JPS59183138A - Vibration preventing equipment - Google Patents

Abstract

PURPOSE:To obtain compact structure and freely variable damping force by moving a movable substance in a cylinder against a belleville spring in order to vary the specific gravity of the magnetic fluid by means of electric current in an electromagnetic coil together with guiding magnetic fluid to flow through an orifice. CONSTITUTION:A cylinder 1 in the form of a short tube is connected to a supporting structure side, while a movable substance 2 that is nearly in a cylindrical form is connected to a supported structure side. When downward load is imposed on the movable substance 2, the load is elastically supported by resilient force of belleville springs 10 and 11 which are locked to the inside surface of the cylinder 1 at both upper and lower parts of a coil case 3. When the movable substance 2 is moved up and down by outside exciting vibration, volume ratio between two, or upper and lower, magnetic fluid chambers 5 and 6 varies corresponding to the position of the movable substance 2. And magnetic fluid the flow rate of which is proportional to the variation in the said ratio flows, passing an orifice 7 or 8 that is formed between the movable substance 2 and the coil case 3, thereby producing damping force. By varying amperage in an electromagnetic coil 4, apparent specific gravity of the magnetic fluid passing the orifice can be changed so that the damping force can be changed at will.

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, for example, a magnetic fluid inside a cylinder mechanism, and an electromagnetic coil is provided at an orifice in the cylinder.
By applying a magnetic field to the magnetic fluid passing through the orifice, the specific gravity is changed and the damping force is changed.

Therefore, conventional devices of this type are large and difficult to make thin, and require separate elastic members such as coil springs and rubber to provide elasticity in addition to damping force. The drawbacks were that it was more difficult to formulate and the structure was more complex.

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. An 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. and a disc spring whose inner peripheral portion is locked to the movable body to form a magnetic fluid storage chamber in the inner portion;
The vibration isolating device is characterized by comprising an orifice provided so that a magnetic fluid flows when the movable body moves relative to the sill.

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 accordingly, the damping force can be adjusted arbitrarily. can be changed to Moreover, since elastic force can be applied to the moving 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 substantially cylindrical movable body 2 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 manner, and an electromagnetic coil 4 is disposed within this coil case 3. It is wrapped in a circular ring. 4a and 4b are conducting wires for power feeding.

Then, with the coil case 3 as the boundary, there is a first
A magnetic fluid storage chamber 5 is formed therein, and a second magnetic fluid storage chamber 6 is formed on the lower side in the figure. Both storage chambers 5.6 can communicate with each other via an orifice 7 formed between the coil case 3 and the movable body 2, or an orifice 7 formed inside the movable body 2. ing. Note that the orifice 7 may be formed using a tolerance between the outer diameter of the movable body 2 and the inner diameter of the coil case 3. Only one of the orifices 7 and 8 may be provided.

Discretes 10 and 11 are provided on the upper and lower surfaces of the coil case 3, respectively.

Each disc spring 10.11 has a retaining ring attached to its outer periphery.
2.13 is used to lock the cylinder 1, and the inner peripheral part is locked to the movable body 2 using other retaining rings 14 and 15, and the movable body 2 is held by the elastic force of the disc springs 10 and 11. is biased upward as shown in the figure. And each plate is 1o,
There are O-rings 16 and 17 on the inner side of No. 1 to obtain liquid tightness.
, 18.19 are provided.

The first magnetic fluid storage chamber 5 is formed in a portion surrounded by the upper disk spring 10 and the upper wall of the coil case 3, while the lower disk spring 10 and the coil case 3 are surrounded by the upper wall of the coil case 3.
A second magnetic fluid storage chamber 6 is formed in a portion surrounded by the lower wall. These storage chambers 5.6 are filled with magnetic fluid 20. Note that 21y22 is a blind plug that is 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 value of the current flowing through the electromagnetic coil 4, or control the magnetic field by turning the current on and off, thereby changing the specific gravity of the magnetic fluid flowing through the Oriice 7.8. , damping force can be changed in accordance with fluctuations in flow resistance, etc. According to the above embodiment, the plate spring 1 (hl1) is used to elastically support the load of the movable body 2,
Disc springs can be made much thinner than coil springs, and each disc spring JO, 11 also functions as a part of the casing that constitutes the walls of the magnetic fluid storage chambers 5, 6, so the device This is extremely effective in reducing the thickness (height of the device in the drawing).

FIG. 2 shows a second embodiment of the present invention, and in this case, a plurality of (for example, four) electromagnetic coils 4 are arranged at equal intervals in the circumferential direction of the movable body 2. Although it is different from the first embodiment, the basic structure of the pond is the same as 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 cylinder 1 is fixed to a support structure 28 by means of a delt 27 via anti-vibration rubbers 25 and 26f. 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, both low frequency and high frequency vibrations can be absorbed. can also be effectively suppressed.

Although the embodiment has been constructed as described above, the shapes and structures of sealing rings, electromagnetic coils, movable bodies, countersunks, orifices, etc. may be changed without departing from the gist of the present invention. It goes without saying that the specific form of {difference can be modified and implemented in various ways.

As mentioned above, according to the present invention, not only can the damping force be changed arbitrarily, but also the device can be constructed in a continuous manner, and the force can also be combined with elasticity and damping properties. It can provide an excellent vibration isolator.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a vibration isolator showing a first embodiment of the present invention;
FIG. 2 is a sectional view showing a second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Movable body, 4... Electromagnetic coil, 5.6... Magnetic fluid storage chamber, 7, 8... Orifice, 10.11... Disc plate, 20. ...Magnetic fluid.

Claims (1)

[Claims] 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, an outer circumferential portion of which is engaged with the cylinder, and an inner circumferential portion of which is engaged with the movable body. The invention is characterized by comprising a disc plate that stops and forms a magnetic fluid storage chamber in its inner portion, and an oriice provided so that the magnetic fluid flows when the movable body moves relative to the cylinder. Anti-vibration device.