JP2007325466A - Driving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving apparatus for efficiently obtaining a driving output, using a compact constitution. <P>SOLUTION: The driving apparatus includes an oscillation section 4 excited in longitudinal first-order vibration mode for generating an expansion/contraction deformation, perpendicular to the driving direction and long; first-order vibration mode for generating an elastic deformation by applying a voltage at a resonance frequency; and two guide rods 3 for pinching both sides of the oscillation section 4 in a pressed state. Rotational movements Ka, Kb that become reverse in rotation are generated on the both sides of the oscillation section 4, contacting the guide rods 3 i.e. protrusions 411-412, 413, by exciting the oscillation section 4 in the longitudinal first-order vibration mode and the primary flection oscillation mode. The oscillation section 4 is moved relative to the guide rods 3 by the rotational movements. The driving output can be extracted efficiently by using such a driving apparatus of compact constitution. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a driving device that performs driving in a predetermined direction.

  Ultrasonic actuators (drive devices) have advantages such as compactness and noise reduction, and are expected to be used in lens drive mechanisms for small cameras.

  An example of the ultrasonic actuator is disclosed in Patent Document 1. In this actuator, a plurality of protrusions are provided at both upper and lower ends of the ultrasonic vibrator (vibrating body), the vibrating body is sandwiched between a pair of guide members, and the stretching vibration in the moving direction of the vibrating body and the secondary vibration shown in FIG. The vibrating body can be moved with respect to the guide member by the rotational motion generated at the upper and lower ends of the vibrating body 9 in which the bending vibration is excited.

JP 2004-104984 A

  However, in the actuator of Patent Document 1, the vibrating body 9 is resonated so that a plurality of vibration nodes and antinodes are generated as shown in FIG. In this way, in order to ensure the required drive stroke with the vibrating body that is long in the moving direction, the guide member becomes longer correspondingly, leading to an increase in the size of the actuator.

  Further, regarding the rotational motion of the upper and lower end portions of the vibrating body 9, as shown in FIG. 22, the rotational motions 91 and 94 and the rotational motions 92 and 93 rotate in opposite directions on the upper end surface 9u of the vibrating body 9, and the lower end surface In 9d, the rotational motions 95 and 98 and the rotational motions 96 and 97 are rotated in opposite directions. On the other hand, in order to move the vibrating body 9, the rotational motion generated between the upper end surface 9u and the lower end surface 9d must be reversed. Therefore, in the vibrating body 9, it is necessary to provide protrusions that contact the guide member at each position of the upper end surface 9u where the rotational motions 91 and 94 occur, and at each position of the lower end surface 9d where the rotational motions 96 and 97 occur. is there.

  However, when the protrusion is provided at such a position, the rotational diameters of the rotational motions 96 and 97 of the lower end surface 9d are smaller than the rotational motions 91 and 94 of the upper end surface 9u. This occurs between the end faces 9u and 9d. As a result, a drive loss occurs and the drive output cannot be taken out efficiently, and it also causes wear.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a drive device that can efficiently extract drive output with a compact configuration.

  In order to solve the above-mentioned problem, the invention of claim 1 is a drive device that performs driving in a predetermined direction, and (a) a first vibration mode that performs expansion and contraction in a direction perpendicular to the predetermined direction; A vibration part that can excite a second vibration mode that performs a deformation different from the expansion and contraction deformation, and (b) arranged along the predetermined direction, and sandwiching both sides of the vibration part in a pressurized state 2 And exciting the first vibration mode and the second vibration mode in the vibration unit, thereby causing rotational motions that are opposite to each other on both sides of the vibration unit, and Driving in the predetermined direction is performed by moving the vibration portion relative to the guide member using the rotational motion.

  According to a second aspect of the present invention, in the drive device according to the first aspect of the present invention, the rotational direction of the rotational motion is the same over the entire side area on both sides of the vibrating section.

  According to a third aspect of the present invention, in the drive device according to the first or second aspect of the present invention, the first vibration mode is a primary vibration mode related to expansion / contraction deformation of the vibration section, and the second vibration mode. The mode is a primary vibration mode related to bending deformation of the vibration part.

  According to a fourth aspect of the present invention, in the drive device according to any one of the first to third aspects, the vibrating section is (a-1) arranged in parallel along a direction perpendicular to the predetermined direction. And a pair of expansion / contraction deformation parts capable of expansion / contraction deformation in the vertical direction, and (a-2) a connecting member that connects both ends of the pair of expansion / contraction deformation parts, and the first vibration mode includes: The pair of expansion / contraction deformation parts are excited by performing in-phase vibration related to expansion / contraction deformation, and the second vibration mode is excited by the pair of expansion / contraction deformation parts performing reverse phase vibration related to expansion / contraction deformation. Is done.

  According to a fifth aspect of the present invention, in the drive device according to any one of the first to fourth aspects of the present invention, the posture of the vibrating portion relative to the guide member is determined by at least one of the two sides of the vibrating portion. Be regulated.

  According to a sixth aspect of the present invention, in the drive device according to the fifth aspect of the present invention, the at least one side is provided with a plurality of protrusions that come into contact with the guide member.

  According to a seventh aspect of the present invention, in the drive device according to the fifth aspect of the present invention, the at least one side is provided with a contact portion that contacts the guide member with a certain contact length.

  The invention according to claim 8 is the drive device according to any one of claims 1 to 7, wherein each of the two guide members includes (b-1) a pipe portion that forms an outer shape of the guide member. And (b-2) a vibration damping member disposed inside the pipe portion.

  According to the first to eighth aspects of the present invention, the vibration section includes the first vibration mode for performing expansion / contraction deformation in a direction perpendicular to the predetermined direction and the second vibration mode for performing deformation different from expansion / contraction deformation. Excitation causes rotational movements that are opposite to each other on both sides of the vibration part, and the vibration part uses the rotational movement to hold the both sides of the vibration part in a pressurized state against the two guide members. Driving in a predetermined direction is performed by relatively moving. As a result, the drive output can be efficiently extracted with a compact configuration.

  In particular, in the invention of claim 2, since the rotational direction of the rotational motion is the same over the entire side of each side of the vibrating section, the configuration of the driving device can be simplified.

  In the invention of claim 3, since the first vibration mode is a primary vibration mode related to expansion and contraction of the vibration part, and the second vibration mode is a primary vibration mode related to bending deformation of the vibration part, Miniaturization can be achieved.

  According to a fourth aspect of the present invention, a pair of expansion / contraction deformation portions arranged in parallel along a vertical direction with respect to a predetermined direction and capable of expansion / contraction deformation in the vertical direction respectively perform vibration in the same phase related to expansion / contraction deformation. The first vibration mode is excited, and the pair of expansion / contraction deformation portions vibrate in the opposite phase with respect to expansion / contraction deformation, thereby exciting the second vibration mode. As a result, the configuration of the vibration part can be simplified.

  In the invention of claim 5, since the posture of the vibrating portion with respect to the guide member is regulated by at least one of the two sides of the vibrating portion, the posture of the vibrating portion can be stabilized.

  In the invention of claim 6, since the plurality of protrusions that contact the guide member are provided on at least one side, the posture of the vibrating portion can be easily stabilized.

  In the invention of claim 7, since the contact portion that contacts the guide member with a constant contact length is provided on at least one side, the posture of the vibration portion can be easily stabilized.

  In the invention of claim 8, since each of the two guide members is provided with a damping member inside the pipe portion that forms the outer shape of the guide member, vibration of the guide member by the vibrating portion is appropriately suppressed. it can.

<First Embodiment>
<Configuration of drive device>
FIG. 1 is a diagram illustrating a main configuration of a drive device 1A according to the first embodiment of the present invention. Here, FIG. 1A shows a front view of the drive device 1A, and FIG. 1B shows a side view of the drive device 1A.

  The drive device 1A is configured as, for example, an ultrasonic actuator, and includes a base portion 2, a pair of guide rods 3 (a lower guide rod 31 and an upper guide rod 32) held by the base portion 2, and the two guides. And a vibrating portion 4 sandwiched between rods (guide members) 3. In the driving device 1A, the vibration unit 3 that resonates when a voltage having a resonance frequency is applied moves along the two guide rods 3 to drive in the driving direction Dk.

  The base portion 2 includes a frame portion 21 having a “U” -shaped outer shape and a pressing member 22 that pressurizes the upper guide bar 32.

  The frame portion 21 is fixed, for example, in a device on which the driving device 1A is mounted. A side hole 21a having a circular shape and fixing the lower guide rod 31 is formed on the side surface 21s, and both ends are circular. An upper hole 21b having a long hole and holding the upper guide rod 32 is formed. The lower guide bar 31 is fixed to the lower hole 21a by press-fitting or bonding, and the upper guide bar 32 is loosely inserted into the upper hole 21b so as to be movable in the vertical direction Ud. At both ends of the upper guide bar 32, ring members 32r that move the upper guide bar 32 in the vertical direction Ud while being parallel to the lower guide bar 31 and prevent the upper guide bar 31 from coming off from the upper hole 21b. It is fixed. The ring member 32r may be molded integrally with the upper guide bar 32.

  The pressure member 22 is configured as, for example, a leaf spring, and a part of the pressure member 22 is fixed to the inner wall of the frame portion 21 and biases the upper guide member 32 toward the lower guide bar 31 with an appropriate pressure. With such a pressure member 22, the two guide rods 3 arranged along the driving direction Dk can hold both sides of the vibration part 4 in a pressurized state. Note that the pressing member 22 is not limited to a leaf spring, and may be configured by a coil spring.

  The two guide rods 3 are configured as rod-shaped members having a circular cross section, and function as guide members that guide the movement of the vibration unit 4. The guide rod 3 is made of, for example, a metal material such as stainless steel that is inexpensive and easy to manufacture. The surface of the guide rod 3 is subjected to surface hardening treatment such as quenching or nitriding treatment in order to suppress wear with the vibrating portion 4. Yes. As for the surface hardening treatment, ceramic coating such as chromium nitride (CrN) or titanium carbonitride (TiCN) may be applied, or the wear resistance may be improved by using ceramic such as alumina or zirconia. good.

  The configuration of the vibration unit 4 will be described with reference to FIG.

  FIG. 2 is a diagram illustrating a main configuration of the vibration unit 4. Here, FIG. 2A shows a front view of the vibration part 4, and FIG. 2B shows a side view of the vibration part 4.

  The vibration part 4 has a substantially rectangular parallelepiped shape, and includes a contact part 41 that comes into contact with the guide rod 3 and a piezoelectric part 42.

  The abutting portion 41 includes two projecting portions 411 and 412 that abut on the lower guide rod 31 and one projecting portion 413 that abuts on the upper guide rod 32. Each protrusion 411 to 413 is formed with a V-groove 41v that engages with the guide rod 3 in order to prevent the vibration part 4 from moving in the front-rear direction Fb as shown in FIG. In this way, by supporting the vibrating portion 4 at the three points of the protruding portions 411 to 413 with respect to the two guide rods 3, the posture of the vibrating portion 4 with respect to the guide rod 3 is stabilized. That is, with the movement of the vibrating portion 4 with respect to the guide rod 3, there is a possibility that the upper guide rod 32 with which only one protrusion 413 contacts is slightly inclined, but the lower guide rod fixed to the lower hole 21a. The posture of the vibrating part 4 supported by the two protrusions 411 and 412 with respect to 32 does not always change. Thereby, highly accurate position control and speed control are attained.

  The protrusions 411 to 413 are made of cemented carbide, ceramics such as alumina or zirconia in order to reduce wear on the guide rod 3, and are fixed to the piezoelectric part 42 by a relatively high elastic adhesive such as epoxy. Has been.

  The piezoelectric portion 42 has a structure in which rectangular piezoelectric ceramic thin plates (hereinafter abbreviated as “piezoelectric thin plates”) 421 having piezoelectric characteristics such as PZT (lead zirconate titanate) are laminated. Between 421, the left internal electrode L1 and the right internal electrode R1 divided into two as shown in FIG. 3A, and the left internal electrode L2 and the right internal electrode divided into two as shown in FIG. Electrodes R2 are alternately inserted. Further, on the front surface and the back surface of the piezoelectric portion 42, there are four external electrodes, specifically, a left front external electrode Lf, a left rear external electrode Lb, a right front external electrode Rf, and a right rear external electrode Rb. Are disposed along the stacking direction. These external electrodes Lf, Lb, Rf, and Rb are made of a metal such as silver and are electrically connected to a drive circuit via a lead wire or a flexible printed wiring board (FPC) (not shown). ).

  The left internal electrode L2 is electrically connected to the left front external electrode Lf, and the left internal electrode L1 is electrically connected to the left rear external electrode Lb. The right internal electrode R2 is electrically connected to the right front external electrode Rf, and the right internal electrode R1 is electrically connected to the right rear external electrode Rb.

  A voltage of a high frequency (for example, a frequency in an ultrasonic region that deviates from the human audible frequency range) that resonates the vibration unit 4 is applied to the vibration unit 4 having the above-described configuration from a drive circuit (not shown). When a periodic displacement is generated in the piezoelectric thin plate 421 of the portion 42, the vibrating portion 42 resonates, for example, as shown in FIG. 4, the protrusions 411 and 412 contacting the lower guide rod 31 have a clockwise elliptical orbit. Is generated, and a rotational motion Kb that draws a counterclockwise elliptical orbit is generated at the protrusion 413 that contacts the upper guide rod 32. When the rotational movements Ka and Kb that rotate in opposite directions are generated at both ends of the vibration part 4 in this way, the driving force for the guide bar 3 is caused by the frictional force that acts between the guide bar 3 and the protrusions 411 to 413. Since the protrusions 411 to 413 occur, the vibration part 4 can move in the direction Dr along the guide rod 3. Note that the protrusions 411 to 413 generate a driving force that is determined by the vertical drag generated by the pressure applied from the pressing member 22 and the friction coefficient with respect to the guide rod 3. Hereinafter, the operation of the piezoelectric unit 42 will be described in detail.

  The piezoelectric part 42 causes the protrusions 411 to 413 to generate a rotational motion by using two kinds of natural vibration modes, that is, a longitudinal (stretching) primary vibration mode and a bending primary vibration mode that are excited by voltage application at a resonance frequency. These vibration modes will be described below.

(i) Longitudinal primary vibration mode FIG. 5A shows a state of deformation of the longitudinal primary vibration mode. The state M1 extended as a whole and the contracted state (not shown) are repeated with respect to the state Mo (not shown by a broken line) when no voltage is applied. The primary vibration mode (first vibration mode) in which the vibration unit 4 performs expansion and contraction in the direction perpendicular to the drive direction Dk (FIG. 1) in this way is the longitudinal primary vibration mode.

  When a voltage of the same polarity is applied between the left front external electrode Lf and the left rear external electrode Lb and between the right front external electrode Rf and the right rear external electrode Rb in the piezoelectric unit 42 of the vibration unit 4, In the part 42, the piezoelectric thin plates 421 in the left half and the right half are subjected to expansion deformation (contraction deformation) in synchronization. Therefore, by applying a voltage in phase with the resonance frequency of the longitudinal primary vibration mode to the left electrode and the right electrode, the longitudinal primary vibration mode is excited and the displacement is greatly expanded in the longitudinal direction (stretching direction). .

(ii) Bending Primary Vibration Mode FIG. 5 (b) shows how the bending primary vibration mode is deformed. The whole bent state M2 and the oppositely bent state not shown are repeated. Thus, the primary vibration mode (second vibration mode) in which the vibration part 4 performs bending deformation different from the extension deformation in the longitudinal primary vibration mode is the bending primary vibration mode.

  When a voltage of reverse polarity is applied between the left front external electrode Lf and the left rear external electrode Lb and between the right front external electrode Rf and the right rear external electrode Rb in the piezoelectric unit 42 of the vibration unit 4, In the portion 42, the left half piezoelectric thin plate 421 expands (or contracts) while the right half piezoelectric thin plate 421 contracts (or expands), so that the piezoelectric portion 42 is bent and deformed rightward or leftward as a whole. Become. Therefore, by applying a voltage having an antiphase with the resonance frequency of the bending primary vibration mode to the left electrode and the right electrode, the bending vibration mode is excited and the displacement is greatly expanded in the bending direction.

  A voltage in which the resonance frequency of the longitudinal primary vibration mode and the resonance frequency of the bending primary vibration mode as described above are substantially matched by adjusting the aspect ratio of the vibration unit 4, for example, and the phase is shifted by 90 degrees at the resonance frequency. A signal (see FIG. 6) is applied to the left and right halves of the piezoelectric portion 42 to simultaneously excite the longitudinal primary vibration mode and the bending primary vibration mode, so that, for example, rotational movements Ka and Kb are applied to the upper and lower ends of the piezoelectric portion 42. (FIG. 4) can be generated. That is, by exciting the longitudinal primary vibration mode and the bending primary vibration mode in the vibration unit 4, rotational movements that are opposite to each other are generated on both sides of the vibration unit 4, and on both sides of the vibration unit 4, The rotational direction of the rotational motion is the same over the entire area.

  Here, with respect to the rotational direction of the rotational motion generated at both ends of the vibration unit 4, the rotational direction can be reversed by advancing the phase of the other voltage signal by 90 degrees or delaying by 90 degrees with respect to one voltage signal. Therefore, the moving direction of the vibration part 4 with respect to the guide rod 3 can be easily changed.

  With the configuration and operation of the driving device 1A described above, the longitudinal primary vibration mode and the bending primary vibration mode are excited in the vibration unit 4 and both sides of the vibration unit 4 in contact with the guide rod 3, that is, the protrusions 411 to 412 and the protrusions Since the vibration part 4 moves with respect to the guide rod 3 by causing the parts 413 to rotate in opposite directions, the drive output can be efficiently extracted with a compact configuration. That is, since the size (length) in the moving direction of the vibration part 4 can be reduced by sandwiching the vibration part 4 between the two guide rods 3 in the vertical vibration direction of the vertical primary vibration mode, the drive stroke of the vibration part 4 can be reduced. The length of the guide bar 3 necessary for securing the driving device 1A can be shortened, and the drive device 1A can be downsized.

  Further, in the driving apparatus 1A, since the driving force is taken out using the rotational motion generated at both ends of the vibrating part 4, a conventional actuator (for example, JP-A-7-143770) that takes out the driving force from only one end of the vibrating body. Compared to the publication No. gazette), a large driving force can be taken out. Further, the conventional actuator that has obtained the drive output from one end of the vibrating body requires a rotation support mechanism such as a roller or a bearing at the other end. However, in the drive device 1A of the present embodiment, such a rotation support mechanism Is unnecessary. Therefore, the size of the drive device 1A can be reduced, and a rotation load (loss) in the rotation support mechanism does not occur.

  In the driving device 1A, two protrusions 411 and 412 are provided on one side of both sides of the vibration part 4, and the vibration part 4 with respect to the guide rod 3 is provided by these protrusions 411 and 412. Is regulated. Thereby, even when moving, the posture of the vibration part 4 is stabilized.

  In addition, each end portion (each side) of the vibrating portion 4 that contacts the guide rod 3 has the same rotational direction of the rotational motion in the entire region of the end face, so that it is not necessary to provide a protrusion and the design of the contact portion is free. The degree is improved. Below, the contact part which has a different structure from the contact part 41 mentioned above is demonstrated, referring FIGS. 7-9. 7-9, (a) has shown the front view of the vibration part, (b) has shown the side view of the vibration part.

  The contact portion 43 shown in FIG. 7 includes a contact portion 431 that contacts the lower guide rod 31 with a certain contact length, and a protrusion 432 that contacts the upper guide rod 32. Here, the contact part 431 has a length La in the longitudinal direction (movement direction of the vibration part 4) of more than half of a length Lb in the movement direction of the vibration part 4, and the protrusion part 432 is the protrusion part described above. 413 (FIG. 2). Since the vibration part 4 is supported by the contact part 431 that comes into contact with the lower guide rod 31 in a relatively wide range by the contact part 43 having such a configuration, the posture of the vibration part 4 is stabilized.

  The contact portion 44 shown in FIG. 8 has a contact portion 441 that contacts the lower guide rod 31 and a contact portion 442 that contacts the upper guide rod 32. Here, each of the contact part 441 and the contact part 442 has the same configuration as the contact part 431 (FIG. 7). Even in the abutting portion 44 having such a configuration, the posture of the vibrating portion 4 sandwiched between the two guide rods 3 is stabilized.

  The contact portion 45 shown in FIG. 9 has a contact portion 451 that contacts the lower guide rod 31 and a contact portion 452 that contacts the upper guide rod 32. Here, each of the contact portion 451 and the contact portion 452 has a rectangular parallelepiped shape that is the same shape as the cross section of the piezoelectric body. And the V-groove 41v (FIG. 2) like the projection parts 411-413 is not formed in the part which contacts the guide rod 3, but it has a flat structure. In addition, since the vibration part 4 cannot be regulated by the contact part 4 having such a flat end surface, a member (regulation means) for regulating movement of the vibration part 4 in the thickness (depth) direction is separately required. Since the abutting portion 45 having the above-described configuration is integral with the laminated structure of the piezoelectric portion 42, the structure is simplified, which is advantageous in terms of manufacturing and cost.

  Moreover, about the piezoelectric part of the vibration part 4, you may have a structure as shown in FIGS. 10, FIG. 12, and FIG. 13, (a) shows a front view of the vibration part, and (b) shows a side view of the vibration part. 12 and 13, (c) shows a rear view of the vibration part. Below, the structure of each contact part shown in FIGS. 10-13 is demonstrated in order.

  The piezoelectric unit 46 shown in FIG. 10 differs from the piezoelectric unit 42 (FIG. 2) described above in which the piezoelectric thin plate 421 is stacked in the height direction (vertical direction) of the vibrating unit 4, and the piezoelectric thin plate 461 is used as the vibrating unit. 4 is laminated in the thickness (depth) direction. Between the piezoelectric thin plates 461, the left internal electrode S1 and the right internal electrode T1 divided into two as shown in FIG. 11A and the left internal electrode divided into two as shown in FIG. S2 and the right internal electrode T2 are alternately inserted. On the left side and right side of the piezoelectric portion 46, there are four external electrodes, specifically, an upper left external electrode Su, a lower left external electrode Sd, an upper right external electrode Tu, and a lower right external electrode Td. 461 is disposed along the stacking direction. The left internal electrode S2 is electrically connected to the upper left external electrode Su, and the left internal electrode S1 is electrically connected to the lower left external electrode Sd. The right internal electrode T2 is electrically connected to the upper right external electrode Tu, and the right internal electrode T1 is electrically connected to the lower right external electrode Td.

  When the same voltage as in the embodiment of FIG. 2 is applied to the piezoelectric portion 46 having the above configuration via the external electrode to extract the drive output along the guide rod 3, the vibration direction of the longitudinal primary vibration mode (longitudinal vibration) (Direction) is a direction perpendicular to the stacking direction (so-called 31 direction), so that the driving amount is reduced as compared with the above-described piezoelectric unit 42 (FIG. 2) in which the longitudinal vibration direction is the stacking direction (so-called 33 direction). In the piezoelectric part 46, since the number of laminated piezoelectric thin plates 461 is reduced, it is more advantageous in manufacturing than the piezoelectric part 42 described above. In addition, since the piezoelectric element constituting the piezoelectric thin plate is weak in the tensile force in the stacking direction, the piezoelectric portion 46 is advantageous in terms of strength as compared with the piezoelectric portion 42 described above.

  The piezoelectric portion 47 shown in FIG. 12 is configured as a single layer (bulk) piezoelectric body 471 instead of a laminated structure in which a plurality of piezoelectric thin plates 461 are laminated like the piezoelectric portion 46 in FIG. Then, the electrode Sf and the electrode Tf divided into two as shown in FIG. 12A are arranged on the front surface of the piezoelectric portion 47, and one electrode as shown in FIG. The electrode STb is disposed as a common electrode.

  When a voltage similar to that of the embodiment of FIG. 2 is applied to the piezoelectric portion 47 having the above-described configuration via an electrode, a drive output along the guide rod 3 can be taken out similarly to the piezoelectric portion 46 described above. The piezoelectric portion 47 requires a high voltage to be taken out in order to extract a driving amount equivalent to the piezoelectric portion 46 having the laminated structure of the piezoelectric thin plates 461, but has a simpler structure than the piezoelectric portion 46. This is advantageous in terms of manufacturing and cost.

  The configuration shown in FIG. 13 has a configuration in which piezoelectric thin plates 481 and 482 are attached to the front and back surfaces of a thin plate-like elastic body 480 with a conductive adhesive or the like. Further, the external electrode Sf and the external electrode Tf divided into two as shown in FIG. 13A are arranged on the front surface of the piezoelectric portion 48, and the rear surface of the piezoelectric portion 48 is shown in FIG. 13C. The external electrode Sb and the external electrode Tb divided into two are disposed, and the external electrode Sf and the external electrode Tb, and the external electrode Tf and the external electrode Sb are connected to be a common electrode. The elastic body 480 is used as a common electrode (GND) for all piezoelectric thin plates. The elastic body 480 is made of a metal material having a low damping coefficient related to vibration and high wear resistance, for example, stainless steel subjected to nitriding treatment.

  When a voltage similar to that of the embodiment of FIG. 2 is applied to the piezoelectric portion 48 having the above configuration via an external electrode, the drive output along the guide rod 3 can be taken out as with the piezoelectric portion 46 described above. And since protrusion part 41a-41c can be integrally formed with respect to the elastic body 480, while simplifying manufacture, since the elastic body 480 is comprised with a metal material with a small attenuation | damping, it is made from a ceramic etc. Compared with driving efficiency.

Second Embodiment
<Configuration of drive device>
FIG. 14 is a diagram showing a main configuration of a drive device 1B according to the second embodiment of the present invention. Here, FIG. 14A shows a front view of the drive device 1B, and FIG. 14B shows a side view of the drive device 1B.

  The drive device 1B has a configuration similar to that of the drive device 1A of the first embodiment, but the vibration part is different. Below, the structure of the vibration part 5 of the drive device 1B is demonstrated in detail.

  FIG. 15 is a diagram illustrating a main configuration of the vibration unit 5. Here, FIG. 5A shows a front view of the vibration part 5, and FIG. 5B shows a side view of the vibration part 5.

  The vibration unit 5 includes a contact portion 51 that contacts the guide rod 3 and a piezoelectric portion 52.

  The piezoelectric portion 52 includes a pair of expansion / contraction deformation portions 52a and 52b that are arranged in parallel along the vertical direction with respect to the driving direction Dk (FIG. 14) and can be expanded and contracted in the vertical direction. Each expansion / contraction deformation part 52a is formed by stacking rectangular piezoelectric thin plates 521 having piezoelectric characteristics such as PZT while sandwiching an internal electrode, and is configured as a so-called general laminated piezoelectric element. In addition, external electrodes Lf, Lb, Rf, and Rb similar to those in the first embodiment are disposed on the front and back surfaces of the respective rectangular parallelepiped expansion / contraction deformation parts 52a and 52b.

  The abutment portion 51 has a relatively high elastic adhesive such as epoxy at both ends of the projection portions 511 to 513 having the same configuration as the projection portions 411 to 413 of the first embodiment and the expansion / contraction deformation portions 52a and 52b. And connecting portions 514 and 515 that are fixed and connected. Each protrusion 511 to 513 is formed with a V-groove 51v that engages with the guide rod 3 in order to prevent the vibration part 5 from moving in the front-rear direction as in the first embodiment.

  In the vibration part 5 having the above-described configuration, similar to the vibration part 4 of the first embodiment, by using the longitudinal primary vibration mode and the bending primary vibration mode excited at the resonance frequency, the protrusions 511 to 513 Causes rotational movement. These vibration modes will be described below.

(i) Longitudinal primary vibration mode FIG. 16A shows a state of deformation in the longitudinal primary vibration mode. The expanded state M11 and the contracted state (not shown) are repeated with respect to the state (not shown) when no voltage is applied. Thus, the primary vibration mode (first vibration mode) in which the piezoelectric section 52 expands and contracts in the direction perpendicular to the drive direction Dk (FIG. 14) is the longitudinal primary vibration mode.

  When a voltage having the same polarity is applied between the external electrode Lf and the external electrode Lb and between the external electrode Rf and the external electrode Rb in the piezoelectric unit 52 of the vibration unit 5, the expansion / contraction deformation units 52 a and 52 b are applied to the piezoelectric unit 52. Performs the expansion deformation (contraction deformation) synchronized with each other. Therefore, by applying a voltage in phase with the resonance frequency of the longitudinal primary vibration mode to the left electrode and the right electrode, the longitudinal primary vibration mode is excited and the displacement is greatly expanded in the longitudinal direction (stretching direction). .

(ii) Bending primary vibration mode FIG. 16 (b) shows the deformation of the bending primary vibration mode. The whole bent state M12 and the oppositely bent state (not shown) are repeated. Thus, the primary vibration mode (second vibration mode) in which the piezoelectric portion 52 performs bending deformation different from the extension deformation in the longitudinal primary vibration mode is the bending primary vibration mode.

  In the piezoelectric part 52 of the vibration part 5, when a voltage having a reverse polarity is applied between the external electrode Lf and the external electrode Lb and between the external electrode Rf and the external electrode Rb, the expansion / contraction deformation part 52 a extends ( On the other hand, since the expansion / contraction deformation part 52b contracts (or expands), the piezoelectric part 52 is bent and deformed rightward or leftward as a whole. Therefore, by applying a voltage having an antiphase with the resonance frequency of the bending primary vibration mode to the left electrode and the right electrode, the bending vibration mode is excited and the displacement is greatly expanded in the bending direction.

  While the resonance frequency of the longitudinal primary vibration mode and the resonance frequency of the bending primary vibration mode as described above substantially coincide with each other, a voltage signal (see FIG. 6) whose phase is shifted by 90 degrees at the resonance frequency is supplied to each expansion / contraction deformation section 52a, 4b, the longitudinal primary vibration mode and the bending primary vibration mode are simultaneously excited to generate, for example, the rotational movements Ka and Kb shown in FIG. The part 5 can be moved. Here, since the vibration part 5 has two independent expansion / contraction deformation parts 52a and 52b, the width and length of each expansion / contraction deformation part 52a and 52b and the distance between the expansion / contraction deformation parts 52a and 52b are parameters. As a result, the resonance frequencies of the longitudinal primary vibration mode and the bending primary vibration mode can be substantially matched. Therefore, the design freedom of the vibration part 5 is increased as compared with the vibration part 4 of the first embodiment.

  With the configuration and operation of the driving device 1B described above, the same effects as those of the driving device 1A of the first embodiment are exhibited. Furthermore, in the drive device 1B, the longitudinal primary vibration mode and the bending primary vibration mode are excited using the two expansion / contraction deformation parts 52a and 52b arranged in parallel, so that the configuration of the vibration part 5 becomes simple.

  Note that the expansion / contraction deformation parts 52a and 52b of the driving device 1B may be constituted by, for example, a laminated piezoelectric element laminated in the thickness direction (depth direction) of the vibration part, and further disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-185055. It may be configured as a roll-type piezoelectric element disclosed.

  The drive device 1A of the first embodiment and the drive device 1B of the second embodiment described above can be used to drive a moving body including, for example, a lens. This usage example will be described below.

  FIG. 17 is a diagram for explaining a configuration for driving the moving body 6 using the driving device 1A.

  The moving body 6 is provided above the front surface of the vibration unit 4 in the driving device 1A (above the paper surface of FIG. 1), and can move along another guide (not shown) arranged in parallel with the guide rod 3. ing. The moving body 6 includes a lens 61, a holder 62 that holds the lens 61, and a leaf spring 63 that is fixed to the holder 62. The leaf spring 63 has a “U” -shaped outer shape, and the vibration portion 4 and the moving body 6 are connected by sandwiching the vicinity of the center of the side surface of the vibration portion 4 with the leaf spring 63. The urging force of the leaf spring 63 that holds the vibration portion 4 is set to a force that does not hinder the vibration of the vibration portion 4 and a flexible adhesive (between the leaf spring 63 and the vibration portion 4). For example, it is preferable to reduce wear by bonding with a rubber adhesive.

  With the configuration as described above, the moving body 6 is driven in conjunction with the movement of the vibration section 4 with respect to the guide rod 3, so that the drive system of the moving body 6 can be made compact.

<Modification>
-About the guide rod in each said embodiment, it is not essential to comprise with a single material, and you may make it comprise combining a some material so that there may exist a vibration-proof effect.

  FIG. 18 is a diagram showing a configuration of a guide bar 3A in which a plurality of materials are combined. Here, FIG. 18A shows a cross-sectional view of the guide bar 3A parallel to the drive direction Dk (see FIG. 1), and FIG. 18B shows a direction perpendicular to the drive direction Dk (see FIG. 1). A cross-sectional view of the guide bar 3A is shown.

  The guide bar 3 </ b> A includes a pipe portion 33 that forms the outer shape of the guide rod 3 </ b> A, and a columnar damping member 34 that is disposed inside the pipe portion 33.

  The pipe portion 33 has a cylindrical shape and is formed of metal or ceramic. The damping member 34 is made of a resin having a large damping coefficient with respect to vibration, or a damping alloy (for example, Mn—Cu alloy, Fe—Cr alloy, Zn—Al alloy, etc.). In addition, when the damping member 34 is a damping alloy, it is preferable to adhere and fix the outer peripheral surface and the inner peripheral surface of the pipe portion 33. On the other hand, when the damping member 34 is resin, insert molding may be performed on the pipe portion 33.

  The guide bar is vibrated in accordance with the vibration of the vibration unit 4, and this vibration may cause a natural vibration of the guide bar. Here, when the natural vibration of the guide rod is generated, there is a possibility that the driving force (thrust) is reduced or abnormal noise is generated due to the interaction between the natural vibration and the rotational motion of the end of the vibration part 4.

  In order to avoid such a situation, the guide rod 3A employs a vibration isolation structure in which the vibration damping member 34 is inserted into the pipe portion 33 as described above. As a result, even if vibration that causes resonance of the pipe portion 33 occurs, the internal damping member 34 converts vibration energy into heat and attenuates vibration (natural vibration), so that it is possible to prevent performance deterioration of the drive device 1A. It becomes.

  -About the guide rod in each said embodiment, it is not essential to have a circular cross section, You may have a cross section of different shapes, such as a square cross section.

  -About the drive device in said each embodiment, it is not essential to provide the one vibration part 4 which moves along a guide rod, You may provide two or more vibration parts 4. FIG. FIG. 19 is a diagram illustrating a configuration of a driving device 1C including two vibrating units 4A and 4B. By applying a voltage to each vibrating unit 4A and 4B, the vibrating units 4A and 4B are independently provided. Can drive. By adopting such a configuration, even when the two vibrating portions 4A and 4B are driven separately, a single set of guide rods 3 is sufficient, and the cost can be reduced.

  In the driving device in each of the above embodiments, it is not essential to move the vibrating portion with respect to the guide rod. For example, as in the driving device 1D shown in FIG. May be moved. Here, FIG. 20A shows a front view of the drive device 1D, and FIG. 20B shows a side view of the drive device 1D.

  In the driving device 1D, the vibration part 4C is sandwiched and held between two leaf springs 71 extending from the fixed part FX, and the two guide rods 35 and 36 that are in contact with both ends of the vibration part 4C are sandwiched. A leaf spring 72 is provided.

  In the drive device 1D having such a configuration, by applying a voltage to the vibration unit 4C and causing it to vibrate, for example, rotational movements Ka and Kb are generated at both ends of the vibration unit 4C, and the guide rods 35 and 36 (and the leaf spring 72). ) Moves in the direction Dt.

  In the drive devices of the above embodiments, it is not essential to perform linear drive, and for example, rotation drive may be performed like the drive device 1E shown in FIG. Here, FIG. 21A shows a plan view of the drive device 1E, and FIG. 21B shows a side view of the drive device 1E.

  The drive device 1E includes ring-shaped guide rings (guide members) 37 and 38 corresponding to the upper guide bar 31 and the lower guide bar 32 described above, and three pieces arranged at equal intervals along the guide rings 37 and 38. The vibration part 4 (FIG. 2) is provided. Further, the drive device 1E includes a ring-shaped base member 23, and for example, the vibrating portion 4 is applied to the upper and lower guide rings 37 and 38 by an urging force from a ring-shaped pressurizing member 24 configured as a wave washer. It is clamped in a pressure state. Here, when the three vibrating portions 4 are fixed and a voltage is applied to the vibrating portions 4 so that the driving forces of the vibrating portions 4 are generated in the same rotation direction with respect to the guide rings 37 and 38, a ring-shaped guide is obtained. The rings 37 to 38 and the base member 23 are rotated about the rotation axis Co.

  If the rotating device such as the rotor is connected to the base member 23 by holding the rotating member such as a rotor on the inner peripheral surface of the base member 23 by the drive device 1E having the above configuration, the rotating member is rotated by applying a voltage to the vibration unit 4. It can be driven. Such a driving device 1E can be applied to, for example, an imaging device that rotationally drives a cam ring or the like to move a lens directly.

It is a figure which shows the principal part structure of 1 A of drive devices which concern on 1st Embodiment of this invention. FIG. 3 is a diagram illustrating a main configuration of a vibration unit 4. FIG. 6 is a diagram for explaining a configuration of a piezoelectric unit. FIG. 6 is a diagram for explaining rotational movements Ka and Kb that occur in protrusions 411 to 413 of the vibration part 4. FIG. 6 is a diagram for explaining two types of natural vibration modes related to a piezoelectric unit. FIG. 4 is a diagram for explaining a voltage signal applied to a piezoelectric unit. It is a figure for demonstrating the other structure regarding a contact part. It is a figure for demonstrating the other structure regarding a contact part. It is a figure for demonstrating the other structure regarding a contact part. It is a figure for demonstrating the other structure regarding a piezoelectric part. It is a figure for demonstrating the other structure regarding a piezoelectric part. It is a figure for demonstrating the other structure regarding a piezoelectric part. It is a figure for demonstrating the other structure regarding a piezoelectric part. It is a figure which shows the principal part structure of the drive device 1B which concerns on 2nd Embodiment of this invention. FIG. 3 is a diagram illustrating a main configuration of a vibration unit 5. FIG. 6 is a diagram for explaining two types of natural vibration modes related to the vibration unit 5. It is a figure for demonstrating the structure which drives the mobile body 6 using the drive device 1A. It is a figure which shows the structure of 3 A of guide bars which combined several material. It is a figure which shows the structure of 1 C of drive devices provided with the two vibration parts 4A and 4B. It is a figure which shows the structure of drive device 1D which moves the guide rods 33 and 34 with respect to the vibration part 4C. It is a figure which shows the structure of the drive device 1E which performs rotational drive. It is a figure explaining operation | movement of the actuator which concerns on a prior art.

Explanation of symbols

1A to 1E Driving device 2 Base portion 3, 31, 32, 35, 36 Guide rod 4, 4A to 4C, 5 Vibration portion 6 Moving body 22 Pressure member 33 Pipe portion 34 Damping member 37, 38 Guide rings 41, 43 45, 51 Abutment part 42, 46-48, 52 Piezoelectric part 52a, 52b Expansion / contraction deformation part 411-413, 511-513 Projection part Ka, Kb

Claims (8)

A driving device for driving in a predetermined direction,
(a) a vibration unit capable of exciting a first vibration mode that performs expansion / contraction deformation in a direction perpendicular to the predetermined direction and a second vibration mode that performs deformation different from the expansion / contraction deformation;
(b) two guide members arranged along the predetermined direction and holding both sides of the vibrating part in a pressurized state;
With
Exciting the first vibration mode and the second vibration mode in the vibration unit to cause rotational movements that are opposite to each other on both sides of the vibration unit,
The drive device according to claim 1, wherein the vibration unit is driven relative to the guide member using the rotational motion to drive in the predetermined direction. The drive device according to claim 1,
The drive device according to claim 1, wherein the rotational direction of the rotational motion is the same over the entire side of each side of the vibration unit. The drive device according to claim 1 or 2,
The drive device according to claim 1, wherein the first vibration mode is a primary vibration mode related to expansion / contraction deformation of the vibration section, and the second vibration mode is a primary vibration mode related to bending deformation of the vibration section. The drive device according to any one of claims 1 to 3,
The vibrating part is
(a-1) a pair of expansion / contraction deformation portions arranged in parallel along the vertical direction with respect to the predetermined direction and capable of expansion / contraction deformation in the vertical direction;
(a-2) a coupling member that couples both ends of the pair of stretchable deformation portions;
Have
The first vibration mode is excited by the pair of expansion / contraction deformation portions performing vibrations in the same phase related to expansion / contraction deformation,
The driving apparatus according to claim 2, wherein the second vibration mode is excited by causing the pair of expansion / contraction deformation portions to perform vibrations in opposite phases related to expansion / contraction deformation. The drive device according to any one of claims 1 to 4,
The drive device according to claim 1, wherein an attitude of the vibration unit with respect to the guide member is restricted by at least one side of both sides of the vibration unit. The drive device according to claim 5, wherein
The drive device according to claim 1, wherein a plurality of protrusions that contact the guide member are provided on the at least one side. The drive device according to claim 5, wherein
The drive device according to claim 1, wherein a contact portion that contacts the guide member with a constant contact length is provided on at least one side. The drive device according to any one of claims 1 to 7,
Each of the two guide members is
(b-1) a pipe portion that forms the outer shape of the guide member;
(b-2) a vibration damping member disposed inside the pipe portion;
A drive device comprising:

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