JP2013183461A - Driving device, lens barrel, and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device capable of easily making driving frequency matching between a first piezoelectric element and a second piezoelectric element.SOLUTION: A driving device includes: a first piezoelectric element 6 causing thickness-shear vibration in a first direction; a first member 3b that vibrates along the first direction by being driven by the first piezoelectric element; a second piezoelectric element 7 that is supported by the first member and causes thickness-shear vibration along a second direction different from the first direction; a second member 3a that vibrates along the second direction by being driven by the second piezoelectric element; and a drive target body driven by the second member. A pore 36 is disposed in at least one of the first member and the second member. The pore is filled with a frequency adjustment member 37 set at a weight to adjust a difference between resonance frequency of the vibration of the first member and resonance frequency of the vibration of the second member.

Description

  The present invention relates to a driving device, a lens barrel, and a camera.

  Conventionally, a driving device using a piezoelectric element is known. Some of such driving devices drive a driven body by driving a plurality of piezoelectric elements and elliptically moving a portion in contact with the driven body.

  For example, in the driving device of Patent Document 1, a tip portion that supports a driven body, a base portion sandwiched between a pair of first piezoelectric elements, a second piezoelectric element provided between the tip portion and the base portion, The elliptical motion of the tip part of the drive piece is realized by vibrations in two different directions. The plurality of drive pieces are arranged in an annular shape, and a base portion having a plurality of protrusions that hold the plurality of drive pieces in a circumferential direction is provided.

JP 2010-288355 A

However, the following problems exist in the conventional technology as described above.
It is preferable for efficient driving that the driving frequencies of the first piezoelectric element and the second piezoelectric element are substantially the same. However, in practice, it is difficult to match the drive frequencies due to manufacturing errors, etc., and it has been attempted to select a semi-finished product combination that provides relatively good results. However, it is difficult to make the driving frequencies coincide with each other, and there is a problem that the yield rate and the driving efficiency are lowered.

  The present invention has been made in consideration of the above points, and provides a driving device, a lens barrel, and a camera that can easily match the driving frequencies of the first piezoelectric element and the second piezoelectric element. With the goal.

  According to the first aspect of the present invention, the first piezoelectric element that vibrates in the first direction in thickness shear, the first member that is driven by the first piezoelectric element and vibrates along the first direction, A second piezoelectric element that is supported by one member and vibrates along a second direction different from the first direction, and a second piezoelectric element that is driven by the second piezoelectric element and vibrates along the second direction. A member and a driven body driven by the second member, wherein at least one of the first member and the second member is provided with a hole, and the hole has a resonance frequency of vibration of the first member. And a frequency adjusting member set to a weight for adjusting a difference between the resonance frequency of the vibration of the second member and a driving device is provided.

  According to the second aspect of the present invention, the first piezoelectric element that vibrates in the thickness direction in the first direction, the first member that is driven by the first piezoelectric element and vibrates along the first direction, A second piezoelectric element that is supported by one member and vibrates along a second direction different from the first direction, and a second piezoelectric element that is driven by the second piezoelectric element and vibrates along the second direction. The resonance frequency of the vibration of the first member is adjusted by adjusting the contact area of the first piezoelectric element that is driven in contact with the member and the second piezoelectric element that is driven in contact with the second member. And a frequency adjusting device that adjusts a difference between the resonance frequency of the vibration of the second member and a driving device.

  According to the third aspect of the present invention, the driving device according to the first or second aspect of the present invention, a cam barrel driven by the driving device, and a lens that is movably held by the cam barrel and performs focus adjustment. And a lens barrel including:

  According to a fourth aspect of the present invention, there is provided the lens barrel according to the third aspect of the present invention, and an imaging element on which an object image is formed on the imaging surface by a lens provided in the lens barrel. A camera is provided.

  In the present invention, the driving frequencies of the first piezoelectric element and the second piezoelectric element can be easily matched, and the yield rate and driving efficiency can be improved.

It is a front view of drive device 1 of one embodiment concerning the present invention. FIG. 2 is a plan view of the driving device 1 1 is a perspective view of a driving device 1. FIG. FIG. 3 is a circuit diagram of the driving device 1. It is a perspective view of the drive device 1 which concerns on 2nd Embodiment. It is an external appearance perspective view of the drive piece 3 except the front-end | tip part 3a. 1 is a schematic configuration diagram of a lens barrel and a camera provided with a driving device 1. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a drive device, a lens barrel and a camera according to the present invention will be described below with reference to FIGS.
This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

(First embodiment)
The driving device according to the present embodiment performs relative driving that relatively displaces the rotor with respect to the base portion, and drives the optical apparatus and the electronic apparatus such as the lens barrel of the camera by the rotor.

  FIG. 1 is a front view of a drive device 1 according to an embodiment of the present invention. FIG. 2 is a plan view of the driving device 1. FIG. 3 is a perspective view of the driving device 1. 2 and 3, the rotor 4 is not shown for convenience.

  As shown in FIG. 1, the drive device 1 includes a base portion 2, a drive piece 3, a rotor (driven body) 4, and a support shaft 5.

  The base part 2 is an elastic body having conductivity, and is formed of a material including, for example, stainless steel. The base portion 2 is formed in a hollow cylindrical shape having an axial through hole in the central portion. For example, an insulating film (not shown) is formed on the surface of the base portion 2 to be insulated. A support shaft 5 is inserted into the through hole of the base portion 2.

  At one end (upper end) of the base portion 2, a plurality of holding portions 2 a are provided at intervals in the circumferential direction of the base portion 2. The holding part 2a is formed in a concave shape. The holding part 2a holds the drive piece 3 so as to be sandwiched from both sides of the base part 2 in the circumferential direction.

  The other end portion (lower end portion) of the base portion 2 is fixed to the attachment portion 101a by a fastening member (not shown) such as a bolt. A groove portion 2 d that is continuous in the circumferential direction is provided in a portion closer to the attachment portion 101 a than the central portion in the height direction of the base portion 2.

  The driving device 1 has two sets of three driving pieces 3 that are driven with a predetermined phase difference. In the present embodiment, among the six drive pieces 3 arranged at equal intervals in the circumferential direction of the base portion 2, three drive pieces 31 belong to the first set, and three drive pieces 32 belong to the second set. Yes. The drive pieces 31 and the drive pieces 32 of each set are alternately arranged in the circumferential direction of the base portion 2, that is, in the rotation direction R of the rotor 4.

  Each drive piece 3 has a base 3b, a tip 3a, a first piezoelectric element 6 that vibrates in a thickness direction along a first direction (substantially a vertical direction in this case), and a first direction different from the first direction. The second piezoelectric element 7 that vibrates in thickness shear along the second direction (here, the horizontal direction) is provided in pairs.

  Each drive piece 3 includes a first piezoelectric element 6 that vibrates in thickness shear along a first direction (here, a substantially vertical direction), a base (first member) 3b, and a tip (second member) 3a. And a structure 3G that is paired with a second piezoelectric element 7 that vibrates in thickness shear along a second direction (here, the horizontal direction) different from the first direction.

  The base 3b has conductivity, and is formed of, for example, a light metal alloy. The base portion 3b is formed in a substantially rectangular parallelepiped shape that is slightly inclined so that a pair of side surfaces 3f1, 3f3 positioned in the circumferential direction of the base portion 2 approach each other as it goes downward. The base portion 3b is supported by the holding portion 2a so as to be drivable in a direction parallel to the support shaft 5. The base 3 b is driven by the first piezoelectric element 6 and vibrates in a direction parallel to the support shaft 5.

  A plurality (four) of first piezoelectric elements 6 are provided on the base 3b. The base 3b supports the two first piezoelectric elements 6 on the first surface 3f1, and supports the remaining two first piezoelectric elements 6 on the third surface (side surface) 3f3 facing the first surface 3f1. ing.

  The tip portion 3a has conductivity, and is formed of, for example, stainless steel. The distal end portion 3a is formed in a mountain-shaped hexagonal shape in a cross-sectional view. The distal end portion 3 a is disposed between the base portion 3 b and the rotor 4. The tip portion 3a protrudes from the holding portion 2a and supports the rotor 4 in contact with the upper surface 35. The tip 3a is driven by the second piezoelectric element 7 and vibrates along the second direction.

  As shown in FIGS. 2 and 3, a hole 36 extending in the first direction is provided on the upper surface 35 that is a contact surface with the rotor 4 in each tip 3 a. The hole 36 is loaded with a frequency adjusting member 37. The frequency adjusting member 37 adjusts the weight (mass) of the distal end portion 3a so that the resonance frequency (natural frequency) of the vibration of the distal end portion 3a and the resonance frequency (natural frequency) of the vibration of the base portion 3b are reduced. The difference is adjusted and is formed in a columnar shape having substantially the same diameter as the hole 36. The material of the frequency adjustment member 37 is selected according to the frequency characteristics, and for example, a metal material, a resin material, or the like can be used.

  The rotor 4 is attached to the support shaft 5 via a bearing (not shown). The rotor 4 is provided to be rotatable forward or backward in the rotation direction R around the support shaft 5. On the outer peripheral surface of the rotor 4, for example, a gear 4a for driving a lens barrel of a camera is formed. A surface of the rotor 4 facing the base portion 2 is supported by a plurality of driving pieces 3.

  The support shaft 5 is a round bar-like member arranged so that the center axis coincides with the rotation axis of the rotor 4. One end (lower end) of the support shaft 5 is fixed to the mounting portion 101a. The support shaft 5 passes through the base portion 2 and the rotor 4. The support shaft 5 is disposed at the center of the plurality of drive pieces 3 disposed along the rotation direction R of the rotor 4.

The first piezoelectric element 6 is made of a material containing, for example, zirconate titanate (PZT). The first piezoelectric element 6 is disposed between the inner surface of the holding portion 2 a of the base portion 2 and the side surface of the base portion 3 b of the driving piece 3. The first piezoelectric element 6 is disposed so as to sandwich the base 3 b of the drive piece 3 from the front and rear (both sides in the circumferential direction) in the rotation direction R of the rotor 4.
The first piezoelectric element 6 is formed to have a longitudinal direction substantially in the axial direction of the support shaft 5. The plurality of (four) first piezoelectric elements 6 undergo thickness shear vibration in the first direction along the side surfaces 3f1 and 3f3 of the base portion 3b. Each first piezoelectric element 6 is provided so as to undergo thickness-shear vibration in a longitudinal direction substantially along the axial direction of the support shaft 5. Each first piezoelectric element 6 is bonded to both the inner surface of the holding portion 2a of the base portion 2 and the side surfaces 3f1 and 3f3 of the base portion 3b of the driving piece 3 with a conductive adhesive.

  The second piezoelectric element 7 is formed of a material containing, for example, zirconate titanate (PZT). The second piezoelectric element 7 is formed to have a length in the tangential direction of the center circle passing through the center of each drive piece 3, that is, in the tangential direction of the rotation circle of the rotor 4 at the center of each drive piece 3. The second piezoelectric element 7 undergoes thickness shear vibration in the second direction along the upper surface 3f2 of the base 3b. The second piezoelectric element 7 is provided so as to undergo thickness-shear vibration in a tangential direction of a center circle passing through the center of each drive piece 3. That is, the second piezoelectric element 7 is provided so as to undergo thickness-shear vibration along the tangential direction of the rotation circle of the rotor 4 at the center of each drive piece 3. The 2nd piezoelectric element 7 is adhere | attached on both the bottom face of the front-end | tip part 3a of the drive piece 3, and the upper surface 3f2 of the base 3b with the adhesive agent which has electroconductivity.

  As shown in FIG. 2, the base portion 2 supports one of the drive pieces 3 arranged in the circumferential direction (rotation direction R of the rotor 4) with the first support surface 2 f 1 and the other with the second support piece 2 f 1. It is supported by the support surface 2f2. Specifically, the base portion 2 supports the side surface 3f3 of the base portion 3b of each drive piece 3 arranged in the circumferential direction with the first support surface 2f1 with the first piezoelectric element 6 interposed therebetween, and the base portion 3b. The side surface 3f1 is supported by the second support surface 2f2 with the first piezoelectric element 6 interposed therebetween.

  FIG. 4 is a circuit diagram of the driving device 1. 4A is a diagram illustrating a connection state between the first piezoelectric element 6 and the power supply unit (applying device) 10, and FIG. 4B is a diagram illustrating a connection state between the second piezoelectric element 7 and the power supply unit 10. FIG. For convenience, the illustration of the second piezoelectric element 7 is omitted in FIG. 4A, and the illustration of the first piezoelectric element 6 is omitted in FIG. 4B.

  As shown in FIGS. 4A and 4B, the driving device 1 includes a power supply unit 10 that supplies a voltage to each of the first piezoelectric element 6 and the second piezoelectric element 7. The power supply unit 10 includes a first terminal T1, a second terminal T2, a third terminal T3, and a fourth terminal T4. The terminals T1 to T4 supply a sine wave voltage having a predetermined frequency to each piezoelectric element. The power supply unit 10 applies a sinusoidal voltage having the same waveform with a predetermined phase difference between the terminals of the first terminal T1 and the second terminal T2 and between the terminals of the third terminal T3 and the fourth terminal T4. Supply to each piezoelectric element.

  As shown in FIGS. 1 and 4A, among the plurality of first piezoelectric elements 6, twelve first piezoelectric elements arranged between the three drive pieces 31 belonging to the first set and the base portion 2. 61 is electrically connected to the first terminal T <b> 1 via the wiring 11. Among the plurality of first piezoelectric elements 6, twelve first piezoelectric elements 62 arranged between the three driving pieces 32 belonging to the second set and the base portion 2 are connected to the second terminal T <b> 2 via the wiring 12. Electrically connected.

  In the driving device 1 configured as described above, before the rotor 4 is rotated by the driving piece 3, the resonance frequency of the vibration of the tip 3 a and the vibration of the base 3 b are inserted into the hole 36 of the tip 3 a for each driving piece 3. A frequency adjusting member 37 having a weight for correcting a difference from the resonance frequency is loaded. Specifically, the frequency adjusting member 37 whose weight is adjusted so that the resonance frequency of the vibration of the tip portion 3a substantially matches the resonance frequency of the vibration of the base portion 3b is loaded. Before the frequency adjustment member 37 is loaded, even if the resonance frequency of the vibration of the tip 3a is different from the resonance frequency of the vibration of the base 3b, the frequency adjustment member 37 is loaded in the hole 36 of the tip 3a. By adjusting the weight, the vibration characteristic of the tip portion 3a is changed by changing the moment of inertia of the tip portion 3a, and the resonance frequency of the vibration of the tip portion 3a is substantially matched with the resonance frequency of the vibration of the base portion 3b. Can do.

  Further, when the frequency adjusting member 37 is loaded, the height of supporting the rotor 4 varies in each of the three driving pieces 31 belonging to the first set and the three driving pieces 32 belonging to the second set. there is a possibility. In this case, by adjusting the height at which the frequency adjusting member 37 protrudes from the upper surface 35 in each group, the support height (the position of the support surface) with respect to the rotor 4 is made parallel to the second direction.

  For adjusting the weight of the frequency adjusting member 37, for example, an adjusting material having the same diameter as the diameter of the hole 36 is prepared, and the length is adjusted so as to have a predetermined weight. Alternatively, a method may be used in which a plurality of adjusting materials having the same diameter as the hole 36 and a unit length are prepared, and the number of adjusting materials is adjusted so as to have a predetermined weight.

  After the frequency adjusting member 37 is loaded into the hole 36, the frequency adjusting member 37 cannot be removed by press-fitting, driving, bonding, welding, or the like in order to prevent the frequency adjusting member 37 from being detached as the driving piece 3 is driven. It is preferable to fix. Furthermore, since it is assumed that the temperature of the driving piece 3 (tip portion 3a) increases as the rotor 4 is driven, the frequency adjusting member 37 made of a material having a linear expansion coefficient larger than the linear expansion coefficient of the tip portion 3a. Is used, the fitting of the frequency adjusting member 37 to the tip 3a is tight due to the difference in expansion due to the temperature rise, and the separation of the frequency adjusting member 37 from the hole 36 can be more effectively prevented.

When the weight is adjusted so that the resonance frequency of the vibration of the tip portion 3a substantially matches the resonance frequency of the vibration of the base portion 3b in each drive piece 3, the drive piece 3 is operated to rotate the rotor 4.
When the rotor 4 is rotated by the drive piece 3, the first set of three drive pieces 31 are driven in synchronization. Then, the second set of three drive pieces 32 is driven in synchronization with the first set of drive pieces 31 in the same manner as the first set of three drive pieces 31 with a predetermined phase difference. As a result, the first set of three driving pieces 31 and the second set of three driving pieces 32 alternately support and rotate the rotor 4.

  Specifically, the first terminal T <b> 1 of the power supply unit 10 supplies a sinusoidal voltage to the first piezoelectric element 61. Then, the first piezoelectric element 61 starts the thickness shear vibration in the first direction along the axial direction of the support shaft 5. The drive piece 31 is driven by the deformation of the first piezoelectric element 61 and moves in a direction away from the base portion 2.

  At this time, the third terminal T <b> 3 of the power supply unit 10 supplies a sinusoidal voltage to the second piezoelectric element 71. Then, the second piezoelectric element 71 has a tangential direction of the center circle passing through the center of each drive piece 3, that is, a tangential direction (second direction) of the rotation circle of the rotor 4 at the center of each drive piece 3. The thickness shear vibration is started in the forward direction of the rotation direction R. The tip 31 a of the driving piece 31 is driven in the second direction by the deformation of the second piezoelectric element 71. At this time, the tip 31 a of the drive piece 31 rotates the rotor 4 forward in the rotation direction R by the frictional force acting between the rotor 4 and the front end 31 a.

  Thereafter, the first piezoelectric element 61 starts deformation in the reverse direction away from the rotor 4 by the sinusoidal voltage supplied from the first terminal T <b> 1 of the power supply unit 10. The first set of drive pieces 31 moves in a direction away from the rotor 4 due to the reverse deformation of the first piezoelectric element 61.

  At this time, the second piezoelectric element 71 starts deformation in the reverse direction to the rear side in the rotation direction R of the rotor 4 by the sinusoidal voltage supplied from the third terminal T3 of the power supply unit 10. The distal end portion 31 a of the first set of driving pieces 31 moves toward the rear side in the rotational direction R of the rotor 4 by deformation in the reverse direction of the second piezoelectric element 71 in a state of being separated from the rotor 4.

  Thereafter, the first set of driving pieces 31 is configured such that the tip portion 31 a contacts the rotor 4, the tip portion 31 a moves forward in the rotational direction R of the rotor 4, the tip portion 31 a is separated from the rotor 4, and the rotor 4 The driving of the tip portion 31a to the rear side in the rotation direction R is repeated. That is, the base 31 b, the second piezoelectric element 71, and the tip 31 a of the drive piece 31 are driven by the first piezoelectric element 61 and vibrate along the axial direction of the support shaft 5. The tip 31a of the drive piece 31 is driven by the second piezoelectric element 71 and is tangential to the rotation circle of the rotor 4 at the center of each drive piece 3 (second direction) with respect to the base 31b and the base 2. ) As a result, the first set of drive pieces 31 are driven such that the tip 31a draws a circular or elliptical orbit.

  The second drive piece 32 has a predetermined phase difference from the first set of drive pieces 31 and is driven in the same manner as the first set of drive pieces 31. That is, the second terminal T2 of the power supply unit 10 has a waveform similar to that of the voltage supplied from the first terminal T1, and a sine wave voltage having a predetermined phase difference from the voltage supplied from the first terminal T1. 1 is supplied to the piezoelectric element 62. The fourth terminal T4 of the power supply unit 10 has a waveform similar to that of the voltage supplied from the third terminal T3. The fourth terminal T4 generates a sinusoidal voltage having a predetermined phase difference from the voltage supplied from the third terminal T3. 2 is supplied to the piezoelectric element 72.

  The leading end portions 32a of the second set of three driving pieces 32 come into contact with the rotor 4 before the leading end portions 31a of the first set of three driving pieces 31 are separated from the rotor 4, and the first set of three driving pieces. After the tip 31 a of 31 contacts the rotor 4, it is separated from the rotor 4. Accordingly, the rotor 4 is driven by being alternately supported by the first set of three drive pieces 31 and the second set of three drive pieces 32, and the position of the support shaft 5 in the axial direction is kept substantially constant. Rotate forward or backward in the rotational direction R at a predetermined rotational speed.

  As described above, in this embodiment, the frequency adjustment member 37 is used to adjust the difference between the resonance frequency of the vibration of the tip portion 3a and the resonance frequency of the vibration of the base portion 3b. It becomes possible to drive the drive piece 3 by voltage variable drive to rotationally drive the rotor 4, thereby realizing an efficient drive operation. Further, in the present embodiment, complicated work such as selecting a product that can obtain a relatively good result from a combination of semi-finished parts is not necessary, and the yield rate can be improved.

  Further, in this embodiment, the frequency adjustment member 37 is loaded on the upper surface 35 that is a contact surface with the rotor 4, and the height adjustment and the posture adjustment of the rotor 4 are also performed. It can be rotated.

(Second Embodiment)
Next, a second embodiment of the drive device 1 will be described with reference to FIG.
In the first embodiment, the frequency adjustment member 37 is loaded only on the distal end portion 3a. In the present embodiment, a configuration in which the frequency adjustment member is provided on both the distal end portion 3a and the base portion 3b will be described. In this figure, the same components as those of the first embodiment shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is omitted.

As shown in FIG. 5, in the present embodiment, each distal end portion 3a is provided with a hole portion 36a, and each base portion 3b is provided with a hole portion 36b. The holes 36a and 36b extend in the radial direction with the support shaft 5 as the center, and open to the outside in the radial direction so as to have the same diameter. Further, the holes 36a and 36b are disposed at the center in the circumferential direction of the tip 3a and the base 3b.
The hole 36a is loaded with a frequency adjustment member (first frequency adjustment member) 37a, and the hole 36b is loaded with a frequency adjustment member (second frequency adjustment member) 37b.

The first and second frequency adjusting members 37a and 37b have the same material and the same diameter, and have different lengths depending on the difference between the resonance frequency of the vibration of the tip portion 3a and the resonance frequency of the vibration of the base portion 3b. .
Other configurations are the same as those of the first embodiment.

  In this embodiment, in addition to obtaining the same operation and effect as the first embodiment, the resonance frequency of the vibration is adjusted at each of the tip portion 3a and the base portion 3b, so that the resonance frequency is adjusted with higher accuracy. can do. In the present embodiment, the frequency adjusting members 37a and 37b are provided to extend in the radial direction at the center position in the circumferential direction with respect to the drive piece 3 that contacts the rotor 4 along the radial direction. It becomes possible to support the rotor 4 in a stable posture without tilting about the extending axis.

  Further, in the present embodiment, since the holes 36a and 36b are provided so as to open outward in the radial direction, the frequency adjustment members 37a and 37b can be easily loaded or detached even after the drive device 1 is assembled. Thus, the workability related to the adjustment can be improved.

  In the second embodiment, the configuration in which the hole portion 36a is provided by opening the tip portion 3a radially outward is provided on the upper surface 35 as shown in the first embodiment. The height and posture of the rotor 4 may be adjusted.

(Third embodiment)
Next, a third embodiment of the drive device 1 will be described with reference to FIG.
In the first and second embodiments, the configuration using the frequency adjusting member 37 set to the weight for adjusting the difference between the resonance frequency of the vibration of the tip portion 3a and the vibration frequency of the vibration of the base portion 3b is exemplified. In the third embodiment, both the contact area of the first piezoelectric element 6 that is driven in contact with the tip 3a and the contact area of the second piezoelectric element 7 that is driven in contact with the base 3b are adjusted. A configuration for adjusting the difference in resonance frequency will be described. In this figure, the same reference numerals are given to the same elements as those of the first and second embodiments shown in FIGS. 1 to 5, and the description thereof is omitted.

FIG. 6 is an external perspective view of the drive piece 3 excluding the tip 3a.
As shown in FIG. 6, the first piezoelectric element 6 in the present embodiment is configured by a plurality of first piezoelectric element constituting bodies 6a extending in the first direction and arranged in a direction parallel to the radial direction. ing. Similarly, the second piezoelectric element 7 is constituted by a plurality of second piezoelectric element constituting bodies 7a extending in the second direction and arranged in a direction parallel to the radial direction.

  An insulator or an insulating film is interposed on the surface where the first piezoelectric element constituting bodies 6a are adjacent to each other. Similarly, an insulator or an insulating film is interposed on the surface where the second piezoelectric element constituting bodies 7a are adjacent to each other. A voltage (electric power) is supplied (applied) to the first piezoelectric element constituting body 6a and the second piezoelectric element constituting body 7a independently from the power supply unit 10.

  In the drive device 1 having the above-described configuration, when adjusting the resonance frequency of the vibration of the distal end portion 3a and the base portion 3b, for example, for each of the first piezoelectric element constituting body 6a and the second piezoelectric element constituting body 7a, The resonance frequency and amplitude are measured by applying a voltage with a combination of the first piezoelectric element constituting body 6a and the second piezoelectric element constituting body 7a selected symmetrically in the radial direction around the center as a basic pattern. The first piezoelectric element constituting body 6a and the second piezoelectric element constituting body 7a having the resonance frequency and amplitude corrected accordingly are appropriately selected and a voltage is applied. Then, measurement of each resonance frequency and amplitude, resonance frequency corrected according to the measurement result, selection of the first piezoelectric element constituting body 6a and the second piezoelectric element constituting body 7a having the amplitude, and the selected first piezoelectric element constituting body By repeating the voltage application to 6a and the second piezoelectric element structure 7a, an optimal combination pattern of the first piezoelectric element structure 6a and the second piezoelectric element structure 7a can be set.

  In addition, the shape, the number, and the like of the first piezoelectric element constituting body 6a and the second piezoelectric element constituting body 7a shown in the third embodiment are examples. It goes without saying that other arrangements can be adopted.

  Next, an example of a lens barrel and a camera provided with the driving device 1 of the present embodiment will be described. The interchangeable lens of this embodiment forms a camera system with a camera body. The interchangeable lens can be switched between an AF mode for performing a focusing operation according to a known AF (autofocus) control and an MF (manual focus) mode for performing a focusing operation according to a manual input from a photographer. ing.

  FIG. 7 is a schematic configuration diagram of a lens barrel and a camera provided with the driving device 1 shown in FIG. As shown in FIG. 7, the camera 101 includes a camera body 102 in which an image sensor 108 is built, and a lens barrel 103 having a lens 107.

  The lens barrel 103 is an interchangeable lens that can be attached to and detached from the camera body 102. The lens barrel 103 includes a lens 107, a cam barrel 106, the driving device 1, and the like. The driving device 1 is used as a driving source that drives the lens 107 during the focusing operation of the camera 101. The driving force obtained from the rotor 4 of the driving device 1 is directly transmitted to the cam cylinder 106. The lens 107 is a focus lens that is held by the cam cylinder 106 and moves in substantially parallel to the optical axis direction L by the driving force of the driving device 1 to perform focus adjustment.

  When the camera 101 is used, a subject image is formed on the imaging surface of the imaging element 108 by a lens group (including the lens 107) provided in the lens barrel 103. The imaged subject image is converted into an electrical signal by the image sensor 108, and image data is obtained by A / D converting the signal.

  As described above, since the camera 101 and the lens barrel 103 include the above-described driving device 1, the focusing operation can be performed efficiently and stably.

  In the present embodiment, the lens barrel 103 is an interchangeable lens. However, the present invention is not limited to this. For example, the lens barrel 103 may be a lens barrel integrated with the camera body.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the second embodiment, the configuration using the frequency adjusting members having the same material and different lengths is illustrated, but the configuration is not limited to this, and the configurations using the frequency adjusting members having the same length and different densities are used. May be taken. Moreover, it is good also as a structure which adjusts a resonance frequency by forming a hole part with an internal thread, forming with a male thread screwing a frequency adjustment member with an internal thread, and adjusting the length and density of an external thread.
Further, as the frequency adjusting member, a self-forming screw that is screwed into at least one of the distal end portion 3a and the base portion 3b may be used, and the hole portion may have a diameter that becomes a pilot hole of the self-forming screw. The resonance frequency may be adjusted by adjusting the length and density of the self-forming screw.

  DESCRIPTION OF SYMBOLS 1 ... Drive apparatus, 3a ... Tip part (2nd member), 3b ... Base part (1st member), 4 ... Rotor (driven body), 6 ... 1st piezoelectric element, 6a ... 1st piezoelectric element structure, 7 DESCRIPTION OF SYMBOLS 2nd piezoelectric element, 7a ... 2nd piezoelectric element structure, 10 ... Power supply part (application apparatus), 35 ... Upper surface (contact surface, contact surface), 36 ... Hole part, 37 ... Frequency adjusting member, 37a ... Frequency Adjustment member (first frequency adjustment member), 37b ... Frequency adjustment member (second frequency adjustment member), 101 ... Camera, 103 ... Lens barrel, 106 ... Cam barrel, 107 ... Lens, 108 ... Imaging element

Claims (12)

A first piezoelectric element that vibrates in thickness shear in a first direction;
A first member that is driven by the first piezoelectric element and vibrates along the first direction;
A second piezoelectric element that is supported by the first member and vibrates in a thickness-shear vibration along a second direction different from the first direction;
A second member that is driven by the second piezoelectric element and vibrates along the second direction;
A driven body driven by the second member;
With
At least one of the first member and the second member is provided with a hole,
The hole is loaded with a frequency adjusting member set to a weight for adjusting a difference between a resonance frequency of vibration of the first member and a resonance frequency of vibration of the second member. Drive device. The first member is provided with a first hole with a predetermined diameter,
The drive device according to claim 1, wherein the second member is provided with a second hole portion having the same diameter as the first hole portion. The first hole is loaded with a first frequency adjusting member made of a predetermined material,
3. The driving apparatus according to claim 2, wherein the second hole is loaded with a second frequency adjusting member made of the same material as the first frequency adjusting member but having a different length. The first hole is loaded with a first frequency adjusting member made of a predetermined material,
The driving device according to claim 2, wherein the second hole is loaded with a second frequency adjusting member formed of a material having a density different from that of the first frequency adjusting member. The frequency adjusting member is a self-forming screw that is screwed into at least one of the first member and the second member;
The drive device according to claim 1, wherein the hole is formed with a diameter that serves as a pilot hole of the self-forming screw. The frequency adjusting member is a male screw,
The drive device according to claim 1, wherein the hole is a female screw that is screwed into the female screw. A plurality of the first piezoelectric element, the first member, the second piezoelectric element, and the second member are provided along the driving direction of the driven body in a set;
The said hole is provided in the contact surface with the said driven body in the said 2nd member so that the height of the said driven body by the said frequency adjustment member can be adjusted. The drive device as described in any one.   The drive device according to claim 1, wherein the frequency adjusting member is fixed so as not to be removable from the hole. A first piezoelectric element that vibrates in thickness shear in a first direction;
A first member that is driven by the first piezoelectric element and vibrates along the first direction;
A second piezoelectric element that is supported by the first member and vibrates in a thickness-shear vibration along a second direction different from the first direction;
A second member that is driven by the second piezoelectric element and vibrates along the second direction;
By adjusting the contact area of the first piezoelectric element that is driven in contact with the first member and the contact area of the second piezoelectric element that is driven in contact with the second member, vibration of the first member is adjusted. A frequency adjusting device for adjusting a difference between a resonance frequency and a resonance frequency of vibration of the second member;
A drive device comprising: The first piezoelectric element includes a plurality of first piezoelectric element structures that can be driven independently,
The second piezoelectric element includes a plurality of second piezoelectric element structures that can be driven independently,
The frequency adjusting device includes a plurality of first piezoelectric element constituting bodies and a plurality of second piezoelectric element constituting bodies based on a resonance frequency of vibration of the first member and a resonance frequency of vibration of the second member. The drive device according to claim 9, further comprising an application device that selectively applies electric power to. The drive device according to any one of claims 1 to 10,
A cam cylinder driven by the drive device;
A lens that is movably held in the cam cylinder and performs focus adjustment;
Lens barrel with The lens barrel according to claim 11,
An image sensor in which a subject image is formed on an imaging surface by the lens provided in the lens barrel;
With a camera.

Images