JP2009276422A - Driving gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To widen a degree of freedom of material selection and the shape of a vibration friction part. <P>SOLUTION: A driving gear (10) for moving members (121, 122) in an extension and contract direction of an electromechanical conversion element (13) includes the electromechanical conversion element (13) having a pair of end faces (13a, 13b) mutually facing in the extension and contract direction each other, the vibration friction part (14) attached to one (13b) of the pair of the end faces of the electromechanical conversion element, and the moving members (121, 122) friction-coupled on the vibration friction part. The driving gear inserts a vibration transmission member (19) between one (13b) of the pair of the end faces of the electromechanical conversion element (13) and an end face (14a) of the vibration friction part (14). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive device, and more particularly to a drive device using an electromechanical transducer such as a piezoelectric element.

  Conventionally, linear actuators using electromechanical transducers such as piezoelectric elements, electrostrictive elements, and magnetostrictive elements have been used as autofocus actuators and zoom actuators for cameras.

  Patent Document 1 discloses a piezoelectric element (electromechanical conversion element), a drive shaft (a wear-resistant vibration rod, a vibration friction portion, a vibration member) that is coupled to the piezoelectric element and extends in the expansion and contraction direction of the piezoelectric element. A drive device including a driven member (zoom lens barrel, moving member) frictionally coupled to the drive shaft is disclosed. In Patent Document 1, a driven signal (zoom lens barrel, moving member) is driven by devising a drive signal to be applied to a piezoelectric element. In Patent Document 1, a drive shaft (vibration friction portion, vibration member) is sandwiched between a driven member (moving member) and a friction plate. In other words, the drive shaft (vibration friction portion, vibration member) passes between the driven member (moving member) and the friction plate. The friction plate is pressed by the pressure contact spring in a direction to sandwich the drive shaft (vibration friction portion, vibration member) with the driven member (moving member).

  Patent Document 2 discloses that the mover is made of a liquid crystal polymer containing carbon fiber, thereby reducing the cost and weight and reducing the moving speed and driving force compared to the case where the mover is made of a metal material. A high-performance drive device using a mover having a high flexural modulus is disclosed. The driving device disclosed in Patent Document 2 includes a piezoelectric element (electromechanical conversion element) that expands and contracts when a voltage is applied, and a drive shaft (vibration friction portion, vibration member) that is fixed to one end of the expansion and contraction direction of the piezoelectric element. ), A mover (moving member) slidably engaged with the drive shaft, and a weight (stationary member, weight) fixedly bonded to the other end in the expansion / contraction direction of the piezoelectric element. The moving element (moving member) is moved along the driving shaft (vibrating friction portion, vibrating member) by causing the driving shaft to vibrate by varying the expansion or contraction speed or acceleration of the piezoelectric element.

  In the drive device disclosed in Patent Document 2, the drive shaft (vibration friction portion, vibration member) is formed of a round rod shaft body extending linearly. The mover (moving member) includes a mover main body and a cap, and both engage with the drive shaft so as to sandwich the drive shaft. In order to allow the mover to move along the drive shaft, the mover body and the cap are pressed against the drive shaft by a substantially U-shaped leaf spring so that a predetermined frictional force is generated between the drive shaft and the mover. . The mover body is provided with a groove having a V-shaped cross section. A drive shaft is fitted into the groove so that two inclined surfaces of the groove come into contact with the drive shaft. Similarly, the cap is provided with a groove having a V-shaped cross section. When the cap is combined with the mover main body, the drive shaft is fitted in the groove of the cap, and the two inclined surfaces of the groove come into contact with the drive shaft. As a material for the drive shaft, a carbon fiber rod or carbon fiber reinforced resin in which carbon fibers are bundled and hardened with a binder is used. Further, a mixture of fluororesin, fluoro oil and solvent is applied on the mutual contact surface of the drive shaft or the mover which is the friction portion.

  Further, Patent Document 3 discloses a driving device that can stably drive a moving member at high speed. The drive device disclosed in Patent Document 3 is coupled to a stationary member, an electromechanical conversion element having one end in the expansion / contraction direction fixed to the stationary member, and the other end in the expansion / contraction direction of the electromechanical conversion element. A drive member (vibration friction part, vibration member) supported so as to be movable in the expansion / contraction direction of the mechanical conversion element, and a movement that is frictionally coupled to the drive member and supported so as to be movable in the expansion / contraction direction of the electromechanical conversion element The apparatus includes a member, and a frictional force applying unit that generates a frictional force between the driving member (vibrating member) and the moving member. The frictional force adding means includes an elastic member that is fixed to the moving member and generates a pressing force, and a sandwiching member that transmits the pressing force generated by the elastic member to the driving member. Moreover, the contact part of a moving member and a drive member and the contact part of a pinching member are made into V-shaped cross section.

  Patent Document 4 discloses a drive device using an electromechanical transducer. The driving device disclosed in Patent Document 4 includes an electromechanical transducer element fixed to a support base (stationary member) at one end, a vibration member (vibration friction portion) fixed to the other end of the electromechanical transducer element, A moving body (moving member) engaged with the vibrating member with a predetermined frictional force is provided. A carbon rod is used as the vibration member.

  Patent Document 5 discloses a drive device having a short overall length. The drive device disclosed in Patent Document 5 includes an electromechanical conversion element having one end fixed to a stationary body (stationary member), and a drive friction member (vibration friction portion, vibration) fixed to the other end of the electromechanical conversion element. Member) and a moving body (moving member) that frictionally engages with the driving friction member. As the material of the drive friction member, ceramic materials, engineering plastics such as polyphenylene sulfide resin (PPS resin) and liquid crystal polymer (LCP resin), carbon reinforced resin, and glass fiber reinforced resin are used.

Japanese Patent No. 3188851 JP 2006-304529 A Japanese Patent No. 3141714 Japanese Patent Laid-Open No. 2002-119074 JP 2006-141133 A

  In any of the lens driving devices disclosed in Patent Documents 1 to 5 described above, the end face of the electromechanical conversion element and the end face of the vibration friction portion (vibration member) are directly coupled. The vibration friction portion needs to efficiently transmit the vibration generated by the expansion and contraction of the electromechanical conversion element to the moving body. Therefore, a certain degree of rigidity is required for the vibration friction portion. The vibration friction portion also has a role of smoothly reciprocating a moving member (moving body) frictionally coupled thereto.

  However, with the miniaturization of the lens driving device, it is very difficult to select the material for the vibration friction part in terms of rigidity and slidability, dimensional stability of parts, and adhesion to the electromechanical transducer. .

  Therefore, the subject of this invention is providing the drive device which can expand the freedom degree of material selection of a vibration friction part.

  The other subject of this invention is providing the drive device which can expand the freedom degree of the shape of a vibration friction part.

  Other objects of the invention will become apparent as the description proceeds.

  According to the present invention, the electromechanical transducer element (13) having a pair of end faces (13a, 13b) facing each other in the expansion / contraction direction, and the vibration attached to one of the pair of end faces (13b) of the electromechanical transducer element. A friction part (14) and a moving member (121; 121A, 122) frictionally coupled to the vibration friction part are provided, and the moving member (121; 121A, 122) is provided in the expansion / contraction direction of the electromechanical transducer (13). In the movable drive device (10, 10A, 10B, 10C), it is disposed between one end face (13b) of the electromechanical transducer (13) and the end face (14a) of the vibration friction portion (14). A drive device characterized by comprising the vibration transmission member (19, 19A) is obtained.

  In the drive device (10B, 10C) according to the present invention, the vibration transmitting member (19A) includes a first recess (191) in which one of the pair of end surfaces (13b) of the electromechanical transducer (13) is loosely fitted. It is preferable to have a second recess (192) in which the end face (14a) of the vibration friction portion (14) is loosely fitted.

  The reference numerals in the parentheses are given for ease of understanding, and are merely examples, and of course are not limited thereto.

  In the present invention, since the vibration transmission member is inserted between one of the pair of end faces of the electromechanical transducer and the end face of the vibration friction part, the degree of freedom in selecting the material of the vibration friction part can be expanded, and the vibration friction part The degree of freedom of the shape can be expanded.

  Embodiments of the present invention will be described below with reference to the drawings.

  A driving apparatus 10 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view showing the driving device 10. FIG. 2 is a partially enlarged perspective view showing an enlarged main part of the driving apparatus 10 shown in FIG. FIG. 3 is a side view of the main part of the driving device 10. Here, as shown in FIGS. 1 to 3, an orthogonal coordinate system (X, Y, Z) is used. In the state shown in FIGS. 1 to 3, in the orthogonal coordinate system (X, Y, Z), the X axis is the front-rear direction (depth direction), the Y axis is the left-right direction (width direction), and the Z axis is The vertical direction (height direction).

  The illustrated driving device 10 is used as an autofocus lens driving unit, for example. In that case, in the example shown in FIGS. 1 to 3, the vertical direction Z is the direction of the optical axis O of the lens.

  Note that the autofocus lens driving unit includes a lens movable unit and a lens driving unit. The lens driving unit drives the lens moving unit as will be described later while supporting the lens moving unit slidably in the optical axis O direction.

  The illustrated driving device 10 is disposed in a housing (not shown). The housing includes a cup-shaped upper cover (not shown) and a lower base (not shown). A stationary member (weight) 11 is mounted on the lower base of the housing. The upper surface of the upper cover has a cylindrical portion (not shown) having the optical axis O as the central axis. On the other hand, although not shown, an image sensor arranged on the substrate is mounted in the center of the lower base. This imaging device captures a subject image formed by a movable lens (described later) and converts it into an electrical signal. The imaging device is configured by, for example, a CCD (charge coupled device) type image sensor, a CMOS (complementary metal oxide semiconductor) type image sensor, or the like.

  A movable lens barrel (lens holder, lens support) 17 as a driven member is accommodated in the housing. The movable lens barrel (lens holder, lens support) 17 has a cylindrical cylindrical portion 170 for holding a lens barrel (lens assembly) 18. A lens barrel (lens assembly) 18 holds an autofocus lens AFL. A female screw (not shown) is cut on the inner peripheral wall of the cylindrical portion 170 of the lens holder 17. On the other hand, a male screw (not shown) that is screwed into the female screw is cut on the outer peripheral wall of the lens barrel 18. Therefore, in order to attach the lens barrel 18 to the lens holder 17, the lens barrel 18 is rotated around the optical axis O and screwed along the optical axis O direction with respect to the cylindrical portion 170 of the lens holder 17. The lens barrel 18 is accommodated in the lens holder 17 and bonded to each other by an adhesive or the like.

  The lens holder 17 has a protrusion 172 that protrudes radially outward on the right side of the cylindrical portion 170 in the left-right direction Y with respect to the optical axis O. The protruding portion 172 extends in the vertical direction Z in parallel with the optical axis O. A rod-shaped first moving body (moving shaft) 121 is fixed to the rear wall of the protruding portion 172. In the illustrated example, the first moving body 121 has a cylindrical shape.

  The lens holder 17 has an extending part 174 that extends to the left in the left-right direction Y at the rear end of the cylindrical part 170. The extending portion 174 is provided with a locking groove 174a for holding the first end 15a of the spring 15. The spring 15 extends along the extending portion 174 from the first end portion 15a to the right end in the left-right direction Y to the second end portion 15b. A rod-shaped second moving body (moving shaft) 122 is fixed to the second end 15 b of the spring 15. In the illustrated example, the second moving body 122 is also cylindrical.

  The second moving body (moving shaft) 122 is biased by the spring 15 in a direction approaching the first moving body (moving shaft) 121 (forward direction of the front-rear direction X). A vibration friction portion (vibrating member) 14 described later is sandwiched between a first moving body (moving shaft) 121 and a second moving body (moving shaft) 122. In the illustrated example, the first moving body 121 is longer than the second moving body 122. The first moving body 121 and the second moving body 122 are made of the same material. The combination of the first moving body 121 and the second moving body 122 is called a moving member.

  The combination of the movable lens barrel (lens holder) 17, lens barrel (lens assembly) 18, spring 15, and first and second moving bodies 121 and 122 constitutes the lens movable part of the autofocus lens driving unit. Is done. As will be described later, a groove having a V-shaped cross section is formed on the friction surface of the vibration friction portion (vibration member) 14. Thereby, the lens movable part can move only in the optical axis O direction of the lens with respect to the housing.

  Next, the lens driving unit of the autofocus lens driving unit will be described. The lens driving unit (driving device) 10 includes a laminated piezoelectric element 13 that functions as an electromechanical conversion element, the stationary member (weight) 11, the vibration friction unit (vibrating member) 14, and a vibration transmitting member 19. The

  The laminated piezoelectric element 13 expands and contracts in the optical axis O direction. The laminated piezoelectric element 13 has a structure in which a plurality of piezoelectric layers are laminated in the optical axis O direction. As shown in FIG. 3, the laminated piezoelectric element 13 has a first end face (lower end face) 13a and a second end face (upper end face) 13b that face each other in the expansion / contraction direction. The stationary member (weight) 11 is coupled to the first end surface (lower end surface) 13a of the laminated piezoelectric element 13 with an adhesive or the like. A combination of the laminated piezoelectric element 13 and the stationary member 11 is called a piezoelectric unit.

The vibration friction portion (vibration member) 14 is attached to the second end surface (upper end surface) 13 b of the multilayer piezoelectric element 13 with an adhesive or the like via the vibration transmission member 19. That is,
The upper end surface 13b of the laminated piezoelectric element 13 is bonded (bonded) to the lower end surface 19a of the vibration transmitting member 19 with an adhesive (adhesive resin), and the lower end surface 14a of the vibration friction portion (vibrating member) 14 is bonded to the adhesive (adhesive). Resin) is joined (joined) to the upper end surface 19b of the vibration transmitting member 19.

  As described above, in the present embodiment, since the vibration transmission member 19 is added (intervened) between the vibration friction portion (vibration member) 14 and the laminated piezoelectric element (electromechanical conversion element) 13, vibration is generated. The friction part (vibrating member) 14 only needs to have a structure that takes into account the slidability with the first and second moving bodies 121 and 122. Therefore, it is not necessary to select the material of the vibration friction portion (vibration member) 14 in consideration of resin adhesiveness with the electromechanical transducer (laminated piezoelectric element) 13. Thereby, the vibration friction part (vibration member) 14 expands not only the freedom degree of the material selection but the freedom degree of the shape. As a result, the adhesive strength between the electromechanical conversion element (laminated piezoelectric element) 13 and the vibration friction portion (vibration member) 14 can be increased.

  In the illustrated embodiment, aluminum whose surface is subjected to fluorine lubrication plating is used as the material of the vibration friction portion (vibration member) 14. On the other hand, as a material of the vibration transmission member 19, an iron alloy (cold rolled thin plate (SPCC), stainless steel (SUS), etc.) is used.

  Further, by adding the vibration transmitting member 19, the material and shape of the vibration transmitting member 19 can be matched with other members, thereby suppressing the resonance phenomenon of the spring 15. In other words, the resonance frequency of the driving device 10 can be set freely.

  Furthermore, it is possible to compensate for the performance variation of each product caused by the dimensional variation of the spring 15 with the vibration transmission member 19 having a relatively simple shape. In other words, since the vibration transmission member 19 can be manufactured with a simple shape, it is possible to reduce variation in performance of each product of the driving device 10.

  The rod-shaped first and second moving bodies (moving shafts) 121 and 122 are frictionally coupled to the vibration friction portion (vibrating member) 14. The vibration friction portion (vibration member) 14 has a first friction coupling portion (first friction surface) between the vibration friction portion 14 and the rod-shaped first moving shaft 121 at the front end in the front-rear direction X. A groove 14b having a V-shaped first cross section is formed, and at the rear end in the front-rear direction X, a second friction coupling part (second second part) between the vibration friction part 14 and the rod-like second moving shaft 122 is formed. A groove 14c having a second V-shaped cross section is formed on the friction surface.

  As described above, the lens moving portion sandwiches the vibration friction portion (vibration member) 14 between the first and second friction surfaces of the first and second moving bodies (movement shafts) 121 and 122 in the form of rods. Spring 15 is provided. That is, the first end 15a of the spring 15 is held by the locking groove 174a of the lens holder 17, and the second moving body (moving shaft) 122 attached to the second end 15b. A pressing force that presses the vibration friction portion (vibrating member) 14 toward the first moving body (moving shaft) 121 is generated. In other words, the spring 15 urges the second moving body (moving shaft) 122 to the vibration friction portion (vibration member) 14 to cause the vibration friction portion (vibration member) 14 to be the first and second movement bodies. As urging means for applying a frictional force between the vibration friction portion (vibrating member) 14 and the first and second moving bodies (moving shafts) 121 and 122 by being sandwiched between the (moving shafts) 121 and 122. Works.

  As described above, the vibration friction portion (vibration member) 14 has both end faces (first and second formed on the first and second friction surfaces) facing each other in the direction orthogonal to the expansion and contraction direction of the multilayer piezoelectric element 13. Are sandwiched between the first and second movable bodies (moving shafts) 121 and 122, so that the position of the lens movable portion can be regulated and the lens movable portion is Rotation around one moving body (moving axis) 121 can be suppressed.

  In the illustrated embodiment, the first moving body 121 and the second moving body 122 are made of the same material. As a result, the first frictional force acting between the first moving body 121 and the first friction surface of the vibration friction portion 14 (first groove V-shaped groove 14b), and the second moving body The second frictional force acting between the second friction surface 122 and the second friction surface (the groove 14c having the second V-shaped cross section) of the vibration friction portion 14 can be made equal. Thereby, a lens movable part can be driven stably.

  Furthermore, the effective length of the spring 15 can be designed to be long. Therefore, even if the dimensions and assembly dimensions of the spring 15 vary, the influence on the load can be reduced. As a result, it is possible to manufacture the drive device 10 with less performance variation for each product.

  In the vibration friction portion 14, a first cross section V-shaped groove 14 b is formed in a first friction coupling portion (first friction surface) between the vibration friction portion 14 and the first moving body 121. . The contact state of the first friction coupling portion (first friction surface) is stabilized and reproduced by the bilinear contact with the first moving body 121 by the groove 14b having the V-shaped first cross section of the vibration friction portion 14. In addition to obtaining an excellent friction drive, the first moving body 121 has an effect of increasing the straight movement as the uniaxial moving body. The angle of the first cross-sectionally V-shaped groove 14b is desirably in the range of 30 degrees to less than 180 degrees.

  Similarly, in the vibration friction portion 14, a second V-shaped groove 14 c is formed in the second friction coupling portion (second friction surface) between the vibration friction portion 14 and the second moving body 122. is doing. The contact state of the second friction coupling portion (second friction surface) is stabilized and reproduced by the bilinear contact with the second moving body 122 by the groove 14c having the V-shaped second cross section of the vibration friction portion 14. The friction drive with good characteristics is obtained, and there is an effect that the straight movement as the uniaxial moving body of the second moving body 122 is improved. The angle of the second cross-section V-shaped groove 14c is desirably in the range of 30 degrees to less than 180 degrees.

  Further, the first and second moving bodies 121 and 122 are pressed against the vibration friction portion 14 by the spring 15. As a result, the first moving body 121 and the second moving body 122 are pressed against the first cross section V-shaped groove 14b and the second cross section V-shaped groove 14c of the vibration friction portion 14, respectively. Therefore, stable line contact of the three parts (the first and second moving bodies 121 and 122 and the vibration friction portion 14) is enabled.

  The lens driving unit and the lens moving unit are juxtaposed with respect to the optical axis O as shown in FIG. Therefore, the drive device 10 can be reduced in height.

  Next, the current supplied to the laminated piezoelectric element 13 and the displacement generated in the laminated piezoelectric element 13 will be described with reference to FIG. FIG. 4 is the same as that shown in FIG. 4A and 4B show a change in current supplied to the laminated piezoelectric element 13 by a drive circuit (not shown) and a displacement of the laminated piezoelectric element 13, respectively.

  As shown in FIG. 4A, a large current (positive direction) and a predetermined constant current (negative direction) are alternately passed through the laminated piezoelectric element 13. In such a situation, as shown in FIG. 4B, the laminated piezoelectric element 13 has a sudden displacement (elongation) corresponding to a large current (positive direction) and a gentle corresponding to a constant current (negative direction). Displacement (shrinkage) occurs alternately.

  That is, a rectangular wave current is applied to the laminated piezoelectric element 13 (FIG. 4A), and a sawtooth wave-like displacement (expansion / contraction) is generated with respect to the laminated piezoelectric element 13 (FIG. 4B).

  The operation of the driving apparatus 10 will be described with reference to FIG. 1 in addition to FIG. First, an operation when the lens movable portion is moved downward along the vertical direction Z will be described.

  First, as shown in FIG. 4A, when a large current in the positive direction is passed through the multilayer piezoelectric element 13, the multilayer piezoelectric element 13 is rapidly displaced in the thickness direction as shown in FIG. 4B. . As a result, the vibration friction portion 14 rapidly moves upward along the optical axis O direction (vertical direction Z) of the lens. At this time, the lens movable part (the first and second moving bodies 121 and 122) is caused to generate a frictional force between the vibration friction part 14 and the rod-like first and second moving bodies 121 and 122 due to its inertial force. It wo n’t move because it ’s virtually in that position.

  Next, as shown in FIG. 4A, when a constant current in the negative direction is passed through the multilayer piezoelectric element 13, the multilayer piezoelectric element 13 is gradually contracted in the thickness direction. As a result, the vibration friction portion 14 moves gently downward along the optical axis O direction (vertical direction Z). At this time, the vibration friction portion 14 and the rod-like first and second moving bodies 121 and 122 are coupled by the frictional force generated on the contact surfaces (first and second friction surfaces) between them. The lens movable portion (the first and second moving bodies 121 and 122) moves downward along the optical axis O direction (vertical direction Z) together with the vibration friction portion 14.

  As described above, the large current in the positive direction and the predetermined constant current in the negative direction are alternately supplied to the laminated piezoelectric element 13 to cause the laminated piezoelectric element 13 to alternately generate the expansion displacement and the contraction displacement, whereby the lens holder 17 ( The lens barrel 18) can be continuously moved downward along the optical axis O direction (vertical direction Z).

  In order to move the lens movable portion upward along the optical axis O direction (vertical direction Z), the negative current in the laminated piezoelectric element 13 and a predetermined constant current in the positive direction are alternately applied to the laminated piezoelectric element 13 contrary to the above. This can be achieved by flushing.

  Next, the laminated piezoelectric element 13 will be described. The laminated piezoelectric element 13 has a rectangular parallelepiped shape, and the element size is 0.9 [mm] × 0.9 [mm] × 1.5 [mm]. A low Qm material such as PZT is used as the piezoelectric material. The laminated piezoelectric element 13 is manufactured by laminating 50 layers of piezoelectric materials having a thickness of 20 [μm] and internal electrodes having a thickness of 2 [μm] alternately in a comb shape. The effective internal electrode size of the laminated piezoelectric element 13 is 0.6 [mm] × 0.6 [mm]. In other words, a ring-shaped dead zone portion (clearance) having a width of 0.15 [mm] exists in the peripheral portion located outside the effective internal electrode of the laminated piezoelectric element 13.

  In the driving apparatus 10 shown in FIGS. 1 to 3, the first moving body 121 and the movable lens barrel (lens holder, lens support body) 17 are separate and fixed to each other, but are shown in FIG. As in the driving device 10A, the first moving body 121 and the movable lens barrel (lens holder, lens support body) 17 may be configured integrally. In this case, the movable lens barrel (lens holder, lens support) 17 and the first moving body 121 are made of the same material.

  A driving device 10B according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a perspective view of the driving device 10B. FIG. 7 is a right side view of the driving device 10B. FIG. 8 is a side sectional view showing the vibration transmitting member 19A used in the driving device 10B together with the vibration friction portion 14 and the laminated piezoelectric element (electromechanical conversion element) 13. Here, as shown in FIGS. 6 and 7, an orthogonal coordinate system (X, Y, Z) is used. 6 and 7, in the Cartesian coordinate system (X, Y, Z), the X axis is the front-rear direction (depth direction), the Y axis is the left-right direction (width direction), and the Z axis is The vertical direction (height direction).

  In the illustrated driving device 10B, the vibration transmitting member 19 is deformed into a vibration transmitting member 19A as described later, and the movable barrel (lens holder, lens support body) and the first moving body are deformed as described later. Except for this point, it has the same configuration as that of the driving device 10 shown in FIGS. Therefore, the reference numerals 17A and 121A are assigned to the movable lens barrel (lens holder and lens support) and the first moving body, respectively. In the following, components having the same functions as those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and only different points will be described for simplification of description.

  The movable lens barrel (lens holder, lens support) 17A has the movable lens barrel (lens holder, lens support) shown in FIGS. 1 to 3 except that the protrusion 172 is changed to the protrusion 172A. Body). The length of the protrusion 172A is shorter than that of the protrusion 172. That is, the ridge portion 172A is formed on the upper portion of the cylindrical portion 170.

  Therefore, the length of the first moving body 121A fixed to the ridge portion 172A is also shorter than that of the first moving body 121 shown in FIGS.

  The vibration transmission member 19 </ b> A has a width (dimension) in the horizontal and horizontal directions that is wider than that of the vibration transmission member 19 shown in FIGS. 1 to 3.

  As shown in FIG. 8, the vibration transmitting member 19 </ b> A has a first recess 191 formed on the surface facing the upper end surface 13 b of the laminated piezoelectric element (electromechanical conversion element) 13, and is below the vibration friction portion 14. A second recess 192 is formed on the surface facing the end surface 14a. Therefore, the upper end surface 13 b of the laminated piezoelectric element (electromechanical transducer) 13 is loosely fitted in the first recess 191, and the lower end surface 14 a of the vibration friction portion 14 is loosely fitted in the second recess 192.

  The 1st recessed part 191 is for clarifying the application | coating area | region of the adhesive agent (adhesive resin) 20 between the upper end surface 13b of the laminated piezoelectric element (electromechanical conversion element) 13 and the lower end surface 19a of the vibration transmission member 19A. . The 2nd recessed part 192 is for clarifying the application | coating area | region of the adhesive agent (adhesive resin) 20 between the lower end surface 14a of the vibration friction part 14, and the upper end surface 19b of the vibration transmission member 19A. Thereby, the assembly property of the drive device 10B can be improved.

  8, when joining (adhering) the lower end surface 19a of the vibration transmitting member 19A and the upper end surface 13b of the laminated piezoelectric element (electromechanical transducer) 13 with an adhesive (adhesive resin) 20, The adhesive (adhesive resin) 20 is pushed to the inner wall side of the first recess 191 of the vibration transmitting member 19A. Similarly, when the upper end surface 19 b of the vibration transmitting member 19 </ b> A and the lower end surface 14 a of the vibration friction portion 14 are joined with the adhesive (adhesive resin) 20, the adhesive (adhesive resin) 20 is used as the second recess 192. It is pushed to the inner wall side.

  As a result, as shown in FIG. 8, the laminated piezoelectric element (electromechanical conversion element) 13, the vibration transmission member 19 </ b> A, and the vibration friction portion 14 can be attached without any adhesive resin layer therebetween. . Therefore, the vibration generated by the expansion and contraction of the laminated piezoelectric element (electromechanical conversion element) 13 is efficiently and efficiently transmitted through the vibration transmission member 19A and the vibration friction portion 14 to the first and second moving bodies (moving members) 121A. , 121 can be transmitted.

  In the driving device 10B shown in FIGS. 6 and 7, the first moving body 121A and the movable lens barrel (lens holder, lens support body) 17A are separate and fixed to each other, but are shown in FIG. As in the driving device 10C, the first moving body 121A and the movable lens barrel (lens holder, lens support body) 17A may be configured integrally. In this case, the movable lens barrel (lens holder, lens support) 17A and the first moving body 121A are made of the same material.

  Although the present invention has been described with reference to preferred embodiments, it is obvious that various modifications can be made by those skilled in the art without departing from the spirit of the present invention.

It is a perspective view which shows the drive device by the 1st Embodiment of this invention. FIG. 2 is a partially enlarged perspective view showing an enlarged main part of the drive device shown in FIG. 1. It is a side view of the principal part of the drive device shown in FIG. It is a wave form diagram for demonstrating the electric current supplied to a laminated piezoelectric element, and the displacement which generate | occur | produces in a laminated piezoelectric element. It is a perspective view which shows the modification of the drive device shown in FIG. It is a perspective view which shows the drive device by the 2nd Embodiment of this invention. It is a right view of the drive device shown in FIG. It is side surface sectional drawing which shows the vibration transmission member used for the drive device shown in FIG. 6 with a vibration friction part and a laminated piezoelectric element (electromechanical conversion element). It is a perspective view which shows the modification of the drive device shown in FIG.

Explanation of symbols

10, 10A, 10B, 10C Driving device 11 Stationary member 121, 121A First moving body 122 Second moving body 13 Multilayer piezoelectric element (electromechanical conversion element)
13a First end face (lower end face)
13b Second end face (upper end face)
14 Vibration friction part (vibration member)
14a Lower end surface 14b, 14c V-shaped cross section 15 Spring 17, 17A Movable lens barrel (lens holder, lens support)
170 Cylindrical part 172, 172A Projection part 174 Extension part 174a Locking groove 18 Lens barrel (lens assembly)
19, 19A Vibration transmission member 19a Lower end surface 19b Upper end surface 191, 192 Recess 20 Adhesive (adhesive resin)
O Optical axis of lens AFL Autofocus lens

Claims (2)

An electromechanical transducer having a pair of end faces opposed to each other in the direction of expansion and contraction; a vibration friction portion attached to one of the pair of end faces of the electromechanical transducer; a moving member frictionally coupled to the vibration friction portion; In the drive device in which the moving member can move in the expansion and contraction direction of the electromechanical conversion element,
A drive device comprising: a vibration transmitting member disposed between one of the pair of end faces of the electromechanical transducer and the end face of the vibration friction portion. The vibration transmitting member is
A first recess into which one of the pair of end faces of the electromechanical transducer is loosely fitted;
A second recess in which an end face of the vibration friction portion is loosely fitted;
The drive device according to claim 1, wherein:

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