JP5447375B2 - Vibration actuator, lens unit, and imaging device - Google Patents

Description

The present invention relates to an actuator, a driving device, a lens unit, and an imaging device. This application is related to the following Japanese application and claims priority from the following Japanese application. For designated countries where incorporation by reference of documents is permitted, the contents described in the following application are incorporated into this application by reference and made a part of this application.
1. Japanese Patent Application No. 2008-174618 Application date July 3, 20082. Japanese Patent Application No. 2009-58646 Filing Date March 11, 2009

There is known an actuator that drives a driven body by applying vibration to the stator in point contact with the driven body by a laminated piezoelectric element (see, for example, Patent Documents 1 and 2). In this actuator, the vertical movement of the contact point with the driven body in the stator by the stacked piezoelectric element and the left and right movement of the contact point with the driven body in the stator by the stacked piezoelectric element are superimposed, thereby overlapping the driven object in the stator. The contact point with the driving body is moved elliptically.
JP 2000-228885 A JP 2008-067539 A

  Each of the actuators drives the driven body by causing the convex portion of the stator to move elliptically by applying a voltage shifted in phase to two stacked piezoelectric elements that are spaced apart from each other. However, it has been difficult to obtain a sufficiently high output with these actuators.

  Accordingly, an object of one aspect of the present invention is to provide a vibration actuator, a lens unit, and an imaging device that can solve the above-described problems. This object is achieved by a combination of features described in the independent claims. The dependent claims define further advantageous specific examples of the present invention.

  In the first embodiment of the present invention, the vibration actuator includes a rotor that is rotatably arranged, a stator that is disposed apart from each other in the rotation direction of the rotor, and that has a plurality of convex portions that protrude toward the rotor. An electromechanical converter that reciprocally moves the plurality of protrusions in the rotation direction of the rotor by relatively expanding and contracting both sides in the rotation direction of the rotor with each of the plurality of protrusions as a boundary.

  In the second embodiment of the present invention, a lens unit includes the vibration actuator and an optical member moved by the vibration actuator.

  In the third embodiment of the present invention, an imaging apparatus includes the vibration actuator, an optical member moved by the vibration actuator, and an imaging unit that captures an image formed by the optical member.

  In the fourth embodiment of the present invention, the actuator for moving the moving element includes a stator having a convex part that contacts the moving element, and both sides of the moving direction of the moving element with the convex part as a boundary. A first electromechanical conversion unit that expands and contracts relatively in a direction that intersects the direction and circularly moves the projection, and expands and contracts in the expansion and contraction direction of the first electromechanical conversion unit and reciprocates the projection in the expansion and contraction direction. And a second electromechanical conversion unit.

  The summary of the invention described above does not enumerate all necessary features, and sub-combinations of these feature groups can also be the invention.

It is a perspective view of actuator 100 concerning one embodiment. It is a disassembled perspective view of the actuator 100 which concerns on one Embodiment. It is a sectional side view of actuator 100 concerning one embodiment. 3 is an exploded perspective view of a first electromechanical conversion unit 172. FIG. 3 is an exploded perspective view of a first electromechanical conversion unit 172. FIG. 6 is an exploded perspective view of a second electromechanical conversion unit 174. FIG. 6 is an exploded perspective view of a second electromechanical conversion unit 174. FIG. FIG. 6 is a side view showing operations of a stator 150 and an electromechanical converter 170. FIG. 6 is a plan view showing operations of a stator 150 and an electromechanical converter 170. It is a figure which shows the outline of other operation | movement of the stator 150. FIG. 5 is a graph showing a drive voltage waveform of a first electromechanical converter 172 and a drive voltage waveform of a second electromechanical converter 174. FIG. 5 is a side sectional view showing operations of a stator 150 and a rotor 140. It is a perspective view which shows the stator 250 which concerns on other embodiment. It is a perspective view which shows the stator 350 which concerns on other embodiment. It is a perspective view which shows the motor 20 provided with the actuator 200 which concerns on other embodiment. 2 is an exploded perspective view showing a motor 20. FIG. 2 is a side sectional view showing a motor 20. FIG. It is 13-13 sectional drawing of FIG. 2 is a perspective view showing an actuator 200. FIG. FIG. 5 is a diagram showing an outline of the operation of a stator 650. It is a graph which shows the drive voltage waveform of the electromechanical converters 660 and 662 and the drive voltage waveform of the electromechanical converter 740. 1 is a side sectional view showing a schematic configuration of an imaging apparatus 700 including an actuator 100. FIG. It is a perspective view which shows the inside of the lens unit 300 provided with the actuator 200. FIG.

20 Motor, 100 Actuator, 110 Rotating shaft, 112 Screw part, 114 Flange part, 120 Mounting plate, 122 Fastening hole, 130 Energizing member, 140 Rotor, 142 Bearing, 144 Gear part, 150 Stator, 152 Base part, 154 Convex Part, 160 flexible printed wiring board, 162 disk part, 164 wiring part, 170 electromechanical converter, 171 piezoelectric material board, 172 first electromechanical converter, 173 signal layer, 174 second electromechanical converter, 175 common layer 176 Insulating layer, 177 electrode pair, 179 electrode, 180 flexible printed wiring board, 181 electrode, 182 disk part, 183, 185, 187 conductor, 184 wiring part, 189 piezoelectric material board, 190 base part, 191 signal layer, 193 Common layer, 195, 197 Conductor, 2 0 Actuator, 210, 220 Nut, 240 Electromechanical conversion part, 250 Stator, 252 Base part, 254 Convex part, 256 Central part, 258 Branch part, 259 Convex part, 260 Displacement part, 300 Lens unit, 302 Lens holding frame, 304 , 306 Guide bar, 308, 310, 312 Bearing part, 314 stay, 316 moving body, 318 leaf spring, 350 stator, 352 base part, 354 convex part, 356 thin part, 410 lens unit, 420 optical member, 422 front lens, 424 compensator lens, 426 focusing lens, 428 main lens, 430 lens barrel, 440 iris unit, 450 mount, 460 body, 470 pentaprism, 480 photometric unit, 490 eyepiece system, 492 half 494 finder finder liquid crystal, 500 image pickup unit, 510 optical filter, 520 shutter, 530 ranging unit, 540 main mirror, 542 sub mirror, 550 control unit, 610 rotating shaft, 612 screw part, 614 flange part, 650 stator, 652 base 653 Groove, 654 Protrusion, 656, 657 Leg, 660, 662 Electromechanical converter, 661 Gap, 670, 672 Flexible printed wiring board, 680, 690 Base, 700 Imaging device, 740 Electromechanical converter, 750 Flexible printed circuit board, 760 base, 1521, 1522 base

  Hereinafter, the (1) aspect of the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the scope of claims, and the features described in the embodiments are as follows. Not all combinations are essential for the solution of the invention.

  FIG. 1 is a perspective view showing an actuator 100 according to an embodiment. FIG. 2 is an exploded perspective view showing the actuator 100. FIG. 3 is a side sectional view showing the actuator 100. For convenience of explanation, the drive output side in the axial direction of the rotating shaft 110 is referred to as an output side, and the opposite side is referred to as a non-output side. Further, the case where the actuator 100 is viewed from the axial direction of the rotating shaft 110 (hereinafter referred to as the rotating shaft direction) will be described as a plan view, and the case where the actuator 100 is viewed from the radial direction of the rotating shaft 110 will be described as a side view.

  As shown in these drawings, the actuator 100 includes a rotating shaft 110, a nut 210 arranged in order from the output side along the rotating shaft 110, a mounting plate 120, a biasing member 130, a rotor 140, a stator 150, a flexible printed wiring. A board 160, an electromechanical converter 170, a flexible printed wiring board 180, a base 190, and a nut 220 are provided. Screw portions 112 and 112 into which nuts 210 and 220 are respectively screwed are formed at both axial ends of the rotating shaft 110, and a disk-shaped flange portion 114 having an enlarged diameter is formed between them. The nut 210, the mounting plate 120, the biasing member 130, and the rotor 140 are arranged on the output side from the flange portion 114, while the stator 150, the flexible printed wiring board 160, the electromechanical converter 170, and the flexible printed wiring board 180. The base portion 190 and the nut 220 are arranged on the non-output side with respect to the flange portion 114.

  The rotor 140 is formed in a disk shape, and a bearing 142 such as a ball bearing is fitted into the shaft center. The rotor 140 is rotatably supported on the rotating shaft 110 via a bearing 142. A gear portion 144 is formed at the output side end of the rotor 140. An example of the urging member 130 is a compression coil spring through which the rotating shaft 110 is inserted.

  The mounting plate 120 is formed in a disk shape, and the rotating shaft 110 is inserted through the axis. Further, the mounting plate 120 is formed with a pair of U-shaped fastening holes 122 symmetrically with respect to the axis, and the mounting plate 120 is fastened by a fastener such as a screw inserted through the fastening hole 122. And fastened to a device that uses the actuator 100 as a drive source.

  The stator 150 includes a base 152 having a disk shape and a uniform cross-sectional shape over the entire circumference, and a plurality of convex portions 154 projecting from the base 152 toward the rotor 140 side. The rotation shaft 110 is inserted through the axis of the base portion 152. Further, the plurality of (four in the present embodiment) convex portions 154 are rectangular plate-like ribs extending in the inner diameter direction from the peripheral edge portion of the base portion 152, and are the rotational direction of the rotor 140 (hereinafter simply referred to as the rotational direction). Are arranged at an equal pitch (in this embodiment, 90 ° intervals). Note that at least the base 152 of the stator 150 is formed of an elastically deformable material.

  The electromechanical conversion unit 170 includes a first electromechanical conversion unit 172 disposed opposite to the stator 150 via the flexible printed wiring board 160 in the rotation axis direction, and the stator 150 is connected to the first electromechanical conversion unit 172. On the opposite side, a first electromechanical conversion unit 172 and a second electromechanical conversion unit 174 arranged opposite to each other in the rotation axis direction are provided. That is, the first electromechanical converter 172 is disposed closer to the stator 150 than the second electromechanical converter 174 along the rotation axis direction. An insulating layer 176 is disposed on the surface between the first electromechanical conversion unit 172 and the second electromechanical conversion unit 174. The first electromechanical converter 172 and the first electromechanical converter 172 may be formed and handled as an integrated unit, or may be formed separately and assembled.

  The flexible printed wiring board 160 includes a disk part 162 in which an electrode is formed on the surface on the first electromechanical conversion part 172 side, and a wiring in which a wiring connected to the electrode is formed and extends from the disk part 162 in the outer diameter direction. Part 164. The rotating shaft 110 is inserted through the axis of the disk portion 162. The flexible printed wiring board 160 supplies an alternating voltage to the first electromechanical converter 172 to expand and contract the first electromechanical converter.

  In addition, the flexible printed wiring board 180 includes a disk part 182 in which an electrode is formed on the surface on the second electromechanical conversion part 174 side, and a wiring connected to the electrode is formed and extends from the disk part 182 in the outer diameter direction. Wiring part 184 to be provided. A rotating shaft 110 is inserted through the axis of the disk portion 182. The flexible printed wiring board 180 supplies an AC voltage to the second electromechanical converter 174 to expand and contract the second electromechanical converter 174.

  The base portion 190 is formed in a disk shape, and the rotation shaft 110 is inserted through the axis. Here, the stator 150, the flexible printed wiring board 160, the electromechanical converter 170, the flexible printed wiring board 180, and the base portion 190 are fastened in the direction of the rotation axis by the flange portion 114 and the nut 220, and are attached to the rotation shaft 110. On the other hand, relative rotation is impossible.

  Further, the rotor 140, the urging member 130, and the mounting plate 120 are fastened by the convex portion 154 of the stator 150 and the nut 210, and the urging member 130 is elastically contracted. For this reason, the mounting plate 120 is pressed against the nut 210 by the elastic force of the urging member 130, while the rotor 140 is pressed against the convex portion 154 by the elastic force of the urging member 130. The mounting plate 120 cannot be rotated relative to the rotating shaft 110 due to the tightening force between the urging member and the nut 210, whereas the rotor 140 is connected to the rotating shaft 110 via the bearing 142. Therefore, it can rotate relative to the rotating shaft 110.

  4 and 5 are exploded perspective views showing the first electromechanical converter 172. FIG. As shown in this figure, the first electromechanical converter 172 includes a plurality of piezoelectric material plates 171 stacked in the axial direction. A signal layer 173 is formed on the surface of the piezoelectric material plate 171 on the second electromechanical conversion unit 174 side, and a common layer 175 is formed on the surface of the piezoelectric material plate 171 on the stator 150 side.

  The signal layer 173 includes a plurality of electrode pairs 177. Each electrode pair 177 includes a pair of electrodes 179 and 181. The electrodes 179 and 181 are divided into sectors having the same shape, and are arranged around the rotation axis 110. The plurality of electrode pairs 177 are arranged at an equal pitch around the rotation shaft 110. Further, the piezoelectric material plate 171 is laminated so that the electrodes having the same reference numerals are overlapped with each other in the rotation axis direction. These electrodes 179 and 181 are electrically connected to the electrodes of the flexible printed wiring board 160 by conducting wires 183 and 185 formed on the outer peripheral surface of the first electromechanical transducer 172, respectively.

  The common layer 175 is formed of a conductive material on the entire surface of the piezoelectric material plate 171 on the stator 150 side, and functions as one ground electrode. The common layer 175 is electrically connected to the ground electrode of the flexible printed wiring board 160 by a conductive wire 187 formed on the outer peripheral surface of the first electromechanical conversion unit 172.

  The piezoelectric material plate 171 includes a piezoelectric material that expands and contracts when a driving voltage is applied. Specifically, piezoelectric materials such as lead zirconate titanate, crystal, lithium niobate, barium titanate, lead titanate, lead metaniobate, polyvinylidene fluoride, lead zinc niobate, lead scandium niobate and the like are included. Since many piezoelectric materials are fragile, they are preferably reinforced with a highly elastic metal material such as phosphor bronze. The electrode may be formed directly on the surface of the piezoelectric material by using an electrode material such as nickel or gold by a method such as plating, sputtering, vapor deposition, or thick film printing.

  Here, the electrode pair 177 is divided in the rotation direction into an electrode 179 and an electrode 181 with a region where the projection 154 is projected in the rotation axis direction as a boundary. On the other hand, the convex portion 154 is not disposed in the region in which the boundary portion between the electrode pairs 177 adjacent in the rotation direction is projected in the rotation axis direction.

  6 and 7 are exploded perspective views showing the second electromechanical converter 174. FIG. As shown in this figure, the second electromechanical conversion unit 174 is disposed on the first electromechanical conversion unit 172 side of the plurality of piezoelectric material plates 189 stacked in the rotation axis direction and the plurality of piezoelectric material plates 189. An insulating layer 176. The insulating layer 176 insulates the first electromechanical conversion unit 172 from the second electromechanical conversion unit 174. A signal layer 191 is formed on the surface of the piezoelectric material plate 189 on the first electromechanical conversion unit 172 side, and a common layer 193 is formed on the surface of the piezoelectric material plate 189 on the base unit 190 side.

  The signal layer 191 is formed of a conductive material on the entire surface of the piezoelectric material plate 189 on the first electromechanical conversion unit 172 side. The electrode is electrically connected to the electrode of the flexible printed wiring board 180 by a conductive wire 195 formed on the outer peripheral surface of the second electromechanical conversion unit 174. The common layer 193 is formed of a conductive material on the entire surface of the piezoelectric material plate 189 on the base portion 190 side, and functions as one ground electrode. The common layer 193 is electrically connected to the ground electrode of the flexible printed wiring board 180 by a conductive wire 197 formed on the outer peripheral surface of the second electromechanical conversion unit 174.

  Next, the operation in this embodiment will be described. FIGS. 8 and 9 are a side view and a plan view showing operations of the stator 150 and the electromechanical converter 170, respectively. As shown in these drawings, alternating voltages having opposite polarities are applied to the electrode 179 and the electrode 181 constituting the electrode pair 177 of the first electromechanical converter 172. In FIG. 8, the operation of the convex portion 154 is exaggerated. For example, the AC voltage applied to the electrodes 179 and 181 of the first electromechanical conversion unit 172 is a sin wave, and the AC voltage applied to the electrode of the second electromechanical conversion unit 174 is a cos wave. Has a phase difference of °.

  In the region where the first electromechanical conversion unit 172 overlaps with the electrode to which the positive drive voltage is applied, expansion in the direction of the rotation axis occurs, while the negative drive voltage is applied to the first electromechanical conversion unit 172. In the region overlapping with the electrode, shortening in the direction of the rotation axis occurs. For this reason, in the region overlapped with the extension region of the first electromechanical transducer 172 in the base 152 of the stator 150, elastic deformation to the opposite side of the first electromechanical transducer 172 occurs. On the other hand, in the region overlapped with the shortened region of the first electromechanical transducer 172 in the base portion 152 of the stator 150, elastic deformation toward the first electromechanical transducer 172 occurs.

  Here, the convex portion 154 is disposed at a boundary portion between the electrode 179 and the electrode 181. For this reason, the convex part 154 tilts to the electrode side to which the negative voltage is applied. Then, the polarity of the voltage applied to the electrodes 179 and 181 is reversed between positive and negative, whereby the tilt direction of the convex portion 154 is reversed. That is, when the polarity of the drive voltage applied to the electrodes 179 and 181 is repeatedly reversed, the convex portion 154 tilts alternately between the electrode 179 side and the electrode 181 side, that is, the convex portion 154 rotates. Reciprocates on the same route in the direction.

  An AC voltage is applied to the plurality of electrodes 179 and the plurality of electrodes 181 in the same phase, and the electrodes are expanded and contracted in the same phase. Thereby, the plurality of convex portions 154 reciprocate in the rotational direction with the same phase.

  In addition, an AC voltage is applied to the electrode of the signal layer 191 of the second electromechanical conversion unit 174. Here, an electrode is covered on the entire surface of each layer of the second electromechanical converter 174, and a ground electrode is covered on the entire other surface, so that the circumferential direction of the second electromechanical converter 174 and The entire radial direction expands and contracts in the axial direction. For this reason, the entire first electromechanical converter 172 and the entire stator 150 reciprocate in the axial direction.

  As a result, the contact point between the tip of the convex portion 154 and the rotor 140 performs an elliptical motion that circulates around the axis along the radial direction of the rotor 140. Therefore, a thrust from the electrode 181 side to the electrode 179 side is generated in the rotor 140 by the contact point moving from the electrode 181 side to the electrode 179 side. On the other hand, the thrust from the electrode 179 side to the electrode 181 side is not generated in the rotor 140 by the contact point moving from the electrode 179 side to the electrode 181 side. Therefore, the plurality of convex portions 154 that synchronize with the ellipse generates a rotational force in one direction on the rotor 140, and a rotational torque is output.

  FIG. 10 is a diagram showing an outline of another operation of the stator 150. FIG. 11 is a graph showing the drive voltage waveform of the first electromechanical converter 172 and the drive voltage waveform of the second electromechanical converter 174.

  The waveform of the AC voltage applied to the electrode 179 of the first electromechanical transducer 172 indicated by the solid line in the upper graph is represented by sin θ. Moreover, the waveform of the alternating voltage applied to the electrode 181 of the first electromechanical conversion unit 172 indicated by a broken line in the upper graph is represented by sin (θ−π / 2). Moreover, the waveform of the alternating voltage applied to the electrode of the 2nd electromechanical conversion part 174 shown with a dashed line in the lower graph is represented by sin (θ−π / 4). Hereinafter, the relationship between the drive voltage change of the first electromechanical conversion unit 172 and the second electromechanical conversion unit 174 and the operation of the stator 150 will be described in detail.

  As shown in FIG. 11, when θ = 0, the drive voltage applied to the electrode 179 of the first electromechanical transducer 172 is 0 V, and the drive voltage applied to the electrode 181 is a negative maximum value (−VMAX). Become. In this state, the portion of the electrode 179 in the first electromechanical transducer 172 does not expand and contract, and the portion of the electrode 181 in the first electromechanical transducer 172 contracts to the maximum. For this reason, the convex part 154 takes the attitude | position which inclines to the electrode 181 side at the maximum.

  Further, when θ = 0, the drive voltage applied to the electrode of the second electromechanical conversion unit 174 becomes an intermediate value (−V1) between 0V and −VMAX. In this state, the entire second electromechanical conversion unit 174 is contracted. Note that the contraction amount of the second electromechanical conversion unit 174 in this state is smaller than the maximum contraction amount.

  When θ = π / 2, the drive voltage applied to the electrode 179 of the first electromechanical conversion unit 172 has a positive maximum value (VMAX), and the drive voltage applied to the electrode 181 becomes 0V. In this state, the portion of the electrode 179 in the first electromechanical converter 172 extends to the maximum. On the other hand, the portion of the electrode 181 in the first electromechanical converter 172 does not expand or contract. For this reason, the convex part 154 takes the attitude | position which inclines to the electrode 181 side at the maximum.

  Further, when θ = π / 2, the drive voltage applied to the electrode of the second electromechanical conversion unit 174 is an intermediate value (V1) between 0V and VMAX. In this state, the entire second electromechanical converter 174 is extended. In this state, the extension amount of the second electromechanical conversion unit 174 is smaller than the maximum extension amount.

  Here, at the time of transition from θ = 0 to θ = π / 2, the convex portion 154 is maintained in a posture inclined toward the electrode 181 by the action of the first electromechanical transducer 172. In addition, the convex portion 154 is displaced toward the rotor 140 when both the first electromechanical conversion unit 172 and the second electromechanical conversion unit 174 increase the extension amount. Furthermore, the convex part 154 is displaced more largely toward the rotor 140 when the second electromechanical conversion part 174 changes from the contracted state to the extended state.

  Next, at θ = 3π / 4, the drive voltage applied to the electrodes 179 and 181 of the first electromechanical conversion unit 172 has the same positive value (V2). Here, the drive voltage V2 is an intermediate value between 0V and VMAX. In this state, the portion of the electrode 179 and the portion of the electrode 181 in the first electromechanical transducer 172 extend by the same amount. For this reason, the convex part 154 takes a posture without inclination.

  In addition, when θ = 3π / 4, the drive voltage applied to the electrode of the second electromechanical conversion unit 174 becomes the maximum value (VMAX). In this state, the entire extension amount of the second electromechanical conversion unit 174 is maximized.

  Here, when transitioning from θ = π / 2 to 3π / 4, the convex portion 154 changes from the posture inclined toward the electrode 181 to the posture without inclination by the action of the first electromechanical conversion unit 172. Further, the convex portion 154 is displaced to the position closest to the rotor 140 (hereinafter, referred to as the uppermost position) when the extension amount of the second electromechanical conversion unit 174 exceeds the contraction amount of the first electromechanical conversion unit 172. . Further, the convex portion 154 is displaced more greatly from the intermediate position on the positive side to the rotor 140 side as the extension amount of the second electromechanical conversion unit 174 increases to the maximum amount.

  Next, at θ = π, the drive voltage applied to the electrode 179 of the first electromechanical converter 172 is 0 V, and the drive voltage applied to the electrode 181 is a positive maximum value (VMAX). In this state, the portion of the electrode 179 in the first electromechanical converter 172 does not expand or contract. On the other hand, the portion of the electrode 181 in the first electromechanical transducer 172 extends to the maximum. For this reason, the convex part 154 takes the attitude | position which inclines to the electrode 179 side at the maximum.

  When θ = π, the drive voltage applied to the electrode of the second electromechanical conversion unit 174 has a positive intermediate value (V1). In this state, the entire extension amount of the second electromechanical conversion unit 174 is smaller than the maximum extension amount.

  Here, when transitioning from θ = 3π / 4 to θ = π, the convex portion 154 transitions from a posture without inclination to a posture inclined toward the electrode 179 by the action of the first electromechanical conversion unit 172. Further, the convex portion 154 is displaced from the uppermost position to the intermediate position when the contraction amount of the first electromechanical conversion unit 172 exceeds the expansion amount of the second electromechanical conversion unit 174. Furthermore, the convex part 154 is displaced more largely to the opposite side of the rotor 140 when the extension amount of the second electromechanical conversion part 174 decreases from the maximum amount.

  Next, at θ = 3π / 2, the drive voltage applied to the electrode 179 of the first electromechanical transducer 172 is −VMAX, and the drive voltage applied to the electrode 181 is 0V. In this state, the portion of the electrode 179 in the first electromechanical transducer 172 contracts to the maximum. On the other hand, the portion of the electrode 181 in the first electromechanical converter 172 does not expand or contract. For this reason, the convex part 154 takes the attitude | position which inclines to the electrode 179 side at the maximum.

  Further, at θ = 3π / 2, the drive voltage applied to the electrode of the second electromechanical conversion unit 174 has a negative intermediate value (−V1). In this state, the total contraction amount of the second electromechanical conversion unit 174 is smaller than the maximum contraction amount.

  Here, when transitioning from θ = π to θ = 3π / 2, the convex portion 154 is maintained in a posture inclined toward the electrode 179 side by the action of the first electromechanical transducer 172. Further, the convex portion 154 is displaced from the uppermost position to the intermediate position when the contraction amount of the first electromechanical conversion unit 172 exceeds the expansion amount of the second electromechanical conversion unit 174. Furthermore, the convex part 154 is displaced more largely to the opposite side of the rotor 140 when the second electromechanical conversion part 174 transitions from the expanded state to the contracted state.

  Next, at θ = 7π / 4, the drive voltage applied to the electrode 179 of the first electromechanical conversion unit 172 becomes a negative equivalent value (−V2). Here, the drive voltage (−V2) is an intermediate value between 0V and −VMAX. In this state, the portion of the electrode 179 and the portion of the electrode 181 in the first electromechanical transducer 172 contract by the same amount. For this reason, the convex part 154 takes a posture without inclination.

  Further, at θ = 7π / 4, the drive voltage applied to the electrode of the second electromechanical conversion unit 174 has a negative maximum value (−VMAX). In this state, the entire contraction amount of the second electromechanical conversion unit 174 is maximized.

  Here, when transitioning from θ = 3π / 2 to 7π / 4, the convex portion 154 changes from the posture inclined toward the electrode 179 to the posture without inclination by the action of the first electromechanical transducer 172. Further, the convex portion 154 is displaced from the intermediate position on the negative side to the lowest position when the contraction amount of the second electromechanical conversion unit 174 exceeds the expansion amount of the first electromechanical conversion unit 172. Furthermore, the convex part 154 is displaced more largely to the opposite side of the rotor 140 when the contraction amount of the second electromechanical conversion part 174 increases to the maximum amount.

  When the transition is made from θ = 7π / 4 to θ = 2π, the convex portion 154 returns to the state of θ = 0 described above.

  Here, the convex portion 154 swings from the electrode 181 side to the electrode 179 side while being raised from the axial intermediate position to the highest position by the action of the first electromechanical transducer 172. Then, the convex portion 154 swings from the electrode 181 side to the electrode 179 side while descending from the highest axial position to the intermediate position by the action of the first electromechanical transducer 172.

  The convex portion 154 swings from the electrode 179 side to the electrode 181 side while descending from the axial intermediate position to the lowest position by the action of the first electromechanical conversion unit 172. The convex portion 154 swings from the electrode 179 side to the electrode 181 side while being raised from the lowest position in the axial direction to the intermediate position in the axial direction by the action of the first electromechanical conversion unit 172.

  That is, the tip portion of the convex portion 154 performs an elliptical motion that circulates around the axis line along the radial direction of the rotor 140 by the action of the first electromechanical transducer 172.

  Further, the convex portion 154 reciprocates in the direction approaching or separating from the rotor 140 by the action of the second electromechanical conversion portion 174. Here, the second electromechanical conversion unit 174 extends and rises as the convex portion 154 moves along the elliptical arc swelled from the electrode 181 side to the electrode 179 side toward the rotor 140 side. Let In addition, the second electromechanical conversion unit 174 contracts as the convex portion 154 moves along the elliptical arc swelled from the electrode 179 side to the electrode 181 side on the opposite side of the rotor 140, and descends the convex portion 154. Let

  That is, as shown in FIG. 12, the contact point P between the tip of the convex portion 154 and the rotor 140 performs an elliptical motion that circulates around an axis along the radial direction of the rotor 140. Therefore, a thrust from the electrode 181 side to the electrode 179 side is generated in the rotor 140 by the contact point P moving from the electrode 181 side to the electrode 179 side. On the other hand, the thrust from the electrode 179 side to the electrode 181 side is not generated in the rotor 140 by the contact point P moving from the electrode 179 side to the electrode 181 side. Therefore, the plurality of convex portions 154 that synchronize with the ellipse generates a rotational force in one direction on the rotor 140, and a rotational torque is output.

  In the present embodiment, the contact point P has an elliptical motion with the rotation direction as the major axis as an example of a circular motion, but as an example of another circular motion, the second electromechanical conversion unit 174 The amount of expansion and contraction in the rotation axis direction may be increased so that the movement locus of the contact point P is a perfect circle or an ellipse having the rotation axis direction as a major axis. That is, the contact point P may be caused to perform a perfect circular motion or an elliptical motion whose major axis is the rotation axis direction.

  Here, since the 1st electromechanical conversion part 172 makes the convex part 154 carry out the elliptical motion which circulates around the axis line along the radial direction of the rotor 140, the 2nd electromechanical conversion part 174 is not provided. Even in this case, the rotor 140 can generate a rotational force in one direction. However, since the second electromechanical converter 174 that exhibits the above-described action is provided, the amount of movement of the convex portion 154 in the rotation axis direction can be amplified. Therefore, the kinetic energy transmitted from the convex part 154 to the rotor 140 can be increased efficiently, and the thrust generated in the rotor 140 can be increased efficiently. In addition, the amount of movement of the convex portion 154 in the rotation axis direction can be increased efficiently, so that the kinetic energy transmitted from the convex portion 154 to the rotor 140 when moving in the direction opposite to the rotation direction of the rotor 140 can be reduced. . Therefore, the output torque of the actuator 100 can be improved efficiently.

  Further, the thrust generated in the rotor 140 by the plurality of convex portions 154 arranged in the rotation direction can further increase the thrust generated in the rotor 140, thereby further increasing the output torque. Here, the plurality of convex portions 154 are arranged at a predetermined pitch in the rotation direction. Further, the base 152 of the stator 150 is formed in a uniform shape over the entire circumference in the circumferential direction. Thereby, the balance of stress generated in the stator 150 can be made uniform in the circumferential direction, and the twist of the stator 150 in the circumferential direction can be suppressed. Therefore, the loss of kinetic energy in the stator 150 can be reduced, and the kinetic energy transmitted from the stator 150 to the rotor 140 can be increased efficiently.

  Further, as the output torque can be increased efficiently, the number of piezoelectric material plates 171 and 189 constituting the electromechanical converter 170 can be reduced or the area can be reduced to obtain the same output torque. . Therefore, the electromechanical conversion unit 170 can be downsized in the rotation axis direction and the radial direction, and thus the actuator 100 can be downsized. Moreover, since the drive voltage of the electromechanical converter 170 can be lowered to obtain the same output torque, power consumption can be reduced.

  Further, since the outputs of the first electromechanical conversion unit 172 and the second electromechanical conversion unit 174 are superimposed, the displacement amount of the convex portion 154 is large. Therefore, even when the resonance of the entire system is not used, the convex portion 154 can be greatly displaced, and a sufficient rotational force can be generated in the rotor 140. Thereby, the freedom degree of design about the shape and dimension of the stator 150 increases. Further, when the resonance is not used, the frequency of the voltage applied to the first electromechanical conversion unit 172 and the second electromechanical conversion unit 174 can be varied, so that the rotational speed of the rotor 140 is controlled by the frequency of the voltage. Can do.

  In the present embodiment, the stator 150, the flexible printed wiring board 160, the first electromechanical converter 172, the second electromechanical converter 174, the flexible printed wiring board 180, and the base 190 are provided on the rotating shaft 110. The flange portion 114 and the nut 220 are fastened and fixed. Thereby, since it is not necessary to adhere | attach these mutually, assembly workability | operativity can be improved. Moreover, since the problem of peeling of the bonded portion cannot occur, reliability can be improved.

  Next, another embodiment of the stator 150 will be described. FIG. 13 is a perspective view showing a stator 250 according to another embodiment. As shown in this figure, the stator 250 includes a base portion 252 and a plurality of convex portions 254 arranged at an equal pitch in the rotation direction. The base portion 252 includes an annular central portion 256 through which the rotary shaft 110 is inserted, a plurality of branch portions 258 extending from the central portion 256 in the outer diameter direction, and both sides of the branch portion 258 from the distal end portion in the rotation direction. And a displacement portion 260 extending in a circular arc shape. A convex portion 254 projects from the central portion of the displacement portion 260 on the extended line of the branch portion 258. In addition, on both sides of the displacement portion 260 in the rotational direction across the convex portion 254, convex portions 259 project toward the electromechanical transducer 170 side.

  That is, the base 252 is divided in the rotational direction between a pair of convex portions 254 adjacent to each other in the rotational direction. As a result, the regions on both sides in the rotational direction with the convex portion 254 as the boundary in the base portion 252 are not constrained in the rotational direction, and the degree of freedom of displacement of the region in the direction of the rotational axis is expanded. The amount of movement in the axial direction can be increased efficiently. Therefore, the kinetic energy transmitted from the convex part 254 to the rotor 140 can be increased efficiently, the thrust generated in the rotor 140 can be increased efficiently, and the output torque can be increased efficiently.

  FIG. 14 is a perspective view showing a stator 350 according to another embodiment. As shown in this figure, the stator 350 includes a base portion 352 and a plurality of convex portions 354 arranged at equal pitches in the rotation direction. The base 352 is formed in a disc shape, and a cross-shaped thin portion 356 is formed on the surface on which the convex portion 354 is projected.

  Here, the convex portion 354 protrudes from the thin portion 356, and both sides of the convex portion 354 in the rotational direction are thinner than other regions. As a result, the bending rigidity of the regions on both sides in the rotational direction with the convex portion 354 at the base portion 352 as a boundary is reduced, and the region is easily displaced in the rotational axis direction, so that the convex portion 354 moves in the axial direction. The amount can be increased efficiently. Therefore, the kinetic energy transmitted from the convex part 354 to the rotor 140 can be increased efficiently, the thrust generated in the rotor 140 can be increased efficiently, and the output torque can be increased efficiently.

  FIG. 15 is a perspective view showing a motor 20 including an actuator 200 according to another embodiment. As shown in this figure, the motor 20 includes a rotating shaft 610, a nut 210 arranged in order from the output side along the rotating shaft 610, a mounting plate 120, a biasing member 130, a rotor 140, three actuators 200, and a base. 690 and a nut 220 are provided.

  The actuator 200 includes a stator 650, a pair of electromechanical converters 660 and 662, a pair of flexible printed wiring boards 670 and 672, a base 760, an electromechanical converter 740, a flexible printed wiring board 750, and a base 680. I have.

  The base 760 is a rectangular plate material, and supports a pair of electromechanical converters 660 and 662 arranged side by side in the longitudinal direction of the base 760. The pair of electromechanical conversion units 660 and 662 are stacked piezoelectric elements in which piezoelectric elements are stacked in the rotation axis direction, and expand and contract in the stacking direction when a driving voltage is supplied. Further, the pair of electromechanical conversion units 660 and 662 are arranged side by side in the longitudinal direction of the base 680. The pair of flexible printed wiring boards 670 and 672 are arranged in the longitudinal direction of the base 760. The flexible printed wiring board 670 is sandwiched between the electromechanical conversion unit 660 and the base 760, and the flexible printed wiring board 672 is sandwiched between the electromechanical conversion unit 662 and the base 760.

  The flexible printed wiring board 670 supplies an alternating drive voltage to the electromechanical conversion unit 660 to expand and contract the electromechanical conversion unit 660 in the rotation axis direction. In addition, the flexible printed wiring board 672 supplies an alternating drive voltage to the electromechanical conversion unit 662 to expand and contract the electromechanical conversion unit 662 in the rotation axis direction.

  Further, the electromechanical conversion unit 740 and the flexible printed wiring board 750 are sandwiched between the base 760 and the base 680. The flexible printed wiring board 750 supplies an alternating drive voltage to the electromechanical conversion unit 740 to expand and contract the electromechanical conversion unit 740 in the rotation axis direction.

  The stator 650 is formed of an elastic material, and includes a rectangular plate-shaped base portion 652 and a protruding portion 654 that protrudes from the central portion of the base portion 652 in the longitudinal direction. One end side in the longitudinal direction of the base portion 652 is joined to the upper end surface of the electromechanical conversion unit 660, and the other end side in the longitudinal direction of the base portion 652 is joined to the upper end surface of the electromechanical conversion unit 662. Further, the protruding portion 654 protrudes from the base portion 652 to the rotor 140 side.

  FIG. 16 is an exploded perspective view showing the motor 20. As shown in this figure, screw portions 612 into which nuts 210 and 220 are screwed are formed at both ends in the axial direction of the rotating shaft 610, and a disk-shaped flange portion 614 having an enlarged diameter is formed between them. It is formed. The nut 210, the mounting plate 120, the biasing member 130, and the rotor 140 are arranged on the output side from the flange portion 614, while the base 690 and the nut 220 are arranged on the non-output side from the flange portion 614. . Further, the three actuators 200 are arranged between the rotor 140 and the base 690 so as to surround the rotating shaft 610. Further, the rotor 140 is rotatably supported on the rotating shaft 610 via the bearing 142.

  FIG. 17 is a side sectional view showing the motor 20. As shown in this figure, the mounting plate 120, the urging member 130, the rotor 140, the actuator 200, and the base 690 are fastened in the direction of the rotation axis by nuts 210 and 220. Here, the biasing member 130 is elastically contracted in the direction of the rotation axis, and presses the rotor 140 against the actuator 100.

  18 is a cross-sectional view taken along line 13-13 of FIG. As shown in this figure, the three actuators 200 are arranged around the rotation axis 610 while being shifted by 2π / 3, and the space surrounded by these is a triangle in plan view. The three protrusions 654 are arranged around the rotation axis 610 while being shifted by 2π / 3.

  FIG. 19 is a perspective view showing the actuator 200. As shown in this figure, in the actuator 200, a pair of electromechanical conversion units 660 and 662 arranged in the rotation direction and an electromechanical conversion unit 240 are arranged so as to overlap in the rotation axis direction.

  In the actuator 200, a gap 661 is provided between the pair of electromechanical conversion units 660 and 662, and the pair of electromechanical conversion units 660 and 662 is in a direction perpendicular to the expansion / contraction direction (that is, the arrangement direction). Are separated.

  In addition, a rectangular groove 653 that bisects the base portion 652 in the longitudinal direction is formed in the center portion in the longitudinal direction of the base portion 652 of the stator 650. The groove 653 extends over the entire width direction of the base portion 652 and is formed so as to overlap with the gap 661 between the pair of electromechanical conversion portions 660 and 662 in the rotation axis direction. Therefore, the entire longitudinal end of the base portion 652 (hereinafter referred to as the base portion 1521) is joined to the entire end surface of the electromechanical transducer 660, and the longitudinal end of the base portion 652 (hereinafter referred to as the base portion). 1522) is joined to the entire end face of the electromechanical transducer 662.

  In addition, the groove 653 extends through the base portion 652 to the base end portion of the protruding portion 654 in the depth direction. Thus, a pair of leg portions 656 and 657 that are divided into two in the longitudinal direction of the base portion 652 by the groove 653 are formed at the base end portion of the projection portion 654. The leg portion 656 extends from the end of the base portion 1521 on the groove 653 side to the opposite side of the electromechanical conversion portion 660. Further, the leg portion 657 extends from the end portion of the base portion 1522 on the groove 653 side to the opposite side of the electromechanical conversion portion 662. That is, the protrusion 654 is supported by the base portion 652 by a U-shaped base end portion including a pair of leg portions 656 and 657.

  Next, the operation in this embodiment will be described. FIG. 20 shows an outline of the operation of the stator 650. 21 shows the drive voltage waveform of the electromechanical converters 660 and 662 and the drive voltage waveform of the electromechanical converter 740.

  The waveform of the AC voltage applied to the electromechanical conversion unit 660 indicated by the solid line in the upper graph is represented by sin θ. In addition, the waveform of the alternating voltage applied to the electromechanical conversion unit 662 indicated by a broken line in the upper graph is represented by sin (θ−π / 2). Moreover, the waveform of the alternating voltage applied to the electromechanical conversion unit 740 indicated by a chain line in the lower graph is represented by sin (θ−π / 4). Hereinafter, the relationship between the change in the driving voltage of the electromechanical converters 660, 662, and 740 and the operation of the stator 650 will be described in detail.

  As shown in FIG. 21, when θ = 0, the drive voltage applied to the electromechanical conversion unit 660 is 0 V, and the drive voltage applied to the electromechanical conversion unit 662 is a negative maximum value (−VMAX). In this state, the electromechanical conversion unit 660 does not expand and contract, and the electromechanical conversion unit 662 contracts to the maximum. For this reason, the protruding portion 654 is inclined to the maximum at the electromechanical conversion portion 662 side.

  When θ = 0, the drive voltage applied to the electromechanical conversion unit 740 is an intermediate value (−V1) between 0V and −VMAX. In this state, the entire electromechanical conversion unit 740 is contracted. Note that the amount of contraction of the electromechanical conversion unit 740 in this state is smaller than the maximum amount of contraction.

  At θ = π / 2, the drive voltage applied to the electromechanical conversion unit 660 is a positive maximum value (VMAX), and the drive voltage applied to the electromechanical conversion unit 662 is 0V. In this state, the electromechanical conversion unit 660 extends to the maximum. On the other hand, the electromechanical converter 662 does not expand or contract. For this reason, the protruding portion 654 is inclined to the maximum at the electromechanical conversion portion 662 side.

  Further, when θ = π / 2, the drive voltage applied to the electrode of the electromechanical conversion unit 740 becomes an intermediate value (V1) between 0V and VMAX. In this state, the entire electromechanical conversion unit 740 is extended. In this state, the extension amount of the electromechanical conversion unit 740 is smaller than the maximum extension amount.

  Here, when transitioning from θ = 0 to θ = π / 2, the protrusion 654 is maintained in a posture inclined toward the electromechanical conversion unit 662 by the action of the electromechanical conversion units 660 and 662. In addition, the protrusion 654 is displaced toward the rotor 140 when both the electromechanical conversion units 660 and 662 increase the extension amount. Furthermore, the protrusion 654 is displaced more largely toward the rotor 140 when the electromechanical conversion unit 740 changes from the contracted state to the extended state.

  Next, at θ = 3π / 4, the drive voltage applied to the electromechanical converters 660 and 662 has the same positive value (V2). Here, the drive voltage V2 is an intermediate value between 0V and VMAX. In this state, the electromechanical conversion unit 660 and the electromechanical conversion unit 662 extend the same amount. For this reason, the projection part 654 takes a posture without inclination.

  In addition, at θ = 3π / 4, the drive voltage applied to the electrode of the electromechanical conversion unit 740 becomes the maximum value (VMAX). In this state, the entire extension amount of the electromechanical conversion unit 740 is maximized.

  Here, when transitioning from θ = π / 2 to 3π / 4, the protrusion 654 is changed from the posture inclined toward the electromechanical conversion unit 662 to the posture without inclination by the action of the electromechanical conversion units 660 and 662. Change. Further, when the extension amount of the electromechanical conversion unit 662 exceeds the contraction amount of the electromechanical conversion unit 660, the protrusion 654 is displaced to the position closest to the rotor 140 (hereinafter referred to as the highest level). Further, the protrusion 654 is displaced more toward the rotor 140 as the extension amount of the electromechanical conversion unit 740 increases to the maximum amount.

  Next, at θ = π, the drive voltage applied to the electromechanical conversion unit 660 is 0 V, and the drive voltage applied to the electromechanical conversion unit 662 is a positive maximum value (VMAX). In this state, the electromechanical conversion unit 660 does not expand or contract. On the other hand, the electromechanical converter 662 extends to the maximum. For this reason, the projection part 654 takes the attitude | position which inclines to the electromechanical conversion part 660 side at the maximum.

  When θ = π, the drive voltage applied to the electrode of the electromechanical conversion unit 740 becomes a positive intermediate value (V1). In this state, the entire extension amount of the electromechanical conversion unit 740 is smaller than the maximum extension amount.

  Here, when transitioning from θ = 3π / 4 to θ = π, the projecting portion 654 is inclined from the non-tilt posture to the electromechanical transducer 660 side by the action of the electromechanical transducers 660 and 662. Transition. Further, the protrusion 654 is displaced from the uppermost position to the intermediate position when the contraction amount of the electromechanical conversion unit 660 exceeds the extension amount of the electromechanical conversion unit 662. Further, the protrusion 654 is displaced more to the opposite side of the rotor 140 when the extension amount of the electromechanical conversion unit 740 is reduced from the maximum amount.

  Next, at θ = 3π / 2, the drive voltage applied to the electromechanical conversion unit 660 is −VMAX, and the drive voltage applied to the electromechanical conversion unit 662 is 0V. In this state, the electromechanical conversion unit 660 contracts to the maximum. On the other hand, the electromechanical converter 662 does not expand and contract. For this reason, the projection part 654 takes the attitude | position which inclines to the electromechanical conversion part 660 side at the maximum.

  At θ = 3π / 2, the drive voltage applied to the electrode of the electromechanical conversion unit 740 becomes a negative intermediate value (−V1). In this state, the total contraction amount of the electromechanical conversion unit 740 is smaller than the maximum contraction amount.

  Here, when transitioning from θ = π to θ = 3π / 2, the protrusion 654 is maintained in a posture inclined toward the electromechanical conversion unit 660 by the action of the electromechanical conversion units 660 and 662. In addition, the protrusion 654 is displaced from the intermediate position on the positive side to the intermediate position on the negative side when the electromechanical conversion units 660 and 662 contract by the same amount. Furthermore, the protrusion 654 is displaced more greatly to the opposite side of the rotor 140 when the electromechanical conversion unit 740 transitions from the expanded state to the contracted state.

  Next, at θ = 7π / 4, the drive voltage applied to the electromechanical conversion unit 660 becomes a negative equivalent value (−V2). Here, the drive voltage (−V2) is an intermediate value between 0V and −VMAX. In this state, the electromechanical conversion unit 660 and the electromechanical conversion unit 662 contract by the same amount. For this reason, the projection part 654 takes a posture without inclination.

  Further, at θ = 7π / 4, the drive voltage applied to the electrode of the electromechanical conversion unit 740 has a negative maximum value (−VMAX). In this state, the entire contraction amount of the electromechanical conversion unit 740 is maximized.

  Here, when transitioning from θ = 3π / 2 to 7π / 4, the protrusion 654 is changed from the posture inclined toward the electromechanical conversion unit 660 to the posture without inclination by the action of the electromechanical conversion units 660 and 662. Change. Further, the protrusion 654 is displaced from the negative intermediate position to the lowest position when the contraction amount of the electromechanical conversion unit 662 exceeds the expansion amount of the electromechanical conversion unit 660. Further, the protrusion 654 is displaced more to the opposite side of the rotor 140 as the contraction amount of the electromechanical conversion unit 740 increases to the maximum amount.

  Then, when transitioning from θ = 7π / 4 to θ = 2π, the protrusion 654 returns to the state of θ = 0 described above.

  Here, the tip of the protrusion 654 is moved upward from the intermediate position in the axial direction to the highest position by the action of the electromechanical converters 660 and 662, and from the electromechanical converter 662 to the electromechanical converter 660 side. Swing to. Then, the tip of the protrusion 654 moves from the electromechanical converter 662 side to the electromechanical converter 660 side while descending from the highest axial position to the intermediate position by the action of the electromechanical converters 660 and 662. Swing.

  And the front-end | tip part of the projection part 654 descend | falls from the intermediate position of an axial direction to the lowest position by the effect | action of the electromechanical conversion parts 660 and 662, and from the electromechanical conversion part 660 side to the electromechanical conversion part 662 side. Swing. The tip portion of the protrusion 654 rises from the lowest position in the axial direction to the intermediate position in the axial direction by the action of the electromechanical conversion portions 660 and 662, and from the electromechanical conversion portion 660 side to the electromechanical conversion portion 662. Swing to the side.

  That is, the tip of the protrusion 654 performs an elliptical motion that circulates around the axis along the radial direction of the rotor 140 by the action of the electromechanical converters 660 and 662.

  Further, the protrusion 654 reciprocates in the direction approaching or separating from the rotor 140 by the action of the electromechanical converter 740. Here, the electromechanical converter 740 extends as the tip of the protrusion 654 moves along an elliptical arc that swells from the electromechanical converter 662 side to the electromechanical converter 660 side toward the rotor 140 side. Then, the protrusion 654 is raised. In addition, the electromechanical conversion unit 740 contracts as the tip of the projection 654 moves along an elliptical arc that swells from the electromechanical conversion unit 660 side to the electromechanical conversion unit 662 side on the opposite side of the rotor 140. Then, the protrusion 654 is lowered.

  For this reason, the rotor 140 has a thrust from the electromechanical conversion unit 662 side to the electromechanical conversion unit 660 side by the tip of the protrusion 654 moving from the electromechanical conversion unit 662 side to the electromechanical conversion unit 660 side. Is generated. On the other hand, depending on the tip of the protrusion 654 moving from the electromechanical conversion unit 660 side to the electromechanical conversion unit 662 side, the rotor 140 may move from the electromechanical conversion unit 660 side to the electromechanical conversion unit 662 side. No thrust is generated. Therefore, the plurality of protrusions 654 that synchronize with each other in the above-described elliptical motion generate a rotational force in one direction on the rotor 140, and a rotational torque is output from the motor 20.

  Here, even if the electromechanical conversion unit 740 is not provided, the electromechanical conversion units 660 and 662 cause the protrusion 654 to make an elliptical motion around the axis along the radial direction of the rotor 140. The rotor 140 can generate a rotational force in one direction. However, since the electromechanical converter 740 that exhibits the above-described action is provided, the amount of movement of the protrusion 654 in the rotation axis direction can be amplified. Therefore, the kinetic energy transmitted from the protrusion 654 to the rotor 140 can be increased efficiently, the thrust generated in the rotor 140 can be increased efficiently, and the output torque can be increased efficiently.

  Further, since the whole of the electromechanical conversion unit 740 in the circumferential direction expands and contracts in the axial direction, the amount of expansion and contraction in the axial direction of the electromechanical conversion unit 740 can be increased efficiently, and the amount of movement of the protrusion 654 in the rotation axis direction Can be increased efficiently. Further, since the amount of movement of the protrusion 654 in the rotation axis direction can be increased efficiently, when the protrusion 654 moves along the rotation direction of the rotor 140, kinetic energy is efficiently transmitted from the protrusion 654 to the rotor 140. On the other hand, when the protrusion 654 moves in the direction opposite to the rotation direction of the rotor 140, the kinetic energy transmitted from the protrusion 654 to the rotor 140 is effectively reduced.

  In addition, the output torque can be increased efficiently, and in order to obtain the same output torque, the number of piezoelectric material plates constituting the electromechanical converters 660, 662, and 740 can be reduced or the area can be reduced. it can. Therefore, the electromechanical conversion units 660, 662, and 740 can be downsized, and thus the actuator 200 can be downsized. Moreover, since the drive voltage of the electromechanical converters 660, 662, and 740 can be lowered to obtain the same output torque, power consumption can be reduced.

  Further, by superimposing the outputs of the electromechanical conversion units 660 and 662 and the electromechanical conversion unit 740, the displacement amount of the protrusion 654 can be increased. Therefore, even if the resonance of the entire system is not used, a sufficient rotational force can be generated in the rotor 140. Thereby, the design freedom about the shape and dimension of the motor 20 increases. Furthermore, when resonance is not used, the frequency of the voltage applied to the electromechanical converters 660, 662, and 740 can be varied, so that the rotational speed of the rotor 140 can be controlled by the frequency of the voltage.

  In addition, although the motor 20 according to the present embodiment includes the three actuators 200, the number of actuators 200 may be two or more than three. Further, it may be singular.

  In the embodiment of FIGS. 1 to 21, the convex portion 154 “reciprocating in the rotational direction of the rotor 140” is not limited to the reciprocating movement in which the forward path and the backward path are the same unless otherwise specified. Includes repetitive motion with a velocity component parallel to the direction of rotation. In this case, the convex portion 154 reciprocates along a route in which the distance monotonously increases from the start point on a forward path from a certain start point to the farthest point and monotonously decreases from the start point on the return path from the farthest point to the start point. It is preferable. More preferably, the reciprocating motion of the convex portion 154 is a circular motion, and an elliptical motion having the rotation axis direction as a short axis or a long axis, thereby driving the electromechanical conversion unit 170 with a simple signal such as a trigonometric function. Can do.

  FIG. 22 is a side cross-sectional view illustrating a schematic configuration of an imaging apparatus 700 including the actuator 100. As shown in this figure, the imaging apparatus 700 includes an optical member 420, a lens barrel 430, an actuator 100, an imaging unit 500, and a control unit 550. The lens barrel 430 accommodates the optical member 420.

  The actuator 100 moves the optical member 420. The imaging unit 500 captures an image formed by the optical member 420. The control unit 550 controls the actuator 100 and the imaging unit 500.

  In addition, the imaging apparatus 700 includes an optical member 420, a lens barrel 430, a lens unit 410 including the actuator 100, and a body 460. The lens unit 410 is detachably attached to the body 460 via the mount 450.

  The optical member 420 includes a front lens 422, a compensator lens 424, a focusing lens 426, and a main lens 428, which are sequentially arranged from the incident end corresponding to the left side in the drawing. An iris unit 440 is disposed between the focusing lens 426 and the main lens 428.

  The actuator 100 is disposed in the middle of the lens barrel 430 in the optical axis direction and below the focusing lens 426 having a relatively small diameter. Thereby, the actuator 100 is accommodated in the lens barrel 430 without increasing the diameter of the lens barrel 430. The actuator 100 advances or retracts the focusing lens 426 in the optical axis direction through, for example, a gear train.

  The body 460 accommodates optical members including the main mirror 540, the pentaprism 470, and the eyepiece system 490. The main mirror 540 is located between a standby position inclined on the optical path of incident light incident through the lens unit 410 and an imaging position (indicated by a dotted line in the figure) that rises while avoiding incident light. Moving.

  The main mirror 540 at the standby position guides most of the incident light to the pentaprism 470 disposed above. Since the pentaprism 470 emits a reflection of incident light toward the eyepiece system 490, the image on the focusing screen can be viewed as a normal image from the eyepiece system 490. The remainder of the incident light is guided to the photometric unit 480 by the pentaprism 470. The photometric unit 480 measures the intensity and distribution of incident light.

  A half mirror 492 is disposed between the pentaprism 470 and the eyepiece system 490 to superimpose the display image formed on the finder liquid crystal 494 on the image of the focusing screen. The display image is displayed so as to overlap the image projected from the pentaprism 470.

  The main mirror 540 has a sub mirror 542 on the back surface of the incident light incident surface. The sub mirror 542 guides part of the incident light transmitted through the main mirror 540 to the distance measuring unit 530 disposed below. Thereby, when the main mirror 540 is in the standby position, the distance measuring unit 530 measures the distance to the subject. When the main mirror 540 is moved to the photographing position, the sub mirror 542 is also retracted from the optical path of the incident light.

  Further, a shutter 520, an optical filter 510, and an imaging unit 500 are sequentially arranged behind the main mirror 540 with respect to incident light. When the shutter 520 is opened, the main mirror 540 moves to the photographing position immediately before the shutter 520 is opened, so that incident light travels straight and enters the imaging unit 500. Thereby, an image formed by incident light is converted into an electrical signal. Thereby, the imaging unit 500 captures an image formed by the lens unit 410.

  In the imaging device 700, the lens unit 410 and the body 460 are also electrically coupled. Therefore, for example, the autofocus mechanism can be formed by controlling the rotation of the actuator 100 in accordance with the distance information to the subject detected by the distance measuring unit 530 on the body 460 side. In addition, a focus aid mechanism can be formed by the distance measuring unit 530 referring to the operation amount of the actuator 100. The actuator 100 and the imaging unit 500 are controlled by the control unit 550 as described above.

  Here, as described above, the output torque of the actuator 100 can be increased efficiently. Therefore, since the driving force of the autofocus mechanism can be increased efficiently, it is possible to save power and drive the autofocus mechanism with a high driving force.

  Although the case where the focusing lens 426 is moved by the actuator 100 has been illustrated, it goes without saying that the opening and closing of the iris unit 440 and the movement of the variator lens of the zoom lens can be driven by the actuator 100. In this case as well, by referring to information with the photometric unit 480, the finder liquid crystal 494, etc. via an electrical signal, the actuator 100 contributes to automating exposure, execution of a scene mode, execution of bracket photography, and the like.

  FIG. 23 is a perspective view showing the inside of the lens unit 300 including the actuator 200. The lens unit 300 can be attached to the body 460. As shown in this figure, the lens unit 300 includes a focusing lens 426, a lens holding frame 302 that holds the focusing lens 426, and a pair of guide bars 304 that guide the movement of the lens holding frame 302 in the optical axis direction. 306 is arranged. A bearing portion 308 is provided on the left side of the lens holding frame 302, and a pair of front and rear bearing portions 310 and 312 are provided on the upper right portion of the lens holding frame 302. The guide bar 304 is slidably inserted into the bearing portion 308, and the guide bar 306 is slidably inserted into the bearing portions 310 and 312.

  The bearing portion 310 and the bearing portion 312 are connected by a stay 314 extending in the optical axis direction. A rectangular plate-like moving body 316 whose longitudinal direction is the optical axis direction is suspended below the stay 314 so as to be displaceable in the vertical direction. Further, a leaf spring 318 is disposed between the lower portion of the stay 314 and the moving body 316. The leaf spring 318 biases the moving body 316 downward.

  Here, the actuator 200 is disposed below the moving body 316, and the moving body 316 is pressed against the protrusion 654 of the actuator 200 by a plate spring 318. The actuator 200 is arranged such that the electromechanical conversion units 660 and 662 are arranged in the optical axis direction. For this reason, when the actuator 200 is operated by the above-described method, a thrust force in the optical axis direction is applied from the protrusion 654 to the moving body 316, and the lens holding frame 302 and the focusing lens 426 are moved in the optical axis direction. Moved. In the lens unit 300, the actuator 100 may be used instead of the actuator 200.

  As described above, the actuator 100 can be suitably used for driving a focusing mechanism, a zoom mechanism, a camera shake correction mechanism, and the like in an optical system such as a photographing machine and binoculars. Furthermore, it can be used for power sources such as precision stages, more specifically electron beam lithography equipment, various stages for inspection equipment, moving mechanisms for cell injectors for biotechnology, moving beds for nuclear magnetic resonance equipment, etc. Needless to say, it is not limited to.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

Claims (18)

A rotor arranged for rotation,
A stator having a plurality of convex portions that are spaced apart from each other in the rotational direction of the rotor and each project toward the rotor;
And an electromechanical transducer unit for reciprocating the plurality of convex portions in the rotational direction of the rotor by relative telescoping both sides of the rotational direction of said rotor of said plurality of protrusions,
The electromechanical converter has a first electromechanical converter and a second electromechanical converter that are arranged along the rotation axis direction of the rotor and are driven separately,
The first electromechanical conversion unit rotates each of the plurality of convex portions by rotating the rotor with both sides of the plurality of convex portions in the rotation direction of the rotor relatively expanding and contracting in the rotation axis direction of the rotor. Reciprocate on the same path in the direction,
The second electromechanical conversion unit reciprocates the plurality of convex portions in the rotation axis direction of the rotor by expanding and contracting in the rotation axis direction of the rotor,
By superimposing the reciprocating motion of the plurality of convex portions by the first electromechanical converting portion and the reciprocating motion of the plurality of convex portions by the second electromechanical converting portion, the plurality of convex portions are made to have a diameter of the rotor. A vibration actuator that causes a circular motion about an axis along a direction and transmits the circular motion of the plurality of convex portions to the rotor to rotate the rotor . A rotor arranged for rotation,
A stator having a plurality of convex portions that are spaced apart from each other in the rotational direction of the rotor and each project toward the rotor;
And an electromechanical transducer unit for reciprocating the plurality of convex portions in the rotational direction of the rotor by relative telescoping both sides of the rotational direction of said rotor of said plurality of protrusions,
The electromechanical converter has a first electromechanical converter and a second electromechanical converter that are arranged along the rotation axis direction of the rotor and are driven separately,
The first electromechanical conversion unit causes the plurality of convex portions to elliptically move by causing both sides of the plurality of convex portions in the rotation direction of the rotor to relatively expand and contract in the rotation axis direction of the rotor,
The second electromechanical conversion unit reciprocates the plurality of convex portions in the rotation axis direction of the rotor by expanding and contracting in the rotation axis direction of the rotor,
By superimposing the elliptical motion of the plurality of convex portions by the first electromechanical conversion portion and the reciprocating motion of the plurality of convex portions by the second electromechanical conversion portion, the plurality of convex portions are made to have a diameter of the rotor. A vibration actuator that causes a circular motion about an axis along a direction and transmits the circular motion of the plurality of convex portions to the rotor to rotate the rotor . 3. The vibration actuator according to claim 1 , wherein the electromechanical converter has an annular shape having a through hole at a position corresponding to a rotation axis of the rotor. 3. The vibration actuator according to claim 1 , wherein a plurality of the electromechanical conversion units are arranged around the rotation axis of the rotor in association with the plurality of convex portions, respectively. 5. The vibration actuator according to claim 1 , wherein the electromechanical conversion unit causes the plurality of convex portions to elliptically move in a rotation direction of the rotor. 6. 2. The vibration actuator according to claim 1, wherein the first electromechanical conversion unit is configured such that both sides of the plurality of convex portions in the rotation direction of the rotor extend and contract in the rotation axis direction of the rotor in opposite phases to each other. 7. The vibration actuator according to claim 1, wherein the first electromechanical conversion unit is arranged closer to the stator than the second electromechanical conversion unit along the rotation axis direction. The vibration actuator according to any one of claims 1 to 7, wherein the plurality of convex portions are arranged at an equal pitch in a rotation direction of the rotor. Said stator, said plurality of protrusions is protruded claim 1 having a base between a pair of adjacent in the rotation direction of the rotor is divided in the direction of rotation of the rotor of the plurality of protrusions 9. The vibration actuator according to any one of 1 to 8 . The stator according to any one of claims 1 to 8, wherein the stator has a base portion in which the plurality of convex portions project and a thin portion is formed between a pair of convex portions adjacent to each other in the rotation direction of the rotor. The vibration actuator described. Said stator, said plurality of protrusions is protruded, any one of claims 1 to 8, characterized in that it has a whole circumference base formed uniformly shaped over the rotational direction of the rotor vibration actuator according to. The vibration actuator according to any one of claims 1 to 11 ,
And a lens unit that is moved by the vibration actuator. The vibration actuator according to any one of claims 1 to 11 ,
An optical member moved by the vibration actuator;
An imaging device comprising: an imaging unit that captures an image formed by the optical member. An actuator for moving the slider,
A stator having a convex portion that abuts the moving element;
A first electromechanical converter that circularly moves the convex part by expanding and contracting relatively in a direction intersecting the moving direction of the movable element on both sides in the moving direction of the movable element with the convex part as a boundary; ,
A second electromechanical conversion unit that expands and contracts in the expansion and contraction direction of the first electromechanical conversion unit and reciprocates the projection in the expansion and contraction direction;
Bei to give a,
By superimposing the circular motion of the convex part by the first electromechanical conversion part and the reciprocation of the convex part by the second electromechanical conversion part, the convex part is moved along the radial direction of the moving element. A vibration actuator that causes a circular motion around and transmits the circular motion of the convex portion to the mover to rotate the mover . An actuator for moving the slider,
A stator having a convex portion that abuts the moving element;
Both sides of the moving direction of the moving element with the convex portion as a boundary are relatively expanded and contracted in a direction intersecting the moving direction of the moving element so that the protruding portion is on the same path in the rotating direction of the moving element. A first electromechanical converter that reciprocates
A second electromechanical conversion unit that expands and contracts in the expansion and contraction direction of the first electromechanical conversion unit and reciprocates the projection in the expansion and contraction direction;
Bei to give a,
By superimposing the reciprocating motion of the convex portion by the first electromechanical converting portion and the reciprocating motion of the convex portion by the second electromechanical converting portion, the convex portion is moved along the radial direction of the moving element. A vibration actuator that causes a circular motion around and transmits the circular motion of the convex portion to the mover to rotate the mover . 16. The vibration actuator according to claim 14 , wherein the first electromechanical converter is disposed closer to the stator than the second electromechanical converter along the direction of expansion and contraction of the first electromechanical converter. . The drive device with which the said vibration actuator of any one of Claim 14 to 16 was distribute | arranged along the moving direction of the said needle | mover. The drive device according to claim 17 , wherein the plurality of convex portions are arranged at an equal pitch along a moving direction of the moving element.

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