JP2010017038A - Vibration actuator, lens unit, and image pickup apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration actuator capable of highly efficiently improve output torque. <P>SOLUTION: The vibration actuator 100 includes: a shaft member 110; a pair of rotors 160, 161 freely rotatable around an axial line L of the shaft member 110; a pair of stators 120, 121 disposed between the pair of rotors 160, 161 so as to contact the pair of rotors 160, 161 respectively; a pair of electromechanical conversion sections 130, 131 disposed between the pair of stators 120, 121 and imparting vibration transiting around the axial line L to the pair of stators 120, 121 respectively; and a holding member 170 disposed between the pair of electromechanical conversion sections 130, 131 and coupled to both the stators 120, 121 to hold the corresponding electromechanical conversion sections 130, 131 between each of the stators 120, 121. The stator 120, 121 and the holding member 170 are coupled near the holding member 170 side away from the electromechanical conversion sections 130, 131. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration actuator, a lens unit, and an imaging apparatus. The present invention particularly relates to a vibration actuator in which a rotor is rotated by vibration generated in a stator by an electromechanical conversion unit, a lens unit including the actuator, and an imaging apparatus.

When pursuing downsizing of a vibration actuator, it has been established that the output torque decreases, and a vibration actuator that is small and has high output torque is desired. Therefore, a vibration actuator has been proposed in which a pair of stators are arranged on both sides of a laminated piezoelectric element, and a pair of rotors fixed to a rotating shaft are arranged on both sides of a pair of stators (for example, Patent Document 1). In this vibration actuator, when the piezoelectric element expands and contracts, vibration is generated in the pair of stators around the axis of the rotation shaft, and the pair of rotors is rotated by the vibration. According to this vibration actuator, high output can be obtained by vibrating the stator at the resonance frequency.
JP 2000-308375 A

However, for example, when the support state of the stator varies, the output decreases when the frequency of the stator varies and deviates from the resonance frequency. In particular, in the above vibration actuator, when the frequency of the pair of stators is deviated and the rotational force generated in one rotor is lower than that in the other rotor, one rotor rotates the other rotor. It becomes a load and the output is further reduced.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vibration actuator, a lens unit, and an imaging device that can efficiently improve output torque even if they are small.

  In order to solve the above-described problem, in the first embodiment of the present invention, the vibration actuator includes a shaft member, a pair of rotors rotatable around the axis of the shaft member, and a pair of rotors in the direction of the axis. A pair of stators that are arranged in contact with each of the pair of rotors and through which the shaft member is inserted, and a shaft member that is arranged between the pair of stators in the direction of the axis and is inserted between the pair of stators. A pair of electromechanical converters that impart vibrations that transition around the shaft, and a shaft member that is disposed between the pair of electromechanical converters in the direction of the axis is coupled to both of the pair of stators. A holding member that holds the corresponding electromechanical converter between each of the stators, and each of the pair of stators and the holding member is more than the pair of electromechanical converters in the axial direction. It is combined in the holding member side.

  In the second aspect of the present invention, the lens unit includes a vibration actuator, an optical member moved by the vibration actuator, and a lens barrel that houses the vibration actuator and the optical member. A pair of rotors rotatable around the axis of the shaft member, a pair of rotors between the pair of rotors in the direction of the axis, and in contact with each of the pair of rotors; A pair of electromechanical converters that are arranged between the pair of stators in the direction of the axis and through which a shaft member is inserted to impart vibrations that change around the axis to each of the pair of stators, and a pair of in the direction of the axis The shaft member is inserted between the electromechanical conversion parts of the two, and is coupled to both of the pair of stators so as to correspond to each of the pair of stators. And a holding member for holding across the 械 conversion section, and each holding member of the pair of stators are combined in the holding member side of the pair of electromechanical transducer unit for the direction of the axis.

  In the third embodiment of the present invention, an imaging device includes a vibration actuator, an optical member moved by the vibration actuator, a lens barrel that houses the optical member, and an imaging unit that captures an image formed by the optical member. And the vibration actuator is disposed between the pair of rotors in contact with each of the pair of rotors between the pair of rotors rotatable about the axis of the shaft member, the shaft member, and the shaft direction. A pair of stators through which the member is inserted, and a pair of electricity that are arranged between the pair of stators in the direction of the axis and through which the shaft member is inserted, and each of the pair of stators applies vibrations that change around the axis. A shaft member is inserted between the mechanical converter and the pair of electromechanical converters in the direction of the axis, and coupled to both of the pair of stators, Each of the pair of stators and the holding member is coupled to the holding member side with respect to the pair of electromechanical conversion units in the direction of the axis. .

  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.

  Hereinafter, 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 all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

  FIG. 1 is a perspective view of a vibration actuator 100 according to an embodiment. FIG. 2 is a side sectional view of the vibration actuator 100. In addition, the drive output side in the axial direction of the shaft member 110 is described as an output side, and the opposite side is described as a non-output side. Further, the case where the vibration actuator 100 is viewed from the axial direction of the shaft member 110 will be described as a plan view, and the case where the vibration actuator 100 is viewed from the radial direction of the output shaft will be described as a side view.

  As shown in these drawings, the vibration actuator 100 includes a shaft member 110, a pair of rotors 160 and 161, a pair of stators 120 and 121, a pair of electromechanical converters 130 and 131, a pair of wiring boards 140 and 141, and a holding member. A gear 180 and a flange portion 190 are provided as a sandwiching member that sandwiches the biasing member 150 in cooperation with the member 170, the biasing member 150, and the holding member 170. The shaft member 110 is formed in a cylindrical shape, and a screw portion 117 is formed on the output side in the direction of the axis L (hereinafter referred to as the axial direction), and a screw portion 118 is formed on the non-output side.

  The pair of rotors 160 and 161 are formed in a disk shape with a through hole formed in the axial center, a so-called donut shape. The rotor 160 is disposed on the axial output side of the shaft member 110, and the rotor 161 is disposed on the non-output side. The shaft member 110 is inserted through these shaft centers. The rotor 160 is screwed into the threaded portion 117 and is further bonded. On the other hand, the rotor 161 is fitted to the output side from the screw part 118 in the shaft member 110.

  In the illustrated example, a key is formed on the shaft member 110, and a key groove is formed on the inner peripheral portion of the rotor 161, and these are fitted. Accordingly, the rotor 161 is coupled to the shaft member 110 so as not to rotate around the axis L and to be displaceable in the axial direction.

  Further, the pair of stators 120 and 121 are arranged in this order from the output side to the non-output side between the pair of rotors 160 and 161, and the shaft member 110 is inserted through these shaft centers. Each of the stators 120 and 121 is formed in a donut shape, has a stator main body 125 and 126 in contact with the corresponding rotor 160 and 161, and a smaller diameter than the stator main bodies 125 and 126, and the stator main bodies 125 and 126. Extending portions 210 and 211 extending in the direction of the axis L.

  The pair of electromechanical converters 130 and 131 are also formed in a donut shape. These electromechanical converters 130 and 131 are arranged in this order from the output side to the non-output side between the pair of stators 120 and 121, and the shaft member 110 is inserted through these shaft centers.

  Each of the pair of wiring boards 140 and 141 includes a donut-shaped electrode portion 142 and a wiring portion 144 extending from the electrode portion 142 in the outer diameter direction. An example of these wiring boards 140 and 141 is a flexible printed wiring board. These wiring boards 140 and 141 are arranged in this order from the output side to the non-output side. The shaft member 110 is inserted through the axial center of the electrode part 142 of the wiring boards 140 and 141.

  The holding member 170 is disposed between the pair of wiring boards 140 and 141. The holding member 170 includes a cylindrical base portion 172 and a donut-shaped flange portion 174 that is formed integrally with the base portion 172 and extends in the outer diameter direction from the central portion in the axial direction of the base portion 172. U-shaped fastening holes 176 are formed at intervals of 90 degrees on the outer peripheral edge of the flange part 174, and the flange part 174 is vibrated by a fastener such as a screw inserted through the fastening hole 176. It fixes to the apparatus which uses the actuator 100 as a drive source. A screw hole 178 is formed in the axial center of the base 172. In the illustrated example, the fastening hole 176 is U-shaped, but instead, the fastening hole 176 can be formed by a circular hole. Further, the fastening hole 176 can be constituted by a screw hole having a thread groove formed on the peripheral surface.

  The extending portion 210 of the stator 120 extends from the axial center of the stator 120 toward the holding member 170, and the shaft member 110 is inserted into the extending portion 210. The extending portion 211 of the stator 120 extends from the axial center of the stator 121 toward the holding member 170, and the shaft member 110 is inserted into the extending portion 211.

  Here, a screw portion 212 is formed at an end portion of the extending portion 210 on the holding member 170 side, and the screw portion 212 and a screw hole 178 existing at the axis of the base portion 172 of the holding member 170 are screwed together. Further, a screw portion 214 is formed at an end portion of the extending portion 211 on the holding member 170 side, and the screw portion 214 and the screw hole 178 are screwed together. Thereby, the stator 120 is coupled to the holding member 170 on the holding member 170 side from the electromechanical conversion unit 130 in the direction of the axis L, and the stator 121 is connected to the holding member 170 side from the electromechanical conversion unit 131 in the direction of the axis L. Combined with the holding member 170.

  The electromechanical conversion unit 130 and the electrode unit 142 of the wiring board 140 are sandwiched between the stator 120 and the holding member 170 and tightened in the axial direction of the shaft member 110. Similarly, the electromechanical conversion unit 131 and the electrode unit 142 of the wiring board 141 are clamped between the stator 121 and the holding member 170 and tightened in the axial direction of the shaft member 110.

  A bearing 122 is embedded in the shaft center of the stators 120 and 121, and the shaft member 110 is rotatably supported by the bearing 122. The total axial length of the screw portion 212 of the extending portion 210 and the screw portion 214 of the extending portion 211 is shorter than the axial length of the screw hole 178 of the holding member 170. That is, the extending part 210 and the extending part 211 are separated from each other in the axial direction of the shaft member 110.

  Further, the gear 180 is screwed to the threaded portion 117 on the output side from the rotor 160 and is further bonded. Further, the flange portion 190 is screwed into the screw portion 118. A biasing member 150 is disposed between the flange portion 190 and the rotor 161. An example of the urging member 150 is the illustrated compression coil spring. The shaft member 110 is inserted into the coil and can be expanded and contracted in the axial direction of the shaft member 110, and the flange portion 190 and the rotor 161 are arranged. It is elastically shrunk by. In the illustrated example, an example in which a compression coil spring is used as the urging member 150 is shown. However, instead of the compression coil spring, another elastic body may be used as the urging member. Further, instead of urging the rotor 161 toward the stator 121 using the elastic reaction force of the elastic body, the urging member 150 urges the rotor 161 toward the stator 121 using magnetic force. May be.

  In addition, annular contacts 162 are formed along the outer circumference on the non-output side of the rotor 160 and the output side of the rotor 161, respectively. The contact 162 formed on the rotor 160 protrudes from the rotor 160 to the non-output side. Further, the contact 162 formed on the rotor 161 protrudes from the rotor 161 to the output side.

  Here, since the urging member 150 is elastically contracted in the axial direction of the shaft member 110, the urging force to the non-output side acts on the flange portion 190, while the rotor 161 has a force toward the output side. The biasing force is acting. As a result, when the shaft member 110 is biased to the non-output side, the contact 162 formed on the rotor 160 is equal to the stator 120, and the contact 162 formed on the rotor 161 is equal to the stator 121. Pressed with force.

  2, the rotor 160, the stator 120, and the electromechanical converter 130 disposed on the output side from the holding member 170, and the rotor 161, the stator 121, disposed on the non-output side from the holding member 170, In addition, the electromechanical conversion unit 131 is disposed at a symmetrical position with respect to the holding member 170. Further, the pair of rotors 160 and 161 are formed in a symmetrical shape with respect to the holding member 170, the pair of stators 120 and 121 are formed in a symmetrical shape with respect to the holding member 170, and further, a pair of electric machines The conversion units 130 and 131 are formed in a symmetrical shape with respect to the holding member 170.

  FIG. 3 is an exploded perspective view of the electromechanical conversion units 130 and 131. As shown in this figure, the electromechanical conversion units 130 and 131 include a plurality of electromechanical conversion element layers 138 stacked in the axial direction of the shaft member 110. Each of the electromechanical conversion element layers 138 includes a piezoelectric material plate 136 and a plurality of electrodes 132, 133, 134, and 135 formed on the surface of the piezoelectric material plate 136.

  The electrodes 132, 133, 134, and 135 have substantially the same sector shape and are arranged around the axis L at equal intervals. In addition, the electromechanical conversion element layer 138 is laminated so that the electrodes having the same reference numerals are overlapped in the axial direction, and each electrode is a conductor formed on the side surfaces of the electromechanical conversion units 130 and 131. As a result, the electrodes of the wiring boards 140 and 141 are electrically connected. In addition, a ground electrode is formed on the back side of the electrode forming surface of the piezoelectric material plate 136, and the ground electrode of each layer is formed by the conductive wires formed on the side surfaces of the electromechanical conversion units 130 and 131. Conducted to the ground electrode. The pair of electromechanical conversion units 130 and 131 are overlapped so that the electrodes having the same reference numerals are overlapped in the axial direction.

  The piezoelectric material plate 136 includes a piezoelectric material that expands when a driving voltage is applied. Specifically, it includes piezoelectric materials such as lead zirconate titanate, crystal, lithium niobate, barium titanate, lead titanate, lead metaniobate, polyvinylidene fluoride, lead zinc niobate, lead scandium niobate . 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.

  Next, the operation in this embodiment will be described. 4A to 4D are perspective views exaggeratingly showing the operations of the stator 120 and the electromechanical conversion unit 130. The arrows written between FIGS. 4A, 4B, 4C, and 4D indicate that the states of the pair of stators 120 and the pair of electromechanical transducers 130 change, and the state transitions circulate. The pair of stators 120 and the pair of electromechanical converters 130 are periodically operated. In addition, although operation | movement of the stator 120 and the electromechanical conversion part 130 is demonstrated here, the stator 121 and the electromechanical conversion part 131 operate | move symmetrically with respect to the stator 120, the electromechanical conversion part 130, and the holding member 170. .

  When a driving voltage is applied to any one of the electrodes 132, 133, 134, and 135, the axial length of the electromechanical conversion unit 130 is set to the electrodes 132, 133, 134, and 135 to which the driving voltage is applied. Increases at corresponding sites. On the other hand, the length in the axial direction of the electromechanical conversion unit 130 does not change in the portions corresponding to the electrodes 132, 133, 134, and 135 to which the drive voltage is not applied. The stator 120 is lifted at a portion where the axial length of the electromechanical transducer 130 is increased. Thereby, the stator 120 inclines.

  When a driving voltage is sequentially applied to the electrodes 132, 133, 134, and 135, the length in the axial direction of the electromechanical conversion unit 130 is sequentially increased at portions corresponding to the electrodes 132, 133, 134, and 135. For example, AC voltages having different phases by 1 / 4π are applied to the electrodes 132, 133, 134, and 135. As a result, the inclination direction of the pair of stators 120 changes in one direction around the axis, and vibration that changes in that direction is generated. Here, the stators 120 and 121 generate vibrations having a resonance frequency.

  The rotor 160 is urged by the urging member 150 and is in constant contact with the stator 120. The rotor 161 is urged by the urging member 150 and is in constant contact with the stator 121. For this reason, the rotor 160 rotates in response to the frictional driving force and the resonance that changes around the axis from the output-side stator 120 that oscillates while rotating around the tilt direction. Similarly, the rotor 161 rotates in response to frictional driving force and resonance that changes around an axis from the stator 121.

  Thereby, since the shaft member 110 rotates integrally with the pair of rotors 160 and 161, the gear 180 coupled to the shaft member 110 so as not to rotate rotates. Therefore, the motor driving force is output.

  In the present embodiment, the extension part 210 formed integrally with the stator main body 125 of the stator 120 is screwed into the holding member 170, so that the stator 120 is closer to the holding member 170 than the electromechanical conversion part 130 in the direction of the axis L. In FIG. Similarly, the extension part 211 formed integrally with the stator main body 126 of the stator 121 is screwed into the holding member 170, whereby the stator 121 is held on the holding member 170 side from the electromechanical conversion part 131 in the direction of the axis L. Coupled to member 170.

  That is, the stators 120 and 121 and the holding member 170 are coupled at a position away from the region where the stator main bodies 125 and 126 and the electromechanical conversion units 130 and 131 are in contact with each other in the direction of the axis L. Therefore, according to this embodiment, it is possible to prevent the influence of the stators 120 and 121 being deformed by being driven from the electromechanical conversion units 130 and 131 from reaching the fastening force between the screw portions 212 and 214 and the screw hole 178. In addition, loosening of the fastening between the extending portions 210 and 211 and the holding member 170 can be suppressed to the maximum.

  In the present embodiment, the pair of extending portions 210 and 211 are configured to be separated from each other in the axial direction of the shaft member 110. Thereby, the stators 120 and 121 and the holding member 170 can be fixed with the electromechanical converters 130 and 131 sandwiched therebetween. Thereby, each of the electromechanical converters 130 and 131 can be reliably brought into contact with the corresponding stator main bodies 125 and 126, and the driving force can be transmitted efficiently.

  In the present embodiment, the rotor 160, the stator 120, and the electromechanical conversion unit 130 disposed on the output side from the holding member 170, and the rotor 161, the stator 121, and the electric device disposed on the non-output side from the holding member 170 are provided. The mechanical conversion unit 131 is disposed at a symmetrical position with respect to the holding member 170. Thereby, the symmetry of the vibration characteristics generated in the pair of stators 120 and 121 can be improved, and the symmetry of the rotation characteristics of the pair of rotors 160 and 161 can be improved.

  In the present embodiment, the pair of rotors 160 and 161, the pair of stators 120 and 121, and the pair of electromechanical converters 130 and 131 are formed symmetrically with respect to the holding member 170. Thereby, the symmetry of the vibration characteristics generated in the pair of stators 120 and 121 can be further improved, and the symmetry of the rotation characteristics of the pair of rotors 160 and 161 can be further improved.

  In the present embodiment, the electromechanical converter 130 corresponding to the rotor 160 and the stator 120 and the electromechanical converter 131 corresponding to the rotor 161 and the stator 121 are provided. As a result, the vibration characteristics of the stators 120 and 121 can be individually adjusted. Therefore, even if a deviation occurs in the vibration characteristics of the pair of stators 120 and 121 due to the dimensional accuracy and assembly accuracy of each part, the deviation is reduced. Can be reduced. Therefore, the symmetry of the rotational characteristics of the pair of rotors 160 and 161 can be secured, and the output can be improved efficiently.

  Next, another embodiment will be described. In addition, the same code | symbol is attached | subjected to the structure similar to the said embodiment, and description is abbreviate | omitted.

  FIG. 5 is a perspective view of a vibration actuator 200 according to another embodiment. FIG. 6 is a side sectional view of the vibration actuator 200. As shown in these drawings, in the vibration actuator 200, a cylindrical nut 230 is rotatably fitted to the shaft centers of the rotors 160 and 161. The nut 230 is screwed into the threaded portions 117 and 118 of the shaft member 110, and the rotors 160 and 161 are rotatably supported by the shaft member 110 via the nut 230.

  Further, a screw hole 182 is formed in the gear 180 in a direction orthogonal to the axis L, and a fixing screw 184 is screwed into the screw hole 182. The distal end portion of the fixing screw 184 is in pressure contact with the screw portion 117 of the shaft member 110. Therefore, when the shaft member 110 rotates, a frictional force is generated at the tip portions of the screw portion 117 and the fixing screw 184, and the gear 180 rotates following the shaft member 110 by the frictional force.

  In the vibration actuator 200, donut-shaped elastic plates 220 and 221 are disposed between the rotor 160 and the gear 180 and between the rotor 161 and the flange portion 190, respectively. The elastic plates 220 and 221 are made of rubber and can be elastically deformed in the thickness direction. The elastic plates 220 and 221 are pressurized and elastically compressed by the rotor 160 and the gear 180 and the rotor 161 and the flange portion 190, respectively. Yes.

  For this reason, when the rotor 160 is rotated by the vibration of the stator 120, a frictional force in the rotational direction is generated between the rotor 160 and the elastic plate 220, and between the elastic plate 220 and the gear 180. The elastic plate 220 rotates following the rotor 160, and the gear 180 rotates following the elastic plate 220. Therefore, the rotor 160, the elastic plate 220, the gear 180, and the shaft member 110 screwed with the gear 180 rotate together.

  Similarly, when the rotor 161 is rotated by the vibration of the stator 120, frictional force in the rotational direction is generated between the rotor 161 and the elastic plate 221 and between the elastic plate 220 and the flange portion 190. Therefore, the rotor 161, the elastic plate 221, the flange portion 190, and the shaft member 110 screwed with the flange portion 190 rotate together. As described above, although the gear 180 and the flange portion 190 are screwed to the shaft member 110, the rotors 160 and 161 existing between them are not required to be screwed or bonded to the shaft member 110 or keyed. Therefore, the assemblability can be improved and the coupling structure between the shaft member 110 and the rotor 160 can be simplified.

  FIG. 7 shows a schematic configuration of an imaging apparatus 700 including the vibration actuator 100 in a side sectional view. As shown in this figure, the imaging apparatus 700 includes an optical member 420, a lens barrel 430, a vibration actuator 100, an imaging unit 500, and a control unit 550. The lens barrel 430 accommodates the optical member 420.

  The vibration 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 vibration 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 vibration 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 vibration 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. Accordingly, the vibration actuator 100 is accommodated in the lens barrel 430 without increasing the diameter of the lens barrel 430. The vibration 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, an autofocus mechanism can be formed by controlling the rotation of the vibration actuator 100 in accordance with the distance information to the subject detected by the distance measuring unit 530 on the body 460 side. Further, when the distance measuring unit 530 refers to the operation amount of the vibration actuator 100, a focus aid mechanism can be formed. The vibration actuator 100 and the imaging unit 500 are controlled by the control unit 550 as described above.

  Here, as described above, the motor output of the vibration actuator 100 can be efficiently increased. 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 vibration actuator 100 has been illustrated, it goes without saying that the vibration actuator 100 can drive the opening / closing of the iris unit 440, the movement of the variator lens of the zoom lens, and the like. Also in this case, the vibration actuator 100 contributes to automating exposure, execution of a scene mode, execution of bracket photography, and the like by referring to information with the photometric unit 480, the finder liquid crystal 494, and the like via an electrical signal. In the present embodiment, the imaging apparatus 700 including the vibration actuator 100 has been described as an example, but the vibration actuator 200 may be provided instead of the vibration actuator 100.

  As described above, the vibration actuators 100 and 200 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.

The vibration actuator 100 which concerns on one Embodiment of this invention is shown with a perspective view. The vibration actuator 100 which concerns on one Embodiment of this invention is shown with a sectional side view. The electromechanical converter 130 is shown in an exploded perspective view. The perspective view explaining operation | movement of the stator 120 and the electromechanical conversion part 130 is shown. The perspective view explaining operation | movement of the stator 120 and the electromechanical conversion part 130 is shown. The perspective view explaining operation | movement of the stator 120 and the electromechanical conversion part 130 is shown. The perspective view explaining operation | movement of the stator 120 and the electromechanical conversion part 130 is shown. The vibration actuator 200 which concerns on other embodiment of this invention is shown with a perspective view. The vibration actuator 200 which concerns on other embodiment of this invention is shown with a sectional side view. A schematic configuration of the imaging apparatus 700 is shown in a side sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Vibration actuator, 110 Shaft member, 117 Thread part, 118 Thread part, 120 Stator, 121 Stator, 122 Bearing, 125 Stator body, 126 Stator body, 130 Electromechanical conversion part, 131 Electromechanical conversion part, 132 electrode, 133 electrode , 134 electrode, 135 electrode, 136 piezoelectric material plate, 138 electromechanical conversion element layer, 140 wiring board, 141 wiring board, 142 electrode part, 144 wiring part, 150 biasing member, 160 rotor, 161 rotor, 162 contactor, 170 holding member, 172 base portion, 174 flange portion, 176 fastening hole, 178 screw hole, 180 gear, 182 screw hole, 184 fixing screw, 190 flange portion, 200 vibration actuator, 210 extension portion, 211 extension portion, 212 screw portion , 214 , 220 elastic plate, 221 elastic plate, 230 nut, 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 mirror, 494 Finder liquid crystal, 500 Imaging unit, 510 Optical filter, 520 Shutter, 530 Distance measuring unit, 540 Main mirror, 542 Sub mirror, 550 Control unit, 700 Imaging device

Claims (8)

A shaft member;
A pair of rotors rotatable around the axis of the shaft member;
A pair of stators arranged in contact with each of the pair of rotors between the pair of rotors in the direction of the axis, and through which the shaft member is inserted;
A pair of electromechanical converters that are arranged between the pair of stators in the direction of the axis and through which the shaft member is inserted to impart vibrations that change around the axis to each of the pair of stators;
The electric machine disposed between the pair of electromechanical converters in the direction of the axis and through which the shaft member is inserted, coupled to both of the pair of stators, and corresponding to each of the pair of stators A holding member that holds the conversion unit in between,
Each of the pair of stators and the holding member is a vibration actuator that is coupled on the holding member side with respect to the pair of electromechanical converters in the direction of the axis.   Each of the pair of stators includes a stator main body that contacts the corresponding rotor, and extends from the stator main body to the holding member, passes through the corresponding electromechanical conversion unit, and the shaft member is inserted, and The vibration actuator according to claim 1, further comprising an extending portion that is screwed with the holding member.   The vibration actuator according to claim 2, wherein the pair of extending portions are separated from each other in the direction of the axis.   The vibration actuator according to claim 1, wherein the pair of rotors, the pair of stators, and the pair of electromechanical converters are arranged symmetrically with respect to the holding member.   5. The vibration actuator according to claim 4, wherein the pair of rotors, the pair of stators, and the pair of electromechanical converters are symmetrical to each other with respect to the holding member. The shaft member is supported by the stator so as to be relatively rotatable,
In each of the pair of rotors, a pair of pinching members disposed on the opposite side of the corresponding stator along the axis and fixed to the shaft member;
Pressurized state between one of the pair of rotors and the pinching member corresponding to the one rotor, and between the other of the pair of rotors and the pinching member corresponding to the other rotor A pair of elastic plates sandwiched between,
The vibration actuator according to claim 1. A vibration actuator;
An optical member moved by the vibration actuator;
A lens barrel that houses the vibration actuator and the optical member;
The vibration actuator is
A shaft member;
A pair of rotors rotatable around the axis of the shaft member;
A pair of stators arranged in contact with each of the pair of rotors between the pair of rotors in the direction of the axis, and through which the shaft member is inserted;
A pair of electromechanical converters that are arranged between the pair of stators in the direction of the axis and through which the shaft member is inserted to impart vibrations that change around the axis to each of the pair of stators;
The electric machine disposed between the pair of electromechanical converters in the direction of the axis and through which the shaft member is inserted, coupled to both of the pair of stators, and corresponding to each of the pair of stators A holding member that holds the conversion unit therebetween,
Each of the pair of stators and the holding member is a lens unit that is coupled on the holding member side with respect to the pair of electromechanical converters in the direction of the axis. A vibration actuator;
An optical member moved by the vibration actuator;
A lens barrel that houses the optical member;
An imaging unit that captures an image formed by the optical member;
With
The vibration actuator is
A shaft member;
A pair of rotors rotatable around the axis of the shaft member;
A pair of stators arranged in contact with each of the pair of rotors between the pair of rotors in the direction of the axis, and through which the shaft member is inserted;
A pair of electromechanical converters that are arranged between the pair of stators in the direction of the axis and through which the shaft member is inserted to impart vibrations that change around the axis to each of the pair of stators;
The electric machine disposed between the pair of electromechanical converters in the direction of the axis and through which the shaft member is inserted, coupled to both of the pair of stators, and corresponding to each of the pair of stators A holding member that holds the conversion unit therebetween,
The imaging device in which each of the pair of stators and the holding member are coupled on the holding member side with respect to the pair of electromechanical conversion units in the direction of the axis.

Images