force can be changed in accordance with changes in flow resistance and the like.

According to the above embodiment, the disc springs 10, 11
is used to elastically support the load of the movable body 2, and disc springs can be formed much thinner than coil springs, and each disc spring 10, 11
Since it also functions as a part of the casing constituting the walls of the magnetic fluid storage chambers 5 and 6, it is extremely effective in reducing the thickness of the device (the height of the device in the drawing).

Note that FIG. 2 shows a second embodiment of the present invention, and in this case, the first embodiment is different from the first embodiment in that a plurality of (for example, four) electromagnetic coils 4 are arranged at equal intervals in the circumferential direction of the movable body 2. Although the second embodiment is different from the first embodiment, other basic structures are the same as those of the first embodiment, and the same functions and effects are exhibited, so common parts are given the same reference numerals and explanations thereof will be omitted.

In this second embodiment, the anti-vibration rubber 25, 2
The cylinder 1 is fixed to a support structure 28 by bolts 27 via bolts 6. The vibration isolating rubbers 25 and 26 absorb relatively high frequency vibrations, and by combining these vibration isolating rubbers 25 and 26 with the vibration isolating device having the above structure, it is possible to absorb both low and high frequency vibrations. vibration can also be effectively suppressed.

Although the embodiments are configured as described above, in carrying out the present invention, specific aspects such as the shapes and structures of the cylinder, electromagnetic coil, movable body, disc spring, orifice, etc. may be modified without departing from the gist of the present invention. It goes without saying that the method can be modified and implemented in various ways.

As described above, according to the present invention, not only can the damping force be changed arbitrarily, but also the device can be constructed compactly, and moreover, an excellent vibration isolating device that has both elasticity and damping properties can be provided. Can be provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a vibration isolator according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a second embodiment of the present invention. 1... Cylinder, 2... Movable body, 4... Electromagnetic coil, 5, 6... Magnetic fluid storage chamber, 7, 8... Orifice, 10, 11... Belleville spring, 20... Magnetic fluid.

Claims (1)

[Claims] 1 A cylinder containing a magnetic fluid, an electromagnetic coil that applies a magnetic field to the magnetic fluid, a movable body that is movable in the axial direction of the cylinder, an outer peripheral part of which is locked to the cylinder, and an inner peripheral part of which is locked to the cylinder. a first disc spring that is engaged with the movable body to form a first magnetic fluid storage chamber in the inner portion of the cylinder; and a first disc spring that is provided at a position opposite to the electromagnetic coil and whose outer peripheral portion is attached to the cylinder. a second disc spring that locks and locks its inner peripheral portion to the movable body to form a second magnetic fluid storage chamber in the inner portion of the cylinder;
A vibration isolator comprising an orifice connecting the magnetic fluid storage chamber and the second magnetic fluid storage chamber, through which the magnetic fluid flows when the movable body moves in the axial direction of the cylinder. .