JPH0527721Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention controls the viscosity of the fluid in the orifice provided between the main fluid chamber and the sub-fluid chamber by sealing in a rheological fluid whose viscosity changes depending on the applied voltage. The present invention relates to a vibration isolator filled with a variable viscosity fluid.

Conventional technology This type of variable viscosity fluid-filled vibration isolator is
For example, a method disclosed in Japanese Patent Application Laid-Open No. 104828/1983 is known, in which the flow state in the orifice is changed by sealing an electrorheological fluid and changing the fluid viscosity in the orifice, thereby suppressing vibration. Adjustment in the frequency domain is now possible.

Therefore, in the case of such a variable viscosity fluid-filled vibration isolator, in order to change the fluid viscosity within the orifice, it is sufficient to simply change the voltage applied to the electrorheological fluid within the orifice. Its configuration can be significantly simplified.

Problems to be Solved by the Invention However, in the conventional vibration damping device filled with variable viscosity fluid, the viscosity change in the orifice is generated by applying a voltage to an electrode plate provided in the orifice. ing.

Therefore, when the amplitude or frequency of the vibration to be suppressed by the vibration isolator is large or the frequency is high, the flow rate of the electrorheological fluid passing through the orifice becomes faster, and the electricity inside the orifice from the electrode plate increases. The time during which voltage is applied to the rheological fluid becomes shorter.

However, since the electrorheological fluid requires a certain amount of time to reach the desired viscosity after voltage is applied, increasing the flow rate of the electrorheological fluid between the electrode plates means that It becomes impossible to obtain sufficient fluid viscosity.

For this reason, even if a preset control voltage depending on the vibration is applied to the electrode plate, there is a problem in that it is no longer possible to obtain a vibration damping effect corresponding to the applied voltage.

Therefore, the present invention applies a voltage in advance to the electrorheological fluid in the main fluid chamber or sub-fluid chamber to be introduced into the orifice, so that when the electrorheological fluid is introduced into the orifice, the target It is an object of the present invention to provide a variable viscosity fluid-filled vibration isolator that can significantly shorten the time required to reach the viscosity.

Means for Solving the Problems In order to achieve the above object, the present invention provides a main fluid chamber whose volume is changed by input vibration, and a sub-fluid whose volume is variable and communicated with the main fluid chamber through an orifice. a chamber, and a pair of electrode plates disposed oppositely within the orifice, and an electrorheological fluid whose viscosity changes depending on the applied voltage is sealed in the main fluid chamber and the sub-fluid chamber. In a variable viscosity fluid-filled vibration isolator in which the damping frequency range is adjusted by changing the viscosity of a rheological fluid within the orifice, electricity introduced into the orifice is placed near the outside of the opening of the orifice. It is constructed by providing an auxiliary electrode plate that pre-changes the viscosity of the rheological fluid.

Effect With the above configuration, in the present invention, the electrorheological fluid introduced into the orifice from the main fluid chamber or the auxiliary fluid chamber in response to vibration input is preliminarily changed in viscosity by the auxiliary electrode plate. Ru.

Therefore, when the electrorheological fluid flows into the orifice from the main and auxiliary fluid chambers, the viscosity has been changed to some extent, and in order to obtain the desired viscosity in the orifice, it is necessary to change the viscosity from the pre-changed viscosity. It is sufficient to change the remaining viscosity up to the desired viscosity.

Therefore, the actual range of viscosity change within the orifice becomes smaller, and accordingly, the time required to obtain the desired viscosity after applying a voltage within the orifice is significantly shortened.

Embodiments Hereinafter, the present invention will be described in detail based on embodiments.

FIG. 1 shows a variable viscosity fluid-filled vibration isolator 10 (hereinafter referred to as a vibration isolator) showing an embodiment of the present invention. state

That is, the vibration isolator 10 is a first frame 1 that is attached via bolts 12 to a power unit (not shown) that is a combination of an engine, a transmission, etc.
4, a second frame 18 attached to the vehicle body side (not shown) via bolts 16, and these first and second frames 1
4 and 18 in a liquid-tight manner.

The inside of the hollow portion 20a of the elastic body 20 is separated in the direction in which the first and second frames 14 and 18 face each other by a partition plate 22 having a trapezoidal cross section and fixed to the second frame 18 side. A chamber on the first frame 14 side separated by the partition plate 22 is defined as a main fluid chamber 24.

On the other hand, the end surface of the partition plate 22 on the second frame body 18 side is closed with a diaphragm 26, and these partition plates 22
The chamber between the diaphragm 26 and the diaphragm 26 is a sub-fluid chamber 28. Further, a lid member 18a is fixed to the lowermost end of the second frame 18, and an air chamber 48 is formed between the lid member 18a and the diaphragm 26.

Inside the main fluid chamber 24 and the sub-fluid chamber 28,
An electrorheological fluid whose viscosity changes depending on the applied voltage is sealed, and the main and auxiliary fluid chambers 24, 2
8 are communicated through an orifice 30 formed in the center of the partition plate 22.

The orifice 30 is configured by an inner cylinder 34 closely fitted into an outer cylinder 32 that is fixedly installed by penetrating the partition plate 22. A pair of electrode plates 36, 36
a is attached to the inner cylinder 34 over substantially the entire length thereof.

The inner and outer cylinders 32 and 34 are each made of an insulating member.

The pair of electrode plates 36, 36a are connected to the control circuit 40 via harnesses 38, 38a, respectively.
and is connected to a power source 42.

The control circuit 40 operates in a frequency range of vibrations to be damped by the vibration isolator 10 (damping frequency range).
According to the power source 42, the electrode plates 36, 36a
(for example, time control by ON/OFF).

Therefore, when a control voltage is applied to the pair of electrode plates 36, 36a, the viscosity of the fluid (electrorheological fluid) within the ORPHIS 30 changes in response to the control voltage.

Here, in this embodiment, the end portion of the inner cylinder 34 on the main fluid chamber 24 side and the end portion of the outer cylinder 32 on the side of the auxiliary fluid chamber 28 are each extended in a truss shape. A pair of auxiliary electrode plates 44, 44a and 46, 46a are provided inside the parts 34a, 32a, respectively.
can be installed.

The auxiliary electrode plates 44, 44a and 4
A preliminary voltage is applied to 6 and 46a via a harness not shown.

With the above configuration, in the vibration isolator 10 of this embodiment, when vibration isolation is input between the first and second frames 14 and 18, the volume of the main fluid chamber 24 changes first, and this main fluid As the volume of the chamber 24 changes, the electrorheological fluid is moved to and from the auxiliary fluid chamber 28 via the orifice 30, and at this time, the electrorheological fluid is vibrated as a liquid column within the orifice 30.

At this time, the electrode plate 36 in the orifice 30,
By applying a control voltage corresponding to the input vibration (vibration to be controlled) outputted from the control circuit 40 to 36a, the electrorheological fluid in the orifice 30 corresponds to the frequency of the vibration to be suppressed. The viscosity changes.

By the way, in this embodiment, when the electrorheological fluid flows in from the main fluid chamber 24 or the auxiliary fluid chamber 28, it passes through the flap-like extensions 34a and 32a provided at the openings at both ends of the orifice 30.

Therefore, when the electrorheological fluid passes through the tangle-shaped extensions 34a, 32a, a preliminary voltage is applied from the auxiliary electrode plates 44, 44a and 46, 46a provided inside the trumpet-shaped extensions 34a, 32a. The electrorheological fluid is pre-changed in viscosity.

Therefore, the electrorheological fluid whose viscosity has been pre-changed is introduced into the orifice 30, and in order to change the electrorheological fluid to the desired viscosity within the orifice 30, it is necessary to change the viscosity from the pre-changed viscosity to the desired viscosity. What is necessary is to change the remaining viscosity up to the target viscosity.

That is, the electrorheological fluid may e.g.
It has viscosity characteristics as shown in the figure.

This viscosity characteristic is shown with electric field (V/mm) on the horizontal axis and clay (η) on the vertical axis, where the pre-changed viscosity is η ₁ (the time required at this time is T ₁ ), If the desired viscosity is η ₂ (the time required at this time is T ₂ ), the remaining viscosity to change within the orifice 30 is (η ₂ - η ₁ ), and the time required for this viscosity change ( T) becomes (T=T ₂ −T ₁ ).

Therefore, in a conventional vibration isolator in which the viscosity is not pre-changed, a time of T ₂ is required to obtain the desired viscosity, but in this example, the time of (T ₂ - _{T 1} ) is sufficient, and the required time is The time is significantly reduced.

Therefore, even if the flow velocity of the electrorheological fluid in the orifice 30 becomes significantly high when the input vibration has a large amplitude or a high frequency, the electrorheological fluid is not required in the orifice 30. It becomes possible to change the viscosity up to the desired viscosity within a short period of time, and a predetermined liquid column resonance can be reliably generated within the orifice 30.

Therefore, in the vibration isolator 10 of this embodiment, tuning to the vibration damping frequency region can be performed accurately, so that the vibration to be damped can be effectively damped.

In addition, the auxiliary electrode plates 44, 44a and 46, 46
The lapel-shaped extension portions 34a and 32a provided with a
Needless to say, the shape is set so as not to affect the liquid column resonance within the orifice 30.

FIG. 3 shows an anti-vibration pair 10a showing another embodiment, in which the same components as in the previous embodiment are denoted by the same reference numerals, and redundant explanations will be omitted.

That is, the orifice 30 of this embodiment includes two pairs of electrode plates 50, 50a, 50b, and 50c, and a first auxiliary electrode formed in a net shape is provided at the opening of the orifice 30 on the main fluid chamber 24 side. Plate 52,
52a, and at the opening on the side of the sub-fluid chamber 28, as shown in FIG. A second auxiliary electrode plate 56 constituted by a plate 54a is provided.

The first auxiliary electrode plates 52, 52a are each formed into a semi-cylindrical shape as shown in FIG.

Therefore, even in this embodiment, the viscosity of the electrorheological fluid introduced into the orifice 30 can be preliminarily changed by the first auxiliary electrode plates 52, 52a and the second auxiliary electrode plate 56. It is possible to exhibit the same functions as in the embodiment.

Note that even in this embodiment, the first auxiliary electrode plate 52,
52a and the mesh plate 5 of the second auxiliary electrode plate 56
4 is formed into a net shape that facilitates the passage of fluid, so that the liquid column resonance within the orifice 30 causes the first,
The influence of the second auxiliary electrode plate is prevented.

Effects of the Invention As explained above, in the variable viscosity fluid filled vibration isolator of the present invention, an auxiliary electrode plate is provided near the outside of the opening of the orifice in which the electrode plate is provided, and Since the viscosity of the electrorheological fluid in the orifice is preliminarily changed, the time required to impart a predetermined viscosity to the electrorheological fluid in the orifice by the control voltage applied to the electrode plate can be greatly reduced. I can do it.

Therefore, even when the amplitude of the vibration to be damped is large or the frequency is high, the fluid viscosity change within the orifice can be sufficiently followed, and the vibration damping effect can be significantly improved. It has excellent advantages.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, Fig. 2 is a viscosity change characteristic diagram of the electrorheological fluid used in the present invention, and Fig. 3 is a longitudinal cross-sectional view showing another embodiment of the present invention. , FIG. 4 is a plan view showing one embodiment of the auxiliary electrode plate used in the present invention, and FIG. 5 is an enlarged sectional view taken along the line - in FIG. 3. 10, 10a...Viscosity variable fluid-filled vibration isolator,
24...Main fluid chamber, 28...Subfluid chamber, 30...
Orifice, 36, 36a... Electrode plate, 44, 4
4a, 44b, 44a... Auxiliary electrode plate, 50, 5
0a, 50b, 50c...electrode plate, 52, 52a
...first auxiliary electrode plate, 56...second auxiliary electrode plate.

Claims (1)

[Claims for Utility Model Registration] A main fluid chamber whose volume is changed by input vibration;
A sub-main flow chamber that communicates with the main fluid chamber via an orifice and has a variable volume, and a pair of electrode plates that are disposed opposite to each other in the orifice; A variable viscosity fluid-filled vibration isolator in which a damping frequency range is adjusted by enclosing an electrorheological fluid whose viscosity changes according to voltage and changing the viscosity of the electrorheological fluid within the orifice, A variable viscosity fluid-filled vibration isolator, characterized in that an auxiliary electrode plate is provided near the outside of the opening of the orifice to preliminarily change the viscosity of the electrorheological fluid introduced into the orifice.