JP6707018B2 - Electromechanical converter - Google Patents

Description

The present invention relates to electromechanical converters.

There is known an electromechanical converter that uses an electret that semi-permanently holds an electric charge as a charging unit, and performs conversion between electric power and power by electrostatic interaction between the charging unit and a counter electrode facing the charging unit. ing. In such an electromechanical converter, generally, a charging unit is arranged on one of the movable member and the fixed substrate, and a counter electrode is arranged on the other, and the charging unit and the counter electrode are patterned in the moving direction of the movable member.

For example, Patent Document 1 includes an electret, a first counter electrode, and a second counter electrode, and the electret has a first region whose polarization direction along the thickness direction is the first direction and a thickness. And a second region in which the polarization direction along the depth direction is a second direction opposite to the first direction, and the first region and the second region are surfaces orthogonal to the thickness direction. Electrostatic induction type electromechanical devices provided so as to be adjacent to each other along a main surface direction that is a direction parallel to a certain main surface, and the first counter electrode and the second counter electrode are provided on both surfaces of the electret, respectively. A conversion element is described.

In Patent Document 2, a first substrate having an electret film formed thereon, which holds electric charges on the surface and is continuously connected, and a second substrate having a collecting electrode arranged on the surface facing the electret film are disclosed. A minute substrate including a substrate and a movable substrate having conductivity, which is disposed between the first substrate and the second substrate and is movably supported in a predetermined direction with respect to the first substrate and the second substrate. An electromechanical generator is described. In this microelectromechanical generator, the movable substrate has an opening that penetrates from the first substrate side toward the second substrate side and allows the electric field radiated from the electret film to pass, and the movable substrate is movable. As a result, the presence or absence of an electric field radiated from the opening to the collector electrode is generated, and the presence or absence of the electric field excites or discharges charges to the collector electrode to generate power.

JP, 2013-115921, A International Publication No. 2013/088645

In the electromechanical converter in which the charging unit and the counter electrode are patterned in the moving direction of the movable member, the width (pattern width) of each charging unit and the counter electrode also decreases when the size of the movable member is reduced. The driving force (generating force) or electric power generated by electrostatic interaction between the charging unit and the counter electrode sharply decreases as the pattern width decreases, so a small electromechanical converter (movable member). However, there is a problem that sufficient output cannot be obtained.

Therefore, it is an object of the present invention to provide an electromechanical converter whose output does not easily decrease even if the movable member is downsized.

An electromechanical converter for converting between electric power and motive power by utilizing electrostatic interaction between a charging unit and a counter electrode, which is a disc-shaped rotating member rotatable about a rotation axis. The circular region centering on the rotation axis is made of a conductive material, and a rotary member in which a plurality of grooves are formed in the circular region of at least one surface at intervals in the rotation direction, and the rotary member A counter substrate arranged to face one surface, a first charging portion formed in a circular area on the outer peripheral side of a circular area on one surface of the rotating member with a space in the rotation direction, A second charging unit, which is arranged on the opposite side of the counter substrate with the rotating member interposed therebetween and integrally formed so as to cover the entire circular region of the rotating member, faces the annular region and the circular region of the rotating member. Thus, there is provided an electromechanical converter having a plurality of counter electrodes formed on the counter substrate at intervals in the rotation direction.

In the electromechanical converter described above, the circular region on the surface of the rotating member opposite to the counter substrate is a flat surface on which no unevenness is formed, and the second charging unit is opposite to the counter substrate of the rotating member. It is preferably arranged in a circular area on the side surface.

The electromechanical converter further includes a second counter substrate arranged on the side opposite to the counter substrate so as to face the rotating member, and the second charging unit includes the rotating member of the second counter substrate. It is preferably arranged on the surface facing to.

In the above electromechanical converter, it is preferable that the plurality of groove portions of the rotary member are through holes that penetrate the circular region of the rotary member.

In the above electromechanical converter, the circular region on the surface of the rotating member opposite to the counter substrate is a flat surface on which no unevenness is formed, and the second charging section is viewed from the plurality of counter electrodes. And is preferably covered with a rotating member.

The electromechanical converter described above is arranged such that a third charging portion formed at an interval in the rotation direction is formed in an annular region on a surface of the rotating member opposite to the counter substrate, and the third charging unit is opposed to the annular region of the rotating member. Therefore, it is preferable to further include a plurality of other counter electrodes formed on the second counter substrate at intervals in the rotation direction.

In the above electromechanical converter, it is preferable that a plurality of through holes be formed in a portion where the first charging portion is not arranged in the annular region of the rotating member.

According to the above electromechanical converter, even if the movable member is small, the output is less likely to decrease as compared with the case where this configuration is not provided.

It is a schematic block diagram of the electromechanical converter 1. 3 is a perspective view of the actuator 10. FIG. It is a figure which shows the cut surface of the actuator 10 along the IIIA line and the IIIB line of FIG. 6 is a plan view showing an annular region D1 and a circular region D2 of the rotating member 12. FIG. 5 is a schematic configuration diagram of an actuator 100 of Comparative Example 1. FIG. 8 is a schematic configuration diagram of an actuator 100' of Comparative Example 2. FIG. 6 is a graph showing the relationship between the pattern width of the rotating members 120 and 120' and the magnitude of the generated force of the actuators 100 and 100'. It is a schematic block diagram of another actuator 10'. It is a schematic block diagram of another actuator 10A. It is a schematic block diagram of another actuator 10B. It is a schematic block diagram of the electromechanical converter 2.

The electromechanical converter will be described below with reference to the drawings. However, it should be understood that the invention is not limited to the drawings or the embodiments described below.

FIG. 1 is a schematic configuration diagram of an electromechanical converter 1. As shown in FIG. 1, the electromechanical converter 1 has an actuator 10 and a drive unit 20. The actuator 10 has a rotating shaft 11, a rotating member 12, fixed substrates 13 and 14, electret portions 15a, 15b and 16a, and counter electrodes 17, 18, 17' and 18'. In FIG. 1, as the actuator 10, the upper surface 131 of the fixed substrate 13, the lower surface 122 of the rotating member 12, the upper surface 121 of the rotating member 12, and the lower surface 142 of the fixed substrate 14 are shown in order from the bottom of the drawing. The electromechanical converter 1 uses the electrostatic force between the electret parts 15a, 15b, 16a and the counter electrodes 17, 18, 17', 18' based on the electric signal input to the drive part 20. It is a drive device (electret motor) that extracts power from electric power by rotating the rotating member 12.

FIG. 2 is a perspective view of the actuator 10. In FIG. 2, the rotating shaft 11, the lower surface 132 of the fixed substrate 13, the lower surface 122 of the rotating member 12, and the lower surface 142 of the fixed substrate 14 are shown. As shown in FIG. 2, the actuator 10 is configured by laminating a disk-shaped fixed substrate 14, a rotating member 12, and a fixed substrate 13 in this order from the upper side of the drawing. As will be described later, the electret portion 15a is formed on the lower surface 122 of the rotating member 12, but the electret portion 15a is omitted in FIG. 2 for simplicity.

The rotary shaft 11 is a shaft that serves as a rotation center of the rotary member 12, and penetrates through the centers of the rotary member 12 and the fixed substrates 13 and 14, as shown in FIG. 2. The upper and lower ends of the rotary shaft 11 are fixed to the casing of the electromechanical converter 1 (not shown) via bearings.

The rotating member 12 is made of a conductive substrate material such as silicon (Si). As shown in FIG. 2, the rotating member 12 is connected to the rotating shaft 11 at its center and can rotate with a fixed distance from the fixed substrates 13 and 14. The rotating member 12 is driven by the electrostatic force generated between the electret parts 15a, 15b, 16a and the counter electrodes 17, 18, 17', 18' in response to the electric signal input to the driving part 20, so that the rotating member 11 rotates. The circumference is rotated in the direction of arrow C in FIG. 2, which is the circumferential direction (clockwise and counterclockwise). For example, the rotating member 12 has a diameter of about 5 to 20 mm and a thickness of about 100 to 500 μm.

In order to reduce the weight of the rotating member 12, a plurality of substantially trapezoidal through holes 128 (an example of a groove portion) are formed at equal intervals along the circumferential direction and in a radial shape around the rotating shaft 11. Has been done. Each of the through holes 128 extends from the center side near the rotary shaft 11 to the outer peripheral side of the rotary member 12 over substantially the entire radial direction of the rotary member 12. Note that in FIG. 1, the number of the through holes 128 is shown smaller than that in FIG. 2 for simplicity.

The fixed substrate 13 is a flat substrate made of a well-known substrate material such as a glass epoxy substrate. The fixed substrate 13 is an example of a counter substrate, and, as shown in FIG. 2, is disposed below the rotating member 12 so as to face the lower surface 122 (one surface) of the rotating member 12.

The fixed substrate 14 is a flat substrate made of, for example, a glass substrate or a silicon substrate. The fixed substrate 14 is an example of a second counter substrate, and as shown in FIG. 2, is disposed on the upper side of the rotating member 12 so as to face the upper surface 121 of the rotating member 12 on the side opposite to the fixed substrate 13. There is. That is, the fixed substrate 14 is arranged on the opposite side of the fixed substrate 13 with the rotating member 12 interposed therebetween, with a space provided between the fixed substrate 14 and the rotating member 12. Although the rotating shaft 11 penetrates through the centers of the fixed substrates 13 and 14, unlike the rotating member 12, the fixed substrates 13 and 14 are fixed to the casing of the electromechanical converter 1.

3A and 3B are views showing cut surfaces of the actuator 10 taken along line IIIA and line IIIB in FIG. 2, respectively. Further, FIG. 4 is a plan view showing an annular region D1 and a circular region D2 of the rotating member 12. 3(A) and 3(B), the lateral direction of the drawing is transformed so as to correspond to the circumferential direction of the rotating member 12 and the fixed substrates 13 and 14 (direction of arrow C in FIG. 2). There is.

The electret portion 15a is an example of a first charging portion, holds negative charges, for example, and is composed of a plurality of substantially trapezoidal partial regions as shown in FIGS. 1 and 3A. The electret portion 15a is located on the lower surface 122 of the rotating member 12 and in the circumferential direction (rotational direction) on the outer peripheral side of the circle C1 having the radius about 1/2 of the radius of the rotating member 12 as the center. ) Are formed at intervals. As shown in FIG. 4, the portion closer to the center than the circle C1 is the circular area D2 of the rotating member 12, and the portion closer to the outer periphery than the circular area D2 is the annular area D1 of the rotating member 12. The electret portion 15a is formed in a portion other than the through hole 128 in the annular region D1, and in the annular region D1, the electret portions 15a and the through holes 128 are alternately arranged in the circumferential direction of the rotating member 12. .. The electret portion 15a is not arranged in the circular area D2, and the portion other than the through hole 128 in the circular area D2 is the flat portion 127.

The electret portion 15b is an example of a second charging portion, and holds, for example, a negative charge, and as shown in FIGS. 1 and 3B, the lower surface 142 of the fixed substrate 14 (the upper surface 121 of the rotating member 12 and the lower surface). It is formed on the center side of the facing surface). That is, the electret portion 15b is a member different from the rotating member 12 and is located at a position that does not directly face the counter electrodes 17 and 18 in the fixed substrate 14 that is arranged on the opposite side of the fixed substrate 13 with the rotating member 12 interposed therebetween. It is arranged. Further, the electret portion 15b is formed on the fixed substrate 14 so as to completely cover a circular area centered on the rotating shaft 11 and having substantially the same size as the circular area D2 of the rotating member 12. In other words, the electret portion 15b is not divided into a plurality of circumferentially spaced partial regions, but is integrally (solid) formed so as to cover the entire circular region D2 of the rotating member 12. ing.

The electret portion 16a is an example of a third charging portion, holds negative charges, for example, and is composed of a plurality of substantially trapezoidal partial regions as shown in FIGS. 1 and 3A. The electret portions 16a are formed in the annular region D1 on the upper surface 121 (the surface opposite to the fixed substrate 13) of the rotating member 12 at intervals in the circumferential direction. Similar to the electret portion 15a, the electret portion 16a is not arranged in the circular region D2 of the rotating member 12, but is formed in a portion other than the through hole 128 in the annular region D1. Also on the upper surface 121, in the annular region D1, the electret portions 16a and the through holes 128 are alternately arranged in the circumferential direction of the rotating member 12, and in the circular region D2, the portions other than the through holes 128 are flat portions 127. is there.

As shown in FIG. 1, FIG. 3(A) and FIG. 3(B), the counter electrodes 17 and 18 are circumferentially arranged on the upper surface 131 of the fixed substrate 13 (the surface facing the lower surface 122 of the rotating member 12 ). They are formed alternately and radially around the rotation axis 11. The counter electrodes 17 and 18 are each made up of a plurality of trapezoidal electrodes, and these electrodes face the annular region D1 and the circular region D2 of the rotating member 12 from the central side near the rotating shaft 11 to the outer peripheral side. , Extends substantially over the entire radial direction of the fixed substrate 13. Therefore, the counter electrodes 17 and 18 are arranged so as to face both the annular region D1 and the circular region D2 of the rotating member 12. Further, the opposing electrodes 17 and the opposing electrodes 18 are formed at intervals in the rotation direction of the rotating member 12 and are arranged at equal intervals.

As shown in FIGS. 1 and 3A, the counter electrodes 17 ′ and 18 ′ are circumferentially alternated on the outer peripheral side of the lower surface 142 of the fixed substrate 14 (the surface facing the upper surface 121 of the rotating member 12 ). In addition, it is formed radially around the rotation axis 11. The counter electrodes 17' and 18' are also each composed of a plurality of substantially trapezoidal electrodes, and these electrodes are arranged so as to face only the annular region D1 of the rotating member 12. Further, the opposing electrodes 17' and the opposing electrodes 18' are also formed at intervals in the rotation direction of the rotating member 12 and arranged at equal intervals.

The counter electrodes 17, 18, 17′, and 18′ have the same width on the same circumference around the rotation shaft 11, and the sizes thereof are the same as the through holes 128 and the electret portions 15a and 16a of the rotation member 12. The width is preferably the same as or substantially the same as the width. Further, it is preferable that the numbers of the partial regions forming the electret portion 15a, the partial regions forming the electret portion 16a, the counter electrode 17, the counter electrode 18, the counter electrode 17', and the counter electrode 18' are all the same.

The drive unit 20 is a circuit for driving the actuator 10, and has a clock 21 and comparators 22 and 23. When the actuator 10 is driven, the drive unit 20 applies an alternating voltage whose polarities are alternately switched to the counter electrodes 17, 18, 17', 18'. Specifically, the drive unit 20 applies a voltage having the same sign as the charging of the electret portions 15a, 15b, 16a to one of the counter electrodes 17 and 17', and the other of the counter electrodes 18 and 18' to the counter electrode 17. , 17' are applied with voltages of opposite signs to alternately invert the signs of those voltages. The driving unit 20 applies an alternating voltage in this manner to generate an electrostatic force by the interaction between the electric field generated by the electret units 15a, 15b, 16a and the electric field generated by the counter electrodes 17, 18, 17', 18'. , Thereby rotating the rotating member 12.

As shown in FIG. 1, the output of the clock 21 is connected to the inputs of the comparators 22 and 23, the output of the comparator 22 is to the counter electrodes 17 and 17', and the output of the comparator 23 is to the counter electrodes 18 and 18'. , Are respectively connected via electric wiring. The comparators 22 and 23 respectively compare the potential of the input signal from the clock 21 with the ground potential and output the result in binary, but the output signals of the comparators 22 and 23 have opposite signs. When the input signal from the clock 21 is H, the counter electrodes 17 and 17′ have a potential of +V, and the counter electrodes 18 and 18′ have a potential of −V. When the input signal is L, the counter electrodes 17 and 17′ have a potential of −V. , The counter electrodes 18 and 18 ′ have a potential of +V.

In the actuator 10, on the outer peripheral side of the rotating member 12, the set of the electret portion 15a and the counter electrodes 17 and 18 is arranged to face each other on the lower surface 122 side, and the set of the electret portion 16a and the counter electrodes 17' and 18 on the upper surface 121 side. 'Sets are arranged facing each other. The drive unit 20 applies an alternating voltage to the counter electrodes 17, 18, 17 ′, 18 ′, so that on the outer peripheral side of the rotating member 12, between the electret unit 15 a and the counter electrodes 17, 18 and between the electret unit 16 a. Since electrostatic force is continuously generated between the counter electrodes 17' and 18', a circumferential driving force can be obtained.

Further, since the rotating member 12 is made of a conductive member, the electric field generated by the electret portion 15b on the fixed substrate 14 is transmitted to the circular area D2 of the rotating member 12, and the upper surface and the lower surface of the circular area D2 have the same potential. .. Since the concavo-convex pattern of the through holes 128 is formed in the rotating member 12, the distance between the lower surface 122 of the rotating member 12 and the counter electrodes 17 and 18 differs depending on the position in the circumferential direction. As a result, the strength of the electric field acting on the counter electrodes 17 and 18 changes. Therefore, even if the electret portion 15b is arranged on the fixed substrate 14, the same state as that in which the electret is formed in the radial pattern on the lower surface 122 of the rotating member 12 is realized. Therefore, when the driving unit 20 applies an alternating voltage to the counter electrodes 17 and 18, static electricity is continuously generated between the flat portion 127 of the rotary member 12 and the counter electrodes 17 and 18 even on the center side of the rotary member 12. Since a force is generated, a circumferential driving force is obtained.

In order to generate the electrostatic force on the center side of the rotating member 12, the circular region D2 of the rotating member 12 may be made of a conductive material. Therefore, the materials of the annular region D1 and the circular region D2 of the rotating member 12 may be different from each other, and in that case, the material of the annular region D1 is not necessarily conductive. The circular region D2 may be made of a metal material, or may be formed by processing an insulator into a shape having a flat portion 127 and a through hole 128 and covering the entire surface with a conductive member.

FIG. 5A and FIG. 5B are schematic configuration diagrams of the actuator 100 of Comparative Example 1. The actuator 100 has a rotating shaft 110, a rotating member 120, fixed substrates 130 and 140, electret portions 150 and 160, and counter electrodes 170 and 180. Like the actuator 10, the actuator 100 is configured such that a disc-shaped rotating member 120 is sandwiched between two fixed substrates 130 and 140. The rotating member 120 is rotatable about a rotating shaft 110 (corresponding to the rotating shaft 11 in FIG. 2) passing through the center thereof. FIG. 5A shows the upper surface 131 of the fixed substrate 130, the lower surface 122 of the rotating member 120, the upper surface 121 of the rotating member 120, and the lower surface 142 of the fixed substrate 140 side by side in order from the bottom of the drawing. FIG. 5B shows a cut surface when the rotary member 120 and the fixed substrates 130 and 140 above and below the rotary member 120 are cut along the circumferential direction.

As shown in FIGS. 5(A) and 5(B), the rotating member 120 has an electret portion 160 on the upper surface and an electret portion 150 on the lower surface, which are arranged at equal intervals in the circumferential direction and center around the rotating shaft 110. Are arranged radially. Unlike the electret portions 15a and 16a of the actuator 10, the electret portions 150 and 160 extend from the center side near the rotating shaft 110 to the outer peripheral side over substantially the entire radial direction of the rotating member 120. In addition, in the rotating member 120, in order to reduce the weight, a plurality of substantially trapezoidal through holes (slits) 128 are formed at equal intervals along the circumferential direction in a portion where the electret portions 150 and 160 are not formed. Has been formed.

In the actuator 100, the counter electrodes 170 and 180 are alternately formed in the circumferential direction on both of the fixed substrates 130 and 140 arranged above and below the rotating member 120 in a radial pattern with the rotating shaft 110 as the center. . The counter electrodes 170 and 180 also extend over the entire radial direction of the fixed substrates 130 and 140 from the center side near the rotating shaft 110 to the outer peripheral side. Therefore, in the actuator 100, the set of the electret section 150 and the counter electrodes 170 and 180 faces the lower surface side of the rotating member 120, and the set of the electret section 160 and the counter electrodes 170 and 180 faces the upper surface side of the rotating member 120, respectively. Are arranged. That is, the actuator 100 of Comparative Example 1 has the same configuration as the outer peripheral side of the actuator 10.

FIGS. 6A and 6B are schematic configuration diagrams of an actuator 100 ′ of Comparative Example 2. The actuator 100 ′ has a rotating shaft 110, a rotating member 120 ′, fixed substrates 130 and 140 ′, an electret part 150 ′, and counter electrodes 170 and 180. FIG. 6A shows the upper surface 131 of the fixed substrate 130, the lower surface 122 of the rotating member 120', the upper surface 121 of the rotating member 120', and the lower surface 142 of the fixed substrate 140' in order from the bottom of the drawing. FIG. 6B shows a cut surface when the rotary member 120' and the fixed substrates 130 and 140' above and below the rotary member 120' are cut along the circumferential direction. The rotating member 120 ′, the fixed substrates 130 and 140 ′, and the counter electrodes 170 and 180 are similar to those of the actuator 100, but the actuator 100 ′ is different from the actuator 100 in the formation position of the electret portion and the counter electrode.

In the actuator 100 ′, the counter electrodes 170 and 180 are not formed on the fixed substrate 140 ′, but only on the fixed substrate 130. The counter electrodes 170 and 180 of the actuator 100 ′ also extend over the entire radial direction of the fixed substrate 130 from the center side of the rotary member 120 ′ near the rotation axis 110 to the outer peripheral side. Further, in the actuator 100′, the electret part 150′ is not formed on the rotating member 120′, and covers the entire area of the lower surface 142 of the fixed substrate 140′ corresponding to the formation positions of the counter electrodes 170 and 180. Is integrally formed (solid). That is, the actuator 100 ′ of Comparative Example 2 has the same configuration as the central side of the actuator 10.

FIG. 7 is a graph showing the relationship between the pattern width of the rotating members 120 and 120' and the magnitude of the generated force of the actuators 100 and 100'. The horizontal axis of the graph is the pattern width d (unit: μm) of the rotating members 120 and 120'. In the actuator 100, the pattern width d is the width of the electret portions 150 and 160 on the circumference centered on the rotation axis 110, and on the actuator 100′, the pattern width d except the through holes 128 on the circumference centered on the rotation axis 110. The width corresponds to the width of each flat portion 127 (spoke portion). In addition, the vertical axis of the graph represents the driving force in the rotation direction (the driving force in the rotation direction generated by the electrostatic interaction between the flat portion 127 or the electret portions 150, 160 arranged with a specific pattern width and the counter electrodes 170, 180). It is the magnitude F (unit: mN/m) of the generated force.

FIG. 7 shows the results when the distance between the lowermost surface of the rotating members 120 and 120 ′ and the upper surface of the fixed substrate 130 is 70 μm for both the actuators 100 and 100 ′. Curve a is a graph for actuator 100 ′ and curve b is a graph for actuator 100 ′. In the pattern width range of 700 to 1100 μm, the generated force obtained is larger in the actuator 100 than in the actuator 100 ′. On the other hand, when the pattern width is in the range of 100 to 700 μm, the generated force obtained by the actuator 100 ′ is larger than that by the actuator 100. This is because, in a range where the pattern width is narrow, it is better to form the electret portions 150′ on the fixed substrate 140′ in a solid manner than to arrange the through holes 128 and the electret portions 150 and 160 alternately in the circumferential direction. It is considered that this is because the total amount of electret increases.

When the pattern of the through holes and the electret portion is radially formed in the disk-shaped rotating member, the pattern width is narrower on the central side of the disk and becomes wider toward the outer peripheral side. Therefore, in consideration of the result of FIG. 7, in the actuator 10, the outer peripheral side having a wide pattern width has the same configuration as the actuator 100 of Comparative Example 1, and the central side having a narrow pattern width has the same configuration as the actuator 100′ of Comparative Example 2. I am trying. With such a configuration, in the actuator 10, the generated force is larger than that of the actuator 100 in the pattern width range of 100 to 700 μm (center side), and the actuator 100′ is in the pattern width range of 700 to 1100 μm (outer peripheral side). Will be generated more than. Therefore, in the actuator 10, even when the rotating member 12 is downsized, the output is less likely to decrease as compared with the actuator 100, which is suitable for downsizing of the electromechanical converter.

Further, in the actuator 10, since the electret portions 15b are solidly arranged on the flat fixed substrate 14 on the center side where the pattern width is narrow, the electret portions 150 and 160 are arranged in a radial pattern up to the vicinity of the center close to the rotating shaft 110. The electret can be formed more easily than when it is arranged. Further, since the actuator 10 generates a smaller force in the direction of the rotating shaft than the actuator 100, the frictional force generated between the rotating shaft and the bearing can be reduced accordingly.

FIG. 8 is a schematic configuration diagram of another actuator 10'. The actuator 10 ′ differs from the actuator 10 only in that the electret portion 16 a of the actuator 10 and the counter electrodes 17 ′ and 18 ′ are omitted, and otherwise has the same configuration as the actuator 10. In FIG. 8, as the actuator 10 ′, the upper surface 131 of the fixed substrate 13, the lower surface 122 of the rotating member 12, the upper surface 121 of the rotating member 12, and the lower surface 142 of the fixed substrate 14 are shown in order from the bottom of the drawing. As shown in FIG. 8, the electret portion 16a and the counter electrodes 17' and 18' of the actuator 10 can be omitted, and the actuator 10' has a simpler structure. However, the actuator 10 has a larger generated force in the rotational direction because of the set of the electret portion 16a and the counter electrodes 17' and 18'.

9A to 9C are schematic configuration diagrams of another actuator 10A. FIG. 9A shows an upper surface 121 and a lower surface 122 of the rotating member 12A of the actuator 10A. Further, FIGS. 9B and 9C are similar to FIGS. 3A and 3B, respectively, along the circumferential direction in the annular region D1 and the circular region D2 of the rotating member 12A, respectively. The cut surface of the actuator 10A is shown. The actuator 10A differs from the actuator 10 only in the shape of the rotating member, and has the same configuration as the actuator 10 in other points. The definitions of the annular region D1 and the circular region D2 are the same as those in the actuator 10.

As shown in FIG. 9A, a plurality of concave portions 125 (an example of groove portions) and convex portions 126 are alternately arranged in the circumferential direction in the annular region D1 and the circular region D2 on the lower surface 122 of the rotating member 12A. In addition, it is formed radially around the rotation axis 11. On the other hand, the annular region D1 and the circular region D2 on the upper surface 121 of the rotating member 12 are flat portions 127 in which no unevenness is formed. That is, the rotating member 12 is provided with irregularities (grooves) only on the surface facing the fixed substrate 13 on the lower side. As shown in FIGS. 9B and 9C, the recess 125 is a recessed portion with respect to the fixed substrate 13, the projection 126 is a portion protruding toward the fixed substrate 13, and the recesses 125 are adjacent to each other. The convex portions 126 are formed at intervals in the circumferential direction. The concave portions 125 and the convex portions 126 are arranged at equal intervals, and the widths of the concave portions 125 and the convex portions 126 are the same on the same circumference around the rotation axis 11.

The rotating member 12A is produced by, for example, performing deep etching or blasting on one surface of a disk-shaped silicon substrate to scrape off the recess 125. Alternatively, the rotating member 12A may be manufactured by separately preparing a flat disk-shaped member and a member on which the pattern of the convex portions 126 is formed, and bonding them together.

As shown in FIGS. 9A and 9B, in the actuator 10A, the electret portion 15a is formed on the convex portion 126 in the annular region D1 on the lower surface 122 side of the rotating member 12. Further, the electret portion 16a is formed in the annular region D1 on the upper surface 121 side of the rotating member 12 at a position corresponding to the electret portion 15a on the lower surface 122 side. In the actuator 10A, the arrangement of the counter electrodes 17 and 18 on the fixed substrate 13 and the arrangement of the electret portion 15b and the counter electrodes 17' and 18' on the fixed substrate 14 are the same as those of the actuator 10. In the actuator 10A, since the through hole is not formed in the rotating member 12A, the electret portion 15b is covered by the rotating member 12 when viewed from the side of the counter electrodes 17 and 18.

Since the concavo-convex pattern is formed on the lower surface 122 of the rotating member 12A by the concave portions 125 and the convex portions 126, the concave portion 125 passes over the individual counter electrodes 17 and 18, and the convex portion 126 passes through. , The strength of the electric field acting on the counter electrodes 17 and 18 changes. Therefore, the actuator 10A can also rotate the rotating member 12A by applying an alternating voltage to the counter electrodes 17 and 18.

Even in the actuator 10A, the generated force is larger on the central side where the pattern width is narrower than that on the actuator 100, and on the outer peripheral side where the pattern width is wide, larger than that generated in the actuator 100'. Hateful. Further, also in the actuator 10A, similarly to the actuator 10, the electret portion 15b can be easily formed, and the frictional force generated between the rotary shaft 11 and the bearing can be reduced. In the actuator 10A as well, like the actuator 10', the electret portion 16a and the counter electrodes 17', 18' can be omitted.

10A to 10C are schematic configuration diagrams of another actuator 10B. FIG. 10A shows the upper surface 121 and the lower surface 122 of the rotating member 12A of the actuator 10B. Further, FIGS. 10B and 10C are similar to FIGS. 3A and 3B, respectively, along the circumferential direction in the annular region D1 and the circular region D2 of the rotating member 12A, respectively. The cut surface of the actuator 10B is shown. The actuator 10B differs from the actuator 10A only in that the fixed substrate 14, the electret portion 16a, and the counter electrodes 17′ and 18′ of the actuator 10 are omitted, and the arrangement position of the electret portion 15b is different from the actuator 10A, and in other respects, the actuator 10A. It has the same configuration as. The definitions of the annular area D1 and the circular area D2 are the same as those of the actuators 10 and 10A.

In the actuator 10B, the electret portion 15b is integrally (solid) formed so as to cover the entire circular region D2 on the upper surface 121 of the rotating member 12. That is, also in the actuator 10B, the electret portion 15b is arranged at a position that does not directly face the counter electrodes 17 and 18, and is covered by the rotating member 12 when viewed from the side of the counter electrodes 17 and 18.

Even in the actuator 10B, the generated force is larger on the central side where the pattern width is narrower than that on the actuator 100 and is larger on the outer peripheral side where the pattern width is wider than that on the actuator 100'. Hateful. Also in the actuator 10B, similarly to the actuator 10, the electret portion 15b can be easily formed, and the frictional force generated between the rotary shaft 11 and the bearing can be reduced. Further, in the actuator 10B, since the electret portion 15b is directly formed on the upper surface of the rotating member 12A, the rotating member 12A makes the rotating member 12A as compared with the actuators 10 and 10A in which a space is provided between the rotating member 12 and the electret portion 15b. The electric field becomes stronger, and the generated force becomes stronger accordingly. Further, in the actuator 10B, since the fixed substrate 14 of the actuator 10 is unnecessary, there are advantages that the number of members can be reduced and the thickness of the actuator itself can be reduced.

FIG. 11 is a schematic configuration diagram of the electromechanical converter 2. As shown in FIG. 11, the electromechanical converter 2 includes a power generation unit 30 and a power storage unit 40. Like the actuator 10, the power generation unit 30 has a rotating shaft 11, a rotating member 12, fixed substrates 13 and 14, electret portions 15a, 15b and 16a, and counter electrodes 17, 18, 17' and 18'. The electromechanical converter 2 is a generator (electret generator) that extracts electric power from power by rotating the rotating member 12 using kinetic energy of the external environment and generating static electricity by electrostatic induction in the power generation unit 30. is there.

The rotary member 12, the fixed substrates 13 and 14, the electret portions 15 a, 15 b and 16 a, and the counter electrodes 17, 18, 17 ′ and 18 ′ are the same as those of the actuator 10. However, for example, the rotating member 12 of the power generation unit 30 is provided with a rotary weight (not shown) having a weight balance deviation. Further, the counter electrodes 17, 18, 17', 18' of the electromechanical converter 2 are connected to the power storage unit 40 via electric wirings, respectively. In the power generation unit 30, the rotary member 12 with a rotary weight rotates in the circumferential direction by using, for example, a motion of a human body carrying the electromechanical converter 2 or a vibration of a machine to which the electromechanical converter 2 is attached as a power source. To do.

When the rotating member 12 rotates, the overlapping area between the electret portions 15a, 15b, 16a and the counter electrodes 17, 18, 17', 18' on the outer peripheral side of the rotating member 12 and the rotating member 12 on the center side accordingly. The overlapping area between the flat portion 127 and the counter electrodes 17 and 18 increases or decreases. For example, if negative charges are held in the electret portions 15a, 15b, 16a, the counter electrodes 17, 18, 17', 18' are generated by the electric field created by the electret portions 15a, 15b, 16a and the circular region D2 of the rotating member 12. The positive charge attracted to the element increases or decreases as the rotating member 12 rotates. In this way, the power generation unit 30 generates alternating current between the counter electrode 17 and the counter electrode 18 and between the counter electrode 17 ′ and the counter electrode 18 ′ to generate power using electrostatic induction.

The power storage unit 40 has a rectifier circuit 41 and a secondary battery 42, and stores electric power generated by electrostatic induction between the electret units 15 a, 15 b, 16 a and the counter electrodes 17, 18 in accordance with the rotation of the rotating member 12. accumulate. The outputs from the counter electrodes 17, 18, 17', 18' are connected to the rectifier circuit 41, and the rectifier circuit 41 is connected to the secondary battery 42. The rectifier circuit 41 is a bridge-type circuit having four diodes, and rectifies the current generated between the counter electrodes 17 and 17' and the counter electrodes 18 and 18'. The secondary battery 42 is a chargeable/dischargeable battery such as a lithium secondary battery, accumulates electric power generated by the power generation unit 30, and supplies the electric power to a drive target circuit (not shown).

Even in the power generation unit 30, even if the pattern width of the rotating member 12 is narrowed, the generated power does not decrease so much. Therefore, even if the rotating member 12 is downsized, the output does not easily decrease.

Also in the power generation unit 30, the electret portion 16a and the counter electrodes 17' and 18' can be omitted. Further, in place of the rotating member 12, the rotating member 12A shown in FIGS. 9A to 9C may be used. Alternatively, also in the power generation unit 30, the fixed substrate 14 is omitted similarly to the actuator 10B shown in FIGS. 10A to 10C, and the electret portion 15b is solidly formed in the circular region D2 on the upper surface 121 of the rotating member 12. It may be formed.

1, 2 electromechanical converter 10, 10', 10A, 10B actuator 11 rotary shaft 12, 12A rotary member 125 concave portion 126 convex portion 127 flat portion 128 through hole 13, 14 fixed substrate 15a, 15b, 16a electret portion 17, 17 ',18,18' counter electrode 20 drive unit 30 power generation unit 40 power storage unit

Claims (7)

An electromechanical converter for converting between electric power and power by utilizing electrostatic interaction between a charging unit and a counter electrode,
A disk-shaped rotating member rotatable about a rotation axis, wherein a circular area centered on the rotation axis is made of a conductive material, and an interval in the rotation direction is provided in the circular area of at least one surface. A rotating member having a plurality of grooves formed in a space,
A counter substrate arranged to face the one surface of the rotating member,
A first charging portion formed at an interval in the rotation direction in an annular region on the outer peripheral side of the circular region on the one surface of the rotating member;
A second charging unit which is arranged on the opposite side of the counter substrate with the rotating member interposed therebetween and which is integrally formed so as to cover the entire circular region of the rotating member;
A plurality of counter electrodes formed at intervals in the rotation direction on the counter substrate so as to face the annular region and the circular region of the rotating member,
An electromechanical converter having: The circular region on the surface of the rotating member opposite to the counter substrate is a flat surface on which no unevenness is formed,
The electromechanical converter according to claim 1, wherein the second charging unit is arranged in the circular region on a surface of the rotating member opposite to the counter substrate. Further comprising a second counter substrate arranged on the side opposite to the counter substrate so as to face the rotating member,
The electromechanical converter according to claim 1, wherein the second charging unit is disposed on a surface of the second counter substrate facing the rotating member. The electromechanical converter according to claim 3, wherein the plurality of groove portions of the rotating member are through holes that penetrate the circular region of the rotating member. The circular region on the surface of the rotating member opposite to the counter substrate is a flat surface on which no unevenness is formed,
The electromechanical converter according to claim 3, wherein the second charging unit is covered by the rotating member when viewed from the plurality of counter electrodes. A third charging portion formed in the annular region on the surface of the rotating member opposite to the counter substrate, with a space formed in the rotating direction;
A plurality of other counter electrodes formed at intervals in the rotation direction on the second counter substrate so as to face the annular region of the rotating member;
The electromechanical converter according to claim 3, further comprising: The electromechanical conversion device according to claim 1, wherein a plurality of through holes are formed in a portion where the first charging unit is not arranged in the annular region of the rotating member. vessel.

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