JP3340234B2 - Electrorheological fluid application equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric viscous fluid damping mount, an electrorheological fluid damper, an electrorheological fluid clutch, an electrorheological fluid shock absorber, an electrorheological fluid tension controller, an electrorheological fluid encapsulating composite material, and the like. The present invention relates to a viscous fluid application device.

[0002]

2. Description of the Related Art An electrorheological fluid is a liquid that undergoes a reversible and instantaneous change in viscosity in response to an electric field when an electric field is applied. Have been. In such an apparatus using an electrorheological fluid, an electrorheological fluid is sealed in a fluid storage space, a relative movement passage of the electrorheological fluid is defined in the liquid sealing space, and an electrode is provided in the relative movement passage. It is common to arrange.

In a device having such a configuration, for example, in the case of a shock absorber or a damper, the viscosity of an electrorheological fluid, that is, the flow resistance in a relative movement passage, can be changed in accordance with the voltage applied to an electrode. Therefore, by adjusting the applied voltage, the vibration damping force of the damper or the like can be appropriately changed according to the transmitted vibration frequency, vibration amplitude, and the like.

[0004]

The electrorheological effect of an electrorheological fluid is generated by an electric field generated by a voltage applied to an electrode. The magnitude (viscosity) of the effect depends on the strength of the electric field between the electrodes, that is, the electric field. It depends on the strength E (unit: V / mm). However, in practice, the electric field strength received at the electrode is not measured, and the voltage applied to the electrode is treated as a substitute value of the electric field strength, and the applied voltage V (unit:
(Volt) to obtain the electrorheological effect.

The electric field strength E is equal to the distance d between the electrodes.
(Unit: mm). That is, E = V / d holds. This means that if the distance between the electrodes changes even if the voltage applied to the electrodes is constant, the electric field strength also changes. In the conventional electrorheological fluid application device, since the applied voltage is not controlled according to the change in the distance d between the electrodes, it is necessary to obtain a stable electrorheological effect, for example, a discharge phenomenon occurs due to the proximity of the electrodes. It was difficult. SUMMARY OF THE INVENTION The present invention has been made as a result of studying to solve such problems of the related art, and an object of the present invention is to provide a device capable of stably maintaining an electrorheological effect.

[0006]

The present invention adopts the following means to achieve the above object. That is, a liquid storage space, an electrorheological fluid sealed in the liquid storage space, a relative movement passage of the electrorheological fluid partitioned in the liquid storage space, a counter electrode provided in the relative movement passage, Wherein the voltage applying means is configured to control an applied voltage based on a value of a current flowing through the electrorheological fluid between the opposed electrodes. An electrorheological fluid application device characterized by:

A voltage setting means for setting a command voltage signal corresponding to the electric field strength between the opposed electrodes; a high voltage power supply for applying a voltage between the opposed electrodes; A current-voltage converting means for converting a current value flowing in the electrorheological fluid into a voltage value, and comparing a command voltage signal set by the command setting unit with a voltage value converted by the current-voltage converting means, An electrorheological fluid application device comprising: a voltage comparison means for determining a control signal of a high-voltage power supply.

[0008] Further, the liquid accommodating space, the relative moving passage of the electrorheological fluid sealed in the liquid accommodating space, and the electrorheological fluid partitioned in the liquid accommodating space, and the interval provided in the relative moving passage vary. In an electrorheological fluid application device including a counter electrode and voltage applying means for applying a voltage to the counter electrode, the voltage applying means applies an applied voltage based on a current value flowing through the electrorheological fluid between the counter electrodes. An electrorheological fluid application device is configured to be controlled.

[0009]

In the electrorheological fluid application device configured as described above, when the device sets the strength of the electric field between the electrodes (electrolysis strength) so as to obtain a desired electrorheological effect, the set value is obtained. The power supply applies a voltage to the electrorheological fluid according to At this time, since the value of the current flowing through the electrorheological fluid corresponds to the actual electrolytic strength between the electrodes, this current value is measured, and the output voltage of the power supply is adjusted based on the measured current value. The adjusting means converts the current signal into a voltage value, compares the value with a voltage value that gives the set electrolytic strength, and converts the current signal into a voltage value, that is, the actual electrolytic strength. Is controlled to make the power equal to the set electrolytic strength. Since the above-described operation is performed, the electrolytic strength between the electrodes can be always maintained at the set electrolytic strength, and a desired electrorheological effect can be obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to specific examples. In this example, a nonaqueous fluid based on carbonaceous powder was used as the electrorheological fluid. FIG.
1 is a schematic sectional view of a shock absorber showing a first embodiment of an electrorheological fluid application device according to the present invention. The cylinder 1 and the piston 2 of the shock absorber 50 have a relatively movable structure. The electrorheological fluid F is filled in the cylinder 1 around the piston 2, and the electrode plate 3 and the electrode plate 4 are disposed to face each other via the electrorheological fluid F. Therefore, when a voltage is applied to the electrode plates 3 and 4, an electric field is generated in the electrorheological fluid F, and an electrorheological effect occurs.

On the other hand, a rubber stopper 5 in the form of a link is arranged on the upper part of the cylinder 1 to prevent the piston 2 from moving in the horizontal direction. Further, the cylinder 1A is fitted to the piston 2A, and the electrodes 3 and 4 do not completely contact each other due to the relative movement up and down.

FIG. 2 is a diagram showing a control device for controlling, for example, the shock absorber shown in FIG. The command setting unit 23 is for setting the strength of an electric field applied so that the buffer 50 has desired characteristics. The command setting unit 23 has a configuration in which this set value can be set continuously or stepwise with a voltage value. have. This set value is unique depending on the type of the electrorheological fluid to be used, the structure of the device using the fluid, and the like. Therefore, when these conditions change, the set value naturally changes.

The high-voltage power supply 20 is a high-voltage power supply for applying an electric field between the electrode plates 3 and 4 arranged in the buffer 50, and the output voltage is determined by a voltage value as a control signal. That is, it is constituted by a circuit for amplifying an input signal of, for example, several volts to about several kilovolts, which is desirable for controlling the viscosity of the electrorheological fluid.

The resistor 24 is provided for converting a current value flowing between the electrodes arranged in the buffer 50 into a voltage value. In this embodiment, the resistor 24 is provided between the high-voltage power supply 20 and the buffer 50. Although the current value flowing between the counter electrodes 3 and 4 of the shock absorber is measured by disposing the damper 24, the current value may be arranged, for example, between the ground-side electrode of the shock absorber 50 and the grounding point.

The voltage measuring section 21 measures the voltage between both ends of the resistor 24. The control signal comparing section 22 measures the value of the current flowing between the electrodes arranged in the shock absorber as a voltage value (actually, the electric field strength). ) Is compared with the voltage signal (the electric field strength that gives the desired viscosity) set by the command setting unit 23 so that the actual electric field strength becomes the set electric field strength. The device to control.

Next, the operation of the control device having the above configuration will be described. FIGS. 5 and 6 show the relationship between the viscosity of the electrorheological fluid used and the applied electric field, and the relationship between the current flowing in the electrorheological fluid and the applied electric field. According to these figures, the viscosity of the electrorheological fluid corresponds to the strength of the applied electric field (electric field strength). Further, there is also a correspondence between the electric field strength of the applied electric field and the current value flowing through the electrorheological fluid. Therefore, the shock absorber can have desired characteristics depending on the value of the current flowing through the electrorheological fluid.

Therefore, when it is desired to provide the buffer 50 with a desired attenuation, it is apparent from FIGS. 5 and 6 that the electric field applied to the electrorheological fluid enclosed in the buffer 50 has a predetermined electric field strength. As described above, by controlling the output voltage of the high-voltage power supply 20 using the current flowing in the electrorheological fluid as a control signal, for example, the electric field applied between the electrodes even when the distance between the electrodes moves in a direction smaller than the initially set interval. Can be made constant.

Specifically, a current value corresponding to the actual electric field strength flowing through the electrorheological fluid enclosed in the shock absorber is converted into a voltage by the resistor 24, and the voltage across the resistor 24 is converted into a voltage value by the voltage measuring unit 21. Measured as And the control signal comparison unit 2
In step 2, the voltage value at both ends of the resistor 24 is compared with a command voltage corresponding to a set electric field strength set so as to obtain a desired viscosity of the electrorheological fluid between the opposed electrodes of the buffer set by the command setting unit. Then, the output control voltage is set so that the voltage across the resistor 24 becomes equal to the command voltage. Then, the output voltage of the high voltage power supply 20 is adjusted by the output control voltage of the control signal comparing section 22.

For example, consider a case where the distance between the electrodes at the time of initial setting is reduced by some external factor. In this case, the value of the current flowing through the electrorheological fluid sealed in the shock absorber is larger than the value of the current flowing during the initial setting. Therefore, the voltage across the resistor 24 is also higher than the voltage at the time of the initial setting. Therefore, the control signal comparison unit 22 performs control to reduce the output voltage of the high-voltage power supply 20 until the voltage between both ends of the resistor 24 becomes equal to the command voltage. Strength and the desired attenuation is obtained. In addition, even when the electrodes approach abnormally, the above control prevents the electric field from becoming abnormally strong, so that discharge between the electrodes does not occur.

Further, even when the electrodes come into contact with each other, the control signal comparing section 22 controls the output voltage of the high-voltage power supply 20 to reduce the output voltage until the applied voltage between the electrodes becomes zero in the process of contacting the electrodes. Therefore, damage to the device can be prevented.

When an electrorheological fluid is applied to a generally known driving fluid clutch or the like, the electrode is designed to have a fixed structure in which the distance between the electrodes does not change. For example, there is a possibility that the contact between the electrodes and the electrode interval may change. Even in such an electrorheological fluid device, the use of the electrorheological application device according to the present invention can prevent electrode discharge and damage to the device.

Further, the current flowing through the electrorheological fluid has a temperature dependency. As shown in FIG. 7, the higher the temperature of the electrorheological fluid, the higher the current value. As the elapsed time of use of the electrorheological fluid device increases, the temperature of the electrorheological fluid increases due to the accumulation of Joule heat. The temperature of the liquid also increases due to a heat source around the electrorheological fluid device. Therefore, in such a case, if the electrorheological fluid application device according to the present invention is used, the applied voltage is changed in accordance with the change in the current corresponding to the change in the liquid temperature, so that the electric field strength is kept constant. In this case, the signal may be fed back to the command setting unit 23 by the signal of the temperature sensor 7.

[0024]

As is evident from the above description, the electrorheological fluid application apparatus of the present invention is always desirable even if the distance between electrode plates to which a voltage is applied or the liquid temperature of the electrorheological fluid changes. An electrorheological effect is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a shock absorber according to an embodiment of the present invention.

FIG. 2 is an electric control circuit showing an embodiment of the present invention.

FIG. 3 is another embodiment having the same function as FIG. 2;

FIG. 4 is a circuit of a conventional electric control.

FIG. 5 is a graph of a change in viscosity of an electrorheological fluid with respect to an electric field.

FIG. 6 is a graph of a change in current with respect to an electric field of an electrorheological fluid.

FIG. 7 is a graph of a change in current with respect to a temperature of an electrorheological fluid.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3, 4 Electrode plate 7 Temperature sensor F Electrorheological fluid 20 High voltage power supply 21 Current-voltage converter (voltage measurement part) 22 Voltage comparator 23 Command setting part 24 Resistance 40 Electrorheological fluid controller 50 Buffer

Claims (4)

(57) [Claims] 1. A liquid storage space, an electrorheological fluid sealed in the liquid storage space, a relative movement passage of the electrorheological fluid partitioned in the liquid storage space, and a counter electrode provided in the relative movement passage. An electrorheological fluid application device comprising: a voltage application means for applying a voltage to the counter electrode; wherein the voltage application means controls an applied voltage based on a current value flowing through the electrorheological fluid between the counter electrodes. An electro-rheological fluid application device, comprising: 2. A command setting unit for setting a command voltage signal corresponding to an electric field intensity between the opposed electrodes, a high voltage power supply for applying a voltage between the opposed electrodes, and Current-voltage converting means for converting a current value flowing through the electrorheological fluid between the opposed electrodes into a voltage value, a command voltage signal set by the command setting unit and a voltage value converted by the current-voltage converting means. And a voltage comparing means for determining a control signal of the high-voltage power supply. 3. A liquid accommodating space, an electrorheological fluid sealed in the liquid accommodating space, a relative moving passage of the electrorheological fluid partitioned in the liquid accommodating space, and a distance provided in the relative moving passage change. An electrorheological fluid application device, comprising: an opposing electrode; and a voltage applying unit that applies a voltage to the opposing electrode, wherein the voltage applying unit is configured to apply an applied voltage based on a current value flowing through the electrorheological fluid between the opposing electrodes. An electrorheological fluid application device configured to control the pressure. 4. A command setting unit for setting a command voltage signal corresponding to an electric field strength between the opposed electrodes, a high voltage power supply for applying a voltage between the opposed electrodes, and Current-voltage converting means for converting a current value flowing through the electrorheological fluid between the opposed electrodes into a voltage value, a command voltage signal set by the command setting unit and a voltage value converted by the current-voltage converting means. And a voltage comparing means for determining a control signal of the high-voltage power supply.