JPH01135938A - Viscosity variable fluid sealed device - Google Patents

Abstract

PURPOSE:To accurately control a workload to the outside as determined by an object by providing a temperature sensor measuring the temperature of electric rheological fluid in a main fluid chamber and a control unit controlling this fluid to optimum viscosity. CONSTITUTION:Electric rheology fluid, which changes its viscosity in accordance with applied voltage, is sealed in a liquid-tight space part 22. A change of viscosity between the first and second electrode plates 26, 30 changes damping force of vibration input between the first and second frame units 14, 18. The second frame unit 18 provides in its side wall a temperature sensor 52 which measures a temperature of the electric rheology fluid in a main fluid chamber 38. A control signal from a control unit 50 is output to the first and second electrodes 26, 30. Thus tuning the viscosity always to an optimum value, a workload to the outside can be adequately controlled as determined by the initial object.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention controls the amount of work to be applied to the outside by enclosing an electrorheological fluid whose viscosity changes according to an applied voltage and using the viscosity variable function of the electrorheological fluid. The present invention relates to a variable viscosity fluid enclosing device.

BACKGROUND ART As a variable viscosity fluid enclosing device of this type, a variable viscosity fluid enclosing type vibration isolator disclosed, for example, in Japanese Patent Application Laid-Open No. 60-104828 is known. By changing the fluid viscosity of
The flow conditions within the orifice are changed to allow adjustment of the percussion frequency range, ie, control of the amount of work to the outside.

Therefore, in 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, thereby significantly simplifying the configuration.

Problems to be Solved by the Invention However, in conventional variable viscosity fluid-filled vibration isolators, the applied voltage corresponding to the frequency range of the vibration to be damped is determined in advance through experiments, etc. The viscosity of the fluid is controlled along.

However, the viscosity of the sealed electrorheological fluid changes depending on the fluid temperature, so even if an attempt is made to tune the fluid viscosity in the orifice to the optimal state with the applied voltage determined above, the tuning will be disrupted due to the viscosity change due to temperature. This has caused the problem that optimal vibration damping cannot be achieved.

Therefore, the present invention takes into consideration the viscosity change due to temperature of the enclosed electrorheological fluid and precisely controls the fluid viscosity within the orifice, thereby making it possible to accurately control the amount of work to the outside as desired. The object of the present invention is to provide a variable viscosity fluid enclosing device.

Means for Solving the Problems In order to achieve the above object, the present invention, as shown in FIG. (2), (b
) In the viscosity variable fluid enclosing device (c), which controls the amount of work to the outside by utilizing the viscosity variable function of the electrorheological fluid existing between The viscosity detection means (d) to detect and the electrode plates (a), (
b) a voltage output means (e) for outputting a voltage to be applied to the electrode plate (a), based on the detected viscosity;
(b) Voltage determining means (f) for determining an applied voltage for controlling the fluid between them to a preset optimum viscosity.

The variable viscosity fluid enclosing device (c) of the present invention has the above-described structure.
In this case, the viscosity value due to temperature change of the electrorheological fluid detected by the viscosity detection means (d) is determined by the voltage determination means (d).
f) is manually determined to determine the optimum control voltage in consideration of the viscosity value.

By applying this determined voltage to the electrode plates (a) and (b) via the voltage output means (e), the fluid viscosity between the electrode plates (a) and (b) is accurately tuned. can do.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 shows a vibration isolator lO (hereinafter referred to as vibration isolator) filled with a variable viscosity fluid as a variable viscosity fluid enclosure device showing an embodiment of the present invention, and when the vibration isolator 10 is used as an engine mount. An example is given below.

That is, the vibration isolator 10 has bolts 1 on the side of a power unit (not shown) that is a combination of an engine, a transmission, etc.
A first frame body 14 is attached to the vehicle body side (not shown) through bolts 16, and a second frame body 14 in the shape of a cylinder with a bottom is attached to the vehicle body side (not shown) through bolts 16.
a frame 18, the outer periphery of the first frame 14 and the second frame 18
A cap-shaped rubber insulator 20 is fixed in a liquid-tight manner between the inner periphery of the upper end opening.

Then, the second
The inside of the frame 14 is a liquid-tight space 22, and the liquid-tight space 22
An electrorheological fluid whose viscosity changes depending on the applied voltage is sealed inside.

On the other hand, in the liquid-tight space 22, a first electrode plate 26 is attached to the extending portion of the bolt 12 of the first frame 14 via an electrical insulator 24, and a first electrode plate 26 is attached to the bottom of the second frame 18. A second electrode plate 30 is attached to the electric insulator 28 via the electric insulator 28 .

1st ft above! The electrode plate 26 and the second electrode plate 30 are arranged to face each other in the vibration input direction between the first and second frames 14 and 18, and are arranged opposite to each other in the vibration input direction between the first and second frames 14 and 18. annular projections 26a, 26b and 30a, 30b concentrically protruding from the second electrode plate 26.30, respectively;
30c are fitted with each other at appropriate intervals.

And the above 1. By applying a voltage between the second and second picture electrode plates 26 and 30, the viscosity of the electrorheological fluid between these picture electrode plates 26 and 30 is changed, and the viscosity of the electrorheological fluid between the two picture electrode plates 26 and 30 is changed. Second
The resistance to relative displacement forces between the frames 14, 18 is varied.

In other words, the above 1. The viscosity change between the second electrode plates 26 and 30 is the same as that between the first and second electrode plates 26 and 30. It acts to change the damping force of vibrations input between the second frames 14 and 18.

It should be noted that there is a first. Second frame 14.18
A rubber body 34 is provided to prevent excessive vibrational displacement between the two.

By the way, the first electrode plate 26 and the second electrode plate 30 are connected to a voltage source 44 as voltage output means via harnesses 42 and 42a, and the voltage output from the voltage source is the first. The configuration is such that the voltage is applied to the second electrode plate 26.30.

From the voltage source 44, the first. The voltage output to the second electrode plate 26.30 is applied to the first vibration sensor 46 on the power unit side.
It is controlled by the control unit 50 based on each vertical acceleration signal detected by the second vibration sensor 48 on the vehicle body side.

That is, in the control unit 5o, the first.
The detection signals of the second vibration sensors 46 and 4B are respectively input, and the first . When the signs of the relative velocity and relative displacement between the second frame bodies 14 and 18 match, the damping is set to low, and when they do not match, the damping is set to the high damping until the time when the damping force due to the viscosity change becomes the same as the spring force of the rubber insulator 20. Furthermore, during the time from that time until the signs match again, a control signal is output to the voltage source 44 to continuously change the damping force from high attenuation to low attenuation.

Therefore, the control voltage from the voltage source 44 in accordance with the control signal in the control unit 50 is transmitted to the first . It is output to the second electrode plate 26.30.

Here, in this embodiment, the main fluid chamber 38 is provided on the side wall of the second frame 18.
A temperature sensor 52 for measuring the temperature (T) of the electrorheological fluid inside is provided, and a detection signal from the temperature sensor 52 is input to the control unit 5o.

By the way, since the viscosity of the electrical fluid changes in response to temperature, the temperature sensor 52 is used as a viscosity detection means.

As shown in FIG. 3, the control unit 50 includes a target viscosity setting circuit 54. A temperature-to-voltage mating circuit 56 and a voltage application timing control circuit 58 are provided as voltage determining means.

The target viscosity setting circuit 54 is connected to the first viscosity setting circuit 54. The detection signals from the second vibration sensors 46 and 48 are input, and the optimal viscosity (target viscosity) (η) of the fluid between the first and second electrode plates 26, 30 is determined using a map or the like stored in advance.

The temperature-viscosity-voltage mapping circuit 56 has a map 60 as shown in FIG. 4 stored in advance, and inputs the output signal of the target viscosity setting circuit 54 and the detection signal of the temperature sensor 52, Determine the voltage (E).

The voltage application timing control circuit 58 inputs the voltage signal determined by the temperature-viscosity-voltage map circuit 56 and outputs the voltage signal from the voltage source 44 to the first voltage application timing control circuit 58 of the vibration isolator lO. Second electrode plate 26
．． ON/OFF timing of the output voltage (
duty ratio).

The vibration isolator lO of this embodiment having the above configuration has the first and second parts.
The vibration input between the frames 14 and 18 is transmitted to the first. Although it is effectively damped with a change in fluid viscosity between the second electrode plates 26 and 30, if the vibration isolator IO is replaced with the one-degree-of-freedom model shown in FIG. 5, the vibration input (F) is F=F
c+PR...represented as ■. In addition, Pc is a damping force, and FR is a spring force.

Figure 6 shows the phase relationship of the three forces (P, FC, PR) in the above equation 0, and as can be understood from the figure, Fc
The region where FII and FII are in phase (hatched area in the figure) and the region where FII is out of phase (
(Other than the shaded area in the figure) exists.

Therefore, in order to reduce the input (F) (dampen the vibration), use FR or F. All you have to do is control it.

That is, by decreasing Pc when Fc and PR are in phase, and increasing Pc when FR and Fc are in opposite phases, the displacement transmission characteristics shown in FIG. 7 can be obtained, and for example, engine shake The reduction equation can be made large in the frequency region.

However, the viscosity of the electrorheological fluid sealed within the vibration isolator 10 has characteristics as shown in FIG. 8 depending on the voltage and temperature.

In particular, when the temperature is low, the initial viscosity is high when no voltage is applied, and the achieved viscosity is low when a voltage is applied, while as the temperature rises, the initial viscosity is low and the achieved viscosity is high.゛For this reason, when the applied voltage is kept constant, the viscosity of the fluid being controlled varies depending on the temperature.
As shown in the characteristics (a) and (b) of FIG. 7, a difference occurs in the displacement transmissibility, and as described in the prior art, stable characteristics cannot be obtained.

Therefore, in this embodiment, the vibration isolator l is controlled by the temperature sensor 52.
The temperature (T) of the electrorheological fluid sealed in O is measured in real time, and the applied voltage (
EQT), and the voltage application timing control unit 58 applies a control voltage that is time-controlled in accordance with the voltage to the voltage source 44.
By outputting from the 1st degree to the second electrode plate 26.30, the optimum 1st degree. The fluid viscosity between the second electrode plates 26,30 can be obtained.

Therefore, the vibration damping region of the vibration isolator 10 can be tuned with high precision to the frequency region of the vibration to be damped, and the vibration damping effect is significantly improved.

FIG. 9 shows a flowchart for executing a program for controlling the viscosity of the fluid in the orifice 36 of the vibration isolator IO. First, in step I, the vertical acceleration of the vibration input to the vibration isolator IO is determined, and In step (2), the temperature (T) of the electrorheological fluid is detected.

Then, in the next step ■, the target viscosity (ηn) is determined based on the input vibration, and in step ■, the voltage (E, T) is determined from the temperature (Tn) and the target viscosity (η.).
seek.

In the next step (2), voltage application timing (duty ratio) is determined based on the voltages (E, , T), and step (2) follows the first step. Second electrode plate 26.30
Outputs control voltage to.

Although this embodiment discloses a means for detecting the viscosity of the encapsulated electrorheological fluid by detecting the temperature of the encapsulated electrorheological fluid, the present invention is not limited to this. Alternatively, the voltage may be controlled based on the difference between the target viscosity and the target viscosity.

In addition, in this embodiment, a variable viscosity fluid filled vibration isolator 1 used for an engine mount is used as a variable viscosity fluid filled device.
Although the present invention is not limited to this, the present invention can also be applied to a device that utilizes the viscosity variable function of an electrorheological fluid by applying a voltage, such as a shock absorber using an electrorheological fluid as a damping medium. Needless to say, it can be applied.

As described in the detailed description of the invention, in the variable viscosity fluid sealed device of the present invention, the voltage applied to the electrorheological fluid in the orifice is adjusted in consideration of the viscosity of the sealed electrorheological fluid that changes with temperature. As a result, the fluid viscosity between the electrode plates is always tuned to the optimal value without being affected by temperature, making it possible to accurately control the amount of work to the outside as originally intended. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the concept of the present invention, FIG. 2 is a sectional view showing an embodiment of the present invention, and FIG. 3 is a schematic configuration diagram showing an embodiment of the viscosity control section of the present invention. Figure 4 is a temperature-voltage diagram used in an embodiment of the present invention, Figure 5 is a model diagram showing the vibration isolator structure of the present invention in one degree of freedom, and Figure 6 is a vibration isolator diagram. Figure 7 is a characteristic diagram showing the phase relationship of spring force, damping force, and vibration input; Figure 7 is a displacement transmission characteristic diagram of a vibration isolator; Figure 8 is a viscosity characteristic diagram of an electrorheological fluid; 3 is a flowchart illustrating an example of processing of a control program performed by the user. lO...Viscosity variable fluid filled vibration isolator (viscosity variable fluid filled device), 20...Rubber insulator, 26...
Second electrode plate, 30... First electrode plate, 34... Rubber body, 36... Orifice, 38... Main fluid chamber, 40...
...Auxiliary fluid chamber, 44...Voltage source (voltage output means), 5
0... Control unit, 52... Temperature sensor (viscosity detection means), 56... Temperature change-viscosity-voltage circuit (voltage determining means). Figure 9

Claims (1)

[Claims] (1) Enclose an electrorheological fluid whose viscosity changes according to the applied voltage, and use the viscosity variable function of the electrorheological fluid that exists between the electrode plates to which the control voltage is applied to reduce the amount of work to the outside. A variable viscosity fluid encapsulation device to be controlled, comprising: viscosity detection means for detecting temperature-changed viscosity of the encapsulated electrorheological fluid; voltage output means for outputting a voltage to be applied to the electrode plate; and voltage determining means for determining an applied voltage for controlling the fluid between the pair of electrode plates to a preset optimum viscosity.