JP5183921B2 - Piezoelectric actuator and electronic device using the same - Google Patents

Description

    The present invention relates to a piezoelectric actuator that frictionally drives a moving body by vibration of a piezoelectric element, and an electronic device to which the piezoelectric actuator is applied.

  In recent years, downsizing of electronic devices has progressed, and downsizing of actuators used there has been required. A typical example of this actuator is an electromagnetic motor, and a method for converting its output into a driving force of an operating member via a reduction gear train or the like has been generally used for a long time.

  However, electromagnetic motors are not only difficult to miniaturize, but the torque becomes extremely weak even if they are miniaturized, so a reduction gear train is required, and the size of the mechanism itself is difficult to reduce. .

  Therefore, development of actuators based on a new principle has been actively carried out, and expectations are also high for small-sized and high-powered piezoelectric elements. For example, a frictional force is generated between the moving body and a shaft that guides the movable body, and the moving body is generated by the inertial force of the moving body that is generated when the piezoelectric element provided at the tip of the shaft is rapidly deformed. Has been developed, and attempts have been made to apply it to camera zoom mechanisms and autofocus mechanisms (Patent Documents 1 and 2).

The piezoelectric element is fixed at one end to a fixed member, and a moving body is in pressure contact with the piezoelectric element. The acceleration or velocity of the displacement in the first direction of the piezoelectric element and the displacement in the second direction A method of driving a moving body by displacing so that the acceleration or speed is different (Patent Document 3).
Japanese Patent Laid-Open No. 9-247967 JP 11-265212 A JP 2005-210888 A

  However, since the operation shown in Patent Document 1 is limited to the linear motion operation, the applied device is limited. In this case, there is a merit that it is possible to operate the operating member directly, but the generated force is small and there is a possibility that the operating part may move if the actuator mounting device falls or vibrates. It was.

  In both Patent Documents 1 and 2, driving efficiency is caused by occurrence of sliding loss at the contact portion between the moving body and the shaft, or between the moving body and the piezoelectric element, or vibration leakage at the support portion of the piezoelectric element. However, there was a problem that low power consumption is required.

  An object of the present invention is to provide a piezoelectric actuator having high driving efficiency, small size, low power consumption, and high output.

Therefore, the piezoelectric actuator of the present invention is integrally formed by a first piezoelectric element that reciprocates in a first direction and a second piezoelectric element that reciprocates in a second direction different from the first direction. A rectangular parallelepiped vibrator configured and a moving body in contact with the friction portion provided on the first piezoelectric element, and the same waveform drive signal is the same on the first piezoelectric element and the second piezoelectric element. The moving body is driven by making the speed of the displacement in the first direction slower than the return speed and making the speed of the displacement in the second direction slower than the return speed. The piezoelectric actuator is characterized by this.

  According to this, since the movement of the first piezoelectric element can be transmitted to the moving body without loss, the output of the moving body is improved and the driving efficiency of the piezoelectric actuator is improved.

  According to the present invention, since the piezoelectric element can be driven in a non-resonant state, current consumption is small, and a piezoelectric actuator that can be driven by a drive circuit having a simple configuration can be realized. Moreover, since the drive efficiency is high, a small and high output piezoelectric actuator can be realized.

  Then, by driving the operating member by the moving body, it is possible to achieve downsizing and low power consumption of the electronic device.

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

(Embodiment 1)
FIG. 1A shows the configuration of the piezoelectric actuator 100 according to Embodiment 1 of the present invention, and FIG. 1B shows the configuration of the vibrator 20 used in the piezoelectric actuator 100 (modification). .

  The piezoelectric actuator 100 of the present invention includes a support member 4, a first piezoelectric element 1, and a second piezoelectric element 2, a vibrator 20 having one end fixed to the support member 4, and the other end of the vibrator 20. , A moving member 7 in contact with the friction unit 3, a pressure spring 6 that generates a contact pressure between the friction unit 3 and the moving member 7, and a guide member that guides the movement of the support member 4. And 5.

  The vibrator 20 has a rectangular parallelepiped shape, and is integrally formed by bonding the first piezoelectric element 1 and the second piezoelectric element 2. The first piezoelectric element 1 and the second piezoelectric element 2 may be integrally sintered so as to be configured in the same piezoelectric element without using an adhesive. The first piezoelectric element 1 is polarized in the direction of the arrow 51, and when a voltage is applied between the electrodes 8 and 9 provided on the end face in the direction orthogonal to the arrow 51, the first piezoelectric element 1 undergoes shear deformation in the x-axis direction in the figure. By performing, the displacement to the moving direction of the moving body 7 (direction orthogonal to the contact pressure direction of the friction part 3 and the moving body 7) generate | occur | produces. The second piezoelectric element 2 is polarized in the direction of the arrow 52, and when a voltage is applied between the electrodes 9 and 10 provided on the end face in the direction of the arrow 52, the second piezoelectric element 2 is subjected to expansion and contraction deformation in the y-axis direction. A displacement in the contact pressure direction between the portion 3 and the moving body 7 is generated.

The moving body 7 rotates by guiding a shaft 7a provided at the rotation center of the moving body 7 with a bearing (not shown). The guide member 5 has a groove portion (not shown) on the two guide surfaces 5a and 5b, and the groove portion engages with the side surfaces 4a and 4b of the support member 4, so that the support member 4 receives the pressing force of the pressure spring 6, This is a guide for moving in the direction of the moving body 7. The friction portion 3 is made of an engineering plastic having excellent wear resistance, an engineering ceramic such as alumina, or the like, and is bonded to the piezoelectric element 11 with an adhesive. However, the surface of the piezoelectric element 1 itself may be used as the friction part 3, or the friction part 3 may be formed by coating or the like.

  Here, the support member 4 is made of a heavy metal such as brass and serves as a counterweight against rapid deformation of the piezoelectric elements 1 and 2. The guide member 5 restricts the movement of the support member 4 in the x direction due to the deformation of the piezoelectric element 1, and the pressure spring 6 helps to restrict the movement of the support member 4 in the y direction due to the deformation of the piezoelectric element 2. Therefore, the operation of the piezoelectric elements 1 and 2 is efficiently converted into the operation of the moving body 7.

  Next, the operation of the vibrator 20 will be specifically described. 2, 3 and 4 show examples of patterns of the drive signals E1 and E2 applied to the piezoelectric elements 1 and 2 (patterns 1, 2 and 3) and the operation of the friction portion 3 which operates correspondingly. It is a thing. FIG. 4B shows changes in the applied signal E1 to the first piezoelectric element 1 and the applied signal E2 to the second piezoelectric element 2, with time on the horizontal axis and voltage level on the vertical axis. . FIG. 4A shows the state of the operation of the friction portion 3 in response to this drive signal with an arrow indicating the direction of displacement and words indicating the speed of displacement.

  In FIG. 2, drive signals having the same waveform shape are applied to the first piezoelectric element 1 and the second piezoelectric element 2. The period P2 in which the voltage decreases rapidly is repeated following the period P1 in which the voltage increases slowly. In the period P1, the friction part 3 moves slowly in the x-axis + direction and also moves in the Y-axis + direction, so that the moving body 7 in contact therewith also moves in accordance with this movement (A1). In the period P2, it rapidly moves in the x-axis direction and moves in the Y-axis direction (A2). At this time, since the contact between the friction portion 3 and the moving body 7 is separated, the operation of the friction portion 3 is not transmitted to the moving body 7. By repeating this operation, the moving body 7 rotates counterclockwise. As described above, the friction unit 3 operates in the direction opposite to the moving direction of the moving body 7 by the first piezoelectric element 1 (in the x-axis direction) and in the direction away from the moving body 7 by the second piezoelectric element 2 ( The movement of the moving body 7 by the first piezoelectric element 1 is accelerated in the y-axis direction), and the movement of the moving body 7 (x-axis direction) is slowly performed. Since the driving force (in the direction) is not transmitted, the driving efficiency of the piezoelectric actuator 100 is improved. In this way, the drive signals applied to the first piezoelectric element 1 and the second piezoelectric element 2 have the same waveform shape, thereby simplifying the configuration of a drive circuit (not shown). By the way, when the moving body 7 is rotated clockwise, as shown in FIG. 2C, the voltage of the drive signal E1 or E2 is changed (the process of changing the voltage abruptly and the process of changing it gently). You can reverse the order.

  Only differences from FIG. 2 will be described with reference to FIGS. In FIG. 3, a drive signal whose phase is shifted by 90 degrees is applied to the first piezoelectric element 1 and the second piezoelectric element 2. In the period P1, the drive signal E1 whose voltage gradually increases is input only to the second piezoelectric element 2, and the friction part 3 is slowly displaced in the y-axis + direction (A1). Furthermore, in the period P2, the voltage of the drive signal applied to the first piezoelectric element 1 increases gradually, and is slowly displaced in the x-axis + direction (A2). Further, in the period P3, the voltage of the drive signal applied to the second piezoelectric element 2 is rapidly decreased, and the friction part 3 is rapidly displaced in the y-axis direction (A3). Furthermore, in the period P4, the voltage of the drive signal E1 applied to the first piezoelectric element 1 rapidly decreases, and the friction part 3 is rapidly displaced in the y-axis direction (A4). Accordingly, the moving body 7 is driven by the operation A2 in the period P2. By repeating this operation, the moving body 7 rotates counterclockwise. Thus, the movement direction (x-axis direction) opposite to the movement direction of the moving body 7 of the friction part 3 (x-axis direction) and the movement direction away from the moving body 7 (y-axis direction) are accelerated. By slowly performing the operation in the axial direction, the driving efficiency of the piezoelectric actuator 100 is improved because no extra driving force is transmitted from the friction portion 3 to the moving body 7.

  In FIG. 4, during the period P1, the drive signal E2 whose voltage increases gently is input only to the second piezoelectric element 2, and the friction part 3 is slowly displaced in the y-axis + direction (A1). Furthermore, in the period P2, the voltage of the drive signal applied to the first piezoelectric element 1 increases gradually, and is slowly displaced in the x-axis + direction (A2). Further, in the period P3, the voltages of the drive signals E1 and E2 applied to the first piezoelectric element 1 and the second piezoelectric element 2 rapidly decrease, and the friction part 3 moves in the x-axis direction and the y-axis direction. Displaces rapidly. Accordingly, the moving body 7 is driven by the operation A2 in the period P2. By repeating this operation, the moving body 7 rotates counterclockwise. Thus, the movement direction (x-axis direction) opposite to the movement direction of the moving body 7 of the friction part 3 (x-axis direction) and the movement direction away from the moving body 7 (y-axis direction) are accelerated. By slowly performing the operation in the axial direction, the driving efficiency of the piezoelectric actuator 100 is improved because no extra driving force is transmitted from the friction portion 3 to the moving body 7.

  As shown in the present embodiment, by using a piezoelectric element capable of generating shear deformation for the first piezoelectric element 1, a large generated force can be obtained and driving can be performed at a high frequency. Can be generated.

  In this embodiment, the piezoelectric element that generates displacement in the x-axis direction in the first piezoelectric element 1 is the piezoelectric element that generates displacement in the y-axis direction in the second piezoelectric element 2. The piezoelectric element that generates a displacement in the y-axis direction in 1 may be replaced with a piezoelectric element that generates a displacement in the x-axis direction in the second piezoelectric element 2.

  Further, although a rotating body is used as the moving body 7, a linear type piezoelectric actuator can be realized if a rod-shaped rail is used. And although the single plate was used for the piezoelectric elements 1 and 2, a laminated piezoelectric element may be used.

(Embodiment 2)
Another embodiment of the vibrator 12 used in the piezoelectric actuator 100 of the present invention will be described based on FIG. 5 with a focus on the difference from the first embodiment.

  In the vibrator 12 of the present invention, instead of the first piezoelectric element 1 in the vibrator 20 of the first embodiment, a piezoelectric element 11 that generates bending displacement is used as the first piezoelectric element. The first piezoelectric element 11 is formed as a bimorph element by overlapping and joining piezoelectric elements 11a and 11b polarized in the thickness direction (directions of arrows 53 and 54 in the figure). Electrodes 13, 14, and 15 are provided on the front and back of the piezoelectric elements 11a and 11b. Here, when the electrode 14 on the bonding surface of the piezoelectric elements 11a and 11b is set to GND and the electrodes 13 and 15 on the other surface of the piezoelectric elements 11a and 11b are short-circuited to apply a voltage, the piezoelectric elements 11a and 11b Since one piezoelectric element extends and the other piezoelectric element contracts, the first piezoelectric element 11 exhibits a bending displacement as a whole. When the polarity of the voltage is changed, the direction of deformation is reversed. Here, instead of the bimorph element, a unimorph may be used that uses a piezoelectric element and an elastic member such as metal. The drive signals E1 and E2 applied to the vibrator 12 may be the same as those shown in the first embodiment.

  Since the large displacement can be obtained by using the bending deformation of the first piezoelectric element 11 in this way, the moving body 7 can be driven at a high speed with a low voltage.

(Embodiment 3)
A third embodiment of the present invention will be described with reference to FIG. The piezoelectric actuator 200 of the present invention includes a vibrator 25 having a structure in which a support member 23 is sandwiched between two bimorphs (piezoelectric elements) 21, 22, a moving body 7 on a circular plate in contact with the vibrator 25, and a support The pressure spring 24 applies pressure to the member 23 and generates a contact pressure between the vibrator 25 and the moving body 7 (FIG. 6A). The bimorph 21 includes a piezoelectric element 21a and a piezoelectric element 21b. The bimorph element 22 includes a piezoelectric element 22 a and a piezoelectric element 22 b and has the same shape as the bimorph 21. A shaft 7a is provided at the rotation center of the moving body 7 and is guided by a bearing (not shown). A shaft 23a is provided at the end of the support member 23, and is guided by a bearing (not shown). The vibrator 25 rotates about the shaft 23a as a rotation center axis. When the pressing force of the pressure spring 24 is applied to the end portion 23 b of the support member 23, the protruding friction portion 27 provided on the bimorph 21 and the moving body 7 are in pressure contact.

In the piezoelectric actuator 200, the bimorph 21 generates a driving force on the moving body 7 as a piezoelectric element driving unit. The free end 21 c of the bimorph 21 is reciprocated in the direction of the arrow 26. By varying the speed of the bimorph 21 toward the displacement and the speed of return, only one operation is transmitted as the driving force of the moving body 7 in contact with the free end 21c. Since the specific driving method is the same as that shown in Patent Document 3 , it will be omitted. The deformation | transformation figure of the bimorphs 21 and 22 is shown by the dotted line of FIG.6 (b), While the bimorph 22 operate | moves synchronizing with the operation | movement of the bimorph 21, the displacement direction becomes a reverse direction. In this way, by displacing the bimorph 22 in the opposite direction to the bimorph 21, the center of gravity of the vibrator 25 does not fluctuate in the support member 23 that is the support portion of the bimorph 21, so there is no vibration leakage and While being able to drive stably, the drive efficiency of the piezoelectric actuator 200 improves. Further, the same effect can be obtained even when the counterweight is set in a stationary state without applying a drive signal to the bimorph 22. Therefore, instead of the bimorph 22, a weight equal to or greater than the mass of the bimorph 21 may be provided. Thus, the bimorph 22 functions as a balance unit that stabilizes the operation of the vibrator 25.

  Further, here, for the sake of simplicity of explanation, an example in which the piezoelectric element 21 that is displaced only in one direction is used is shown. However, as shown in the first and second embodiments, the displacement is independently generated in two different directions. Thus, it may be a piezoelectric actuator that obtains a driving force.

(Embodiment 4)
A modification of the third embodiment will be described with reference to FIG. Since the vibrator 35 can be replaced in the actuator 100 of the first embodiment instead of the vibrator 20, only the operation of the vibrator 35 will be described.

  7A and 7B are a front view and a side view of the vibrator 35, respectively. The piezoelectric elements 31 and 32 are arranged in parallel and are fixed to the support member 4. The friction part 33 is fixed to the free end of the piezoelectric element 31. The piezoelectric elements 31 and 32 generate shear deformation when a drive signal is applied. The piezoelectric elements 31 and 32 are deformed in opposite directions (see FIG. 7C).

  The piezoelectric element 31 generates a driving force on the moving body 7 as a piezoelectric element driving unit. The friction part 33 provided at the free end of the piezoelectric element 31 is reciprocated in the direction of the arrow 34. Only the one operation is transmitted as the driving force of the moving body 7 by making the speed of the displacement of the piezoelectric element 31 different from the speed of the return. The piezoelectric element 32 operates in synchronization with the operation of the piezoelectric element 31, but the displacement direction is the reverse direction. In this way, by displacing the piezoelectric element 32 in the opposite direction to the piezoelectric element 31, the position of the support member 4 does not vary with the operation of the vibrator 35, so there is no vibration leakage, and the moving body 7 is moved. While being able to drive stably, the drive efficiency of the piezoelectric actuator 100 improves. Further, the same effect can be obtained by causing the piezoelectric element 32 to function as a counterweight in a stationary state without applying a drive signal. Therefore, instead of the piezoelectric element 32, a weight equal to or greater than the mass of the piezoelectric element 31 may be provided. Thus, the piezoelectric element 32 functions as a balance unit that stabilizes the operation of the vibrator 35.

(Embodiment 5)
A piezoelectric actuator 400 of the present invention will be described with reference to FIG. The piezoelectric actuator 400 includes a piezoelectric element 41, a guide shaft 43 fixed to one end of the piezoelectric element 41, a moving body 44 in contact with the guide shaft 43, a weight 42 fixed to the other end of the piezoelectric element 41, and the piezoelectric element 41. And a support member 45 that supports The piezoelectric element 41 generates expansion / contraction displacement by application of a drive signal. The support member 45 supports the central portion of the piezoelectric element 41, that is, a point where expansion and contraction does not occur. The moving body 44 is in pressure contact with the guide shaft 43 by the pressure of a pressure spring (not shown).

  Next, the operation of the piezoelectric actuator 400 will be specifically described. When a drive signal whose voltage value gradually increases is applied to the piezoelectric element 41 from the initial position (FIG. 8A), the piezoelectric element 41 is gently expanded. At this time, the moving body 44 also moves with the movement of the guide shaft 43 (FIG. 8B). Next, when the voltage value of the drive signal applied to the piezoelectric element 41 is rapidly lowered, the piezoelectric element 41 is also rapidly contracted, causing slippage between the moving body 44 and the guide shaft 43, resulting in the movement of the moving body 44. The position is in a state advanced from the initial position (FIG. 8C). By repeating this series of operations, the moving body 44 continues to move.

  During this operation, the two portions 41a and 41b divided at the center of the piezoelectric element 41 are displaced in the opposite directions. One portion 41a of the piezoelectric element 41 provides a driving force to the moving body 44 as a piezoelectric element driving unit. The other portion 41 b of the piezoelectric element 41 moves the weight 42 in the direction opposite to the guide shaft 43. Since the force generated by the two portions 41 a and 41 b of the piezoelectric element 41 is canceled by the support member 45, no force is generated on the support member 45. Thereby, vibration does not leak through the support member 45. Thus, the piezoelectric element 41b functions as a balance portion with the weight 42. The mass of the weight 42 is preferably equal to the mass of the guide shaft 43.

(Embodiment 6)
A piezoelectric actuator 600 of the present invention will be described with reference to FIG. The piezoelectric actuator 600 shown in FIG. 9A basically uses the structure of the piezoelectric actuator 200 shown in the third embodiment, and is a slight modification. The piezoelectric actuator 600, which will be described below with a focus on the difference between the two, is provided with a rail-like moving body 61 instead of the moving body 7 of the piezoelectric actuator 200. The moving body 61 is supported by two guide members 62 and 63. When the guide members 62 and 63 rotate, the moving body 61 in contact therewith can be operated in the direction of the arrow x in the figure. Further, the piezoelectric actuator 600 is provided with a friction portion 64 made of engineering plastic or ceramic having high wear resistance at the tip of the bimorph (piezoelectric element) 21. The friction part 64 is characterized by having convex parts 64 a and 64 b at two places on both ends of the bimorph (piezoelectric element) 21 in the width direction.

  Next, the operation of the piezoelectric actuator 600 will be described. The driving method of the piezoelectric actuator 600 is the same as that shown in the third embodiment, and the bimorphs (piezoelectric elements) 21 and 22 are bent and deformed (FIG. 9B). Then, the moving body 61 is frictionally driven by the frictional portion 64 along with this displacement in the operation of the slow displacement by changing the going and return speeds of the bending deformation, and the moving body 61 is moved to the frictional portion in the operation of the high speed displacement. No slippage occurs due to slippage with 64, or the amount of movement is small. Accordingly, the moving body 64 moves in the direction of the slow displacement operation.

  Here, the friction part 64 has convex parts 64 a and 64 b at two places on both ends in the width direction of the bimorph (piezoelectric element) 21. As a result, the bimorph (piezoelectric element) 21 can stably contact the moving body 61 at two points where the displacement in the direction of the arrow y in the drawing becomes maximum. Accordingly, the surface of the moving body 61 is not affected by the undulation, and the contact of the friction portion 64 and the moving body 61 at one point due to the influence of the bimorph (piezoelectric element) 21 or the moving body 61 can be avoided. Then, by bringing the friction part 64 and the moving body 61 into contact with each other at the maximum point of displacement in the y direction, it is difficult to transmit the fast moving motion of the bimorph (piezoelectric element) 21 to the moving body 61, and the slow moving motion is performed. Since it becomes easy to convey to the moving body 61, the output of the moving body 61 becomes large.

  FIG. 10 shows a modification of the friction part 64. The friction part 64 has projecting parts 65 a and 65 b at both ends in the width direction of the bimorph (piezoelectric element) 21. By adopting such a structure, the displacement of the bimorph (piezoelectric element) 21 is enlarged, so that the moving body 61 can be driven stably and the displacement operation with a low speed can be reliably transmitted to the moving body 61. The output of the actuator 600 increases.

  Further, if the protruding portions 65a and 65b of the friction portion 65 are provided with projections as in FIG. 10, the contact between the friction portion 65 and the moving body 61 is stabilized, so that the efficiency of the piezoelectric actuator 600 is improved and the output is increased. The performance variation of each piezoelectric actuator 600 can be reduced.

  In the present embodiment, an example of improving the friction portion is shown based on the piezoelectric actuator 200. However, the moving body is friction-driven by making a difference between the speed of the displacement of the piezoelectric element that undergoes bending deformation and the speed of the return displacement. Any piezoelectric actuator can be applied, and the frictional portion 64 or 65 may be provided in the vibrator 12 shown in the second embodiment.

(Embodiment 7)
This embodiment shows an example in which the piezoelectric actuator of the present invention is applied to a drive source of an electronic device.

  FIG. 11 is a block diagram showing the configuration of an electronic apparatus equipped with a piezoelectric actuator 500 based on the principle and structure of the present invention. The piezoelectric actuator 500 is mainly composed of a piezoelectric element 52 and a moving body 53. When a command from a control circuit 50 such as a CPU in the electronic device is transmitted to the driver 51, the driver 51 outputs a drive signal to the piezoelectric element 52. The moving body 53 moves by receiving the driving force of the piezoelectric element 52. At that time, the operating member 54 moves under the force of the moving body 53.

  When the electronic device is a camera, when a command to start zooming is transmitted from the control circuit 50, the driver 51 applies a drive signal to the piezoelectric element 52 to rotate the moving body 53. The lens as the operating member 54 is moved through a cam (not shown) under the force of the moving body 53.

  When the electronic device is a timepiece, the operating member 54 is a hand or a calendar display board. When the electronic device is a printer, the operating member 54 is a print head. When the electronic device is an information recording device such as an HDD or an optical disk, the operating member 54 is a read head.

  In such a small electronic device, by using the piezoelectric actuator 500 based on the principle and structure of the present invention, the electronic device is small and has low power consumption.

  In particular, since the positioning resolution is high and power is not consumed when the moving body 53 is in a stop state, and the holding power is provided, the effect is exhibited in an electronic device that requires highly accurate positioning. When the electronic device is a stage, the operating member 54 is a table or a sample table, and when the electronic device is a machine tool, the operating member 54 is a work such as a cutting tool or a grindstone.

Since the piezoelectric actuator of the present invention is small and has low power consumption, it can be applied to small electronic devices such as clocks, cameras, printers, information storage devices such as HDDs and optical disks.
In addition, since precise positioning is possible, application to various precision stages and machine tools is possible.

It is a figure which shows the structure of the piezoelectric actuator of Embodiment 1 of this invention. It is a figure which shows the mode 1 of the drive signal applied to the piezoelectric actuator of this invention, and the mode of operation | movement of the friction part in that case. It is a figure which shows the mode of the operation | movement of the pattern 2 of the drive signal applied to the piezoelectric actuator of this invention, and the friction part in that case. It is a figure which shows the mode 3 of the drive signal pattern 3 applied to the piezoelectric actuator of this invention, and the mode of operation | movement of the friction part in that case. It is a figure which shows the structure of the piezoelectric actuator of Embodiment 2 of this invention. It is a figure which shows the structure of the piezoelectric actuator of Embodiment 3 of this invention. It is a figure which shows the structure of the vibrator | oscillator of the piezoelectric actuator of Embodiment 4 of this invention. It is a figure which shows the structure of the piezoelectric actuator of Embodiment 5 of this invention. It is a figure which shows the structure of the piezoelectric actuator of Embodiment 6 of this invention. It is a figure which shows another example of the friction part of the piezoelectric actuator of Embodiment 6 of this invention. It is a block diagram which shows the structure of the electronic device carrying the piezoelectric actuator of this invention.

Explanation of symbols

1, 2, 11, 21, 22, 31, 32, 41, 52 Piezoelectric elements 100, 200, 400, 500 Piezoelectric actuators 12, 20, 25, 35 Vibrators 4, 23, 45 Support members 7, 44, 53, 61 Moving body 5 Guide member 6 Pressure spring 64, 65 Friction part

Claims (6)

A first piezoelectric element that reciprocates in a first direction;
A second piezoelectric element that reciprocates in a second direction different from the first direction;
A rectangular parallelepiped vibrator integrally formed by:
A moving body in contact with the friction portion provided in the first piezoelectric element;
Consists of
A drive signal having the same waveform shape is applied to the first piezoelectric element and the second piezoelectric element at the same timing, so that the speed of displacement in the first direction is made slower than the return speed, and the first A piezoelectric actuator characterized in that the moving body is driven by making a speed of displacement in two directions slower than a return speed. A support member provided on the second piezoelectric element and supporting the second piezoelectric element;
A guide member that guides the movement of the support member so that the friction portion applies a contact pressure to the moving body;
The piezoelectric actuator according to claim 1, further comprising a pressure spring that pressurizes the support member so as to generate a contact pressure between the friction portion and the movable body. The first direction is a moving direction of the moving body,
The piezoelectric actuator according to claim 1, wherein the second direction is a contact pressure direction between the friction portion and the movable body.   The piezoelectric actuator according to claim 1, wherein one of the first piezoelectric element and the second piezoelectric element is a piezoelectric element that bends and deforms.   The piezoelectric actuator according to claim 1, wherein one of the first piezoelectric element and the second piezoelectric element is a piezoelectric element that undergoes shear deformation.   An electronic apparatus comprising an operation member driven by the piezoelectric actuator according to claim 1.

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