JP3180242B2 - Electrostatic linear actuator and driving method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic linear actuator that generates a thrust force by electrostatic force.

[0002]

2. Description of the Related Art Conventionally, a large number of fixed electrodes are formed on a surface of a fixed electric insulating plate at predetermined intervals in a predetermined direction.
An inductive charging in which a plate-shaped or film-shaped movable dielectric is placed on the fixed electric insulating plate, and a surface of the movable dielectric on the side opposite to the fixed electric insulating plate is coated with a resistor layer having a predetermined electric resistivity. An electrostatic linear actuator of the type has been proposed.

[0003] This electrostatic linear actuator operates based on an operation principle similar to an electromagnetic induction motor. When a traveling electric field is formed by applying, for example, a three-phase AC voltage to each fixed electrode, the traveling electric field causes Electric charges are induced on the surface of the movable dielectric on the side of the fixed electric insulating plate, and the driving force in the direction of the traveling electric field acts on the movable dielectric due to the attraction and repulsion of the charges of the fixed electrode and the induced charges of the movable dielectric.

The induced charge q induced in the movable dielectric is such that the gap between the fixed electric insulating plate and the movable dielectric is regarded as 0, and the fixed electrode is considered to be in contact with the surface of the movable dielectric. When schematically considered, if the voltage between two adjacent fixed electrodes is V, and the capacitance between the fixed electrode and the resistor layer is C, finally,

[0005]

## EQU1 ## q = CV = εSV / 2t Here, ε is the permittivity of the movable dielectric, t is the thickness of the movable dielectric, and S is the area of the fixed electrode. However, the equivalent circuit between two adjacent fixed electrodes is formed by connecting two capacitors C and the resistor R of the resistor layer in series, and when a step-like voltage V is applied between two adjacent fixed electrodes. The response q of the amount q of the induced charge induced on the surface of the movable dielectric is delayed by a value defined by the time constant CR.

This electrostatic linear actuator utilizes the response delay of the induced charge of the movable dielectric, and the surface charge of the movable dielectric responds instantaneously to the traveling electric field, that is, the charge of the fixed electrode. In this case, the movable dielectric adsorbs to the fixed electrode due to the Coulomb force, but due to the response delay described above, charges of the same polarity remain on the surface of the movable dielectric facing the fixed electrode with respect to the polarity of the fixed electrode. And
Thereby, the movable dielectric is repelled from the fixed electrode, and a thrust force is generated in the movable dielectric by the attraction force of the adjacent fixed electrode on the downstream side of the traveling electric field and the repulsive force of the adjacent fixed electrode on the upstream side of the traveling electric field.

The electrostatic linear actuator does not require a magnetic circuit or a coil as compared with a practically used electromagnetic linear solenoid, so that it can be remarkably downsized. This has the advantage that power consumption at the time is small.

[0008]

However, since the above-mentioned conventional electrostatic linear actuator has a flat plate structure or a laminated plate structure in which flat plates are stacked, a small size of, for example, 10 μm or less due to bending of the flat plate and electrostatic force. There is a problem that it is extremely difficult to stably maintain the clearance. Since the Coulomb force is considered to be substantially inversely proportional to the square of the distance, only an output performance of about 1 [N / cm ² ] has been obtained at present. Further, since the gap is maintained by the glass beads, there is also a problem that the movable dielectric and the fixed electric insulating plate which are in sliding contact with the glass beads are greatly worn.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide an electrostatic linear actuator capable of improving the thrust force, reducing the sliding resistance, and reducing the size. It is an issue.

[0010]

According to a first aspect of the present invention, there is provided:
It has a large number of holes formed in the axial direction, and a plurality of electrode plates
Predetermined axially with each other while forming an electrostatic field in each of the holes
Columns arranged at a distance and slidably housed in each of the holes
A large number of movable bars, each of which protrudes from the hole
An operating body fixed to one end of the movable bar, and each of the electrode plates
And an AC power supply for applying an AC voltage for forming a traveling electric field.
The movable bar includes a resistance wire having a predetermined resistivity,
The composition is the same at each part of the surface of the resistance wire and the electrode plate
And a dielectric portion covering all surface portions that can be faced.
An electrostatic linear actuator characterized in that:

A second configuration of the present invention is the same as the first configuration.
In addition, the column body is wound with a thin and long dielectric plate.
And extended in the axial direction on the surface of the dielectric plate.
It has a dielectric spacer consisting of a ridge, and the electrode plate has
The surface of the dielectric plate is substantially separated from each other at a predetermined interval in the axial direction.
Extending in the winding direction, the plurality of holes are provided in the spacer and
And a dielectric plate.

According to a third aspect of the present invention, there is provided the first or second aspect.
Further, a viscous movable bar slidably received in a viscous hole formed in the column body in the axial direction and a viscous voltage controllable are generated between the viscous hole and the viscous movable bar. And a voltage control viscous mechanism for causing the voltage to be controlled. The fourth configuration of the present invention is the first to third configurations .
The structure according to any one of the above, further comprising:
Lubricating oil or silicone oil
It is characterized by.

The fifth configuration of the present invention is characterized in that
In the configuration according to any one of the above, the AC power supply may further include:
Each of the electrode plates divided into the first to fourth groups in order is
As a result, the adjacent first and second electrode plates become high potential.
Ri Zhou third, fourth said collector electrode plate to be adjacent a lower potential
While maintaining the state, the high potential area for the two adjacent electrodes is sequentially
The four-phase driving voltage to be moved in the axial direction is applied to the traveling electric field.
It is characterized by being generated as an AC voltage for use.

A sixth configuration of the present invention is characterized in that, in the fifth configuration, the four-phase driving voltages have phases different from each other by 90 degrees and a duty ratio of approximately 50%. The seventh aspect of the invention, the first to
In the configuration of the sixth embodiment, further, the exchange at the end of the stroke is performed.
It is possible to change the phase of the
It is characterized by.

[0015]

In a first configuration of the operation and effect of the present invention, it was a
For example , a movable bar is slidably inserted into a hole of a columnar body composed of alternately laminated dielectric plates and electrode plates, and the movable bar is driven by applying a polyphase AC voltage to each electrode plate. With this configuration, the movable bar can be linearly driven based on the principle of the inductively charged electrostatic linear actuator described in the section of the related art.

Note that the columnar body of this configuration corresponds to the fixed electric insulating plate, the movable bar of the present invention corresponds to the movable dielectric, and the resistance wire of the present invention corresponds to the resistor layer. This electrostatic linear actuator has the following functions and effects. First, since the electrostatic force acts between the inner peripheral surface of the sliding hole and the outer peripheral surface of the movable bar, it is possible to stably and minutely maintain the gap where the electrostatic force acts without using glass beads. And therefore the Coulomb force can be enhanced. In other words, the induced charge of the dielectric portion of the movable bar and the electrostatic force between the electrode plates surrounding it are formed in the centripetal direction all around the dielectric portion. Unlike the case where the electrostatic force works, the electrostatic forces cancel each other, and thus the gap management becomes easy. That is, since the static force at rest works in the suction direction in the conventional flat plate face-to-face driving method, glass beads are required to secure a gap. However, in the present invention, each radial component of the electrostatic force is canceled out. The minute gap can be maintained very easily and stably, and as a result, a large electrostatic force, that is, a propulsive force can be obtained. That is, since the electrostatic force is substantially inversely proportional to the size of the gap, a large propulsive force can be obtained by reducing the gap. Also,
Although the use of the conventional glass beads has resulted in wear of each part, reduction of the life, and variation in the gap, the present invention does not require the glass beads, so that the life and accurate gap management are realized.

Further, in the conventional flat-plate-to-plane drive system, since the flexure and deformation of the planar movable dielectric are large, it is not easy to secure the rigidity of the movable body. As a result, according to the present invention, the flatness of each movable bar is much smaller than that of the conventional movable bar, and the deflection thereof is small. In addition, since the holes can be provided in the pillar body in the form of lotus root, a large number of holes can be easily formed, and the rigidity of the pillar body can be improved, and the required space for the pillar body can be reduced, thereby miniaturizing the actuator. can do.

That is, the electrostatic linear actuator of the present invention can reduce bending and deformation in a direction perpendicular to the traveling direction. Further, the electrostatic linear actuator of the present invention
According to the conventional technology, it is necessary to form the
The required resistor layer is much more
Can be replaced with multiple small resistance wires
In comparison with this large-area resistor layer, the resistance of each part of the resistance wire
The rate can be easily made uniform. According to the second configuration of the present invention, a dielectric pillar is formed by spirally winding a thin dielectric plate having a large number of electrodes disposed on the surface of the dielectric plate. On the surface of the dielectric plate, a dielectric spacer consisting of a ridge for securing a hole is formed in the axial direction from above or below the electrode, and the hole is formed on the outer side adjacent to a pair of adjacent spacers. And an inner dielectric plate.

Each of the holes accommodates a movable bar having the same structure as that of the first structure, and a thrust is applied to the movable bar by applying an AC voltage for forming a traveling electric field to each electrode. In this way, the multi-hole electrostatic linear actuator of the present invention can be manufactured by a simple process. Hereinafter, in this specification, it referred electrostatic linear actuator of the upper Symbol second configuration as MakiSoshiki electrostatic linear actuator.

[0020] The third configuration of the present invention is the above-mentioned first or second embodiment.
Further, in the configuration of, forming a viscous hole in the column in the axial direction,
A viscous movable bar is inserted into the viscous hole, and a voltage control viscous mechanism for generating a voltage-controllable viscosity is provided between the viscous hole and the viscous movable bar. The voltage control viscous mechanism includes, for example, a liquid crystal material injected between the viscous hole and the viscous movable bar, and electrodes formed on the inner peripheral surface of the viscous hole and the viscous movable bar with the liquid crystal material interposed therebetween. By applying a voltage to these electrodes, the viscosity of the liquid crystal changes. By fixing one end of the viscous movable bar to the operating body, it is possible to control the viscosity of the operating body, that is, the movement resistance characteristics.

In a fourth configuration of the present invention, a hole is formed in a pillar body.
Improved lubricity due to the injection of con oil
In addition, high-voltage driving becomes possible. A fifth configuration of the present invention includes:
In the electrostatic linear actuator having the above configuration, a four-phase drive voltage is applied to each electrode.

In this manner, the driving force can be remarkably improved, as will be described later, as compared with the conventional three-phase driving. The sixth configuration of the present invention further uses a four-phase drive voltage having a phase different from that of the fifth configuration by 90 degrees and a duty ratio of approximately 50%. By doing so, the driving force can be further improved. Note that the above-mentioned approximately 50% means 41% to 59%.

According to a seventh aspect of the present invention, there is provided the above-described first or second aspect.
In the electrostatic linear actuator having the above configuration or the above-described conventional configuration, the phase or frequency of the multiphase clock voltage at the end of the stroke is changed to generate the thrust in the reverse direction.
With this configuration, it is possible to reduce the stop shock at the end of the stroke with a simple configuration, reduce the impact force applied to each part, and improve the durability and the usability.

[0024]

【Example】

(Example 1) (Structure) As an example of the present invention, FIG. 1 shows a principle diagram of a laminated electrostatic linear actuator, and FIG. 2 shows a cross-sectional view taken along line XX of FIG.

This electrostatic linear actuator comprises a dielectric plate 1
1 and an electrode plate 12 are alternately stacked to form a hexagonal columnar column 1. A large number of circular holes 13 are formed in the column 1 in the axial direction. The movable bar 2 is housed so as to be able to advance and retreat. The thickness of each of the dielectric plates 11 is made equal, and the thickness of each of the electrode plates 12 is made equal, so that the electrode plate 12 and the dielectric plate 11 have substantially the same thickness.

The movable bar 2 has a circular rod shape formed by covering a resistance wire 21 made of a rod containing carbon or metal powder having a predetermined resistivity with a dielectric portion 22 made of a dielectric material 1 such as polyimide. I have. Further, in order to reduce the frictional resistance of each movable bar 2, silicone oil is applied to the inside of the circular hole 13. Reference numeral 14 denotes a fixing bar inserted into some of the holes 13.

(Operation) Each electrode plate 12 has an electrode plate 12a,
12b, 12c, and 12d are sequentially stacked, and a voltage V1 is applied to the electrode 12a, a voltage V2 is applied to the electrode 12b, a voltage V3 is applied to the electrode 12c, and a voltage V4 is applied to the electrode 12d. I do. As a result, a traveling electric field is formed in the circular hole 13 and advances to one side or the other side in the axial direction, and each movable bar 2 is driven by the traveling electric field.

FIGS. 3 to 6 show four-phase AC voltages V1 to V4.
Fig. 7 shows a traveling electric field when using (see Fig. 7) and the movement of the movable bar 2 due to it. FIG. 3 shows a stable state in which the voltages V1 and V2 are at a high level and the voltages V3 and V4 are at a low level and do not change. As a result, electric charges are induced in the respective regions a to d of the dielectric part 22 facing the respective electrode plates 12a to 12d. That is, if the capacitance of the gap capacitor formed by the gap d (extremely enlarged in FIGS. 3 to 6) is Cd, and the partial capacitance of each of the regions a to d is C. In this circuit, 0.5 Cd and C are applied between a pair of adjacent electrode plates (for example, 12 a and 12 b).
And the resistance r are equal to the charging circuit connected in series, and this state is stably maintained, so that each of the areas a to d corresponds to the voltage divided by the ratio of the capacitance Cd to the capacitance C. Is induced.

Next, the four-phase AC voltages V1 to V4 (see FIG. 7) change from phase 0 to phase 1, and the voltage V1
Changes to a low level and the voltage V3 changes to a high level (see FIG. 4). In this case, since there is a delay time defined by the time constant between the resistance wire 21 and the equivalent capacitance, the charges in the respective regions a to d of the dielectric portion 22 do not change immediately, as shown in FIG. , Dielectric part 2 of movable bar 2
The radial attractive force between all the induced charges in each of the regions a to d and the electrode plates 12a to 12d radially adjacent (facing) to each other is canceled out.

However, all the induced charges in each of the regions a to d are displaced by one pitch toward the upstream side and the electrode plates 12a to
While being repelled from 2d, it is sucked from the electrode plates 12a to 12d which are shifted by one pitch to the downstream side, whereby the respective regions a to d are directed in the downstream direction (downward in FIGS. 3 to 6).
Propulsion is generated. Next, consider a case in which the four-phase AC voltages V1 to V4 (see FIG. 7) change from phase 1 to phase 2, and the voltage V2 changes to low level and the voltage V4 changes to high level (see FIG. 5).

When the four-phase AC voltages V1 to V4 are changed at a timing corresponding to the above time constant, the phase 2
, The charge in the region a gradually changes to +, and the charge in the region c gradually changes to-. As a result, as shown in FIG. 5, a situation similar to that in the phase 1 occurs, and a propulsive force is generated in the dielectric portion 22. Next, four-phase AC voltages V1 to V4 (FIG. 7)
Changes from phase 2 to phase 3 and the voltage V
Consider a case where 1 changes to a high level and the voltage V3 changes to a low level (see FIG. 6).

Also in this case, the four-phase AC voltages V1 to V4 change at the timing corresponding to the above time constant, similarly to the phase 2, and in the phase 3, the charges in the region b gradually become + and the charges in the region d gradually become-. Shall change. As a result, as shown in FIG. 5, a situation similar to that in the phase 1 occurs, and a propulsive force is generated in the dielectric portion 22. Hereinafter, similarly, a thrust is generated in the dielectric portion 22 by the phase shift.

The following can also be considered.
If the time constant is much longer than the period of the clock voltages V1 to V4, the dielectric portion 22 responds to the four-phase traveling electric field formed by the electrode plates 12a to 12d by the charging and discharging. Rather, it is easier to shift in the traveling direction one after another by the generated propulsion force at the above timing, and as a result, the propulsion force is applied to the movable bar 2. Depending on the setting of the clock frequency, the above two principles of generating the propulsion force can be considered. In any case, the propulsion force is applied to the movable bar 2 in the direction of the traveling electric field.

FIG. 8 shows an example of a circuit for generating the clock voltages V1 to V4. If two two-stage shift registers are used, the four-phase clock voltage shown in FIG. 7 can be easily generated. The driving principle will be further described. The moving speed of the movable bar 2 is particularly slow in the early stage of the start, as compared with the CR time constant (for example, C = 10 ^-11 farad, R = 10 ⁷ ohms) which is usually obtained. In this situation, a thrust (forward force) is generated as shown in the drawing for a short period after the traveling electric field is shifted by one electrode pitch from a stable state (for example, see FIG. 3).
Thereafter, since the CR time constant is small, the state immediately becomes stable, and thereafter, a state occurs in which thrust does not occur until the next traveling electric field shifts by one electrode pitch again. Therefore, it is preferable to apply a clock voltage having a frequency whose cycle is slightly shorter than the CR time constant.

(Effects of the present embodiment) In this way, the advantages of the small and lightweight electrostatic linear actuator can be further improved, and the movable bar 2 is less twisted or bent, and a smooth thrust can be generated. The use of glass beads can also be omitted. Furthermore, movable bar 2
Is almost uniform and axially symmetric,
Even if suction force is generated at the time of polarity switching, the gap acts as a centripetal force as a whole, so that the gap is always kept uniform.

Further, in this embodiment, since each electrode plate 12 is driven by a four-phase clock voltage, as shown in FIGS. 3 to 6, each of the dielectric portions 22 of the movable bar 2 has an attractive force and a repulsive force. Works, the propulsive force of the movable bar 2 is 3
The number is significantly increased as compared with the phase drive. (Embodiment 2) Next, a muscle fiber type unit (hereinafter referred to as a variable viscosity viscoelastic unit) comprising a linear actuator having the same characteristics as the muscle using the electrostatic linear actuator of the embodiment 1 is shown in FIG. Fig. 1 shows the dynamic model.
0 is shown.

(Structure) The column 1 composed of the dielectric plate 11 and the electrode plate 12 is accommodated in a case 41 having both ends opened.
One end is closed by a bottom plate 43 having an air flow hole 42. The outer end of each movable bar 2 is fixed to a plate (operating body in the present invention) 5, and the plate 5 is connected to the case 41 through a weak spring 6 and to the head 8 through a strong spring 7.

On the other hand, a cylindrical electrode 91 is fitted into an axial through hole 13a formed in the axis of the column 1 and the cylindrical electrode 91
, A tube-shaped electrode 92 is inserted to be axially displaceable. A cylindrical sealing member 93 made of rubber is fitted in the shaft center through hole with the cylindrical electrode 91 interposed therebetween, and the electrode 92 slidably penetrates the sealing member 93. The outer end of the tubular electrode 92 is fixed to the plate 6. An insulating film 94 made of resin electrically insulates the cylindrical electrode 91 from the electrode plate 12.

The opening of the electrode 92 is closed by a stopper 95, and an electrorheological fluid such as a liquid crystal is sealed in the inside. The gap between the electrode 92 and the cylindrical electrode 91 is about 0.1
mm, and the electrorheological fluid is injected while being sealed by the seal member 93. A small hole (not shown) is opened in the outer peripheral surface of the electrode 92, and an electrorheological fluid is supplied from the inside of the electrode 92 in response to leakage of the electrorheological fluid in the gap.

Each of the electrodes 92 is a highly conductive working body 5,
The cylindrical electrode 9 is grounded to a ground electrode (not shown) connected to the case 91 through the spring 6 and the case 41.
1 is supplied with a control voltage V5 from a controller (AC power supply in the present invention) 10. (Operation) Since the viscosity of the electrorheological fluid is controlled by controlling the voltage applied between the electrodes 91 and 92, the unit in FIG. 9 becomes a viscoelastic linear actuator with variable viscosity as shown in FIG.

FIG. 11 shows a structure in which seven viscous variable viscoelastic units (muscle fiber units) shown in FIG. 9 are stacked in a honeycomb shape. The case 41 has a hexagonal column shape, and thus can be easily connected in a honeycomb shape. However, the rear end of each unit is fixed by supporting each bottom plate 43 on a disk-shaped fixing member 96, and the front end of each unit is fixed by fitting the case 41 into a hole of a perforated disk (not shown). ing. The head 80
Are fixed to the biasing ends of the springs 7 of the respective units.

As described above, a necessary propulsion force can be generated by combining a plurality of the variable viscosity viscoelastic units. When no external force acts on the head 8, the movable bar 2 of the variable viscosity viscoelastic unit shown in FIG. 9 protrudes leftward in FIG. 9 by the action of the spring 6 when it is not driven, and the clock voltages V1 to V4 are applied. Moves the movable bar 2 in the direction in which the movable bar 2 is accommodated in the column 1, but it is naturally possible to drive the movable bar 2 in a direction to protrude from the column 1 by reversing the direction of the traveling electric field. .

Further, the controller 10 may control the driving of each of the variable viscosity viscoelastic units one by one or in groups. By doing so, the elastic force of the elastic elements of the springs 6 and 7 is always constant, so that only the propulsive force and the viscosity are variably controlled, and a linear actuator having a constant elastic force can be configured. In addition, the thrust can be arbitrarily controlled by applying a common clock voltage V1 to V4 to each of the viscosity variable viscoelastic units and controlling the frequency and voltage of the clock voltages V1 to V4. .

(Function and Effect) The linear actuator configured as described above has the viscoelasticity capable of controlling the viscosity and the thrust as described above, and has a compact structure despite having extremely similar characteristics to muscles. be able to. (Embodiment 3) (Structure) As another example of the present invention, a wound-type electrostatic linear actuator will be described with reference to FIGS. FIG.
Fig. 13 shows a part of a cross section of the wound electrostatic linear actuator cut in the radial direction, and Fig. 13 shows a cross section taken along line AA (circumferential section).

This wound type electrostatic linear actuator has a columnar structure in which a dielectric and flexible dielectric plate 110 having a strip-shaped electrode plate 120 disposed on both sides is wound a predetermined number of times around a cylindrical column (not shown). It has a body 100. In this embodiment, the dielectric plate 110 is made of a polyimide film having a predetermined thickness (for example, 1 mm), and the electrode plate 120 is formed to have accurate dimensions by etching a copper plate attached to both surfaces of the dielectric plate 110.

As shown in FIG. 13, each electrode plate 120 is disposed in a strip shape at a predetermined interval in the axial direction, and each electrode plate 120 is connected to each phase voltage output terminal of a controller (not shown). ing. In addition, each electrode plate 1
After 20 are disposed on both surfaces of the dielectric plate 110, a resin layer 130 is applied thereon. The resin layer 130 is applied, dipped,
It is formed by a method such as spraying, but it is preferable that after the resin film is attached, the resin film is softened by heating and fixed to the surface of each electrode plate 12 and the dielectric plate 110. Thereby, good electrical insulation between the electrode plates 120 is ensured.

On one surface of the resin layer 130, the dielectric plate 1
Before the above winding of 10, an electrically insulating spacer 140 is attached. The spacers 140 extend in the axial direction at regular intervals in the circumferential direction. The spacer 140 can be accurately patterned by photolithography, and the spacer 140 and the electrode plate 120 can be formed by a printing method. Thus, after winding of the dielectric plate 110, the spacers 14 adjacent in the circumferential direction are
A number of axially extending slots 150 are formed between 0 and 140.

Each slot 150 has the first embodiment.
A movable bar 200 similar to the above is accommodated so as to be axially displaceable. However, the movable bar 200 of this embodiment is the same as that of the first embodiment.
Has a cross-sectional shape different from that of the movable bar 2. That is, the resistance plate of the movable bar 200 is formed by covering a strip-shaped resistance plate 210 having a predetermined resistivity with the dielectric portion 220 made of a resin layer. Of course, also in the present embodiment, lubricating oil, silicon oil, or the like can be sealed in each slot 150. These oils reduce frictional resistance and wear and increase the capacitance of the gap to achieve improved output.

(Operation) With this configuration,
When a predetermined phase clock voltage is applied to each electrode plate 120 to form a traveling electric field, the movable bar 200 is propelled in the traveling direction of the traveling electric field. (Effects) In this way, in addition to the same advantages as in the first embodiment, the column 100 can be formed only by winding the dielectric plate 110 around a column (not shown) a predetermined number of times, and the manufacturing process is simplified. There is an effect that there is. In addition, floating (parallel) irrespective of thrust generation as compared with the stacked type of the first embodiment.
The capacitance can be reduced, and the driving power can be reduced.

In each of the above embodiments, at the end of the forward travel or the backward travel, a traveling electric field is generated in each electrode in a direction opposite to the traveling electric field, or a DC voltage is applied to each of the electrode plates 12 and 120. can do. This allows
An effect similar to compression of a spring or an effect similar to viscous resistance can be obtained. With this configuration, the movable body (including the movable bar) can be stopped smoothly, so that a linear actuator that performs a soft movement with less shock can be configured.

For example, when a DC voltage is applied to each electrode plate 12, a static attraction force acts between the movable bar 2 and the electrode plate 12, and the movement of the movable bar 2 is suppressed. Further, when an AC voltage for forming a backward traveling electric field is applied to each electrode plate 12, the movement of the movable body can be further suppressed. (Embodiment 4) In the present embodiment, the phase of the multiphase clock voltage is changed at the end of a stroke to generate a thrust in the reverse direction.

In this embodiment, the magnitude of the load is known in advance, and therefore, assuming that the generated thrust is constant, it is possible to predict the stroke end time from the multiphase clock voltage application start time. Therefore, a predetermined time (preferably 80 strokes) from the start of multiphase clock voltage application.
%), The phase of some of the multiphase clock voltages is inverted to generate a traveling electric field in the opposite direction.

In this way, it is possible to reduce the stop shock at the end of the stroke, reduce the impact force applied to each part, and improve the durability and the usability. The time delay from the start of the application of the multi-phase clock voltage may be performed by using a normal timer. The phase of the multi-phase clock voltage is switched by, for example, exchanging a pair of phase voltages whose phases are different from each other by 180 degrees. The illustration is omitted.

Note that this soft stop method can be used even at the end of the retreat stroke of the actuator. In this case, after the predetermined time has elapsed from the start of retreat, the forward switching thrust is generated by the phase switching. Good. In the above-described embodiment, the phase switching using the timer has been described. However, a groove is formed in the end of the dielectric portion 22 of the movable bar 2 to be moved, and the electrostatic capacitance is compared with the main portion of the dielectric portion 22. The capacitance is reduced, and a pair of electrode plates 12 for position detection are provided at one end of the fixed electrode group, and a predetermined AC voltage is applied between the electrode plates 12 for position detection and a predetermined resistance. The position of the movable bar 2 can be detected by detecting the voltage drop of the resistor.

That is, when the end of the dielectric portion 22 enters between the electrode plates 12 for position detection, the voltage drop of the resistance becomes relatively small. It can be detected that the multi-phase clock voltage application start position has been reached. Therefore, a desired thrust force can be obtained by detecting the position with such a simple position sensor and controlling the magnitude (or duty ratio) and phase of the multiphase clock voltage.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the principle of an electrostatic linear actuator according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

3 is an axial sectional view of a main part of FIG. 1 showing a state of phase 0 of the electrostatic linear actuator of FIG. 1;

4 is an essential part axial sectional view of FIG. 1 showing a state of phase 1 of the electrostatic linear actuator of FIG. 1;

5 is an axial sectional view of a main part of FIG. 1 showing a state of phase 2 of the electrostatic linear actuator of FIG. 1;

6 is an essential part axial sectional view of FIG. 1 showing a state of phase 3 of the electrostatic linear actuator of FIG. 1;

FIG. 7 is a waveform diagram of clock voltages V1 to V4 applied to the electrostatic linear actuator of FIG.

8 is a block circuit diagram showing an example of a circuit for generating clock voltages V1 to V4 of FIG.

FIG. 9A is an axial sectional view showing a variable viscosity viscoelastic unit using the electrostatic linear actuator of the first embodiment. (B) It is the XX sectional view taken on the line of (a).

FIG. 10 is a mechanical model diagram of the variable viscosity viscoelastic unit of FIG. 9;

11A is a side view showing a synthetic viscosity variable viscoelastic linear actuator formed by combining seven variable viscosity viscoelastic units of FIG. 9; FIG. FIG. 2B is a schematic cross-sectional view taken along line XX of FIG.

FIG. 12 is an axial sectional view of a main part of a wound electrostatic linear actuator according to a third embodiment.

FIG. 13 is a cross-sectional view of the electrostatic linear actuator of FIG. 12 taken along line XX.

[Explanation of symbols]

1 is a column, 2 is a movable bar, 11 is a dielectric plate, 12 is an electrode plate, 10 is an AC power source, 5 is an operating body, 21 is a resistance wire, 22
Is a dielectric portion, 100 is a column, 120 is an electrode plate (electrode),
110 is a dielectric plate, 200 is a movable bar. 210 is a resistance plate (resistance wire), 220 is a dielectric part.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02N 1/00

Claims (7)

(57) [Claims] A plurality of holes formed in an axial direction;
Electrode plates form an electrostatic field in the hole,
Columns arranged at a predetermined distance apart in the axial direction, a number of movable bars slidably housed in the holes , and fixed to one end of each of the movable bars projecting from the holes.
And an AC for applying an AC voltage for forming a traveling electric field to each of the electrode plates.
And a power supply , wherein the movable bar has a resistance wire having a predetermined resistivity, and each part of a surface of the resistance wire.
Surfaces that have the same composition and can face each part of the electrode plate
And a dielectric part covering all the parts.
Electrostatic linear actuator. 2. The column body is formed by winding a thin and long dielectric plate.
And extended in the axial direction on the surface of the dielectric plate.
The electrode plate has a dielectric spacer formed of a ridge, and the electrode plates are spaced apart from each other at a predetermined interval in the axial direction.
The plurality of holes extend substantially in the winding direction on the surface of the electric plate, and the plurality of holes are partitioned by the spacer and the dielectric plate.
The electrostatic linear amplifier according to claim 1, wherein
Kucheta. 3. A viscous movable bar slidably housed in a viscous hole formed in the column in the axial direction, and a voltage controllable viscosity is generated between the viscous hole and the viscous movable bar. claims, characterized in that it comprises a voltage controlled viscous mechanism for
Item 3. The electrostatic linear actuator according to Item 1 or 2 . 4. A lubricating oil or a silicone oil is provided in said hole of said column.
2. A con oil is injected.
4. The electrostatic linear actuator according to any one of items 3 to 3. 5. The AC power supply includes a first to a fourth group in order.
For each of the electrode plates divided into
2 has a high potential, and the third and fourth adjacent
While maintaining the state where the electrode plate is at a low potential, the adjacent 2
Four-phase drive that sequentially moves the high-potential area for the electrodes in the axial direction
A dynamic voltage is generated as the AC voltage for forming the traveling electric field.
The static electricity according to any one of claims 1 to 4, wherein
Method of driving the electric Riniaa Kucheta. 6. The driving method for an electrostatic linear actuator according to claim 5, wherein said four-phase driving voltages have phases different from each other by 90 degrees and a duty ratio of about 50%. 7. The method of claim 1 to the driving method of the electrostatic linear actuator according 6, characterized in that to generate a reverse thrust by changing the phase of the AC voltage at the stroke end.