WO2013129573A1 - Vibration actuator and lens barrel - Google Patents

Vibration actuator and lens barrel Download PDF

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Publication number
WO2013129573A1
WO2013129573A1 PCT/JP2013/055412 JP2013055412W WO2013129573A1 WO 2013129573 A1 WO2013129573 A1 WO 2013129573A1 JP 2013055412 W JP2013055412 W JP 2013055412W WO 2013129573 A1 WO2013129573 A1 WO 2013129573A1
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WO
WIPO (PCT)
Prior art keywords
stator
vibration actuator
elastic body
radial direction
piezoelectric element
Prior art date
Application number
PCT/JP2013/055412
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French (fr)
Japanese (ja)
Inventor
光輝 日野
佐藤　高広
慎二 西原
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株式会社ニコン
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Publication of WO2013129573A1 publication Critical patent/WO2013129573A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/10—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors
    • H02N2/16—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors using travelling waves, i.e. Rayleigh surface waves
    • H02N2/163—Motors with ring stator
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
    • G02B7/08—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification adapted to co-operate with a remote control mechanism
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
    • G02B7/10—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification by relative axial movement of several lenses, e.g. of varifocal objective lens
    • G02B7/102—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification by relative axial movement of several lenses, e.g. of varifocal objective lens controlled by a microcomputer

Definitions

  • the present invention relates to a vibration actuator and a lens barrel including the vibration actuator.
  • the vibration actuator includes a stator in which an elastic body and an electromechanical conversion element are combined.
  • the electromechanical transducer of the vibration actuator is excited by a drive signal to generate a traveling wave on the surface of the elastic body. This traveling wave causes an elliptical motion on the surface of the elastic body.
  • the movable element in pressure contact with the surface of the elastic body is driven by the wavefront of the elliptical motion and converted into a rotational motion.
  • An object of the present invention is to provide a vibration actuator and a lens barrel that can be further thinned.
  • an annular elastic body and a stator having an electromechanical transducer for generating a traveling wave in the elastic body, and the traveling wave generated in the elastic body in contact with the elastic body.
  • a vibration actuator comprising a mover that moves relative to the stator, wherein the elastic body has a contact surface with the mover provided on a side surface in a radial direction.
  • the elastic body is provided with a contact surface with the moving element on a radially inner side, and the electromechanical transducer element on a radially outer side. Is provided.
  • the elastic body in the vibration actuator according to the first aspect, is provided with a contact surface with the moving element on a radially outer side, and the electromechanical transducer element on a radially inner side. Is provided.
  • the elastic body in the vibration actuator according to the first aspect, is provided with a contact surface with the moving element on a radially inner side, and the elastic body has the surface on at least one surface in the central axis direction.
  • An electromechanical conversion element is provided.
  • the elastic body is provided with a contact surface with the moving element on a radially outer side, and the elastic body has the surface on at least one surface in the central axis direction.
  • An electromechanical conversion element is provided.
  • the electromechanical conversion element is provided on both surfaces in the central axis direction of the elastic body.
  • a seventh aspect of the present invention is the vibration actuator according to the sixth aspect, wherein the electromechanical transducer elements provided on both surfaces of the elastic body in the central axis direction are wavelength relative to each other when viewed from the direction of the central axis. Is characterized by a 1 ⁇ 4 shift.
  • a stator including an annular elastic body, an electromechanical transducer that generates a traveling wave in the elastic body, and the elastic body in contact with the stator.
  • a moving actuator that moves relative to the stator by waves, The elastic body and the mover are vibration actuators that are brought into pressure contact in a radial direction.
  • the invention described in claim 9 is a lens barrel comprising the vibration actuator according to any one of claims 1 to 8 and an optical member driven by the vibration actuator.
  • FIG. 1 is a schematic configuration diagram of a camera 1 on which an ultrasonic motor 10 of Embodiment 1 is mounted. It is a top view when the ultrasonic motor 10 of Embodiment 1 is seen from the central axis direction.
  • 1 is a perspective view showing a stator base 11a in an ultrasonic motor 10 according to Embodiment 1.
  • FIG. 1 is a perspective view showing a piezoelectric element 12 in an ultrasonic motor 10 according to Embodiment 1.
  • FIG. FIG. 3 is a plan view when comb teeth 11b are formed on a radially outer peripheral surface of a stator 11 in the ultrasonic motor 10 according to the first embodiment.
  • FIG. 6 is a perspective view showing an ultrasonic motor 20 according to a second embodiment.
  • FIG. 6 is a plan view when the stator 21 of the second embodiment is viewed from the phase A side of the piezoelectric element 22.
  • FIG. 6 is a plan view when the stator 21 of the second embodiment is viewed from the B phase portion side of the piezoelectric element 22.
  • FIG. 6 is a perspective view of the ultrasonic motor 20 according to the second embodiment when comb teeth 21b are formed on the inner circumferential surface of the stator 21 in the radial direction.
  • FIG. 1 is a schematic configuration diagram of a camera 1 equipped with the ultrasonic motor 10 of the first embodiment.
  • the camera 1 includes a camera body 2 and a lens barrel 3.
  • the camera body 2 includes an image sensor 6.
  • the imaging element 6 is an imaging device that captures a subject image formed by the lens barrel 3.
  • the lens barrel 3 is an interchangeable lens that is detachably attached to the camera body 2.
  • the lens barrel 3 is an interchangeable lens.
  • the present invention is not limited to this, and a lens barrel integrated with the camera body may be used.
  • the lens barrel 3 includes a lens 4 as an optical member, a cam barrel 5, an ultrasonic motor 10, and other members (not shown).
  • the ultrasonic motor 10 of the present embodiment is used as a drive source for driving the lens 4 when adjusting the focus of the camera 1.
  • the driving force extracted from the ultrasonic motor 10 is transmitted to the cam cylinder 5 through a power transmission mechanism (not shown).
  • the cam cylinder 5 is engaged with the lens 4 by a cam mechanism.
  • the cam cylinder 5 is rotated by the driving force of the ultrasonic motor 10, the lens 4 is moved in the direction of the optical axis A by the cam mechanism. Thereby, focus adjustment is performed.
  • FIG. 2 is a plan view of the ultrasonic motor 10 according to the first embodiment when viewed from the central axis direction.
  • FIG. 3 is a perspective view showing the stator base 11a in the ultrasonic motor 10 of the first embodiment.
  • FIG. 4 is a perspective view showing the piezoelectric element 12 in the ultrasonic motor 10 according to the first embodiment.
  • the ultrasonic motor 10 of the present embodiment includes a stator 11 as a stator and a rotor 13 as a mover.
  • the stator 11 includes a stator base 11a and comb teeth 11b shown in FIG. 3, and a piezoelectric element 12 shown in FIG.
  • the stator base 11a is an elastic body formed in an annular shape as shown in FIG.
  • the stator base 11a is made of an elastically deformable metal material such as an iron alloy such as stainless steel or invar material or brass.
  • the comb teeth 11b are portions formed on the inner circumferential surface of the stator base 11a in the radial direction.
  • the comb tooth 11b is an amplification (enlargement) mechanism that amplifies the amplitude of the traveling wave.
  • a stator sliding surface 11c is formed on the tip surface of the comb teeth 11b.
  • the outer peripheral surface of the rotor 16 is brought into pressure contact with the stator sliding surface 11c.
  • the stator sliding surface 11 c is a contact surface between the stator base 11 a and the rotor 16.
  • the stator 11 includes a piezoelectric element bonding surface 11d on the outer circumferential surface of the stator base 11a in the radial direction.
  • the piezoelectric element 12 is bonded to the piezoelectric element bonding surface 11d.
  • the piezoelectric element 12 is excited by being supplied with a drive signal, and generates a traveling wave in the stator base 11a.
  • the elliptical motion generated in the stator base 11a by this traveling wave is amplified by the comb teeth 11b.
  • the amplified elliptical motion is converted into rotational motion by the rotor 13 in pressure contact with the stator sliding surface 11c.
  • the piezoelectric element 12 is a cylindrical electrode member as shown in FIG.
  • the piezoelectric element 12 is an electromechanical transducer that converts electrical energy into mechanical energy.
  • the piezoelectric element 12 is made of, for example, PZT (lead zirconate titanate), ceramics, or the like. As shown in FIG. 2, the piezoelectric element 12 is bonded to the outer peripheral surface (piezoelectric element bonding surface 11d) of the stator base 11a.
  • the piezoelectric element 12 of this embodiment is polarized so as to have 6 wavelengths (6 ⁇ ) over the entire circumference.
  • the piezoelectric element 12 includes an A-phase portion 12a, a B-phase portion 12b, a ⁇ / 4 portion 12c, and a 3 / 4 ⁇ portion 12d.
  • the A-phase portion 12a is polarized so that the polarization directions are alternately reversed (A +, A-, A +, A-, A +) every half wavelength.
  • the B phase portion 12b is also polarized so that the polarization direction is alternately reversed (B +, B ⁇ , B +, B ⁇ , B +) for each half wavelength.
  • the ⁇ / 4 portion 12c is an unpolarized region formed in order to shift the A phase portion 12a and the B phase portion 12b from each other by 1 ⁇ 4 wavelength.
  • the 3 / 4 ⁇ portion 12d is an unpolarized region formed to shift the A phase portion 12a and the B phase portion 12b by 3/4 wavelengths from each other.
  • the A-phase portion 12a and the B-phase portion 12b are arranged symmetrically with the ⁇ / 4 portion 12c and the 3 / 4 ⁇ portion 12d interposed therebetween.
  • the A phase part 12a and the B phase part 12b of the piezoelectric element 12 are connected to a flexible printed circuit board (not shown) provided inside the lens barrel 3 (FIG. 1).
  • a lens CPU (not shown) is mounted on the flexible printed circuit board.
  • the piezoelectric element 12 is excited by a drive signal supplied from a flexible printed board, and generates a traveling wave in the stator base 11a.
  • the stator base 11a generates an elliptical motion by this traveling wave. This elliptical motion is further amplified by the comb teeth 11b.
  • the rotor 13 is a member formed in an annular shape as shown in FIG.
  • the rotor 13 is disposed inside the stator 11 in the radial direction.
  • the rotor 13 is in pressure contact with the stator sliding surface 11c of the comb teeth 11b by a pressure mechanism (not shown).
  • the rotor 13 is supported by a support mechanism (not shown) so as to be rotatable around the central axis.
  • the rotor 13 in pressure contact with the stator sliding surface 11 c moves (rotates) relative to the stator 11 by the elliptical motion amplified by the comb teeth 11 b of the stator 11.
  • the elliptical motion amplified by the comb teeth 11b of the stator 11 is converted into rotational motion by the rotor 13 and transmitted to the cam cylinder 5 (FIG. 1) via a power transmission mechanism (not shown).
  • the ultrasonic motor 10 has the following effects.
  • the stator 11 includes a stator sliding surface 11c in pressure contact with the rotor 13 on the radially inner side. Thereby, the direction of taking out the rotational motion by the rotor 13 is the radial direction of the stator 11. For this reason, the length of the rotation axis direction of the ultrasonic motor 10 can be shortened. Therefore, the ultrasonic motor 10 can be further reduced in thickness. And the optical apparatus carrying this ultrasonic motor 10 can shorten the full length of an optical axis direction. Accordingly, it is possible to mount the ultrasonic motor on a thin optical device, which has been difficult in the past.
  • the rotor 13 is disposed inside the stator 11 in the radial direction. For this reason, the radial dimension in the lens barrel 3 can be reduced. Since the drive signal supplied to the piezoelectric element 12 is two alternating voltages whose phases are different from each other by 90 degrees, the peripheral drive circuit can be simplified.
  • the ultrasonic motor 10 of the first embodiment the example in which the comb teeth 11b are formed on the inner circumferential surface in the radial direction of the stator base 11a has been described. However, as illustrated in FIG. You may form in the outer peripheral surface of radial direction. In this case, the rotor 13 is disposed outside the stator 11 and is in pressure contact with the stator sliding surface 11c of the comb teeth 11b. Even when the ultrasonic motor 10 of the first embodiment is configured as shown in FIG. 5, the ultrasonic motor 10 can be further reduced in thickness.
  • FIG. 6 is a perspective view showing the ultrasonic motor 20 of the second embodiment.
  • FIG. 7 is a side view of the stator 21 according to the second embodiment when viewed from the radial direction.
  • FIG. 8 is a plan view when the stator 21 of the second embodiment is viewed from the phase A side of the piezoelectric element 22.
  • FIG. 9 is a plan view when the stator 21 of the second embodiment is viewed from the B-phase portion side of the piezoelectric element 22.
  • the ultrasonic motor 20 of the present embodiment includes a stator 21 as a stator and a rotor 23 as a mover.
  • the stator 21 includes a stator base 21a, comb teeth 21b, and a piezoelectric element 22.
  • the stator base 21a is an elastic body formed in an annular shape as shown in FIG.
  • the stator base 21a is made of an elastically deformable metal material such as an iron alloy such as stainless steel or invar material or brass.
  • the comb teeth 21b are portions formed on the outer peripheral surface of the stator base 21a in the radial direction.
  • the comb tooth 21b is an amplification (enlargement) mechanism that amplifies the amplitude of the traveling wave.
  • a stator sliding surface 21c is formed on the tip surface of the comb teeth 21b.
  • the inner peripheral surface of the rotor 23 is brought into pressure contact with the stator sliding surface 21c.
  • the stator sliding surface 21 c is a contact surface between the stator base 21 a and the rotor 23.
  • the stator 21 has an A-phase portion 22a of a piezoelectric element 22 joined to the upper surface of the stator base 21a in the central axis direction.
  • the stator 21 has a B-phase portion 22b of the piezoelectric element 22 joined to the lower surface of the stator base 21a in the central axis direction.
  • the piezoelectric elements 22 bonded to both surfaces in the central axis direction are excited by a drive signal to generate a traveling wave in the stator base 21a.
  • the stator base 21a generates an elliptical motion by this traveling wave. This elliptical motion is amplified by the comb teeth 21b.
  • the elliptical motion amplified by the comb teeth 21b is converted into rotational motion by the rotor 23 in pressure contact with the stator sliding surface 21c.
  • the piezoelectric element 22 is an electrode member formed in an annular shape.
  • the piezoelectric element 22 is an electromechanical transducer that converts electrical energy into mechanical energy.
  • the piezoelectric element 22 is made of, for example, PZT (lead zirconate titanate), ceramics, or the like.
  • the piezoelectric element 22 of the present embodiment is polarized so as to have 9 wavelengths (9 ⁇ ) on the upper and lower surfaces of the stator base 21a. That is, the piezoelectric element 22 includes an A phase portion 22a and a B phase portion 22b. As shown in FIG. 8, in the A phase portion 22a of the piezoelectric element 22, the polarization directions are alternately reversed (A +, A ⁇ , A +,... A ⁇ , A +, A ⁇ ) every half wavelength. Are polarized to 18 poles. Further, as shown in FIG. 9, the B-phase portion 22b of the piezoelectric element 22 has a polarization direction alternately reversed every half wavelength (B +, B ⁇ , B +,... B ⁇ , B +, B ⁇ ). It is polarized to 18 poles. In the A-phase portion 22a and the B-phase portion 22b of the piezoelectric element 22, a pair of adjacent poles (+, ⁇ ) whose polarization directions are opposite to each other correspond to one wavelength.
  • the A-phase portion 22a and the B-phase portion 22b of the piezoelectric element 22 are joined so as to be shifted by a quarter wavelength ( ⁇ ) in the circumferential direction of the stator 21, as shown in FIG.
  • ⁇ quarter wavelength
  • region of (lambda) / 4 part 12c and 3/4 (lambda) part 12d for shifting A phase part 12a and B phase part 12b by predetermined wavelength becomes unnecessary.
  • the A-phase portion 22a and the B-phase portion 22b of the piezoelectric element 22 are connected to a flexible printed circuit board (not shown) provided inside the lens barrel 3 (FIG. 1).
  • a lens CPU (not shown) is mounted on the flexible printed circuit board. From the flexible printed board, two AC voltages whose phases are different from each other by 90 degrees are supplied to the A-phase portion 22a and the B-phase portion 22b of the piezoelectric element 22 as drive signals.
  • the piezoelectric element 22 is excited by a drive signal supplied from a flexible printed board, and generates a traveling wave in the stator base 21a.
  • the rotor 23 is a member formed in an annular shape as shown in FIG.
  • the rotor 23 is disposed outside the stator 21 in the radial direction.
  • the rotor 23 is in pressure contact with the stator sliding surface 21c of the comb tooth 21b by a pressure mechanism (not shown).
  • the rotor 23 is supported by a support mechanism (not shown) so as to be rotatable around the central axis.
  • the rotor 23 moves (rotates) relative to the stator 21 by the elliptical motion amplified by the comb teeth 21b of the stator 21. That is, the elliptical motion amplified by the comb teeth 21b of the stator 21 is converted into rotational motion by the rotor 23 and transmitted to the cam cylinder 5 (FIG. 1) via a power transmission mechanism (not shown).
  • the ultrasonic motor 20 has the following effects.
  • the stator 21 includes a stator sliding surface 21c that is in pressure contact with the rotor 23 on the radially outer side.
  • the direction in which the rotary motion is extracted by the rotor 23 is the radial direction of the stator 21.
  • the length of the rotation axis direction of the ultrasonic motor 20 can be shortened. Therefore, the ultrasonic motor 20 can be further reduced in thickness.
  • the optical apparatus carrying this ultrasonic motor 20 can shorten the full length of an optical axis direction. Accordingly, it is possible to mount the ultrasonic motor on a thin optical device, which has been difficult in the past.
  • the rotor 23 is disposed outside the stator 21 in the radial direction. For this reason, the space for accommodating the cam cylinder 5 and the lens 4 can be widened on the inner side in the radial direction.
  • the A-phase portion 22 a and the B-phase portion 22 b of the piezoelectric element 22 are joined so as to be shifted by a quarter wavelength ( ⁇ ) in the circumferential direction of the stator 21. For this reason, the area
  • the ultrasonic motor 20 according to the second embodiment the example in which the comb teeth 21b are formed on the radial outer peripheral surface of the stator base 21a has been described. However, as illustrated in FIG. You may form in the inner peripheral surface of a direction. In this case, the rotor 23 is disposed inside the stator 21 and is in pressure contact with the stator sliding surface 21c of the comb teeth 21b. Even when the ultrasonic motor 20 of the second embodiment is configured as shown in FIG. 10, the ultrasonic motor 20 can be further reduced in thickness.
  • the present invention can be variously modified and changed as described below, and these are also within the scope of the present invention.
  • the annular base shown in the second embodiment is formed on both surfaces (or one surface) of the stator base 11a in the central axis direction.
  • the piezoelectric element 22 may be bonded.
  • the piezoelectric element 22 (A phase portion 22a or B phase portion 22b) may be bonded only to one surface of the stator base 11a in the central axis direction. In that case, as in the first embodiment, the ⁇ / 4 portion 12c and the 3 / 4 ⁇ portion 12d are arranged.
  • the cylindrical piezoelectric element 12 shown in the first embodiment is bonded to the inner peripheral surface of the stator base 21a in addition to the annular piezoelectric element 22 bonded to both surfaces in the central axis direction of the stator base 21a. May be.
  • the vibration actuator a rotary ultrasonic motor in which the rotor is driven to rotate is described as an example.
  • the present invention is not limited to this, and a linear actuator may be used.
  • the ultrasonic actuator using the vibration in the ultrasonic region is described as an example of the vibration actuator.
  • the present invention is not limited to this.
  • the present invention may be applied to a vibration actuator that uses vibrations outside the ultrasonic range.
  • the example which used the ultrasonic motors 10 and 20 as a drive source for driving the lens 4 at the time of the focus adjustment of the camera 1 was demonstrated.
  • the present invention is not limited to this.
  • the lens barrel 3 when the lens barrel 3 is a zoom lens, the lens barrel 3 may be used as a drive source during zoom driving. Further, it may be used as a drive source of a camera shake correction mechanism that drives a part of the lens 4 to correct camera shake.
  • the present invention can be applied to optical devices other than cameras. Further, it can also be used in a driving unit of a copying machine or a facsimile, a steering wheel tilt device or a headrest driving unit of an automobile, a driving device of a watch, or the like.

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  • Lens Barrels (AREA)
  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)

Abstract

Provided is a vibration actuator and a lens barrel for which the thickness can be reduced. The vibration actuator (10) according to the present invention is a vibration actuator (10, 20) equipped with a stator, which has an annular elastic body (11a) and an electromechanical conversion element (12) that generates traveling waves in the elastic body, and a moving element, which makes contact with the elastic body and is moved relative to the stator by the traveling waves generated in the elastic body, said vibration actuator being characterized in that the contact surface (11c) of the elastic body with respect to the moving element is provided on the side surface in the radial direction.

Description

振動アクチュエータ及びレンズ鏡筒Vibration actuator and lens barrel
　本発明は、振動アクチュエータ、それを備えたレンズ鏡筒に関するものである。 The present invention relates to a vibration actuator and a lens barrel including the vibration actuator.
　近年、振動アクチュエータを備えたレンズ鏡筒やカメラボディ等の光学機器が製品化されている。振動アクチュエータは、弾性体と電気機械変換素子とを組み合わせた固定子を備えている。振動アクチュエータの電気機械変換素子は、駆動信号により励振し、弾性体の表面に進行波を発生させる。この進行波により弾性体の表面には楕円運動が生じる。そして、弾性体の表面に加圧接触された移動子が楕円運動の波頭により駆動され、回転運動に変換される。 In recent years, optical devices such as lens barrels and camera bodies equipped with vibration actuators have been commercialized. The vibration actuator includes a stator in which an elastic body and an electromechanical conversion element are combined. The electromechanical transducer of the vibration actuator is excited by a drive signal to generate a traveling wave on the surface of the elastic body. This traveling wave causes an elliptical motion on the surface of the elastic body. Then, the movable element in pressure contact with the surface of the elastic body is driven by the wavefront of the elliptical motion and converted into a rotational motion.
　ところで、レンズ鏡筒に搭載されている振動アクチュエータは、固定子と移動子とが回転軸方向に沿って配置されている。このため、レンズ鏡筒が光軸方向に長くなる傾向がある。これを解消するため、固定子と移動子とを加圧接触させる加圧手段を、固定子の側方に配置した振動アクチュエータが提案されている（特許文献１参照）。 Incidentally, in the vibration actuator mounted on the lens barrel, the stator and the mover are arranged along the rotation axis direction. For this reason, the lens barrel tends to be long in the optical axis direction. In order to solve this problem, there has been proposed a vibration actuator in which a pressurizing unit that pressurizes and contacts the stator and the mover is disposed on the side of the stator (see Patent Document 1).
特開昭６３－１０３６７５号公報JP-A-63-103675
　しかしながら、上述した従来の振動アクチュエータにおいても、固定子と移動子とが回転軸方向に沿って配置されているため、更に薄型化することは困難であった。 However, in the conventional vibration actuator described above, since the stator and the mover are arranged along the direction of the rotation axis, it is difficult to further reduce the thickness.
　本発明の課題は、更なる薄型化を可能とした振動アクチュエータ及びレンズ鏡筒を提供することにある。 An object of the present invention is to provide a vibration actuator and a lens barrel that can be further thinned.
　本発明は、以下のような解決手段により前記課題を解決する。
　請求項１に記載の発明は、円環形の弾性体及び当該弾性体に進行波を発生させる電気機械変換素子を有する固定子と、前記弾性体と接触し、当該弾性体に発生した進行波により前記固定子と相対移動する移動子と、を備えた振動アクチュエータであって、前記弾性体が、前記移動子との接触面が径方向の側面に設けられていることを特徴とする。
　請求項２に記載の発明は、請求項１に記載の振動アクチュエータにおいて、前記弾性体は、径方向の内側に前記移動子との接触面が設けられ、径方向の外側に前記電気機械変換素子が設けられていることを特徴とする。
　請求項３に記載の発明は、請求項１に記載の振動アクチュエータにおいて、前記弾性体は、径方向の外側に前記移動子との接触面が設けられ、径方向の内側に前記電気機械変換素子が設けられていることを特徴とする。
　請求項４に記載の発明は、請求項１に記載の振動アクチュエータにおいて、前記弾性体は、径方向の内側に前記移動子との接触面が設けられ、中心軸方向の少なくとも一方の面に前記電気機械変換素子が設けられていることを特徴とする。
　請求項５に記載の発明は、請求項１に記載の振動アクチュエータにおいて、前記弾性体は、径方向の外側に前記移動子との接触面が設けられ、中心軸方向の少なくとも一方の面に前記電気機械変換素子が設けられていることを特徴とする。
　請求項６に記載の発明は、請求項４又は５に記載の振動アクチュエータにおいて、前記弾性体は、中心軸方向の両方の面にそれぞれ前記電気機械変換素子が設けられていることを特徴とする。
　請求項７に記載の発明は、請求項６に記載の振動アクチュエータにおいて、前記弾性体の中心軸方向の両面に設けられた前記電気機械変換素子は、中心軸方向からの矢視において、互いに波長が１／４ずれていることを特徴とする。
　請求項８に記載の発明は、円環形の弾性体と、前記弾性体に進行波を発生させる電気機械変換素子とにより構成される固定子と、前記弾性体と接触し、前記弾性体の進行波により前記固定子に対して相対移動する移動子と、を備えた振動アクチュエータであって、
　前記弾性体と、前記移動子とは、径方向の加圧接触されることを特徴とする振動アクチュエータである。
　請求項９に記載の発明は、請求項１～８のいずれか１項に記載の振動アクチュエータと、前記振動アクチュエータにより駆動される光学部材と、を備えることを特徴とするレンズ鏡筒である。 The present invention solves the above problems by the following means.
According to the first aspect of the present invention, an annular elastic body and a stator having an electromechanical transducer for generating a traveling wave in the elastic body, and the traveling wave generated in the elastic body in contact with the elastic body. A vibration actuator comprising a mover that moves relative to the stator, wherein the elastic body has a contact surface with the mover provided on a side surface in a radial direction.
According to a second aspect of the present invention, in the vibration actuator according to the first aspect, the elastic body is provided with a contact surface with the moving element on a radially inner side, and the electromechanical transducer element on a radially outer side. Is provided.
According to a third aspect of the present invention, in the vibration actuator according to the first aspect, the elastic body is provided with a contact surface with the moving element on a radially outer side, and the electromechanical transducer element on a radially inner side. Is provided.
According to a fourth aspect of the present invention, in the vibration actuator according to the first aspect, the elastic body is provided with a contact surface with the moving element on a radially inner side, and the elastic body has the surface on at least one surface in the central axis direction. An electromechanical conversion element is provided.
According to a fifth aspect of the present invention, in the vibration actuator according to the first aspect, the elastic body is provided with a contact surface with the moving element on a radially outer side, and the elastic body has the surface on at least one surface in the central axis direction. An electromechanical conversion element is provided.
According to a sixth aspect of the present invention, in the vibration actuator according to the fourth or fifth aspect, the electromechanical conversion element is provided on both surfaces in the central axis direction of the elastic body. .
A seventh aspect of the present invention is the vibration actuator according to the sixth aspect, wherein the electromechanical transducer elements provided on both surfaces of the elastic body in the central axis direction are wavelength relative to each other when viewed from the direction of the central axis. Is characterized by a ¼ shift.
According to an eighth aspect of the present invention, there is provided a stator including an annular elastic body, an electromechanical transducer that generates a traveling wave in the elastic body, and the elastic body in contact with the stator. A moving actuator that moves relative to the stator by waves,
The elastic body and the mover are vibration actuators that are brought into pressure contact in a radial direction.
The invention described in claim 9 is a lens barrel comprising the vibration actuator according to any one of claims 1 to 8 and an optical member driven by the vibration actuator.
　本発明によれば、更なる薄型化を可能とした振動アクチュエータ及びレンズ鏡筒を提供することができる。 According to the present invention, it is possible to provide a vibration actuator and a lens barrel that can be further reduced in thickness.
実施形態１の超音波モータ１０を搭載したカメラ１の概略構成図である。1 is a schematic configuration diagram of a camera 1 on which an ultrasonic motor 10 of Embodiment 1 is mounted. 実施形態１の超音波モータ１０を中心軸方向から見たときの平面図である。It is a top view when the ultrasonic motor 10 of Embodiment 1 is seen from the central axis direction. 実施形態１の超音波モータ１０におけるステータベース１１ａを示す斜視図である。1 is a perspective view showing a stator base 11a in an ultrasonic motor 10 according to Embodiment 1. FIG. 実施形態１の超音波モータ１０における圧電素子１２を示す斜視図である。1 is a perspective view showing a piezoelectric element 12 in an ultrasonic motor 10 according to Embodiment 1. FIG. 実施形態１の超音波モータ１０において櫛歯１１ｂをステータ１１の径方向の外周面に形成した場合の平面図である。FIG. 3 is a plan view when comb teeth 11b are formed on a radially outer peripheral surface of a stator 11 in the ultrasonic motor 10 according to the first embodiment. 実施形態２の超音波モータ２０を示す斜視図である。FIG. 6 is a perspective view showing an ultrasonic motor 20 according to a second embodiment. 実施形態２のステータ２１を径方向から見たときの側面図である。It is a side view when the stator 21 of Embodiment 2 is seen from radial direction. 実施形態２のステータ２１を圧電素子２２のＡ相部側から見たときの平面図である。FIG. 6 is a plan view when the stator 21 of the second embodiment is viewed from the phase A side of the piezoelectric element 22. 実施形態２のステータ２１を圧電素子２２のＢ相部側から見たときの平面図である。FIG. 6 is a plan view when the stator 21 of the second embodiment is viewed from the B phase portion side of the piezoelectric element 22. 実施形態２の超音波モータ２０において櫛歯２１ｂをステータ２１の径方向の内周面に形成した場合の斜視図である。FIG. 6 is a perspective view of the ultrasonic motor 20 according to the second embodiment when comb teeth 21b are formed on the inner circumferential surface of the stator 21 in the radial direction.
　以下、図面を参照して、本発明に係る振動アクチュエータ、それを備えたレンズ鏡筒の実施形態について説明する。以下の実施形態では、振動アクチュエータとして、超音波域の振動を利用した超音波モータを例に挙げて説明する。 Hereinafter, an embodiment of a vibration actuator according to the present invention and a lens barrel including the vibration actuator will be described with reference to the drawings. In the following embodiments, an ultrasonic motor using vibration in the ultrasonic region will be described as an example of the vibration actuator.
（実施形態１）
　図１は、実施形態１の超音波モータ１０を搭載したカメラ１の概略構成図である。カメラ１は、カメラボディ２と、レンズ鏡筒３と、を備える。カメラボディ２は、撮像素子６を備える。撮像素子６は、レンズ鏡筒３により結像された被写体像を撮像する撮像装置である。レンズ鏡筒３は、カメラボディ２に対し着脱自在に装着された交換レンズである。本実施形態のカメラ１では、レンズ鏡筒３が交換レンズである例を示している。しかしながら、これに限らず、カメラボディと一体型のレンズ鏡筒であってもよい。 (Embodiment 1)
FIG. 1 is a schematic configuration diagram of a camera 1 equipped with the ultrasonic motor 10 of the first embodiment. The camera 1 includes a camera body 2 and a lens barrel 3. The camera body 2 includes an image sensor 6. The imaging element 6 is an imaging device that captures a subject image formed by the lens barrel 3. The lens barrel 3 is an interchangeable lens that is detachably attached to the camera body 2. In the camera 1 of the present embodiment, an example in which the lens barrel 3 is an interchangeable lens is shown. However, the present invention is not limited to this, and a lens barrel integrated with the camera body may be used.
　レンズ鏡筒３は、光学部材としてのレンズ４、カム筒５、超音波モータ１０、及びその他の部材（不図示）を備える。本実施形態の超音波モータ１０は、カメラ１の焦点調節時にレンズ４を駆動するための駆動源として用いられている。超音波モータ１０から取り出された駆動力は、動力伝達機構（不図示）を介してカム筒５に伝達される。カム筒５は、レンズ４とカム機構により係合している。超音波モータ１０の駆動力によりカム筒５が回転すると、レンズ４はカム機構により光軸Ａの方向に移動する。これにより、焦点調節が行われる。 The lens barrel 3 includes a lens 4 as an optical member, a cam barrel 5, an ultrasonic motor 10, and other members (not shown). The ultrasonic motor 10 of the present embodiment is used as a drive source for driving the lens 4 when adjusting the focus of the camera 1. The driving force extracted from the ultrasonic motor 10 is transmitted to the cam cylinder 5 through a power transmission mechanism (not shown). The cam cylinder 5 is engaged with the lens 4 by a cam mechanism. When the cam cylinder 5 is rotated by the driving force of the ultrasonic motor 10, the lens 4 is moved in the direction of the optical axis A by the cam mechanism. Thereby, focus adjustment is performed.
　次に、本実施形態の超音波モータ１０について説明する。図２は、実施形態１の超音波モータ１０を中心軸方向から見たときの平面図である。図３は、実施形態１の超音波モータ１０におけるステータベース１１ａを示す斜視図である。図４は、実施形態１の超音波モータ１０における圧電素子１２を示す斜視図である。 Next, the ultrasonic motor 10 of this embodiment will be described. FIG. 2 is a plan view of the ultrasonic motor 10 according to the first embodiment when viewed from the central axis direction. FIG. 3 is a perspective view showing the stator base 11a in the ultrasonic motor 10 of the first embodiment. FIG. 4 is a perspective view showing the piezoelectric element 12 in the ultrasonic motor 10 according to the first embodiment.
　本実施形態の超音波モータ１０は、図２に示すように、固定子としてのステータ１１と、移動子としてのロータ１３と、を備える。 As shown in FIG. 2, the ultrasonic motor 10 of the present embodiment includes a stator 11 as a stator and a rotor 13 as a mover.
　ステータ１１は、図３に示すステータベース１１ａ及び櫛歯１１ｂと、図４に示す圧電素子１２と、を備える。 The stator 11 includes a stator base 11a and comb teeth 11b shown in FIG. 3, and a piezoelectric element 12 shown in FIG.
　ステータベース１１ａは、図３に示すように、円環形に形成された弾性体である。ステータベース１１ａは、例えば、ステンレス材、インバー材等の鉄合金や真鍮等の弾性変形可能な金属材料により構成される。 The stator base 11a is an elastic body formed in an annular shape as shown in FIG. The stator base 11a is made of an elastically deformable metal material such as an iron alloy such as stainless steel or invar material or brass.
　櫛歯１１ｂは、ステータベース１１ａの径方向の内周面に形成された部位である。櫛歯１１ｂは、進行波の振幅を増幅する増幅（拡大）機構である。櫛歯１１ｂの先端面には、ステータ摺動面１１ｃが形成されている。ステータ摺動面１１ｃには、ロータ１６の外周面が加圧接触される。ステータ摺動面１１ｃは、ステータベース１１ａとロータ１６との接触面となる。 The comb teeth 11b are portions formed on the inner circumferential surface of the stator base 11a in the radial direction. The comb tooth 11b is an amplification (enlargement) mechanism that amplifies the amplitude of the traveling wave. A stator sliding surface 11c is formed on the tip surface of the comb teeth 11b. The outer peripheral surface of the rotor 16 is brought into pressure contact with the stator sliding surface 11c. The stator sliding surface 11 c is a contact surface between the stator base 11 a and the rotor 16.
　ステータ１１は、図３に示すように、ステータベース１１ａの径方向の外周面に圧電素子接合面１１ｄを備える。圧電素子接合面１１ｄには、圧電素子１２が接合される。この圧電素子１２は、駆動信号が供給されることにより励振し、ステータベース１１ａに進行波を発生させる。この進行波によりステータベース１１ａに生じた楕円運動は、櫛歯１１ｂにより増幅される。増幅された楕円運動は、ステータ摺動面１１ｃと加圧接触するロータ１３により回転運動に変換される。 As shown in FIG. 3, the stator 11 includes a piezoelectric element bonding surface 11d on the outer circumferential surface of the stator base 11a in the radial direction. The piezoelectric element 12 is bonded to the piezoelectric element bonding surface 11d. The piezoelectric element 12 is excited by being supplied with a drive signal, and generates a traveling wave in the stator base 11a. The elliptical motion generated in the stator base 11a by this traveling wave is amplified by the comb teeth 11b. The amplified elliptical motion is converted into rotational motion by the rotor 13 in pressure contact with the stator sliding surface 11c.
　圧電素子１２は、図４に示すように、円筒形に形成された電極部材である。圧電素子１２は、電気エネルギーを機械エネルギーに変換する電気機械変換素子である。圧電素子１２は、例えば、ＰＺＴ（チタン酸ジルコン酸鉛）、セラミックス等により構成される。圧電素子１２は、図２に示すように、ステータベース１１ａの外周面（圧電素子接合面１１ｄ）に接合される。 The piezoelectric element 12 is a cylindrical electrode member as shown in FIG. The piezoelectric element 12 is an electromechanical transducer that converts electrical energy into mechanical energy. The piezoelectric element 12 is made of, for example, PZT (lead zirconate titanate), ceramics, or the like. As shown in FIG. 2, the piezoelectric element 12 is bonded to the outer peripheral surface (piezoelectric element bonding surface 11d) of the stator base 11a.
　本実施形態の圧電素子１２は、全周に亘って、６波長（６λ）となるように分極されている。圧電素子１２は、Ａ相部１２ａ、Ｂ相部１２ｂ、λ／４部１２ｃ、及び３／４λ部１２ｄを備える。Ａ相部１２ａは、半波長毎に分極方向が交互に逆向き（Ａ＋、Ａ－、Ａ＋、Ａ－、Ａ＋）となるように分極されている。同様に、Ｂ相部１２ｂも、半波長毎に分極方向が交互に逆向き（Ｂ＋、Ｂ－、Ｂ＋、Ｂ－、Ｂ＋）となるように分極されている。 The piezoelectric element 12 of this embodiment is polarized so as to have 6 wavelengths (6λ) over the entire circumference. The piezoelectric element 12 includes an A-phase portion 12a, a B-phase portion 12b, a λ / 4 portion 12c, and a 3 / 4λ portion 12d. The A-phase portion 12a is polarized so that the polarization directions are alternately reversed (A +, A-, A +, A-, A +) every half wavelength. Similarly, the B phase portion 12b is also polarized so that the polarization direction is alternately reversed (B +, B−, B +, B−, B +) for each half wavelength.
　λ／４部１２ｃは、Ａ相部１２ａとＢ相部１２ｂとを互いに１／４波長分ずらすために形成された未分極の領域である。３／４λ部１２ｄは、Ａ相部１２ａとＢ相部１２ｂとを互いに３／４波長分ずらすために形成された未分極の領域である。Ａ相部１２ａとＢ相部１２ｂは、λ／４部１２ｃ及び３／４λ部１２ｄを挟んで対称に配置されている。 The λ / 4 portion 12c is an unpolarized region formed in order to shift the A phase portion 12a and the B phase portion 12b from each other by ¼ wavelength. The 3 / 4λ portion 12d is an unpolarized region formed to shift the A phase portion 12a and the B phase portion 12b by 3/4 wavelengths from each other. The A-phase portion 12a and the B-phase portion 12b are arranged symmetrically with the λ / 4 portion 12c and the 3 / 4λ portion 12d interposed therebetween.
　圧電素子１２のＡ相部１２ａ及びＢ相部１２ｂは、レンズ鏡筒３（図１）の内部に設けられたフレキシブルプリント基板（不図示）と接続されている。フレキシブルプリント基板には、レンズＣＰＵ（不図示）が搭載されている。フレキシブルプリント基板からは、駆動信号として、互いに位相が９０度異なる２つの交流電圧が、圧電素子１２のＡ相部１２ａ及びＢ相部１２ｂにそれぞれ供給される。圧電素子１２は、フレキシブルプリント基板から供給された駆動信号により励振して、ステータベース１１ａに進行波を発生させる。ステータベース１１ａは、この進行波により楕円運動を生じる。この楕円運動は、更に櫛歯１１ｂにより増幅される。 The A phase part 12a and the B phase part 12b of the piezoelectric element 12 are connected to a flexible printed circuit board (not shown) provided inside the lens barrel 3 (FIG. 1). A lens CPU (not shown) is mounted on the flexible printed circuit board. From the flexible printed circuit board, two AC voltages whose phases are different from each other by 90 degrees are supplied as drive signals to the A-phase portion 12a and the B-phase portion 12b of the piezoelectric element 12, respectively. The piezoelectric element 12 is excited by a drive signal supplied from a flexible printed board, and generates a traveling wave in the stator base 11a. The stator base 11a generates an elliptical motion by this traveling wave. This elliptical motion is further amplified by the comb teeth 11b.
　ロータ１３は、図２に示すように、円環形に形成された部材である。ロータ１３は、ステータ１１の径方向の内側に配置されている。ロータ１３は、加圧機構（不図示）により、櫛歯１１ｂのステータ摺動面１１ｃに加圧接触する。また、ロータ１３は、支持機構（不図示）により、中心軸回りに回転可能に支持されている。そして、ステータ摺動面１１ｃに加圧接触されたロータ１３は、ステータ１１の櫛歯１１ｂで増幅された楕円運動により、ステータ１１に対して相対移動（回転）する。すなわち、ステータ１１の櫛歯１１ｂで増幅された楕円運動は、ロータ１３により回転運動に変換され、動力伝達機構（不図示）を介してカム筒５（図１）に伝達される。 The rotor 13 is a member formed in an annular shape as shown in FIG. The rotor 13 is disposed inside the stator 11 in the radial direction. The rotor 13 is in pressure contact with the stator sliding surface 11c of the comb teeth 11b by a pressure mechanism (not shown). The rotor 13 is supported by a support mechanism (not shown) so as to be rotatable around the central axis. Then, the rotor 13 in pressure contact with the stator sliding surface 11 c moves (rotates) relative to the stator 11 by the elliptical motion amplified by the comb teeth 11 b of the stator 11. In other words, the elliptical motion amplified by the comb teeth 11b of the stator 11 is converted into rotational motion by the rotor 13 and transmitted to the cam cylinder 5 (FIG. 1) via a power transmission mechanism (not shown).
　上述した実施形態１の超音波モータ１０によれば、以下の効果を奏する。
（１）ステータ１１は、径方向の内側にロータ１３と加圧接触するステータ摺動面１１ｃを備える。これにより、ロータ１３による回転運動の取り出し方向は、ステータ１１の径方向となる。このため、超音波モータ１０の回転軸方向の長さを短縮することができる。従って、超音波モータ１０の更なる薄型化が可能となる。そして、この超音波モータ１０を搭載した光学機器は、光軸方向の全長を短縮することができる。これによって、従来は困難であった、薄型の光学機器にも超音波モータを搭載することが可能となる。
（２）ロータ１３は、ステータ１１の径方向の内側に配置される。このため、レンズ鏡筒３における径方向の寸法を小さくすることができる。
圧電素子１２に供給する駆動信号は、互いに位相が９０度異なる２つの交流電圧であるため、周辺の駆動回路を簡素化することができる。 The ultrasonic motor 10 according to the first embodiment described above has the following effects.
(1) The stator 11 includes a stator sliding surface 11c in pressure contact with the rotor 13 on the radially inner side. Thereby, the direction of taking out the rotational motion by the rotor 13 is the radial direction of the stator 11. For this reason, the length of the rotation axis direction of the ultrasonic motor 10 can be shortened. Therefore, the ultrasonic motor 10 can be further reduced in thickness. And the optical apparatus carrying this ultrasonic motor 10 can shorten the full length of an optical axis direction. Accordingly, it is possible to mount the ultrasonic motor on a thin optical device, which has been difficult in the past.
(2) The rotor 13 is disposed inside the stator 11 in the radial direction. For this reason, the radial dimension in the lens barrel 3 can be reduced.
Since the drive signal supplied to the piezoelectric element 12 is two alternating voltages whose phases are different from each other by 90 degrees, the peripheral drive circuit can be simplified.
　なお、実施形態１の超音波モータ１０では、櫛歯１１ｂをステータベース１１ａの径方向の内周面に形成した例について説明したが、図５に示すように、櫛歯１１ｂを、ステータ１１の径方向の外周面に形成してもよい。この場合、ロータ１３は、ステータ１１の外側に配置され、櫛歯１１ｂのステータ摺動面１１ｃに加圧接触される。実施形態１の超音波モータ１０を、図５のように構成した場合においても、超音波モータ１０の更なる薄型化が可能となる。 In the ultrasonic motor 10 of the first embodiment, the example in which the comb teeth 11b are formed on the inner circumferential surface in the radial direction of the stator base 11a has been described. However, as illustrated in FIG. You may form in the outer peripheral surface of radial direction. In this case, the rotor 13 is disposed outside the stator 11 and is in pressure contact with the stator sliding surface 11c of the comb teeth 11b. Even when the ultrasonic motor 10 of the first embodiment is configured as shown in FIG. 5, the ultrasonic motor 10 can be further reduced in thickness.
（実施形態２）
　次に、実施形態２の超音波モータ２０について説明する。この実施形態２の超音波モータ２０についても、実施形態１の超音波モータ１０と同様に、図１に示すレンズ鏡筒３に適用される。 (Embodiment 2)
Next, the ultrasonic motor 20 according to the second embodiment will be described. Similarly to the ultrasonic motor 10 of the first embodiment, the ultrasonic motor 20 of the second embodiment is applied to the lens barrel 3 shown in FIG.
　図６は、実施形態２の超音波モータ２０を示す斜視図である。図７は、実施形態２のステータ２１を径方向から見たときの側面図である。図８は、実施形態２のステータ２１を圧電素子２２のＡ相部側から見たときの平面図である。図９は、実施形態２のステータ２１を圧電素子２２のＢ相部側から見たときの平面図である。 FIG. 6 is a perspective view showing the ultrasonic motor 20 of the second embodiment. FIG. 7 is a side view of the stator 21 according to the second embodiment when viewed from the radial direction. FIG. 8 is a plan view when the stator 21 of the second embodiment is viewed from the phase A side of the piezoelectric element 22. FIG. 9 is a plan view when the stator 21 of the second embodiment is viewed from the B-phase portion side of the piezoelectric element 22.
　本実施形態の超音波モータ２０は、図６に示すように、固定子としてのステータ２１と、移動子としてのロータ２３と、を備える。 As shown in FIG. 6, the ultrasonic motor 20 of the present embodiment includes a stator 21 as a stator and a rotor 23 as a mover.
　ステータ２１は、ステータベース２１ａ及び櫛歯２１ｂと、圧電素子２２と、を備える。 The stator 21 includes a stator base 21a, comb teeth 21b, and a piezoelectric element 22.
　ステータベース２１ａは、図６に示すように、円環形に形成された弾性体である。ステータベース２１ａは、例えば、ステンレス材、インバー材等の鉄合金や真鍮等の弾性変形可能な金属材料により構成される。 The stator base 21a is an elastic body formed in an annular shape as shown in FIG. The stator base 21a is made of an elastically deformable metal material such as an iron alloy such as stainless steel or invar material or brass.
　櫛歯２１ｂは、ステータベース２１ａの径方向の外周面に形成された部位である。櫛歯２１ｂは、進行波の振幅を増幅する増幅（拡大）機構である。櫛歯２１ｂの先端面には、ステータ摺動面２１ｃが形成されている。ステータ摺動面２１ｃには、ロータ２３の内周面が加圧接触される。ステータ摺動面２１ｃは、ステータベース２１ａとロータ２３との接触面となる。 The comb teeth 21b are portions formed on the outer peripheral surface of the stator base 21a in the radial direction. The comb tooth 21b is an amplification (enlargement) mechanism that amplifies the amplitude of the traveling wave. A stator sliding surface 21c is formed on the tip surface of the comb teeth 21b. The inner peripheral surface of the rotor 23 is brought into pressure contact with the stator sliding surface 21c. The stator sliding surface 21 c is a contact surface between the stator base 21 a and the rotor 23.
　ステータ２１は、図７に示すように、ステータベース２１ａの中心軸方向の上面に、圧電素子２２のＡ相部２２ａが接合されている。また、ステータ２１は、ステータベース２１ａの中心軸方向の下面に、圧電素子２２のＢ相部２２ｂが接合されている。中心軸方向の両面に接合された圧電素子２２は、駆動信号により励振して、ステータベース２１ａに進行波を発生させる。ステータベース２１ａは、この進行波により楕円運動を生じる。この楕円運動は、櫛歯２１ｂにより増幅される。櫛歯２１ｂにより増幅された楕円運動は、ステータ摺動面２１ｃと加圧接触するロータ２３により回転運動に変換される。 As shown in FIG. 7, the stator 21 has an A-phase portion 22a of a piezoelectric element 22 joined to the upper surface of the stator base 21a in the central axis direction. The stator 21 has a B-phase portion 22b of the piezoelectric element 22 joined to the lower surface of the stator base 21a in the central axis direction. The piezoelectric elements 22 bonded to both surfaces in the central axis direction are excited by a drive signal to generate a traveling wave in the stator base 21a. The stator base 21a generates an elliptical motion by this traveling wave. This elliptical motion is amplified by the comb teeth 21b. The elliptical motion amplified by the comb teeth 21b is converted into rotational motion by the rotor 23 in pressure contact with the stator sliding surface 21c.
　圧電素子２２は、円環形に形成された電極部材である。圧電素子２２は、電気エネルギーを機械エネルギーに変換する電気機械変換素子である。圧電素子２２は、例えば、ＰＺＴ（チタン酸ジルコン酸鉛）、セラミックス等により構成される。 The piezoelectric element 22 is an electrode member formed in an annular shape. The piezoelectric element 22 is an electromechanical transducer that converts electrical energy into mechanical energy. The piezoelectric element 22 is made of, for example, PZT (lead zirconate titanate), ceramics, or the like.
　本実施形態の圧電素子２２は、ステータベース２１ａの上下面において、９波長（９λ）となるように分極されている。すなわち、圧電素子２２は、Ａ相部２２ａと、Ｂ相部２２ｂと、を備える。圧電素子２２のＡ相部２２ａは、図８に示すように、半波長毎に分極方向が交互に逆向き（Ａ＋、Ａ－、Ａ＋、・・・Ａ－、Ａ＋、Ａ－）となるように１８の極に分極されている。また、圧電素子２２のＢ相部２２ｂは、図９に示すように、半波長毎に分極方向が交互に逆向き（Ｂ＋、Ｂ－、Ｂ＋、・・・Ｂ－、Ｂ＋、Ｂ－）となるように１８の極に分極されている。なお、圧電素子２２のＡ相部２２ａ及びＢ相部２２ｂにおいて、分極方向が逆向きとなる隣接する１組の極（＋、－）が１波長に対応する。 The piezoelectric element 22 of the present embodiment is polarized so as to have 9 wavelengths (9λ) on the upper and lower surfaces of the stator base 21a. That is, the piezoelectric element 22 includes an A phase portion 22a and a B phase portion 22b. As shown in FIG. 8, in the A phase portion 22a of the piezoelectric element 22, the polarization directions are alternately reversed (A +, A−, A +,... A−, A +, A−) every half wavelength. Are polarized to 18 poles. Further, as shown in FIG. 9, the B-phase portion 22b of the piezoelectric element 22 has a polarization direction alternately reversed every half wavelength (B +, B−, B +,... B−, B +, B−). It is polarized to 18 poles. In the A-phase portion 22a and the B-phase portion 22b of the piezoelectric element 22, a pair of adjacent poles (+, −) whose polarization directions are opposite to each other correspond to one wavelength.
　更に、圧電素子２２のＡ相部２２ａ及びＢ相部２２ｂは、図７に示すように、ステータ２１の円周方向に１／４波長（λ）分ずれるように接合されている。これにより、実施形態１のステータ１１のように、Ａ相部１２ａ及びＢ相部１２ｂを所定の波長分だけずらすためのλ／４部１２ｃや３／４λ部１２ｄの領域が不要となる。 Furthermore, the A-phase portion 22a and the B-phase portion 22b of the piezoelectric element 22 are joined so as to be shifted by a quarter wavelength (λ) in the circumferential direction of the stator 21, as shown in FIG. Thereby, like the stator 11 of Embodiment 1, the area | region of (lambda) / 4 part 12c and 3/4 (lambda) part 12d for shifting A phase part 12a and B phase part 12b by predetermined wavelength becomes unnecessary.
　一方、圧電素子２２のＡ相部２２ａ及びＢ相部２２ｂは、レンズ鏡筒３（図１）の内部に設けられたフレキシブルプリント基板（不図示）と接続されている。フレキシブルプリント基板には、レンズＣＰＵ（不図示）が搭載されている。フレキシブルプリント基板からは、駆動信号として、互いに位相が９０度異なる２つの交流電圧が、圧電素子２２のＡ相部２２ａ及びＢ相部２２ｂにそれぞれ供給される。圧電素子２２は、フレキシブルプリント基板から供給された駆動信号により励振して、ステータベース２１ａに進行波を発生させる。 On the other hand, the A-phase portion 22a and the B-phase portion 22b of the piezoelectric element 22 are connected to a flexible printed circuit board (not shown) provided inside the lens barrel 3 (FIG. 1). A lens CPU (not shown) is mounted on the flexible printed circuit board. From the flexible printed board, two AC voltages whose phases are different from each other by 90 degrees are supplied to the A-phase portion 22a and the B-phase portion 22b of the piezoelectric element 22 as drive signals. The piezoelectric element 22 is excited by a drive signal supplied from a flexible printed board, and generates a traveling wave in the stator base 21a.
　ロータ２３は、図６に示すように、円環形に形成された部材である。ロータ２３は、ステータ２１の径方向の外側に配置されている。ロータ２３は、加圧機構（不図示）により、櫛歯２１ｂのステータ摺動面２１ｃに加圧接触する。また、ロータ２３は、支持機構（不図示）により、中心軸回りに回転可能に支持されている。そして、ロータ２３は、ステータ２１の櫛歯２１ｂで増幅された楕円運動により、ステータ２１に対して相対移動（回転）する。すなわち、ステータ２１の櫛歯２１ｂで増幅した楕円運動は、ロータ２３により回転運動に変換され、動力伝達機構（不図示）を介してカム筒５（図１）に伝達される。 The rotor 23 is a member formed in an annular shape as shown in FIG. The rotor 23 is disposed outside the stator 21 in the radial direction. The rotor 23 is in pressure contact with the stator sliding surface 21c of the comb tooth 21b by a pressure mechanism (not shown). The rotor 23 is supported by a support mechanism (not shown) so as to be rotatable around the central axis. The rotor 23 moves (rotates) relative to the stator 21 by the elliptical motion amplified by the comb teeth 21b of the stator 21. That is, the elliptical motion amplified by the comb teeth 21b of the stator 21 is converted into rotational motion by the rotor 23 and transmitted to the cam cylinder 5 (FIG. 1) via a power transmission mechanism (not shown).
　上述した実施形態２の超音波モータ２０によれば、以下の効果を奏する。
（１）ステータ２１は、径方向の外側にロータ２３と加圧接触するステータ摺動面２１ｃを備える。これにより、ロータ２３による回転運動の取り出し方向は、ステータ２１の径方向となる。このため、超音波モータ２０の回転軸方向の長さを短縮することができる。従って、超音波モータ２０の更なる薄型化が可能となる。そして、この超音波モータ２０を搭載した光学機器は、光軸方向の全長を短縮することができる。これによって、従来は困難であった、薄型の光学機器にも超音波モータを搭載することが可能となる。
（２）ロータ２３は、ステータ２１の径方向の外側に配置される。このため、径方向の内側において、カム筒５やレンズ４を収納するスペースを広くすることができる。
圧電素子２２のＡ相部２２ａ及びＢ相部２２ｂは、ステータ２１の円周方向に１／４波長（λ）分ずれるように接合されている。このため、λ／４部や３／４λ部の領域が不要となり、Ａ相部２２ａ及びＢ相部２２ｂの面積を増加させることができる。このため、圧電素子２２の単位重量当たりの出力を向上させることができる。
圧電素子２２に供給する駆動信号は、互いに位相が９０度異なる２つの交流電圧であるため、周辺の駆動回路を簡素化することができる。 The ultrasonic motor 20 according to the second embodiment described above has the following effects.
(1) The stator 21 includes a stator sliding surface 21c that is in pressure contact with the rotor 23 on the radially outer side. As a result, the direction in which the rotary motion is extracted by the rotor 23 is the radial direction of the stator 21. For this reason, the length of the rotation axis direction of the ultrasonic motor 20 can be shortened. Therefore, the ultrasonic motor 20 can be further reduced in thickness. And the optical apparatus carrying this ultrasonic motor 20 can shorten the full length of an optical axis direction. Accordingly, it is possible to mount the ultrasonic motor on a thin optical device, which has been difficult in the past.
(2) The rotor 23 is disposed outside the stator 21 in the radial direction. For this reason, the space for accommodating the cam cylinder 5 and the lens 4 can be widened on the inner side in the radial direction.
The A-phase portion 22 a and the B-phase portion 22 b of the piezoelectric element 22 are joined so as to be shifted by a quarter wavelength (λ) in the circumferential direction of the stator 21. For this reason, the area | region of (lambda) / 4 part and 3/4 (lambda) part becomes unnecessary, and the area of A phase part 22a and B phase part 22b can be increased. For this reason, the output per unit weight of the piezoelectric element 22 can be improved.
Since the drive signal supplied to the piezoelectric element 22 is two AC voltages whose phases are different from each other by 90 degrees, the peripheral drive circuit can be simplified.
　なお、実施形態２の超音波モータ２０では、櫛歯２１ｂをステータベース２１ａの径方向の外周面に形成した例について説明したが、図１０に示すように、櫛歯２１ｂを、ステータ２１の径方向の内周面に形成してもよい。この場合、ロータ２３は、ステータ２１の内側に配置され、櫛歯２１ｂのステータ摺動面２１ｃに加圧接触される。実施形態２の超音波モータ２０を、図１０のように構成した場合においても、超音波モータ２０の更なる薄型化が可能となる。 In the ultrasonic motor 20 according to the second embodiment, the example in which the comb teeth 21b are formed on the radial outer peripheral surface of the stator base 21a has been described. However, as illustrated in FIG. You may form in the inner peripheral surface of a direction. In this case, the rotor 23 is disposed inside the stator 21 and is in pressure contact with the stator sliding surface 21c of the comb teeth 21b. Even when the ultrasonic motor 20 of the second embodiment is configured as shown in FIG. 10, the ultrasonic motor 20 can be further reduced in thickness.
（変形形態）
　以上説明した実施形態に限定されることなく、本発明は以下に示すような種々の変形や変更が可能であり、それらも本発明の範囲内である。
（１）実施形態１において、ステータベース１１ａの外周面に接合した円筒形の圧電素子１２に加えて、ステータベース１１ａの中心軸方向の両面（又は片面）に、実施形態２に示す円環形の圧電素子２２を接合してもよい。 (Deformation)
Without being limited to the embodiment described above, the present invention can be variously modified and changed as described below, and these are also within the scope of the present invention.
(1) In the first embodiment, in addition to the cylindrical piezoelectric element 12 joined to the outer peripheral surface of the stator base 11a, the annular base shown in the second embodiment is formed on both surfaces (or one surface) of the stator base 11a in the central axis direction. The piezoelectric element 22 may be bonded.
（２）実施形態２において、ステータベース１１ａの中心軸方向の片面にのみ圧電素子２２（Ａ相部２２ａ又はＢ相部２２ｂ）を接合してもよい。その場合は、実施形態１と同様に、λ／４部１２ｃ及び３／４λ部１２ｄを配置する。 (2) In the second embodiment, the piezoelectric element 22 (A phase portion 22a or B phase portion 22b) may be bonded only to one surface of the stator base 11a in the central axis direction. In that case, as in the first embodiment, the λ / 4 portion 12c and the 3 / 4λ portion 12d are arranged.
実施形態２において、ステータベース２１ａの中心軸方向の両面に接合した円環形の圧電素子２２に加えて、ステータベース２１ａの内周面に、実施形態１に示す円筒形の圧電素子１２を接合してもよい。 In the second embodiment, the cylindrical piezoelectric element 12 shown in the first embodiment is bonded to the inner peripheral surface of the stator base 21a in addition to the annular piezoelectric element 22 bonded to both surfaces in the central axis direction of the stator base 21a. May be.
本実施形態では、振動アクチュエータとして、ロータが回転駆動される回転型の超音波モータを例に挙げて説明した。しかし、これに限らず、リニア型のアクチュエータとしてもよい。また、ロッド型、ペンシル型、円盤型等のアクチュエータとしてもよい。 In the present embodiment, as the vibration actuator, a rotary ultrasonic motor in which the rotor is driven to rotate is described as an example. However, the present invention is not limited to this, and a linear actuator may be used. Moreover, it is good also as actuators, such as a rod type, a pencil type, and a disk type.
（５）本実施形態では、振動アクチュエータとして、超音波域の振動を利用した超音波モータを例に挙げて説明した。しかし、これに限らず、例えば、超音波域以外の振動を利用した振動アクチュエータに適用してもよい。 (5) In the present embodiment, the ultrasonic actuator using the vibration in the ultrasonic region is described as an example of the vibration actuator. However, the present invention is not limited to this. For example, the present invention may be applied to a vibration actuator that uses vibrations outside the ultrasonic range.
（６）本実施形態においては、超音波モータ１０及び２０を、カメラ１の焦点調節時にレンズ４を駆動するための駆動源として用いた例について説明した。しかし、これに限らず、例えば、レンズ鏡筒３がズームレンズである場合に、そのズーム駆動時の駆動源として用いてもよい。また、レンズ４の一部を駆動して手振れを補正する、手振れ補正機構の駆動源として用いてもよい。この他、カメラ以外の光学機器に適用することもできる。更に、複写機やファクシミリの駆動部、自動車のハンドルチルト装置やヘッドレストの駆動部、時計の駆動装置等に用いることもできる。 (6) In this embodiment, the example which used the ultrasonic motors 10 and 20 as a drive source for driving the lens 4 at the time of the focus adjustment of the camera 1 was demonstrated. However, the present invention is not limited to this. For example, when the lens barrel 3 is a zoom lens, the lens barrel 3 may be used as a drive source during zoom driving. Further, it may be used as a drive source of a camera shake correction mechanism that drives a part of the lens 4 to correct camera shake. In addition, the present invention can be applied to optical devices other than cameras. Further, it can also be used in a driving unit of a copying machine or a facsimile, a steering wheel tilt device or a headrest driving unit of an automobile, a driving device of a watch, or the like.
　また、上記実施形態及び変形形態は適宜に組み合わせて用いることができるが、各実施形態の構成は図示と説明により明らかであるため、詳細な説明を省略する。更に、本発明は以上説明した実施形態によって限定されることはない。 In addition, although the above-described embodiments and modifications can be used in appropriate combinations, the configuration of each embodiment is clear from the illustration and description, and thus detailed description is omitted. Furthermore, the present invention is not limited by the embodiment described above.
　３：レンズ鏡筒、４：レンズ、１０，２０：超音波モータ、１１，２１：ステータ、１１ｂ，２１ｂ：櫛歯、１１ｃ，２１ｃ：ステータ摺動面、１２，２２：圧電素子、１３，２３：ロータ 3: lens barrel, 4: lens, 10, 20: ultrasonic motor, 11, 21: stator, 11b, 21b: comb teeth, 11c, 21c: stator sliding surface, 12, 22: piezoelectric element, 13, 23 : Rotor

Claims (9)

  1. 　円環形の弾性体及び当該弾性体に進行波を発生させる電気機械変換素子を有する固定子と、前記弾性体と接触し、当該弾性体に発生した進行波により前記固定子と相対移動する移動子と、を備えた振動アクチュエータであって、
    　前記弾性体は、前記移動子との接触面が径方向の側面に設けられていることを特徴とする振動アクチュエータ。     A stator having an annular elastic body and an electromechanical conversion element for generating a traveling wave in the elastic body, and a moving element that contacts the elastic body and moves relative to the stator by the traveling wave generated in the elastic body And a vibration actuator comprising:
    The elastic actuator is characterized in that a contact surface with the moving element is provided on a side surface in a radial direction.
  2. 　請求項１に記載の振動アクチュエータにおいて、
    　前記弾性体は、径方向の内側に前記移動子との接触面が設けられ、径方向の外側に前記電気機械変換素子が設けられていることを特徴とする振動アクチュエータ。     The vibration actuator according to claim 1,
    The vibration actuator is characterized in that a contact surface with the moving element is provided on the inner side in the radial direction, and the electromechanical conversion element is provided on the outer side in the radial direction.
  3. 　請求項１に記載の振動アクチュエータにおいて、
    　前記弾性体は、径方向の外側に前記移動子との接触面が設けられ、径方向の内側に前記電気機械変換素子が設けられていることを特徴とする振動アクチュエータ。     The vibration actuator according to claim 1,
    The vibration actuator is characterized in that a contact surface with the moving element is provided on the outer side in the radial direction, and the electromechanical conversion element is provided on the inner side in the radial direction.
  4. 　請求項１に記載の振動アクチュエータにおいて、
    　前記弾性体は、径方向の内側に前記移動子との接触面が設けられ、中心軸方向の少なくとも一方の面に前記電気機械変換素子が設けられていることを特徴とする振動アクチュエータ。     The vibration actuator according to claim 1,
    The vibration actuator is characterized in that a contact surface with the moving element is provided inside in a radial direction, and the electromechanical conversion element is provided on at least one surface in a central axis direction.
  5. 　請求項１に記載の振動アクチュエータにおいて、
    　前記弾性体は、径方向の外側に前記移動子との接触面が設けられ、中心軸方向の少なくとも一方の面に前記電気機械変換素子が設けられていることを特徴とする振動アクチュエータ。     The vibration actuator according to claim 1,
    The vibration actuator is characterized in that a contact surface with the moving element is provided on the outer side in the radial direction, and the electromechanical conversion element is provided on at least one surface in the central axis direction.
  6. 　請求項４又は５に記載の振動アクチュエータにおいて、
    　前記弾性体は、中心軸方向の両方の面にそれぞれ前記電気機械変換素子が設けられていることを特徴とする振動アクチュエータ。     The vibration actuator according to claim 4 or 5,
    The vibration actuator is characterized in that the electromechanical conversion element is provided on both surfaces in the central axis direction.
  7. 　請求項６に記載の振動アクチュエータにおいて、
    　前記弾性体の中心軸方向の両面に設けられた前記電気機械変換素子は、中心軸方向からの矢視において、互いに波長が１／４ずれていることを特徴とする振動アクチュエータ。     The vibration actuator according to claim 6, wherein
    2. The vibration actuator according to claim 1, wherein the electromechanical transducers provided on both surfaces of the elastic body in the central axis direction have wavelengths shifted from each other by a quarter as viewed from the direction of the central axis.
  8. 　円環形の弾性体と、前記弾性体に進行波を発生させる電気機械変換素子とにより構成される固定子と、
    　前記弾性体と接触し、前記弾性体の進行波により前記固定子に対して相対移動する移動子と、を備えた振動アクチュエータであって、
    　前記弾性体と、前記移動子とは、径方向の加圧接触されることを特徴とする振動アクチュエータ。     A stator composed of an annular elastic body and an electromechanical transducer that generates a traveling wave in the elastic body;
    A moving actuator that contacts the elastic body and moves relative to the stator by a traveling wave of the elastic body,
    The vibration actuator according to claim 1, wherein the elastic body and the moving element are brought into pressure contact in a radial direction.
  9. 　請求項１～８のいずれか１項に記載の振動アクチュエータと、
    　前記振動アクチュエータにより駆動される光学部材と、
    　を備えることを特徴とするレンズ鏡筒。     The vibration actuator according to any one of claims 1 to 8,
    An optical member driven by the vibration actuator;
    A lens barrel comprising:
PCT/JP2013/055412 2012-02-28 2013-02-28 Vibration actuator and lens barrel WO2013129573A1 (en)

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JP2012041182 2012-02-28
JP2012-041182 2012-02-28

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62225182A (en) * 1986-03-25 1987-10-03 Canon Inc Oscillatory wave motor
JPS6389080A (en) * 1986-09-30 1988-04-20 Canon Inc Oscillatory-wave motor
JPH04101680A (en) * 1990-08-21 1992-04-03 Nec Corp Piezoelectric motor
JP2006101593A (en) * 2004-09-28 2006-04-13 Sanyo Electric Co Ltd Reciprocating drive mechanism and optical device using the same
JP2010226854A (en) * 2009-03-23 2010-10-07 Nikon Corp Vibration actuator, lens barrel including the same, and camera

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62225182A (en) * 1986-03-25 1987-10-03 Canon Inc Oscillatory wave motor
JPS6389080A (en) * 1986-09-30 1988-04-20 Canon Inc Oscillatory-wave motor
JPH04101680A (en) * 1990-08-21 1992-04-03 Nec Corp Piezoelectric motor
JP2006101593A (en) * 2004-09-28 2006-04-13 Sanyo Electric Co Ltd Reciprocating drive mechanism and optical device using the same
JP2010226854A (en) * 2009-03-23 2010-10-07 Nikon Corp Vibration actuator, lens barrel including the same, and camera

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