JP4625951B2 - Electrostatic actuator - Google Patents

Description

  The present invention relates to an electrostatic actuator that can efficiently convert electrostatic attraction to mechanical work.

As shown in FIG. 19, the conventional electrostatic actuator has a structure in which an electrode plate is supported by an elastic member such as a spring. The electrostatic attractive force Fe is represented by ε ₀ sV ² / 2d ² . FIG. 19 is a schematic view showing the generated force of the parallel plate electrostatic microactuator. The electrostatic attractive force has a characteristic of increasing rapidly as the electrode interval decreases. Therefore, conventionally, there is a problem that the initial generated force is weak and a sufficient work amount cannot be taken out actually while having a potential capable of converting electrostatic attraction into work. This is because there is no mechanism for effectively extracting the electrostatic attractive force to the outside, and the elastic support simply ends up wasting energy against the electrostatic attractive force.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to use an elastic body such as a spring not only as a support but also as a member that accumulates mechanical energy. To provide a small electrostatic actuator that can convert an attractive force into an elastic force and then work, can efficiently convert an electrostatic attractive force into a mechanical work, and can generate a large force and work. is there.

According to a first aspect of the present invention, there is provided an electrostatic actuator , wherein a first electrode and a second electrode , at least one of which is a movable electrode, generate a electrostatic attractive force between a pair of electrodes arranged at a predetermined interval. A voltage applying means for attracting both electrodes to each other; a non-linear spring for accumulating an electrostatic attractive force as an elastic force; and a movable spring when the movable electrode is attracted. When the strain of the nonlinear spring is released, but when the strain is released, when the voltage is applied between the output part moving between the release of the strain and the movable electrode and the output part Is an electrostatic actuator comprising a braking means for controlling braking for moving the output unit and the movable electrode together when the connection between the movable electrode and the output unit is released and the voltage is released .

An electrostatic actuator according to a second aspect of the present invention is the actuator according to the first aspect, further comprising a braking unit that prevents the output unit from returning after the output unit has moved.

  According to the electrostatic actuator according to the present invention, work can be performed after the electrostatic attraction is converted into an elastic force. Therefore, the electrostatic attraction can be efficiently converted into mechanical work, and a large force and work are generated. It can be made small. That is, in FIG. 1, the work amount W1 that can be achieved only by the electrostatic actuator is indicated by a region W1. On the other hand, the work amount in the case of using conversion from electrostatic attraction to elastic force in the electrostatic actuator according to the present invention becomes the region W2 and the region W3 according to the distance between electrostatic attraction. That is, the amount of work; W2 / W1 = 4.16, and W3 / W1 = 6.5 times, and it is possible to work larger than the electrostatic attraction alone. Further, the generated force can be 25 times and 156 times, respectively.

Hereinafter, an electrostatic actuator according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 2 is a schematic view showing the electrostatic actuator of the first embodiment according to the present invention. FIG. 3 is a partially exploded view of the electrostatic actuator of FIG. In the figure, an electrostatic actuator 10 includes a rectangular movable electrode 12, a fixed electrode 14 having the same rectangular shape and the same area as the movable electrode, arranged at a predetermined interval facing the movable electrode, And the non-linear spring 16 provided at each corner of the four fixed electrodes, and the output unit driven by releasing the non-linear spring force 18.

  The movable electrode 12 is attached to four electric plungers 22 provided on the upper surface 21 of the frame body 20. The electric plunger 22 moves the movable electrode up and down. The fixed electrode 14 is fixed to the lower surface 23 of the frame body at a position facing the movable electrode 12. Each nonlinear spring 16 is disposed between a fixed electrode disposed opposite to the movable electrode, one end of the nonlinear spring is fixed to the lower surface of the frame body, and the other end is disposed on the movable electrode. It is in contact. A non-linear leaf spring is used as the non-linear spring, but the non-linear leaf spring can be realized by a deformed shape, a change in plate thickness, a change in spring width, a combination of a plurality of springs, etc. so that the spring constant changes in proportion to the load. . For example, a progressive spring that increases the spring constant by reducing the effective span is used as the nonlinear spring.

  The output unit 18 is provided so as to be movable in the vertical direction by inserting substantially the centers of the movable electrode and the fixed electrode. The movement of the output unit is controlled by a ratchet electrode 24 disposed on the movable electrode and a return preventing electrode 26 disposed on the lower surface 23. In this figure, the ratchet electrode 24 is fixed to the movable electrode 12 and plays a role when the movable electrode 12 moves upward with the output portion by opening the nonlinear spring. The return prevention electrode 26 is fixedly provided on the lower surface 23 of the frame body and is mechanically connected to the output unit 18 to prevent the output unit from moving downward by opening the ratchet electrode 24 (voltage OFF). To play a role.

  When a voltage is applied to the movable electrode and the fixed electrode, an electrostatic attractive force is generated between the movable electrode and the fixed electrode. The electrostatic attractive force depends on the distance between the movable electrode and the fixed electrode. The movable electrode moves to the fixed electrode due to the electrostatic attractive force generated between the movable electrode and the fixed electrode, but the work at this time is converted into the elastic force of the nonlinear spring. The output unit moves upward by the elastic force generated by opening the converted nonlinear spring.

  Hereinafter, the operation of the output unit will be described in detail with reference to FIGS.

Step 1, voltage application; the movable electrode and the fixed electrode are turned off, the ratchet electrode is turned off, and the return prevention electrode is turned on (FIG. 4).
Step 2, voltage application; the movable electrode and the fixed electrode are turned on. The movable electrode moves downward toward the fixed electrode (FIG. 5). Thus, the movable electrode moves downward toward the fixed electrode and reaches the fixed electrode. The electrostatic attraction changes depending on the change of the moving distance, that is, the distance between the electrodes. The electrostatic attractive force exerts a compressing force on the nonlinear spring, so that the nonlinear spring accumulates an elastic force. At this time, the ratchet electrode is OFF and the return prevention electrode is ON.

  Step 3, the ratchet electrode is turned ON, and the ratchet electrode is fixed to the output portion. Thereafter, the return electrode, the movable electrode, and the fixed electrode are turned off. The elastic force accumulated in the nonlinear spring force is released, and the movable electrode starts to move upward. As the movable electrode moves upward, the output unit moves upward (FIG. 6). Then, the movable electrode reaches the upper surface of the frame. The return prevention electrode is turned on to prevent the output unit from returning downward (FIG. 7).

FIG. 8 is a schematic view showing an electrostatic actuator according to a second embodiment of the present invention.
In the figure, the difference between the electrostatic actuator of the second embodiment and the electrostatic actuator of the first embodiment is that the movable electrode is replaced with the fixed electrode, that is, the first movable electrode and the second movable electrode are opposed to each other. It is that it has been arranged.

In the drawing, the electrostatic actuator 30 includes an upper movable electrode 12 and a lower movable electrode 32 disposed at a predetermined interval so as to face the upper movable electrode. A non-linear spring 16 that converts and accumulates work due to electrostatic attraction generated according to the distance between the upper movable electrode 12 and the lower movable electrode 32 into an elastic force, and an output unit 18 that is driven by releasing the non-linear spring force; Is provided. The non-linear spring is disposed between the lower movable electrode and the lower movable electrode disposed to face the upper movable electrode.
The upper movable electrode 12 is pushed downward by the electric plunger 22 provided on the upper surface 21 of the frame body 20. The upper movable electrode 12 includes a movable electrode bar extending vertically.

  The output unit 18 is inserted into substantially the center of the lower surface 23 and extends downward to be provided on the lower movable electrode. The upper movable electrode 12 and the lower movable electrode 32 are integrated on the lower movable electrode side, and move upward by releasing the elastic force of the nonlinear spring. At this time, when the ratchet electrode is turned off, the output unit 18 moves upward following the upward movement of both electrodes. The ratchet electrode 24 is fixed to the lower surface of the frame and controls the movement of the output unit.

The operation of the output unit will be described in detail below with reference to FIGS.
Step 1 (Start), the voltage application; and OFF the upper movable electrode and lower portions movable electrode, the ratchet electrodes to ON.
Step 2, voltage application; the upper movable electrode and the lower movable electrode are turned ON. The upper movable electrode moves toward the lower movable electrode (FIG. 9), and the upper electrode adheres to the lower movable electrode and stops (FIG. 10). The upper movable electrode moves toward the lower movable electrode, thereby generating an electrostatic attractive force depending on the distance between the electrodes. The nonlinear spring is compressed by the electrostatic attractive force, and the nonlinear spring accumulates an elastic force.

  Step 3, voltage application: The upper movable electrode and the lower movable electrode are maintained in the ON state, and the ratchet electrode is turned OFF. Thus, the elastic force accumulated in the non-linear spring force is released, and the upper movable electrode and the lower movable electrode are integrated to start moving upward (FIG. 11). As the movable electrodes move upward, the output unit moves upward. These movable electrodes reach the upper surface of the frame.

FIG. 12 is a schematic view showing an electrostatic actuator of a third embodiment according to the present invention.
In the figure, the difference between the electrostatic actuators of the first embodiment and the second embodiment is that each member is arranged on a flat plate 55, and the electrostatic force depends on the distance between the fixed electrode and the movable member. The elastic means for accumulating as an elastic force consists of the non-linear spring 43 and the non-linear leaf spring 44 of the movable member. In addition, you may comprise a movable member with a linear spring. That is, the electrostatic actuator 40 includes a fixed electrode 14 and a movable member 42 disposed to face the fixed electrode 14. Work due to electrostatic attraction generated between the fixed electrode 14 and the movable member 42 is converted and accumulated as an elastic force in the nonlinear spring 43 and the nonlinear leaf spring 44 constituting the movable member. Furthermore, the movable member 42 is integrally provided with a ratchet electrode 46 for controlling the movement of the output unit. The adjustment of the distance between the movable member 42 and the fixed electrode 14 is performed by the movement of the piezoelectric actuator 48 for adjusting the distance. A return prevention electrode 26 is provided to prevent the movement of the output unit 18 from returning.

Hereinafter, the operation of the output unit will be described in detail with reference to FIGS.
Step 1 (start), voltage application; the movable electrode and the fixed electrode are turned off, the ratchet electrode is turned off, and the return prevention electrode is turned on.
Step 2, voltage application; when a voltage is applied between the movable electrode and the fixed electrode, the movable member 42 moves toward the fixed electrode. The movable electrode moves toward the fixed electrode (FIG. 13), and the movable member adheres to the fixed electrode and stops (FIG. 14). Thus, when the movable member moves toward the fixed electrode, an electrostatic attractive force is generated depending on the distance between the electrodes. As the electrostatic attractive force compresses the nonlinear spring and the nonlinear leaf spring, the nonlinear spring accumulates an elastic force.

Step 3, voltage application; the ratchet electrode of the movable member is turned on, the return preventing electrode is turned off, the movable member is fixed to the output portion, and the elastic force accumulated in the nonlinear spring force is released, so that the output member is Starts moving to the left of (Fig. 15). Then, with all of the elastic force released, the return prevention electrode is turned on and the movement of the output unit is completely stopped (FIG. 16).
17 and 18 are schematic views showing nonlinear and linear structures of other movable electrodes in the electrostatic actuator, respectively. In FIG. 17, the electrostatic actuator includes a fixed electrode 14 disposed on a flat plate 55 with a predetermined interval below the movable electrode 42, and has a structure for converting changes in electrostatic attraction and electrode interval into nonlinear displacement. Have. That is, the movable electrode 42 is a function of the leaf spring 50 and the distance. It has a non-linear spring-loaded guide portion 52 having a curve, and converts the downward displacement of the movable electrode into a non-linear lateral or longitudinal displacement.

  In FIG. 18, the electrostatic actuator has a structure for converting a change in electrostatic attraction force and electrode spacing into a linear displacement. In FIG. 18, the electrostatic actuator includes a fixed electrode 14 disposed below the movable electrode 42 with a predetermined interval, and has a structure for converting a change in electrostatic attraction and electrode interval into a linear displacement. That is, the movable electrode 42 has a leaf spring 50 and a linear spring pushing guide portion 54, here, an inclined surface having a predetermined angle, and converts the downward displacement of the movable electrode into a linear lateral displacement. .

  Since the movable electrode can be manufactured parallel to the substrate, it is easier to manufacture an electrode having a larger area than the vertical electrode. Therefore, it is easy to generate a large electrostatic attraction. In addition, a wedge effect is added, so that the force generated by the actuator can be increased and the spring can be deformed to a large elastic force. In FIG. 17 and FIG. 18, a slide type guide that can move the movable electrode up and down may be used instead of the leaf spring.

  It can be used for electrostatic actuators, nano electrostatic actuators, and near-field electrostatic actuators that are practical, energy-saving, energy-saving, small, and have a low environmental impact. The electrostatic actuator can be used for medical and information equipment.

It is the schematic which shows the generated force of the electrostatic actuator which concerns on this invention. It is the schematic which shows the electrostatic actuator of 1st Example which concerns on this invention. FIG. 3 is a partially exploded view of the electrostatic actuator of FIG. 2. FIG. 3 is an operation diagram of an output unit of the electrostatic actuator of FIG. 2, and is a schematic diagram when a movable electrode and a fixed electrode are turned off, a ratchet electrode is turned off, and a return prevention electrode is turned on. FIG. 3 is an operation diagram of an output unit of the electrostatic actuator of FIG. 2, and is a schematic diagram in a case where a movable electrode is moved downward toward a fixed electrode. 2 is an operation diagram of the output portion of the electrostatic actuator, and is a schematic view when the energy accumulated in the nonlinear spring force is released and the movable electrode starts to move upward. 2 is an operation diagram of the output portion of the electrostatic actuator, is a schematic diagram when the movable electrode reaches the upper surface of the frame. It is the schematic which shows the electrostatic actuator of 2nd Example which concerns on this invention. It is the schematic for demonstrating operation | movement of the output part of the electrostatic actuator of FIG. It is explanatory drawing for demonstrating operation | movement of the output part of the electrostatic actuator of FIG. 8, and explaining that an upper electrode adheres to a lower movable electrode, and stops. FIG. 9 is an explanatory diagram illustrating the operation of the output unit of the electrostatic actuator of FIG. 8, in which the upper movable electrode and the lower movable electrode are integrated and start moving upward. It is the schematic which shows the electrostatic actuator of 3rd Example which concerns on this invention. FIG. 13 is an explanatory diagram illustrating the operation of the output unit of the electrostatic actuator of FIG. It is explanatory drawing when the operation | movement of the output part of the electrostatic actuator of FIG. 12 is shown, and a movable member adheres to a fixed movable electrode and stops. FIG. 13 is an explanatory diagram illustrating the operation of the output unit of the electrostatic actuator of FIG. 12, in which the movable member is fixed to the output unit to release the energy accumulated in the nonlinear spring force. It is explanatory drawing of the state which showed operation | movement of the output part of the electrostatic actuator of FIG. 12, and all the elastic energy was released. It is the schematic which shows the nonlinear structure of the movable electrode in the electrostatic actuator of FIG. It is the schematic which shows the linear structure of the movable electrode in the electrostatic actuator of FIG. It is the schematic which shows the conventional parallel plate type electrostatic microactuator.

Explanation of symbols

10, 30, 40 Electrostatic actuator 12, 32, 42 Movable electrode 14 Fixed electrode 16, 43 Non-linear spring 18 Output 20 Frame body 22 Electric plunger 24, 46 Ratchet electrode 26 Return prevention electrode 44, 50 Leaf spring 48 Piezo actuator 52 Nonlinear shaped spring pushing guide part 54 Linear shaped spring pushing guide part 55 Flat plate

Claims (2)

A first electrode and a second electrode, at least one of which is a movable electrode, have a pair of electrodes arranged at a predetermined interval, and a voltage for generating an electrostatic attractive force between the electrodes and pulling both electrodes toward each other An application means and a non-linear spring for accumulating electrostatic attraction as an elastic force due to the two electrodes being attracted and a non-linear spring that does not move accompanying the movable electrode when it is attracted, When the strain of the output is released, the output unit that moves together with the release of the strain is interposed between the movable electrode and the output unit. When a voltage is applied between the electrodes, the output unit moves between the movable electrode and the output unit. An electrostatic actuator comprising a braking means for controlling braking for moving the output unit and the movable electrode together when the connection is released and the voltage is released. 2. The electrostatic actuator according to claim 1, further comprising braking means for preventing the output portion from returning after moving.

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