JP2010259193A - Drive device and robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive device which has a simple configuration, can be miniaturized and attains cost reduction, and to provide a robot. <P>SOLUTION: The drive device includes: a mover driven in a predetermined driving direction; an electromechanical conversion element, having a piezoelectric layer pair formed by integrating a pair of piezoelectric layers polarized in different directions and formed to vibrate in a direction close to the mover and vibrate in the driving direction of the mover; and a control section for causing the electromechanical conversion element to selectively vibrate in the closing direction and the driving direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a drive device and a robot apparatus.

  For example, as a motor device such as an ultrasonic motor, a composite vibration type ultrasonic motor device combining a longitudinal vibration mode and a torsional vibration mode is known (for example, see Patent Document 1). In this motor device, a longitudinal vibration mode piezoelectric element and a torsional vibration mode piezoelectric element are used in combination.

JP 61-121777 A

  However, when a configuration in which two types of vibration mode piezoelectric elements are combined as in the motor device described above, there is a problem that the structure becomes complicated and it is difficult to reduce the size.

  In view of the circumstances as described above, it is an object of the present invention to provide a drive device and a robot device that can have a simple configuration and can be miniaturized.

  The driving device (1) according to the present invention includes a piezoelectric layer pair (35) in which a mover (2) driven in a predetermined driving direction and a pair of piezoelectric layers (31) polarized in opposite directions are integrated. And an electromechanical transducer element (30) formed so as to vibrate in the proximity direction to the mover and to vibrate in the drive direction of the mover, and the proximity to the electromechanical transducer element And a control unit (CONT) that selectively performs vibration in the driving direction and vibration in the driving direction.

  A robot apparatus (RBT) according to the present invention includes a moving member (104a) and a driving apparatus (ACT) for driving the moving member, and the driving apparatus (1) is used as the driving apparatus. It is characterized by that.

  According to the present invention, a simple configuration can be achieved, and downsizing is possible.

Schematic which shows the structure of the drive device which concerns on 1st Embodiment of this invention. The figure which shows the structure of a part of drive device which concerns on this embodiment. The figure which shows the structure of the piezoelectric element which concerns on this embodiment. The figure which shows the structure of a part of piezoelectric element which concerns on this embodiment. The figure which shows the mode of the vibration of the piezoelectric layer pair which concerns on this embodiment. The figure which shows the structure of a part of piezoelectric element which concerns on this embodiment. The figure which shows an example of operation | movement of the piezoelectric element which concerns on this embodiment. Schematic which shows the structure of a part of drive device which concerns on 2nd Embodiment of this invention. The figure which shows the structure of a part of drive device which concerns on this embodiment. The figure which shows the structure of a part of robot apparatus which concerns on 3rd Embodiment of this invention. The figure which shows the other structure of the drive device which concerns on embodiment of this invention. The figure which shows the other structure of the drive device which concerns on embodiment of this invention. The figure which shows the other structure of the drive device which concerns on embodiment of this invention. The figure which shows the other structure of the drive device which concerns on embodiment of this invention.

  Hereinafter, a first embodiment of a drive device according to the present invention will be described with reference to the drawings, but the present invention is not limited to this. In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. In this embodiment, the rotation axis direction of the drive device (and the direction parallel to the rotation axis direction) is the Z axis direction, the predetermined direction in the horizontal plane perpendicular to the Z axis direction is the X axis direction, and the X axis is in the horizontal plane. A direction orthogonal to the direction is defined as a Y-axis direction. The rotation direction of the drive device, that is, the rotation direction around the Z axis is defined as the θZ direction.

FIG. 1 is a perspective view showing a configuration of a driving device 1 according to the present embodiment.
As illustrated in FIG. 1, the drive device 1 includes a rotor 2, a drive unit 3, a holding unit 4, and a control unit CONT. The drive device 1 has a configuration in which the rotor 2 and the drive unit 3 are held by a holding unit 4.

  The rotor 2 is disposed substantially at the center in the Z direction of the drive device 1 and is formed in an annular shape in plan view. In FIG. 1, the rotor 2 is shown in a transparent manner so that the configuration of the driving device 1 can be easily discriminated. The rotor 2 is a rotor in the present invention.

  The drive unit 3 is disposed on the −Z side of the rotor 2. The drive unit 3 has a plurality of piezoelectric elements 30. For example, three piezoelectric elements 30 are provided along the rotation direction (θZ direction) of the driving device 1.

  The holding part 4 includes a pedestal part 41, a rotor side support part 42, a shaft part 43, and a pressing part 44. The pedestal portion 41 is a placement portion on which each piezoelectric element 30 is placed. The pedestal portion 41 has a flat surface (+ Z side surface) on which the piezoelectric element 30 is placed. The rotor side support part 42 supports the rotor 2 from the + Z side. The drive unit side support unit 41 and the rotor side support unit 42 are arranged at positions sandwiching the drive unit 3 and the rotor 2.

  The shaft portion 43 is integrally formed so as to connect the pedestal portion 41 and the rotor side support portion 42. The shaft portion 43 is formed so as to penetrate the central portion of the rotor 2 and the drive portion 3 as viewed in the Z direction. A bearing mechanism (not shown) is provided between the shaft portion 43 and the rotor 2, for example.

  The pressing portion 44 is disposed between the rotor side support portion 42 and the rotor 2. The pressing portion 44 applies a force in the −Z direction from the rotor side support portion 42 to the rotor 2. By pressing the rotor 2 to the −Z side by the pressing portion 44, the driving force of the driving portion 3 is easily transmitted to the rotor 2.

  The control part CONT is connected to each piezoelectric element 30 of the drive part 3 as shown in FIG. The control unit CONT controls the driving operation by the driving unit 3.

FIG. 2 is a diagram showing the arrangement of the piezoelectric elements 30 when viewed in the Z direction.
As shown in the figure, the three piezoelectric elements 30 are arranged at positions shifted by, for example, 120 ° in the θZ direction. A direction indicated by an arrow in FIG. 2 is a driving direction of each piezoelectric element 30. Each piezoelectric element 30 drives the rotor 2 in the direction indicated by the arrow. Each piezoelectric element 30 is disposed so as to extend in the radial direction from the shaft portion 43.

FIG. 3 is a perspective view showing the configuration of the piezoelectric element 30.
The piezoelectric element 30 has a piezoelectric layer 31, an electrode 32, and a contact 33. The piezoelectric element 30 is an electromechanical vibrator that vibrates when a voltage is applied thereto. The piezoelectric layer 31 is formed in a rectangular plate shape, for example. The piezoelectric layer 31 in the present embodiment is, for example, a piezo or the like, and includes a piezoelectric body.

  The electrode 32 applies a voltage to the piezoelectric layer 31. The electrode 32 is connected to the control unit CONT. The piezoelectric element 30 has a configuration (laminated structure 34) in which piezoelectric layers 31 and electrodes 32 are alternately stacked. The contact 33 is formed, for example, in a cylindrical shape, and is fixed on the + Z side end face of the laminated structure 34. The contactor 33 is a part that contacts the rotor 2 and directly transmits the driving force of the piezoelectric element 30 to the rotor 2.

FIG. 4 is a diagram showing the configuration of the piezoelectric layer 31 in the present embodiment.
As shown in FIG. 4A, each piezoelectric layer 31 is polarized in the thickness direction of the plate. When an electric field is generated in the direction opposite to the polarization direction with respect to the piezoelectric layer 31, vibration (d33 mode) that displaces and expands in the polarization direction of the piezoelectric layer 31, or displaces and expands in a direction perpendicular to the polarization direction. Vibration (d31 mode) occurs. Among these vibration modes, in the present embodiment, d31 mode vibration is used. Therefore, the piezoelectric layer 31 is arranged so that the direction perpendicular to the polarization direction, which is the vibration direction of the d31 mode, is the proximity direction to the rotor 2. Therefore, in the present embodiment, the orthogonal direction of the polarization direction of the piezoelectric layer 31, the vibration direction of the piezoelectric layer 31, and the proximity direction to the rotor 2 are configured to match. Each of these directions corresponds to the Z direction in the present embodiment.

  In the present embodiment, the piezoelectric layer 31 having such a configuration is combined as a piezoelectric layer pair 35 as shown in FIG. As shown in FIG. 4B, the piezoelectric layer pair 35 is bonded so that the two piezoelectric layers 31 face each other in the polarization direction. An electrode 32 is disposed between the two piezoelectric layers 31. The electrode 32 is provided so as to be sandwiched between the two piezoelectric layers 31. Further, electrodes 32 are also formed on the surface opposite to the facing surface of each piezoelectric layer 31.

  In the following description, one (for example, the left side in the figure) of the two piezoelectric layers 31 constituting the piezoelectric layer pair 35 is denoted as a piezoelectric layer 31A, and the other (for example, the right side in the figure) is denoted as a piezoelectric layer 31B. Regarding the electrode 32, the electrodes formed on the opposite side of the opposing surfaces of the piezoelectric layers 31A and 31B are referred to as electrodes 32A and 32B so as to correspond to the reference numerals of the piezoelectric elements. An electrode sandwiched between the piezoelectric layer 31A and the piezoelectric layer 31B is referred to as an electrode 32C.

  As shown in FIG. 4B, when a voltage is applied to the piezoelectric layer 31A and the piezoelectric layer 31B with the electrode 32C as a positive electrode and the electrodes 32A and 32B as a negative electrode, the piezoelectric layer 31A and the piezoelectric layer 31B are simultaneously perpendicular to the polarization direction. Elongate. Although illustration is omitted, when a voltage is applied to the piezoelectric layer 31A and the piezoelectric layer 31B using the electrode C as a negative electrode and the electrodes 32A and 32B as positive electrodes, the piezoelectric layer 31A and the piezoelectric layer 31B simultaneously contract in the direction perpendicular to the polarization direction.

  As shown in FIG. 4C, when only the voltage applied to one piezoelectric layer 31 (for example, the piezoelectric layer 31A) is reversed from the state where the piezoelectric layer 31A and the piezoelectric layer 31B are simultaneously expanded, the piezoelectric layer Only 31A vibrates in the contraction direction. As a result, the piezoelectric layer pair 35 is pulled by the contraction of the piezoelectric layer 31A and bends to the left in the drawing.

  Although not shown, when only the voltage applied to the piezoelectric layer 31B is reversed from the state of FIG. 4B, the piezoelectric layer pair 35 bends to the right side in the drawing. Similarly, when one piezoelectric layer 31 is extended from a state in which the two piezoelectric layers 31 are contracted, the piezoelectric layer pair 35 is bent so as to be pulled by the contracting piezoelectric layer 31. As described above, when a voltage is applied so that one of the two piezoelectric layers 31 is expanded and the other is contracted, the piezoelectric layer pair 35 is bent so as to be pulled toward the contracting piezoelectric layer 31.

  Using this property, in this embodiment, as shown in FIG. 4D, for example, sinusoidal voltages having different phases are applied to the piezoelectric layer 31A and the piezoelectric layer 31B, respectively. In FIG. 4D, a sine wave voltage is applied to the piezoelectric layer 31A using the power source D1, and a cosine wave voltage is applied to the piezoelectric layer 31B using the power source D2.

  FIG. 5 is a conceptual diagram showing a change in the shape of the piezoelectric layer pair 35 when a voltage is applied to the two piezoelectric layers 31 using the configuration shown in FIG. In FIG. 5, the voltage waveforms of the power supply D <b> 1 and the power supply D <b> 2 are associated with the shape of the piezoelectric layer pair 35. In FIG. 5, the case where a voltage is applied to the electrode 32C is shown as a positive voltage.

  As shown in FIG. 5, between time 0 and π / 2, both the power supply D1 and the power supply D2 apply a positive voltage. Therefore, a voltage is applied so that the piezoelectric layer 31A and the piezoelectric layer 31B extend together. In this case, the piezoelectric layer pair 35 extends in a direction orthogonal to the polarization direction.

  During time π / 2 to π, the power source D1 is in a state where a positive voltage is applied, and the power source D2 is in a state where a negative voltage is applied. Therefore, a voltage is applied so that the piezoelectric layer 31A expands and the piezoelectric layer 31B contracts. In this case, since the piezoelectric layer pair 35 is bent so as to be pulled by the contracting piezoelectric layer 31B, it is bent to the right side in the drawing as shown in FIG.

  Between times π and 3π / 2, the power source D1 is in a state where a negative voltage is applied, and the power source D2 is in a state where a negative voltage is applied. Therefore, a voltage is applied so that the piezoelectric layer 31A and the piezoelectric layer 31B contract together. In this case, the piezoelectric layer pair 35 contracts in a direction orthogonal to the polarization direction.

  During the time 3π / 2 to 2π, the power supply D1 is in a state where a negative voltage is applied, and the power supply D2 is in a state where a positive voltage is applied. Therefore, a voltage is applied so that the piezoelectric layer 31A contracts and the piezoelectric layer 31B expands. In this case, since the piezoelectric layer pair 35 is bent so as to be pulled by the contracting piezoelectric layer 31A, the piezoelectric layer pair 35 is bent leftward in the drawing as shown in FIG.

  By periodically repeating such an operation, the upper end of the piezoelectric layer pair 35 in the figure rotates, for example, in the clockwise direction in the figure. Further, the upper ends of the piezoelectric layer pair 35 in the figure can be rotated counterclockwise by reversing the voltages of the power source D1 and the power source D2.

FIG. 6 shows a configuration of a laminated structure 34 in which a plurality of such piezoelectric layer pairs 35 are combined.
As an example, the laminated structure 34 shown in FIG. 6 has a configuration in which eight piezoelectric layers 31 are laminated. Of the eight piezoelectric layers 31, the four piezoelectric layers 31 on the left side in the figure are piezoelectric elements corresponding to the piezoelectric layer 31A. The four piezoelectric layers 31 on the right side in the figure are piezoelectric elements corresponding to the piezoelectric layer 31B.

  In general, the piezoelectric layer 31 has an effect of increasing the amount of voltage versus strain by increasing the number of stacked layers. By utilizing this, in the present embodiment, voltage signals of sine waves are supplied to the four piezoelectric layers 31A on the left side in the figure with respect to the eight piezoelectric layers 31, and the voltages of cosine waves are supplied to the four piezoelectric layers 31B on the right side in the figure. The signal is supplied. The control of the voltage signal is performed in, for example, the control unit CONT.

FIG. 7 is a diagram illustrating a driving operation of the piezoelectric element 30.
First, as shown in FIG. 7A, the control unit CONT supplies a voltage signal so that the laminated structure 34 is bent toward the upstream side in the rotation direction. From this state, the control unit CONT supplies a voltage signal so as to extend the laminated structure 34 toward the rotor 2 side. By this operation, the contactor 33 moves in the rotation direction of the rotor 2 while approaching the rotor 2 side in the Z direction. In the state where the laminated structure 34 is extended most, the upper surface of the contactor 33 comes into contact with the rotor 2 as shown in FIG.

  From this state, as shown in FIG. 7C, the control unit CONT supplies a voltage signal so that the laminated structure 34 is bent downstream in the rotation direction. By this operation, the contactor 33 moves in the rotation direction of the rotor 2. During this movement, friction occurs between the contactor 33 and the rotor 2, and the rotor 2 rotates due to the frictional force.

  Thus, according to the present embodiment, the piezoelectric element 30 is configured using the piezoelectric layer pair 35 in which the pair of piezoelectric layers 31A and 31B polarized in opposite directions is integrated, and the control unit CONT Since the rotor 2 is rotated by vibrating the piezoelectric element 30 in the direction close to the rotor 2 and in the rotating direction of the rotor 2, the piezoelectric element has two types of vibration modes for longitudinal vibration and torsional vibration. There is no need to use an element. Thereby, since the drive part 3 can be made into a simple structure, the drive device 1 can be reduced in size and cost reduction is realizable. Further, according to the present embodiment, it is possible to realize a small and high torque drive device 1.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, the same components as those in the first embodiment will be described with the same reference numerals. In the present embodiment, the arrangement of the piezoelectric elements and the shape of the pedestal portion are different from those of the first embodiment, and the other parts have substantially the same configuration as that of the first embodiment. Hereinafter, the difference will be mainly described. In the present embodiment, description will be made using an XYZ coordinate system common to the first embodiment.

FIG. 8 is a diagram showing the arrangement of the piezoelectric elements 130 when viewed in the Z direction.
As shown in FIG. 8A, the piezoelectric element 130 is formed so as to extend along the rotation direction of the rotor. The piezoelectric element 130 is arranged so as to be shifted by 120 ° in the rotation direction of the rotor, and this is the same as in the first embodiment.

  As shown in FIG. 8B, each piezoelectric element 130 is fixed to the side portion of the pedestal portion 41 via a fixing member 48 such as a screw. The piezoelectric element 130 of the present embodiment is configured to rotate the rotor in the extending direction. The piezoelectric element 130 has a piezoelectric layer pair 135 including a stacked body 131A and a stacked body 131B. The stacked body 131A and the stacked body 131B are arranged adjacent to each other in the rotation direction of the rotor.

  FIG. 9 is a diagram illustrating a configuration of the piezoelectric element 130 according to the present embodiment. FIG. 9A is a schematic diagram showing an overall configuration of the piezoelectric element 130, and FIG. 9B is a diagram showing a cross-sectional configuration of the piezoelectric element 130.

  As shown in FIGS. 9A and 9B, the piezoelectric element 130 includes a stacked body 131A, a stacked body 131B, an electrode 132A, an electrode 132B, and an electrode 132C. The stacked body 131A includes four piezoelectric layers 136A to 139A stacked in a direction orthogonal to the rotation direction of the rotor. The stacked body 131B includes four piezoelectric layers 136B to 139B stacked in a direction orthogonal to the rotational direction of the rotor. The laminate 131A and the laminate 131B are fixed by an adhesive or the like.

  The stacked body 131A is disposed so that the polarization directions of the piezoelectric layer 136A and the piezoelectric layer 137A are opposed to each other, and the polarization directions of the piezoelectric layer 138A and the piezoelectric layer 139A are opposed to each other. The stacked body 131B is disposed so that the polarization directions of the piezoelectric layer 136B and the piezoelectric layer 137B are opposed to each other, and the polarization directions of the piezoelectric layer 138B and the piezoelectric layer 139B are opposed to each other.

  The electrode 132A has a portion disposed between the piezoelectric layer 136A and the piezoelectric layer 137A and a portion disposed between the piezoelectric layer 138A and the piezoelectric layer 139A, and the two portions are connected. It is configured. Similarly, the electrode 132B has a portion disposed between the piezoelectric layer 136B and the piezoelectric layer 137B, and a portion disposed between the piezoelectric layer 138B and the piezoelectric layer 139B. Connected configuration. The electrode 132A and the electrode 132B are connected to a power source D1 that supplies a voltage signal of, for example, a sine wave.

  The electrode 132C is disposed on the surface of the piezoelectric layers 136A to 139A and the piezoelectric layers 136B to 139B where the electrode 132A and the electrode 132B are not provided. The electrode 132C is connected to a power source D2 that supplies, for example, a cosine wave voltage signal.

  Also in the piezoelectric element 130 configured as described above, by supplying a voltage signal to the stacked body 131A and the stacked body 131B using the power source D1 and the power source D2, the stacked body 131A and the stacked body 131B are respectively moved up and down in the drawing. Can vibrate in the direction. For this reason, as in the first embodiment, one piezoelectric element can be extended and the other piezoelectric element can be contracted to bend toward the contracting piezoelectric element.

  By using this operation, even when the piezoelectric element 130 is extended along the rotation direction of the rotor, the piezoelectric element 130 is vibrated in the direction close to the rotor and is vibrated in the rotation direction of the rotor. The rotor can be rotated. In the present embodiment, the piezoelectric layers 136A to 139A and the piezoelectric layers 136B to 139B each constitute a piezoelectric layer pair.

  In the present embodiment, as in the first embodiment, the vibration mode (d31 mode) extending in the direction perpendicular to the polarization direction is used as the vibration mode of the piezoelectric layers 136A to 139A and the piezoelectric layers 136B to 139B. Used. Similarly to the first embodiment, the stacked body 131A and the stacked body 131B are arranged so that the vibration directions of the piezoelectric layers 136A to 139A and the piezoelectric layers 136B to 139B are close to the rotor 2.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.
FIG. 10 is a diagram illustrating a configuration of a part (tip of a finger portion) of a robot apparatus RBT including the driving apparatus 1 described in the first embodiment.

  As shown in the figure, the robot apparatus RBT includes a distal node portion 101, a middle node portion 102, and a joint portion 103, and the distal node portion 101 and the middle node portion 102 are connected via the joint portion 103. It has become. The joint portion 103 is provided with a shaft support portion 103a and a shaft portion 103b. The shaft support portion 103 a is fixed to the middle joint portion 102. The shaft portion 103b is supported in a state of being fixed by the shaft support portion 103a.

  The end node portion 101 includes a connecting portion 101a and a gear 101b. The shaft portion 103b of the joint portion 103 is penetrated through the connecting portion 101a, and the end node portion 101 is rotatable with the shaft portion 103b as a rotation axis. The gear 101b is a bevel gear fixed to the connecting portion 101a. The connecting portion 101a rotates integrally with the gear 101b.

  The middle joint portion 102 includes a housing 102a and a motor device ACT. The motor apparatus ACT can use the driving apparatus 1 described in the above embodiment. The motor device ACT is provided in the housing 102a. A rotation shaft member 104a is attached to the motor device ACT. A gear 104b is provided at the tip of the rotating shaft member 104a. The gear 104b is a bevel gear fixed to the rotating shaft member 104a. The gear 104b is in mesh with the gear 101b.

  In the robot apparatus RBT configured as described above, the rotation shaft member 104a is rotated by driving the motor apparatus ACT, and the gear 104b is rotated integrally with the rotation shaft member 104a. The rotation of the gear 104b is transmitted to the gear 101b meshed with the gear 104b, and the gear 101b rotates. As the gear 101b rotates, the connecting portion 101a also rotates, whereby the end node portion 101 rotates about the shaft portion 103b.

  As described above, according to the present embodiment, by mounting the motor device ACT capable of outputting low-speed and high-torque rotation at a low voltage, for example, the end joint 101 can be directly rotated without using a speed reducer. it can. Furthermore, in the present embodiment, since the motor device ACT is configured to be driven non-resonantly, most of it can be configured with a light material such as resin.

The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.
For example, in the first embodiment, with respect to the arrangement of the piezoelectric layer 31A and the piezoelectric layer 31B in the piezoelectric element 30, as shown in FIG. 6, the four left piezoelectric layers 31 in the figure are piezoelectric elements corresponding to the piezoelectric layer 31A. Although the four piezoelectric layers 31 on the right side in the figure are piezoelectric elements corresponding to the piezoelectric layer 31B, the present invention is not limited to this.

  For example, as shown in FIG. 11, the configuration may be such that the central four piezoelectric elements of the eight piezoelectric layers 31 correspond to the piezoelectric layer 31B, and the two left and right piezoelectric elements correspond to the piezoelectric layer 31A. In this case, for example, a cosine wave voltage signal is supplied to the four piezoelectric layers 31B in the center, a sine voltage signal is supplied to the two piezoelectric layers 31A on the left side in the figure, and the two piezoelectric layers 31A on the right side in the figure. Is supplied with a signal obtained by inverting a sine wave voltage signal. Thereby, the upper end of the laminated structure 34 can be rotated.

  In this case, the control unit CONT causes the central four piezoelectric layers 31B to vibrate in the direction close to the rotor 2, and causes the left and right piezoelectric layers 31A to vibrate in the bending direction. The signal may be controlled. The bending moment is given by (stress x distance to the bending center). By disposing the bending piezoelectric layer 31A on the outer side in the stacking direction, the distance from the center in the stacking direction, which is the bending center, to the piezoelectric layer 31A, which is the stress generating portion, is increased. For this reason, a large bending can be generated.

  In addition, as shown in FIG. 12, the polarization directions of the two piezoelectric layers 31A on the right side in the figure may be opposite to the other sets, that is, the polarization directions of each other may be opposite to the opposing direction. Absent. In this case, a sinusoidal voltage signal is supplied to the two piezoelectric layers 31A. As a result, the circuit configuration can be simplified.

  In the first embodiment, the number of piezoelectric layers 31 is two, four, two, and a total of eight. However, the number of layers is not limited to this. For example, four, ten, four, In the case of a total of 18 layers, the number of layers may be increased according to the applied voltage and amplitude.

  Further, for example, in the second embodiment, the stacked body 131A and the stacked body 131B are arranged adjacent to each other in the rotational direction of the rotor. However, the present invention is not limited to this. For example, as shown in FIG. 13, two stacked bodies 131A and one stacked body 131B may be arranged along the rotation direction of the rotor, and the stacked bodies 131B may be joined so as to be sandwiched between the two stacked bodies 131A. I do not care. In this case, the voltage signal may be controlled such that the laminated body 131B disposed in the center performs vibration in the direction close to the rotor, and the left and right laminated bodies 131A perform vibration in the bending direction. . Thereby, a big bending can be generated like the above.

  Further, in each of the above embodiments, the example in which the piezoelectric layer 31 vibrates due to the distortion effect due to the electric field has been described, but the present invention is not limited to this. For example, it is possible to increase the vibration amplitude of the piezoelectric layer 31 by generating mechanical resonance in the piezoelectric layer 31 and improve the driving efficiency.

  It is known that the piezoelectric layer 31 itself has a mechanical longitudinal vibration mode and a bending mode. The mechanical shape and dimensions of the piezoelectric layer 31 are adjusted so that the frequency of the longitudinal vibration mode of the piezoelectric layer 31 and the frequency of the primary bending mode (or secondary bending mode) of the piezoelectric layer 31 are substantially the same. To do.

  When the piezoelectric layer 31 formed in this way is driven at the frequency, mechanical resonance occurs and the vibration amplitude of the contactor 33 increases. As a result, a large rotation can be obtained with a small electric power. In addition, it is possible to generate mechanical resonance using only one of the frequencies of the longitudinal vibration mode and the bending mode without making them close to each other, and it is possible to drive without generating mechanical resonance.

  In each of the above embodiments, when a voltage is applied to the piezoelectric layer in a direction opposite to the polarization direction, a vibration mode (d31 mode) extending in a direction perpendicular to the polarization direction is used. There is no limit. For example, when a voltage is applied in the direction opposite to the polarization direction, a configuration using a vibration mode (d33 mode) extending in the polarization direction may be used.

As such a configuration, for example, the configuration shown in FIG. 14 can be adopted.
The laminated structure 34 shown in FIG. 14 has a configuration in which the piezoelectric layer 31A and the piezoelectric layer 31B are laminated in the Z direction. On the piezoelectric layer 31A side, four sets of a pair of piezoelectric layers 31A are laminated, and the piezoelectric layers 31A of each set are arranged so that the polarization directions face each other. Similarly, on the piezoelectric layer 31B side, four pairs of piezoelectric layers 31B are stacked, and the piezoelectric layers 31B of each pair are arranged so that the polarization directions are opposed to each other.

  In the electrode 32A, on the piezoelectric layer 31A side, a portion sandwiched between the pair of piezoelectric layers 31A is provided for each set, and these portions are connected. In the electrode 32B, on the piezoelectric layer 31B side, a portion sandwiched between the pair of piezoelectric layers 31B is provided for each set, and these portions are connected. The electrode 32C is provided between each pair of the piezoelectric layers 31A and each pair of the piezoelectric layers 31B.

  A power supply D1 is connected between the electrode 32A and the electrode 32C. The power source D1 can supply a sine wave voltage signal between the electrode 32A and the electrode 32C. A power supply D2 is connected between the electrode 32B and the electrode 32C. The power source D2 can supply a cosine wave voltage signal between the electrode 32B and the electrode 32C.

  In such a configuration, by supplying voltage signals from the power supply D1 and the power supply D2, for example, the piezoelectric layer 31A and the piezoelectric layer 31B can be extended and vibrated in the polarization direction (stacking direction, Z direction), and the vibration is used. Thus, the laminated structure 34 can be bent. As described above, the present invention can be applied to any vibration mode of the piezoelectric layer 31A and the piezoelectric layer 31B.

  Moreover, in the said embodiment, although the structure which rotates a rotor using the drive device 1 was mentioned as an example and demonstrated, it is not restricted to this, For example, when moving a needle | mover straightly, or when moving a curve The present invention can be applied even when a movement other than the rotational movement is performed.

CONT ... control unit 1 ... drive device 2 ... rotor (rotor) 3 ... drive unit 30 ... piezoelectric element (electromechanical vibrator) 31, 31A, 31B, 136A-139A, 136B-139B ... piezoelectric layer 34 ... stacked structure 35 ... Piezoelectric layer pair

Claims (15)

A mover driven in a predetermined drive direction;
An electric machine having a piezoelectric layer pair in which a pair of piezoelectric layers polarized in directions opposite to each other is integrated, and vibrates in a direction close to the movable element and vibrates in a driving direction of the movable element A conversion element;
A drive unit comprising: a control unit that selectively causes the electromechanical transducer to vibrate in the proximity direction and vibration in the drive direction. The drive device according to claim 1, wherein the electromechanical conversion element is formed by stacking a plurality of the piezoelectric layer pairs. The control unit vibrates a part of the piezoelectric layer pairs in the proximity direction among the plurality of piezoelectric layer pairs, and vibrates the other piezoelectric layer pairs in the driving direction. The driving device according to claim 2. 4. The drive according to claim 2, wherein the controller vibrates the piezoelectric layer pair arranged on the end side in the stacking direction among the plurality of piezoelectric layer pairs in the driving direction. 5. apparatus. 5. The control unit according to claim 1, wherein the control unit causes the electromechanical conversion element to alternately repeat the vibration in the proximity direction and the vibration in the driving direction. 6. Drive device. The driving device according to claim 5, wherein the control unit supplies sinusoidal signals having different phases to the electromechanical transducer. The drive device according to claim 1, further comprising a contact between the movable element and the electromechanical conversion element. The drive device according to any one of claims 1 to 7, wherein a plurality of the electromechanical transducer elements are arranged along the drive direction. The drive device according to any one of claims 1 to 8, wherein the drive direction is a direction in which the mover is rotated. The drive device according to any one of claims 1 to 9, wherein the drive direction is a direction in which the mover moves straight. The electromechanical transducer is formed by laminating a plurality of the piezoelectric layer pairs in a direction orthogonal to the polarization direction of the piezoelectric layer or in a direction parallel to the orthogonal direction. The drive device according to claim 10. The driving device according to any one of claims 1 to 11, wherein the proximity direction is a direction orthogonal to a polarization direction of the piezoelectric layer or a direction parallel to the orthogonal direction. The electromechanical transducer is formed by laminating a plurality of the piezoelectric layer pairs in a polarization direction of the piezoelectric layer or in a direction parallel to the polarization direction. The drive device as described in any one. The drive device according to any one of claims 1 to 10, wherein the proximity direction is a polarization direction of the piezoelectric layer or a direction parallel to the polarization direction. A moving member;
A driving device for driving the moving member,
The robot device according to claim 1, wherein the drive device according to claim 1 is used as the drive device.

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