阅读说明：本技术 压电驱动装置、机器人以及打印机 (Piezoelectric driving device, robot, and printer ) 是由 梶野喜一 高桥智明 小西晃雄 于 2019-08-29 设计创作，主要内容包括：本发明提供通过获得精度较高的检测信号而能够稳定地进行驱动的压电驱动装置、机器人以及打印机。该压电驱动装置的特征在于,具有振动部和控制所述振动部的振动的控制部；所述振动部具备：压电体,具有处于表背关系的第一面和第二面；驱动用电极,具备配置于所述第一面的第一电极和配置于所述第二面的第二电极,并通过将来自所述控制部的驱动信号输入所述第二电极而使所述压电体振动；以及检测用电极,具备配置于所述第一面的第三电极和配置于所述第二面的第四电极,并将与所述压电体的振动对应的检测信号经由所述第四电极输出至所述控制部,在所述第一面上,所述第一电极与所述第三电极分离,并且,在所述第二面上,所述第二电极与所述第四电极分离。(The invention provides a piezoelectric driving device, a robot and a printer which can stably drive by obtaining a detection signal with high precision. The piezoelectric driving device is characterized by comprising a vibration part and a control part for controlling the vibration of the vibration part; the vibration unit includes: a piezoelectric body having a first surface and a second surface in a front-back relationship; a driving electrode that includes a first electrode disposed on the first surface and a second electrode disposed on the second surface, and vibrates the piezoelectric body by inputting a driving signal from the control unit to the second electrode; and a detection electrode including a third electrode disposed on the first surface and a fourth electrode disposed on the second surface, and configured to output a detection signal corresponding to vibration of the piezoelectric body to the control unit via the fourth electrode, wherein the first electrode is separated from the third electrode on the first surface, and the second electrode is separated from the fourth electrode on the second surface.)

1. A piezoelectric driving device is characterized by comprising:

a vibrating section that drives the driven member by vibration; and

a control section that controls vibration of the vibration section,

the vibration unit includes:

a piezoelectric body having a first surface and a second surface in a front-back relationship;

a driving electrode that includes a first electrode disposed on the first surface and a second electrode disposed on the second surface, and vibrates the piezoelectric body by inputting a driving signal from the control unit to the second electrode; and

a detection electrode including a third electrode disposed on the first surface and a fourth electrode disposed on the second surface, and configured to output a detection signal corresponding to vibration of the piezoelectric body to the control unit via the fourth electrode,

on the first face, the first electrode is separated from the third electrode, and on the second face, the second electrode is separated from the fourth electrode.

2. The piezoelectric driving apparatus according to claim 1, comprising:

a first detection wiring electrically connecting the third electrode and the control unit; and

a second detection wiring electrically connecting the fourth electrode and the control section,

when a portion of the first detection wiring line disposed in the vibration portion is set as a first vibration portion wiring line and a portion of the second detection wiring line disposed in the vibration portion is set as a second vibration portion wiring line,

the first vibrating portion wiring line and the second vibrating portion wiring line are disposed separately.

3. Piezoelectric driving device according to claim 2,

the control unit has a differential amplifier connected to the first detection line and the second detection line.

4. Piezoelectric driving device according to claim 2 or 3,

has a first reference potential wiring and a second reference potential wiring connected to a reference potential,

the first vibrating portion wiring and the second vibrating portion wiring are disposed between the first reference potential wiring and the second reference potential wiring.

5. The piezoelectric driving apparatus according to claim 4,

a third reference potential wiring connected to the reference potential,

the first reference potential wiring, the second reference potential wiring, the first vibrating portion wiring, and the second vibrating portion wiring overlap with the third reference potential wiring in a plan view of the first surface.

6. Piezoelectric driving device according to claim 2,

the length of the first vibrating portion wiring is identical to the length of the second vibrating portion wiring.

7. Piezoelectric driving device according to claim 2,

the first vibrating portion wiring and the second vibrating portion wiring are made of the same material and are disposed on the same surface.

8. Piezoelectric driving device according to claim 2,

the vibrating section includes a substrate and the piezoelectric body disposed on one surface side of the substrate,

the parasitic capacitances between the first and third vibrating portion wirings and the substrate are the same as the parasitic capacitances between the second and fourth vibrating portion wirings and the substrate.

9. A robot is characterized by comprising a piezoelectric driving device which is provided with a vibration part and a control part for controlling the vibration of the vibration part, and which vibrates the vibration part to drive a driven member in contact with the vibration part,

the vibration unit includes:

a piezoelectric body having a first surface and a second surface in a front-back relationship;

a driving electrode that includes a first electrode disposed on the first surface and a second electrode disposed on the second surface, and vibrates the piezoelectric body by inputting a driving signal from the control unit to the second electrode; and

a detection electrode including a third electrode disposed on the first surface and a fourth electrode disposed on the second surface, and configured to output a detection signal corresponding to vibration of the piezoelectric body to the control unit via the fourth electrode,

on the first face, the first electrode is separated from the third electrode, and on the second face, the second electrode is separated from the fourth electrode.

10. A printer includes a piezoelectric driving device including a vibrating portion and a control portion that controls vibration of the vibrating portion, and configured to vibrate the vibrating portion to drive a driven member that is in contact with the vibrating portion,

the vibration unit includes:

a piezoelectric body having a first surface and a second surface in a front-back relationship;

a driving electrode that includes a first electrode disposed on the first surface and a second electrode disposed on the second surface, and vibrates the piezoelectric body by inputting a driving signal from the control unit to the second electrode; and

a detection electrode including a third electrode disposed on the first surface and a fourth electrode disposed on the second surface, and configured to output a detection signal corresponding to vibration of the piezoelectric body to the control unit via the fourth electrode,

on the first face, the first electrode is separated from the third electrode, and on the second face, the second electrode is separated from the fourth electrode.

Technical Field

The invention relates to a piezoelectric driving device, a robot and a printer.

Background

The transducer described in patent document 1 is a transducer that can detect adhesion of a fine substance, a change in viscosity of a liquid, or the like by oscillating the transducer in a main vibration mode having a constant frequency and amplitude. Such a vibrator includes a substrate, a base electrode formed on a thin portion of the substrate, a piezoelectric layer formed on the base electrode, and a drive electrode and a detection electrode formed on the piezoelectric layer. In this vibrator, the base electrode is disposed so as to overlap both the drive electrode and the detection electrode when viewed in the thickness direction of the piezoelectric layer. That is, the base electrode serves as a counter electrode common to both the drive electrode and the detection electrode.

Patent document 1: japanese patent laid-open No. 2009-284375

Disclosure of Invention

In the transducer described in patent document 1, as described above, the base electrode facing the drive electrode and the base electrode facing the detection electrode are shared. Therefore, when a voltage is applied between the drive electrode and the base electrode and a current flows between the drive electrode and the base electrode along with this, noise included in the current overlaps via waveforms of potential differences generated between the base electrode and the detection electrode and the base electrode. Therefore, the waveform of the potential difference superimposed with noise is extracted from the detection electrode. This has the problem that when the amplitude or phase is obtained from the waveform of the extracted potential difference, the accuracy of the obtained value is lowered.

A piezoelectric driving device according to an application example of the present invention includes: a vibrating section that drives the driven member by vibration; and a control unit that controls vibration of the vibration unit, the vibration unit including: a piezoelectric body having a first surface and a second surface in a front-back relationship; a driving electrode that includes a first electrode disposed on the first surface and a second electrode disposed on the second surface, and vibrates the piezoelectric body by inputting a driving signal from the control unit to the second electrode; and a detection electrode including a third electrode disposed on the first surface and a fourth electrode disposed on the second surface, and configured to output a detection signal corresponding to vibration of the piezoelectric body to the control unit via the fourth electrode, wherein the first electrode is separated from the third electrode on the first surface, and the second electrode is separated from the fourth electrode on the second surface.

Drawings

Fig. 1 is a plan view showing a piezoelectric motor according to a first embodiment of the present invention.

Fig. 2 is a plan view showing the arrangement of electrodes in the piezoelectric actuator included in the piezoelectric motor shown in fig. 1.

Fig. 3 is a plan view showing the arrangement of wiring in the piezoelectric actuator included in the piezoelectric motor shown in fig. 1.

Fig. 4 is a sectional view taken along line a-a of fig. 3.

Fig. 5 is a sectional view taken along line B-B of fig. 3.

Fig. 6 is a cross-sectional view taken along line C-C of fig. 3.

Fig. 7 is a sectional view taken along line D-D of fig. 3.

Fig. 8 is a diagram showing an alternating voltage applied to the piezoelectric actuator shown in fig. 2.

Fig. 9 is a plan view showing a driving state of the piezoelectric motor shown in fig. 1.

Fig. 10 is a plan view showing a driving state of the piezoelectric motor shown in fig. 1.

Fig. 11 is a sectional view taken along line E-E of fig. 1.

Fig. 12 is a circuit diagram showing the control device shown in fig. 1 and 3.

Fig. 13 is a diagram schematically showing a circuit included in a conventional piezoelectric drive device.

Fig. 14 is a diagram schematically showing a circuit included in the piezoelectric drive device according to the present embodiment.

Fig. 15 is a partially enlarged view of the support portion shown in fig. 7.

Fig. 16 is a perspective view showing a robot according to a second embodiment of the present invention.

Fig. 17 is a schematic diagram showing the overall configuration of a printer according to a third embodiment of the present invention.

Description of the reference numerals

1 … piezoelectric motor; 2 … rotor; 3 … piezoelectric driving device; 3' … piezoelectric drive; 4 … piezoelectric actuator; 5 … force applying component; 6a … piezoelectric element; 6B … piezoelectric element; a 6C … piezoelectric element; 6D … piezoelectric element; 6E … piezoelectric element; a 6F … piezoelectric element; 6G … piezoelectric element; 7 … control device; 9 … encoder; 11 … a vibrating body; 21 … outer peripheral surface; 22 … major faces; 41 … vibrating body; 42 … support portion; a 43 … connection; 44 … protrusions; 51 … a first substrate; 52 … a second substrate; 53 … spacer; 59 … through holes; 60 … piezoelectric element unit; a 60a … piezoelectric element; a 60B … piezoelectric element; a 60C … piezoelectric element; a 60D … piezoelectric element; a 60E … piezoelectric element; a 60F … piezoelectric element; a 60G … piezoelectric element; a 61 … substrate; 63 … a protective layer; 69 … adhesive; 71 … driving pulse signal generating part; 71A … electrode; 71B … electrode; 71C … switching element; 72 … drive signal generating part; 72A … buffer; 72B … coil; 73 … detecting a pulse signal generating part; 73A … differential amplifier; 73B … comparator; a 74 … phase difference acquisition unit; 75 … a drive control unit; 81 … first detection wiring; 81a … first vibrating portion wiring; side 81b …; an 81c … terminal; 82 … second detection wiring; 82a … second vibrating portion wiring; 82b … side; 82c … terminal; 83 … reference potential wiring; 84 … reference potential wiring; 84c … terminals; 85 … drive side wiring; 85a … third vibrating portion wiring; 86 … through wiring; scale 91 …; 92 … optical element; 431 … a first connection; 432 … second connection; 512 … support portion; 513 … spring portions; 522 … support portion; 601 … a first electrode; 602 … piezoelectric bodies; 603 … second electrode; 604 … a third electrode; 606 … fourth electrode; 711 … a first driving pulse signal generating unit; 712 … second driving pulse signal generating part; 713 … third driving pulse signal generating section; 721 … a first drive signal generating section; 722 … a second drive signal generating section; 723 … a third driving signal generating part; 921 … light emitting element; 922 … image pickup element; 1000 … robot; 1010 … base; 1020 … arms; 1030 … arm; 1040 … arms; 1050 … arm; 1060 … arm; 1070 … arm; 1080 … control the device; 1090 … end effector; 3000 … printer; 3010 … device body; 3011 … trays; 3012 … paper discharge port; 3013 … operating panel; 3020 … printing mechanism; 3021 … head unit; 3021a … magnetic head; 3021b … ink cartridge; 3021c … carriage; 3022 … carriage motor; 3023 … reciprocating mechanism; 3023a … carriage guide shaft; 3023b … timing belt; 3030 … paper supply mechanism; 3031 … driven rollers; 3032 … driving the rollers; 3040 … controlling the device; 6021 … lower surface; 6022 … upper surface; a1 … arrow; a2 … arrow; b1 … arrow; b2 … arrow; o … central axis; p … recording paper; pd … drive pulse signal; ps … detecting the pulse signal; r1 … internal resistance; r2 … internal resistance; r3 … internal resistance; r4 … internal resistance; sd … drive signal; ss … detect a signal; v1 … alternating voltage; v2 … alternating voltage; v3 … alternating voltage; the potential of V601 …; the potential of V602 …; the potential of V604 …; the potential of V606 …; id … current.

Detailed Description

Hereinafter, preferred embodiments of the piezoelectric driving device, the robot, and the printer according to the present invention will be described in detail with reference to the drawings.

First embodiment

Fig. 1 is a plan view showing a piezoelectric motor according to a first embodiment of the present invention. Fig. 2 is a plan view showing the arrangement of electrodes in the piezoelectric actuator included in the piezoelectric motor shown in fig. 1. Fig. 3 is a plan view showing the arrangement of wiring in the piezoelectric actuator included in the piezoelectric motor shown in fig. 1. Fig. 4 is a sectional view taken along line a-a of fig. 3. Fig. 5 is a sectional view taken along line B-B of fig. 3. Fig. 6 is a cross-sectional view taken along line C-C of fig. 3. Fig. 7 is a sectional view taken along line D-D of fig. 3. Fig. 8 is a diagram showing an alternating voltage applied to the piezoelectric actuator shown in fig. 2. Fig. 9 and 10 are plan views each showing a driving state of the piezoelectric motor shown in fig. 1. Fig. 11 is a sectional view taken along line E-E of fig. 1.

For convenience of explanation, three axes orthogonal to each other are referred to as an X axis, a Y axis, and a Z axis, and a direction along the X axis is also referred to as an X axis direction, a direction along the Y axis is also referred to as a Y axis direction, and a direction along the Z axis is also referred to as a Z axis direction. The arrow side of each axis is also referred to as "positive side", and the opposite side of the arrow is also referred to as "negative side". The X-axis direction positive side is also referred to as "upper" or "upper side", and the X-axis direction negative side is also referred to as "lower" or "lower side".

The piezoelectric motor 1 shown in fig. 1 is disc-shaped and includes a rotor 2 as a driven member rotatable about a central axis O thereof and a piezoelectric driving device 3 in contact with an outer peripheral surface 21 of the rotor 2. In such a piezoelectric motor 1, when the piezoelectric drive device 3 is caused to perform flexural vibration, the rotor 2 rotates about the central axis O parallel to the X axis. The structure of the piezoelectric motor 1 is not limited to the structure shown in fig. 1. For example, a plurality of piezoelectric drive devices 3 may be arranged along the circumferential direction of the rotor 2, and the rotor 2 may be rotated by driving the plurality of piezoelectric drive devices 3. The piezoelectric drive device 3 may be in contact with the main surface 22 of the rotor 2, instead of being in contact with the outer peripheral surface 21 of the rotor 2. The driven member is not limited to a rotating body such as the rotor 2, and may be, for example, a linearly moving slider.

In the present embodiment, the encoder 9 is provided on the rotor 2, and the motion of the rotor 2, particularly the rotation amount and the angular velocity, can be detected by the encoder 9. The encoder 9 is not particularly limited, and may be, for example, an incremental encoder that detects the amount of rotation of the rotor 2 when the rotor 2 rotates, or an absolute encoder that detects the absolute position of the rotor 2 with respect to the origin regardless of whether the rotor 2 rotates.

The encoder 9 of the present embodiment includes a scale 91 fixed to the upper surface of the rotor 2, and an optical element 92 provided above the scale 91. The scale 91 has a disc shape, and a pattern, not shown, is provided on the upper surface thereof. On the other hand, the optical element 92 includes a light emitting element 921 for emitting light toward the pattern of the scale 91, and an image pickup element 922 for picking up an image of the pattern of the scale 91. In the encoder 9 configured as described above, the rotation amount, the driving speed, the absolute position, and the like of the rotor 2 can be detected by template matching the image of the pattern acquired by the image pickup device 922. However, the configuration of the encoder 9 is not limited to the above configuration. For example, a configuration may be adopted in which a light receiving element that receives reflected light or transmitted light from the scale 91 is provided instead of the imaging element 922.

The piezoelectric drive device 3 includes a piezoelectric actuator 4 as a vibration unit, a biasing member 5 for biasing the piezoelectric actuator 4 toward the rotor 2, and a control device 7 as a control unit for controlling the drive of the piezoelectric actuator 4.

As shown in fig. 2, the piezoelectric actuator 4 includes a vibrator 41, a support portion 42 that supports the vibrator 41, a connecting portion 43 that connects the vibrator 41 and the support portion 42, and a protrusion 44 that is connected to the vibrator 41 and transmits the vibration of the vibrator 41 to the rotor 2.

The vibrator 41 has a plate shape extending in the Y-Z plane including the Y axis and the Z axis with the X axis direction as the thickness direction, and vibrates in an S-shape by stretching in the Y axis direction and bending in the Z axis direction. The vibrator 41 has an elongated shape with the Y-axis direction as the expansion and contraction direction being the long side when viewed from the X-axis direction. However, the shape of the vibrator 41 is not particularly limited as long as the function thereof can be exhibited.

As shown in fig. 2, the vibrator 41 includes driving piezoelectric elements 6A to 6F for bending and vibrating the vibrator 41, and a detecting piezoelectric element 6G for detecting the vibration of the vibrator 41.

The piezoelectric elements 6C and 6D are arranged along the longitudinal direction (Y-axis direction) of the vibrator 41 at the center portion of the vibrator 41 in the Z-axis direction. The piezoelectric element 6C is located on the Y-axis direction positive side of the piezoelectric element 6D, and the piezoelectric element 6D is located on the Y-axis direction negative side of the piezoelectric element 6C. Further, a piezoelectric element 6G is disposed between the piezoelectric element 6C and the piezoelectric element 6D. The piezoelectric element 6C and the piezoelectric element 6D are electrically connected to each other.

Instead of the two piezoelectric elements 6C and 6D, one piezoelectric element may be provided.

The piezoelectric elements 6A and 6B are arranged in the longitudinal direction of the vibrator 41 on the positive side of the vibrator 41 in the Z-axis direction with respect to the piezoelectric elements 6C and 6D, and the piezoelectric elements 6E and 6F are arranged in the longitudinal direction of the vibrator 41 on the negative side of the vibrator in the Z-axis direction. The piezoelectric elements 6A to 6F expand and contract in the longitudinal direction (Y-axis direction) of the vibrator 41 by energization. The piezoelectric elements 6A and 6F are electrically connected to each other, and the piezoelectric elements 6B and 6E are electrically connected to each other. As described below, by applying alternating voltages of the same frequency with different phases to the piezoelectric elements 6C and 6D, the piezoelectric elements 6A and 6F, and the piezoelectric elements 6B and 6E, respectively, and shifting the expansion and contraction timings of the piezoelectric elements, the vibrator 41 can be caused to perform S-shaped bending vibration in the plane thereof.

The piezoelectric element 6G is located between the piezoelectric element 6C and the piezoelectric element 6D. That is, the piezoelectric element 6G is arranged in the expansion and contraction direction (Y-axis direction) of the piezoelectric elements 6C and 6D. The piezoelectric element 6G receives an external force corresponding to the vibration of the vibrator 41 generated as the piezoelectric elements 6A to 6F are driven, and outputs a signal corresponding to the received external force. Therefore, the vibration state of the vibrator 41 can be detected based on the signal output from the piezoelectric element 6G. Further, "the piezoelectric element 6G is arranged in the extending and contracting direction with respect to the piezoelectric elements 6C and 6D" means: at least a part of the piezoelectric element 6G, preferably the entire piezoelectric element 6G is located in a region where a region extending the piezoelectric element 6C in the telescopic direction (Y-axis direction) and a region extending the piezoelectric element 6D in the telescopic direction (Y-axis direction) overlap each other.

The piezoelectric element 6G is disposed in a portion of the vibrator 41 that is a node of the bending vibration. The node of the bending vibration is: the portion where the amplitude in the Z-axis direction is substantially 0 (zero), that is, the portion where bending vibration is not substantially generated. By arranging the piezoelectric element 6G so as to be aligned with the piezoelectric elements 6C and 6D in the expansion and contraction direction (Y-axis direction) and at a portion including a node of the bending vibration, the expansion and contraction vibration of the vibrator 41 in the Y-axis direction is easily transmitted to the piezoelectric element 6G, and the bending vibration of the vibrator 41 in the Z-axis direction is hardly transmitted to the piezoelectric element 6G. That is, the sensitivity of the stretching vibration can be improved, and the sensitivity of the bending vibration can be reduced. Therefore, the expansion and contraction vibration of the vibrator 41 in the Y-axis direction can be detected with higher accuracy by the piezoelectric element 6G.

However, the piezoelectric element 6G is not particularly limited as long as it can detect the stretching vibration of the vibrator 41 in the Y axis direction, and may be disposed in a portion of the vibrator 41 that becomes an antinode of the bending vibration, for example. The piezoelectric element 6G may be divided into a plurality of pieces.

Further, the support portion 42 supports the vibrator 41. The support portion 42 has a U-shape surrounding the base end side (the Y-axis direction negative side) of the vibrator 41 when viewed in plan from the X-axis direction. However, the shape and arrangement of the support portion 42 are not particularly limited as long as the function thereof can be exhibited.

The connecting portion 43 connects a portion of the vibrator 41 that becomes a node of the bending vibration, specifically, a center portion of the vibrator 41 in the Y axis direction, to the support portion 42. The connection portion 43 has a first connection portion 431 located on the Z-axis direction negative side with respect to the vibrator 41, and a second connection portion 432 located on the Z-axis direction positive side. However, the structure of the connecting portion 43 is not particularly limited as long as it can exhibit its function.

As shown in fig. 4 to 7, the vibrator 41, the support portion 42, and the connecting portion 43 as described above are configured by bonding two piezoelectric element units 60 to face each other. That is, in the sectional views shown in fig. 4 to 7, the piezoelectric element units 60 satisfy a mirror image relationship with respect to a line passing through therebetween. Each piezoelectric element unit 60 includes a substrate 61, piezoelectric elements 60A, 60B, 60C, 60D, 60E, and 60F for driving and a piezoelectric element 60G for detection, which are disposed on the substrate 61, and a protective layer 63 covering the piezoelectric elements 60A to 60G. The protective layer 63 is also referred to as an insulating portion because it has insulating properties. The substrate 61 is not particularly limited, and for example, a silicon substrate can be used. In the following description, the piezoelectric element unit 60 positioned below each of the two piezoelectric element units 60 shown in fig. 4 to 7 will be described as a representative.

As shown in fig. 4, each of the piezoelectric elements 60A to 60F includes a first electrode 601 disposed on the substrate 61, a piezoelectric body 602 disposed on the first electrode 601, and a second electrode 603 disposed on the piezoelectric body 602. The first electrode 601, the piezoelectric body 602, and the second electrode 603 are provided independently on the piezoelectric elements 60A to 60F, respectively. That is, the first electrode 601 and the second electrode 603 are driving electrodes for vibrating the piezoelectric bodies 602 of the driving piezoelectric elements 60A to 60F in response to a driving signal.

On the other hand, as shown in fig. 5, the piezoelectric element 60G includes a third electrode 604 disposed on the substrate 61, a piezoelectric body 602 disposed on the third electrode 604, and a fourth electrode 606 disposed on the piezoelectric body 602. The third electrode 604 is provided separately from the first electrode 601, and the fourth electrode 606 is provided separately from the second electrode 603. That is, the third electrode 604 and the fourth electrode 606 are detection electrodes for outputting a detection signal corresponding to the vibration of the piezoelectric body 602 of the piezoelectric element 60G for detection to the control device 7 described later.

The two piezoelectric element units 60 are bonded via an adhesive 69 in a state where the surfaces on the sides where the piezoelectric elements 60A to 60G are arranged face each other. The piezoelectric element units 60 may be used individually. The number of lamination is not limited to two, and may be three or more.

The first electrodes 601 of the piezoelectric elements 60A are electrically connected to each other via a wiring, not shown, or the like. The second electrodes 603 of the piezoelectric elements 60A are electrically connected to each other via a wiring, not shown, or the like. The two piezoelectric elements 60A constitute the piezoelectric element 6A. Similarly, the other piezoelectric elements 60B to 60F are configured such that the piezoelectric element 6B is configured by two piezoelectric elements 60B, the piezoelectric element 6C is configured by two piezoelectric elements 60C, the piezoelectric element 6D is configured by two piezoelectric elements 60D, the piezoelectric element 6E is configured by two piezoelectric elements 60E, and the piezoelectric element 6F is configured by two piezoelectric elements 60F.

On the other hand, the third electrodes 604 of the piezoelectric elements 60G are electrically connected to each other via a wiring or the like, not shown. The fourth electrodes 606 of the piezoelectric elements 60G are electrically connected to each other via a wiring, not shown, or the like. The two piezoelectric elements 60G constitute a piezoelectric element 6G.

The material of the piezoelectric body 602 is not particularly limited, and piezoelectric ceramics such as lead zirconate titanate (PZT), barium titanate, lead titanate, potassium niobate, lithium tantalate, sodium tungstate, zinc oxide, Barium Strontium Titanate (BST), Strontium Bismuth Tantalate (SBT), lead meta-niobate, and lead scandium niobate can be used, for example. As the piezoelectric body 602, polyvinylidene fluoride, quartz, or the like can be used in addition to the piezoelectric ceramics.

The piezoelectric body 602 may be formed of a bulk material, or may be formed by a sol-gel method or a sputtering method. In the present embodiment, the piezoelectric body 602 is formed by a sol-gel method. This makes it possible to obtain a thinner piezoelectric body 602 than when it is formed of a bulk material, for example, and to reduce the thickness of the piezoelectric drive device 3.

The convex portion 44 is provided at the tip end portion of the vibrator 41 and protrudes from the vibrator 41 toward the Y-axis direction positive side. The tip of the projection 44 contacts the outer peripheral surface 21 of the rotor 2. Therefore, the vibration of the vibrating body 41 is transmitted to the rotor 2 via the convex portion 44. The material of the projection 44 is not particularly limited, and examples thereof include various ceramics such as zirconia, alumina, and titania. This provides the protruding portion 44 having excellent durability.

In the piezoelectric actuator 4, when the alternating voltage V1 shown in fig. 8 is applied to the piezoelectric elements 6A and 6F, the alternating voltage V2 is applied to the piezoelectric elements 6C and 6D, and the alternating voltage V3 is applied to the piezoelectric elements 6B and 6E, the vibrator 41 expands and contracts in the Y-axis direction and bends in an S-shape in the Z-axis direction as shown in fig. 9, and these vibrations are combined, and the tip of the convex portion 44 elliptically moves along an elliptical orbit (rotational movement) in the counterclockwise direction as shown by an arrow a 1. Therefore, the alternating voltages V1, V2, V3 are the driving signals Sd in the piezoelectric driving device 3. The rotor 2 is fed by the elliptical motion of the projection 44, and the rotor 2 rotates clockwise as indicated by an arrow B1. In response to the vibration of the vibrator 41, the detection signal Ss is output from the piezoelectric element 6G.

Further, in the elliptical motion of the convex portion 44 shown by the arrow a1, from the point a1 'to the point a1 ", the convex portion 44 abuts against the outer peripheral surface 21 of the rotor 2 to send the rotor 2 in the direction of the arrow B1, and from the point a 1" to the point a 1', the convex portion 44 is separated from the outer peripheral surface 21 of the rotor 2. Therefore, the rotation of the rotor 2 toward the opposite side of the arrow B1 is suppressed.

When the alternating voltages V1 and V3 are switched, that is, when the alternating voltage V1 is applied to the piezoelectric elements 6B and 6E, the alternating voltage V2 is applied to the piezoelectric elements 6C and 6D, and the alternating voltage V3 is applied to the piezoelectric elements 6A and 6F, the vibrator 41 expands and contracts in the Y-axis direction and bends in an S-shape in the Z-axis direction as shown in fig. 10, and these vibrations are combined, and the convex portion 44 makes an elliptical motion in the clockwise direction as shown by an arrow a 2. The rotor 2 is fed by the elliptical motion of the projection 44, and the rotor 2 rotates counterclockwise as indicated by an arrow B2. In response to the vibration of the vibrator 41, the detection signal Ss is output from the piezoelectric element 6G.

Further, in the elliptical motion of the convex portion 44 shown by the arrow a2, from the point a2 'to the point a2 ", the convex portion 44 abuts against the outer peripheral surface 21 of the rotor 2 to send the rotor 2 in the direction of the arrow B2, and from the point a 2" to the point a 2', the convex portion 44 is separated from the outer peripheral surface 21 of the rotor 2. Therefore, the rotation of the rotor 2 toward the opposite side of the arrow B2 is suppressed.

However, in the present embodiment, the pattern of the alternating voltage applied to the piezoelectric elements 6A to 6F is not particularly limited as long as the rotor 2 can be rotated in at least one direction. The voltage applied to the piezoelectric elements 6A to 6F may not be an alternating voltage, and may be, for example, a dc voltage intermittently applied.

The convex portion 44 may be provided as needed, and may be replaced with another member.

The biasing member 5 biases the convex portion 44 toward the outer peripheral surface 21 of the rotor 2. As shown in fig. 11, the urging member 5 includes a first substrate 51 positioned on the upper surface side (positive side in the X-axis direction) of the piezoelectric actuator 4, and a second substrate 52 positioned on the lower surface side (negative side in the X-axis direction) of the piezoelectric actuator 4. The piezoelectric actuator 4 is sandwiched between the first substrate 51 and the second substrate 52. The first substrate 51 and the second substrate 52 are not particularly limited, and for example, a silicon substrate can be used.

In the present embodiment, one piezoelectric actuator 4 is sandwiched between the first substrate 51 and the second substrate 52, but the present invention is not limited to this, and may be configured as a laminate in which a plurality of piezoelectric actuators 4 are laminated between the first substrate 51 and the second substrate 52. As a result, since the number of piezoelectric actuators 4 included in one piezoelectric drive device 3 increases, the rotor 2 can be rotated by a large torque.

As shown in fig. 11, a spacer 53 having a thickness equal to that of the piezoelectric actuator 4 is provided between the support portions 512 and 522. A through hole 59 penetrating in the X axis direction is formed in this portion, and the urging member 5 is screwed to the frame or the like by this through hole 59. By fixing the biasing member 5 to the housing or the like in a state where the spring portion 513 is deflected in the Y-axis direction, the convex portion 44 can be biased toward the outer peripheral surface 21 of the rotor 2 by the restoring force of the spring portion 513.

The biasing member 5 has been described above, but the configuration of the biasing member 5 is not particularly limited as long as the convex portion 44 can be biased toward the outer peripheral surface 21 of the rotor 2. For example, one of the first substrate 51 and the second substrate 52 may be omitted. For example, a coil spring, a leaf spring, or the like may be used as the biasing member 5.

The control device 7 controls the driving of the piezoelectric drive device 3 by applying the alternating voltages V1, V2, and V3 to the piezoelectric elements 6A to 6F.

Fig. 12 is a circuit diagram showing the control device shown in fig. 1 and 3.

As shown in fig. 12, the control device 7 includes: a drive pulse signal generation unit 71 that generates a drive pulse signal Pd, a drive signal generation unit 72 that generates a drive signal Sd applied to the piezoelectric elements 6A, 6B, 6C, 6D, 6E, and 6F from the drive pulse signal Pd, a detection pulse signal generation unit 73 that generates a detection pulse signal Ps by binarizing the detection signal Ss output from the piezoelectric element 6G, a phase difference acquisition unit 74 that acquires a phase difference between the drive pulse signal Pd and the detection pulse signal Ps, and a drive control unit 75 that controls the drive of the drive pulse signal generation unit 71 based on the phase difference.

The drive pulse signal generation unit 71 is a circuit that generates a drive pulse signal Pd (digital signal) for generating a drive signal Sd. As shown in fig. 12, the drive pulse signal Pd generated by the drive pulse signal generation unit 71 is a rectangular wave binary to High/Low. The drive pulse signal generation unit 71 can change the Duty ratio (Duty) of the drive pulse signal Pd. By changing the duty ratio of the driving pulse signal Pd, the amplitude of the driving signal Sd can be changed. For example, if the duty ratio is set to 50%, the amplitude of the driving signal Sd is the maximum, and as the duty ratio approaches 0%, the amplitude of the driving signal Sd decreases.

The configuration of the drive pulse signal generation unit 71 is not particularly limited as long as the drive pulse signal Pd can be generated and the duty ratio of the drive pulse signal Pd can be changed. As shown in fig. 12, the drive pulse signal generation unit 71 of the present embodiment is configured to: the driving pulse signal Pd is generated by alternately switching a state in which the electrode 71A is connected to the switching element 71C and a state in which the electrode 71B is connected to the switching element 71C, with the electrode 71A having a potential of GND, the electrode 71B having a potential of + VDD, and the switching element 71C. In the present embodiment, the drive pulse signal generator 71 includes the first drive pulse signal generator 711, the second drive pulse signal generator 712, and the third drive pulse signal generator 713, and generates three different drive signals, for example, alternating voltages V1, V2, and V3 or signals having different phases.

The drive signal generation unit 72 is a circuit that generates a drive signal Sd as an analog signal from the drive pulse signal Pd generated by the drive pulse signal generation unit 71. As shown in fig. 12, the drive signal Sd generated by the drive signal generation unit 72 is a substantially sinusoidal signal.

The configuration of the drive signal generator 72 is not particularly limited as long as the drive signal Sd can be generated. As shown in fig. 12, the drive signal generating unit 72 of the present embodiment is mainly configured to include a buffer 72A and a coil 72B. In the present embodiment, the drive signal generator 72 includes a first drive signal generator 721 connected to the first drive pulse signal generator 711, a second drive signal generator 722 connected to the second drive pulse signal generator 712, and a third drive signal generator 723 connected to the third drive pulse signal generator 713, and generates three different drive signals, for example, alternating voltages V1, V2, and V3 or signals having different phases.

By applying the three drive signals, here the alternating voltages V1, V2, V3, generated by the drive signal generating section 72 to the piezoelectric elements 6A, 6B, 6C, 6D, 6E, 6F, the vibrator 41 performs flexural vibration as described above, and the rotor 2 rotates along with this.

The detection pulse signal generation unit 73 is a circuit that generates a detection pulse signal Ps as a digital signal by binarizing the detection signal Ss as an analog signal output from the piezoelectric element 6G in accordance with the bending vibration of the vibrator 41. As shown in fig. 12, the detection signal Ss output from the piezoelectric element 6G is a substantially sinusoidal signal corresponding to the amplitude of the vibrator 41, and the detection pulse signal Ps is a rectangular wave signal obtained by binarizing the detection signal Ss to High/Low. The configuration of the detection pulse signal generation unit 73 is not particularly limited as long as the detection pulse signal Ps can be generated. As shown in fig. 12, the detection pulse signal generation unit 73 of the present embodiment has a differential amplifier 73A and a comparator 73B.

The phase difference acquisition unit 74 is a circuit that acquires the phase difference between the drive pulse signal Pd and the detection pulse signal Ps. By obtaining the phase difference in this manner, the vibration state of the vibrator 41 can be monitored.

The drive control unit 75 is a circuit that controls the drive of the drive pulse signal generation unit 71 based on the phase difference acquired by the phase difference acquisition unit 74. The drive control unit 75 changes the frequency of each drive pulse signal Pd at any time, for example, so that the phase difference follows a predetermined value. Since the amplitude of vibrator 41 has a correlation with the phase difference, rotor 2 can be rotated at a higher speed by matching the phase difference with the value at which the amplitude of vibrator 41 becomes maximum.

In this way, the drive of the piezoelectric drive device 3 can be controlled.

Here, fig. 13 is a diagram schematically showing a circuit included in a conventional piezoelectric drive device. For convenience of explanation, the same reference numerals as those used in fig. 2 are used in fig. 13.

In the conventional piezoelectric drive device 3' shown in fig. 13, the piezoelectric elements 6A to 6F for driving have the first electrode 601 and the second electrode 603, respectively, as described above. The first electrode 601 is connected to GND (reference potential). The second electrode 603 is electrically connected to the drive pulse signal generation unit 71 and the drive signal generation unit 72.

The piezoelectric element 6G for detection shown in fig. 13 has the third electrode 604 and the fourth electrode 606 as described above. The third electrode 604 is electrically connected to the first electrode 601. That is, in the conventional circuit, the first electrode 601 of the piezoelectric elements 6A to 6F for driving and the third electrode 604 of the piezoelectric element 6G for detection are common electrodes. The fourth electrode 606 is electrically connected to the detection pulse signal generation unit.

Further, the wiring or the like connecting the drive signal generating unit 72 and the piezoelectric elements 6A to 6F has an internal resistance R1. Similarly, the internal resistance R2 is present in the wiring or the like connecting the piezoelectric elements 6A to 6F and GND. Further, the internal resistance R3 is also present in the wiring or the like connecting the piezoelectric element 6G and the detection pulse signal generation unit 73.

When driving such a conventional piezoelectric driving device 3', a driving signal Sd having a voltage waveform of, for example, a substantially sinusoidal waveform is input from the driving signal generating unit 72 to the driving piezoelectric elements 6A to 6F. When such a driving signal Sd is input, a current id having a waveform corresponding to the voltage waveform of the driving signal Sd flows between the first electrode 601 and the second electrode 603 of the piezoelectric elements 6A to 6F for driving.

However, in the current id, a noise component higher than the driving signal Sd is superimposed due to the influence of parasitic capacitance of the wiring that changes with time and the vibration of the piezoelectric elements 6A to 6F. That is, the current id has a waveform in which a noise component of a harmonic is superimposed on a substantially sinusoidal waveform. When such a current id flows through the internal resistor R2, a potential difference is generated between both ends of the internal resistor R2, which is a product of the current id and the resistance value. Therefore, the waveform of the potential V601 of the first electrode 601 is a waveform reflecting the waveform of the current id superimposed with the noise component.

In the conventional piezoelectric drive device 3', the first electrode 601 is electrically connected to the third electrode 604 as described above. Therefore, the waveform of the potential V604 of the third electrode 604 is substantially the same as the waveform of the potential V601 of the first electrode 601. That is, the noise component superimposed on the potential V601 in the piezoelectric elements 6A to 6F for driving is directly transferred to the potential V604.

When the piezoelectric body 602 is deformed by the potential V603 of the second electrode 603 of the piezoelectric elements 6A to 6F and the vibrator 41 vibrates, electric charges corresponding to the deformation are generated in the fourth electrode 606 of the piezoelectric element 6G. Therefore, the waveform of the potential V606 of the fourth electrode 606 of the piezoelectric element 6G includes a signal component that is a component reflecting the vibration of the vibrator 41.

Here, when a current flows between the third electrode 604 and the fourth electrode 606 of the piezoelectric element for detection 6G, a noise component superimposed on the potential V604 is also transferred to the potential V606 of the fourth electrode 606. Thus, the waveform of the potential V606 is a waveform in which not only the signal component due to the vibration of the vibrator 41 but also the noise component are superimposed. For convenience of explanation, the waveform of the potential V606 shown in fig. 13 is a waveform obtained by subtracting a signal component, that is, a waveform obtained by only showing a noise component.

In the conventional piezoelectric driving device 3' as described above, the waveform of the potential V606 superimposed with the noise component is input to a comparator, and a detection pulse signal is generated. Therefore, in the conventional piezoelectric drive device 3 ', a detection pulse signal is generated based on the potential V606 including the noise component, and the drive of the piezoelectric drive device 3' is controlled based on the detection pulse signal. Therefore, in the conventional piezoelectric drive device 3', it is difficult to accurately control the drive thereof.

In contrast, fig. 14 is a diagram schematically showing a circuit included in the piezoelectric drive device according to the present embodiment. In the following description, differences from the conventional piezoelectric drive device 3' shown in fig. 13 will be mainly described, and descriptions of the same matters will be omitted.

In the piezoelectric driving device 3 shown in fig. 14, as described above, the third electrode 604 is provided separately from the first electrode 601. That is, the first electrode 601 and the third electrode 604 are disposed on the lower surface 6021 (first surface) of the piezoelectric body 602 shown in fig. 4 and 5, respectively, and are separated from each other on the lower surface 6021.

On the other hand, as described above, the fourth electrode 606 is provided separately from the second electrode 603. The second electrode 603 and the fourth electrode 606 are disposed on the upper surface 6022 (second surface) of the piezoelectric body 602 shown in fig. 4 and 5, respectively, and are separated from each other on the upper surface 6022. Here, the separation means a state of not being connected via a conductor such as a wiring. In this embodiment, the first electrode 601 and the third electrode 604, and the second electrode 603 and the fourth electrode 606 are connected to each other via a nonconductor such as the substrate 61.

The third electrode 604 is connected to the negative input terminal of the differential amplifier 73A. The fourth electrode 606 is connected to the positive input terminal of the differential amplifier 73A. The internal resistance R3 is present in the wiring or the like connecting the fourth electrode 606 of the piezoelectric element 6G and the differential amplifier 73A, but the internal resistance R4 is also present in the wiring or the like connecting the third electrode 604 and the differential amplifier 73A.

In the piezoelectric driving device 3 according to the present embodiment, the driving signal Sd is input from the driving signal generating unit 72 to the second electrodes 603 of the driving piezoelectric elements 6A to 6F. When such a driving signal Sd is input, a current id having a waveform corresponding to the voltage waveform of the driving signal Sd flows between the first electrode 601 and the second electrode 603 of the piezoelectric elements 6A to 6F for driving.

However, as described above, a noise component higher than the drive signal Sd is superimposed on the current id due to the influence of the parasitic capacitance of the wiring and the vibration of the piezoelectric elements 6A to 6F, which change with time. When such a current id flows through the internal resistor R2, a potential difference is generated between both ends of the internal resistor R2, which is a product of the current id and the resistance value. Therefore, the waveform of the potential V601 on the first electrode 601 side based on the potential difference is a waveform reflecting the waveform of the current id superimposed with the noise component. In this case, in the conventional piezoelectric drive device 3', the third electrode 604 of the piezoelectric element 6G for detection is shared with the first electrode 601, and the potential V604 of the third electrode 604 is equal to the potential V601. Further, the noise component superimposed on the potential V604 is also transferred to the potential V606 of the fourth electrode 606. Therefore, the waveform of the potential V606 is a waveform in which the noise component of the potential V601 is superimposed almost without attenuation.

Here, in the piezoelectric drive device 3 according to the present embodiment shown in fig. 14, the third electrode 604 is provided separately from the first electrode 601 as described above. Therefore, the waveform of the potential V601 of the first electrode 601 is not directly transferred to the waveform of the potential V604 of the third electrode 604 in principle. However, as described above, the first electrode 601 and the third electrode 604 are structurally connected via the substrate 61 or the like, and therefore, the first electrode 601 and the third electrode 604 may be electrically coupled to each other. In this case, the noise component included in the waveform of the potential V601 is attenuated and superimposed on the potential V604. Therefore, the waveform of the potential V604 of the third electrode 604 includes the attenuated noise component.

The noise component superimposed on the potential V604 is also transferred to the potential V606 of the fourth electrode 606. Thus, the waveform of the potential V606 is a waveform in which not only the signal component due to the vibration of the vibrator 41 but also the attenuated noise component are superimposed. For convenience of explanation, the waveform of the potential V606 shown in fig. 14 is a waveform obtained by subtracting a signal component, that is, a waveform obtained by only showing a noise component.

In the piezoelectric driving device 3 as described above, the waveform of the detection signal Ss including the waveform of the potential V606 of the fourth electrode 606 is a waveform including a noise component, but the noise component is attenuated compared to the conventional art. Therefore, the detection signal Ss is extracted as a signal with higher accuracy from the fourth electrode 606. Further, the detection signal Ss is output to the control device 7 via the fourth electrode 606. Therefore, when the detection pulse signal Ps is generated from the detection signal Ss, the detection pulse signal generation unit 73 generates the detection pulse signal Ps with high accuracy, and the phase difference acquisition unit 74 can acquire the phase difference between the drive pulse signal Pd and the detection pulse signal Ps with higher accuracy. This enables more accurate control of the driving pulse signal generating unit 71, and enables stable control of the driving of the piezoelectric driving device 3.

The piezoelectric drive device 3 as described above includes the piezoelectric actuator 4 (vibrating portion) for driving the rotor 2 (driven member) by vibration, and the control device 7 (control portion) for controlling the vibration of the piezoelectric actuator 4. The piezoelectric actuator 4 includes: a piezoelectric body 602 having a lower surface 6021 (first surface) and an upper surface 6022 (second surface) in a front-back relationship; a driving electrode which has a first electrode 601 disposed on the lower surface 6021 and a second electrode 603 disposed on the upper surface 6022, and vibrates the piezoelectric body 602 by inputting a driving signal Sd from the control device 7 to the second electrode 603; and a detection electrode that has a third electrode 604 disposed on the lower surface 6021 and a fourth electrode 606 disposed on the upper surface 6022, and outputs a detection signal Ss corresponding to the vibration of the piezoelectric body 602 to the control device 7 (control unit) via the fourth electrode 606. Further, on the lower surface 6021, the first electrode 601 is separated from the third electrode 604, and on the upper surface 6022, the second electrode 603 is separated from the fourth electrode 606.

According to the piezoelectric drive device 3, the detection signal Ss can be obtained with high accuracy. Therefore, the piezoelectric drive device 3 which can be stably driven can be realized.

As described above, the control device 7 (control unit) includes the differential amplifier 73A included in the detection pulse signal generation unit 73. The potential V606 of the fourth electrode 606, that is, the detection signal Ss taken out from the fourth electrode 606 is input to the positive input terminal of the differential amplifier 73A.

The detection signal Ss includes a noise component superimposed on the above-described path together with a signal component generated by the vibration of the vibrator 41. This noise component causes a reduction in the S/N ratio of the detection signal Ss, and therefore, for example, the accuracy in determining the phase difference between the drive pulse signal Pd and the detection pulse signal Ps is reduced.

On the other hand, the potential V604 of the third electrode 604 is input to the negative input terminal of the differential amplifier 73A. The potential V604 is also superimposed with a noise component to the same extent as the noise component superimposed on the detection signal Ss.

The differential amplifier 73A suppresses the same phase component and amplifies different phase components. Therefore, the noise component input to the positive input terminal and the noise component input to the negative input terminal have a high probability of being in the same phase, and therefore can be selectively attenuated in the differential amplifier 73A. Thus, the differential amplifier 73A can output a signal component to be originally detected with high accuracy, and then input the signal component to the comparator 73B. Thus, the S/N ratio of the detection signal Ss can be increased by the cancellation of the noise component in the differential amplifier 73A, and the phase of the detection pulse signal Ps can be accurately obtained in the phase difference acquisition unit 74.

The control device 7 according to the present embodiment includes the differential amplifier 73A, but the differential amplifier 73A may be omitted when the noise component is small. The differential amplifier 73A may be replaced with another element, circuit, software, or the like having the same function as that of the element.

In order to cancel the noise component by the differential amplifier 73A or the like, it is preferable that the electrical characteristics match between the path from the third electrode 604 to the differential amplifier 73A and the path from the fourth electrode 606 to the differential amplifier 73A. This makes it easy to match the waveforms of the noise components in both paths, and the noise components can be more favorably canceled out and reduced in the differential amplifier 73A.

Specifically, as shown in fig. 2, 3, and 5, the piezoelectric driving device 3 includes a first detection wiring 81 that electrically connects the third electrode 604 to the control device 7 (control unit), and a second detection wiring 82 that electrically connects the fourth electrode 606 to the control device 7. When the portion of the first detection wiring 81 disposed on the piezoelectric actuator 4 (vibrating portion) is referred to as a first vibrating portion wiring 81a and the portion of the second detection wiring 82 disposed on the piezoelectric actuator 4 is referred to as a second vibrating portion wiring 82a, the first vibrating portion wiring 81a and the second vibrating portion wiring 82a are disposed on the substrate 61 in the piezoelectric drive device 3 so as to be separated from each other, as shown in fig. 3, 6, and 7.

With this arrangement, it is relatively easy to make the electrical characteristics such as the parasitic capacitance and the resistance of the first vibrating portion wiring 81a and the second vibrating portion wiring 82a uniform by controlling adjustable parameters such as the area of the first vibrating portion wiring 81a and the area of the second vibrating portion wiring 82 a. In addition, since the first vibrating portion wiring 81a and the second vibrating portion wiring 82a are also portions where parasitic capacitance or resistance capacitance of the first detection wiring 81 and the second detection wiring 82 tends to increase, it is easier to make the electrical characteristics of the entire first detection wiring 81 and the second detection wiring 82 uniform by designing in this way. Thus, the waveforms of the noise components are less likely to be shifted from each other in the first detection line 81 and the second detection line 82, and the noise components can be more favorably canceled and reduced in the differential amplifier 73A.

The fourth electrode 606 and the second vibrating portion wiring 82a are electrically connected to each other via a through wiring 86 that penetrates the protective layer 63.

On the other hand, as shown in fig. 3, the piezoelectric driving device 3 has a driving-side wiring 85 that electrically connects the second electrode 603 and the control device 7. A portion of the driving-side wiring 85 disposed on the piezoelectric actuator 4 is referred to as a third vibrating portion wiring 85 a. In the piezoelectric driving device 3, as shown in fig. 3, the third vibrating portion wiring 85a is disposed in a range from the connecting portion 43 to the supporting portion 42.

The first vibration portion wiring 81a and the second vibration portion wiring 82a are disposed in the range from the support portion 42 to the connection portion 43 in the piezoelectric actuator 4. The first vibrating portion wiring 81a is connected to the third electrode 604, and the second vibrating portion wiring 82a is connected to the fourth electrode 606.

On the other hand, the piezoelectric driving device 3 according to the present embodiment includes a reference potential wiring 83 extending in parallel with the first vibrating portion wiring 81a and the second vibrating portion wiring 82a on the substrate 61.

As shown in fig. 15, the piezoelectric driving device 3 according to the present embodiment includes a reference potential wiring 84 provided on the protective layer 63 covering the first vibrating portion wiring 81a and the second vibrating portion wiring 82 a. The reference potential wiring 84 is electrically connected to a terminal 84c provided on the substrate 61 via a wiring not shown.

The reference potential wirings 83 and 84 are connected to the reference potential, that is, the potential of GND, respectively.

Fig. 15 is a partially enlarged view of the support portion 42 shown in fig. 7.

In the first vibrating portion wiring 81a shown in fig. 15, the left surface, the right surface, and the upper surface are all the side surfaces 81 b. Similarly, in the second vibrating portion wiring 82a shown in fig. 15, the left surface, the right surface, and the upper surface are all the side surfaces 82 b.

In the piezoelectric driving device 3 according to the present embodiment, the reference potential wirings 83 and 84 are disposed so as to overlap the side surface 81b of the first vibrating portion wiring 81a via the protective layer 63. Similarly, in the piezoelectric driving device 3, the reference potential wirings 83 and 84 are disposed so as to overlap the side surface 82b of the second vibrating portion wiring 82a via the protective layer 63.

Specifically, the reference potential wiring 83 (the first reference potential wiring and the second reference potential wiring) is disposed so as to overlap with the left surface and the right surface of the side surface 81b shown in fig. 15, respectively. That is, the first vibrating portion wire 81a and the second vibrating portion wire 82a are arranged between the two reference potential wires 83, i.e., the first reference potential wire and the second reference potential wire. The reference potential wiring 84 is disposed so as to overlap the upper surface of the side surface 81b shown in fig. 15.

Similarly, the reference potential wiring 83 is disposed so as to overlap the left surface and the right surface of the side surface 82b shown in fig. 15. The reference potential wiring 84 is disposed so as to overlap the upper surface of the side surface 82b shown in fig. 15.

By disposing the reference potential wirings 83 and 84 in this manner, parasitic capacitances between the first vibrating portion wiring 81a and the second vibrating portion wiring 82a and the reference potential wirings 83 and 84 can be easily matched. That is, by disposing the reference potential wirings 83 and 84 so as to overlap the side surfaces 81b and 82b, the capacitances parasitic on the first vibrating portion wiring 81a and the second vibrating portion wiring 82a can be easily and forcibly made uniform. Thus, the electrical characteristics of the first detection wiring 81 and the second detection wiring 82 match each other, and the waveforms of the noise components are less likely to deviate from each other. This makes it possible to further favorably cancel and reduce the noise component in the differential amplifier 73A.

By disposing the reference potential wirings 83 and 84 in this manner, for example, an electromagnetic shielding function of suppressing the noise component induced by the electromagnetic wave propagating through the space from being superimposed on the first vibration portion wiring 81a or the second vibration portion wiring 82a can be added. Therefore, the noise component overlapping in the above-described path can be suppressed, and the noise component can be more favorably reduced in the differential amplifier 73A.

In this case, by connecting the reference potential wirings 83 and 84 to the reference potential (GND), respectively, the eddy current generated in the reference potential wirings 83 and 84 can be minimized, and a function of suppressing the noise component induced by the eddy current can be added.

The side surfaces 81b and 82b overlap the reference potential wirings 83 and 84 by: when the side surfaces 81b and 82b are viewed in plan, the reference potential wirings 83 and 84 are disposed through the protective layer 63 so as to cover at least a part of the side surfaces 81b and 82 b. The reference potential wirings 83 and 84 are preferably disposed so as to cover half or more of the side surfaces 81b and 82b, respectively.

The reference potential wiring 83 according to the present embodiment is disposed so as to overlap the left and right surfaces of the first vibrating portion wiring 81a and the second vibrating portion wiring 82a, respectively, but may be disposed so as to overlap only either one of them.

Further, the reference potential wiring 84 may be provided as needed, and may be omitted, or the reference potential wiring 83 may be omitted when the reference potential wiring 84 is provided.

Further, the reference potential wiring 84 (third reference potential wiring) is arranged such that: when the lower surface 6021 (first surface) of the piezoelectric body 602 is viewed in plan, the two reference potential wirings 83 (first reference potential wiring and second reference potential wiring) and the first vibrating portion wiring 81a and the second vibrating portion wiring 82a overlap each other.

Accordingly, the electrical characteristics of the first detection wiring 81 and the second detection wiring 82 are particularly accurately matched, and the waveforms of the noise components are less likely to be shifted from each other between the two. This makes it possible to further favorably cancel and reduce the noise component in the differential amplifier 73A.

In addition, by disposing the reference potential wirings 83 and 84 in this manner, the above-described function as an electromagnetic shield can be further enhanced. Therefore, overlapping of noise components propagating in the space can be more reliably suppressed, and the noise components can be more favorably reduced in the differential amplifier 73A.

In other words, the reference potential wirings 83 and 84 are arranged to overlap the side surface 81b of the first vibrating portion wiring 81a and the side surface 82b of the second vibrating portion wiring 82 a. That is, the reference potential wirings 83 and 84 are disposed at a position surrounding the first vibrating portion wiring 81a and a position surrounding the second vibrating portion wiring 82a, respectively.

The position of the surrounding is a position covering at least a part of each of the three surfaces, i.e., the left surface, the right surface, and the top surface of the first vibrating portion wiring 81a shown in fig. 15, and a position covering at least a part of each of the three surfaces, i.e., the left surface, the right surface, and the top surface of the second vibrating portion wiring 82a shown in fig. 15.

From this viewpoint, the function as an electromagnetic shield can be further enhanced.

As described above, the first and second vibrating portion wires 81a and 82a are disposed on the substrate 61, respectively, but in the present embodiment, the arrangement direction thereof is the width direction of the first vibrating portion wire 81 a. By arranging the first vibrating portion wiring 81a and the second vibrating portion wiring 82a in parallel in this way, the number and area of the reference potential wirings 83 and 84 can be reduced, and the reference potential wirings 83 and 84 can be arranged so as to overlap the side surfaces 81b and 82b as shown in fig. 15. This can reduce the size of the piezoelectric actuator 4.

Further, by arranging this, it is easy to make the distance between the first vibrating portion wiring 81a and the reference potential wiring 83 and the distance between the second vibrating portion wiring 82a and the reference potential wiring 83 coincide with each other. That is, in the present embodiment, the sum of the distances between the first vibrating portion wiring 81a and the two reference potential wirings 83 and the sum of the distances between the second vibrating portion wiring 82a and the two reference potential wirings 83 shown in fig. 15 are easily made equal to each other. This makes it possible to match the parasitic capacitance in the first vibrating portion wiring 81a with the parasitic capacitance in the second vibrating portion wiring 82a, and the waveforms of the noise components are less likely to deviate from each other between the first vibrating portion wiring 81a and the second vibrating portion wiring 82 a. This makes it possible to further favorably cancel and reduce the noise component in the differential amplifier 73A.

Further, the reference potential wiring 83 may be added between the first vibrating portion wiring 81a and the second vibrating portion wiring 82a as needed.

The length of the first vibrating portion wire 81a and the length of the second vibrating portion wire 82a may be different from each other, but are preferably equal to each other. Thus, for example, by matching the width of the first vibrating portion wiring 81a with the width of the second vibrating portion wiring 82a, electrical characteristics such as the resistance of the first detection wiring 81 and the second detection wiring 82 can be more easily matched. This makes it possible to further favorably cancel and reduce the noise component in the differential amplifier 73A.

Further, the lengths are consistent with each other: when the lengths of line segments passing through the width centers of the respective wirings are compared, the difference converges to a state of 5% or less of the shorter length.

The first vibrating portion wiring 81a and the second vibrating portion wiring 82a may be formed of different materials, but preferably are formed of the same material. The constituent material is not particularly limited, and examples thereof include various metal materials.

The first and second vibrating portion wires 81a and 82a may be provided at different positions from each other, but preferably, as shown in fig. 7, the positions of the piezoelectric body 602 in the X-axis direction are the same. Specifically, the first vibrating portion wiring 81a and the second vibrating portion wiring 82a are both disposed on the same surface of the substrate 61. By satisfying these, the electrical characteristics of the first detection wiring 81 and the second detection wiring 82 are particularly likely to be matched, and the waveforms of the noise components are less likely to be shifted from each other between the two. This makes it possible to further favorably cancel and reduce the noise component in the differential amplifier 73A. In addition, according to such a configuration, there is also an advantage that the first vibrating portion wiring 81a and the second vibrating portion wiring 82a are easily formed.

The piezoelectric actuator 4 according to the present embodiment includes a substrate 61 and a piezoelectric body 602 disposed on one surface side of the substrate 61. In this case, in the piezoelectric actuator 4, the parasitic capacitances between the first and third vibrating portion wires 81a and 604 and the substrate 61 and between the second and fourth vibrating portion wires 82a and 606 and the substrate 61 may be different from each other, but are preferably the same. Accordingly, the amount of change in the noise component caused by the parasitic capacitance can be suppressed, and the waveforms of the superimposed noise component are less likely to deviate from each other between the first vibrating portion wiring 81a and the second vibrating portion wiring 82 a. This makes it possible to further favorably cancel and reduce the noise component in the differential amplifier 73A.

In order to make the parasitic capacitances between the first and third vibrating portion wires 81a and 604 and the substrate 61 and between the second and fourth vibrating portion wires 82a and 606 and the substrate 61 the same, for example, the area of the first vibrating portion wire 81a and the area of the second vibrating portion wire 82a may be made the same, or the distance between the first vibrating portion wire 81a and the substrate 61 and the distance between the second vibrating portion wire 82a and the substrate 61 may be made the same. For example, in the case of a portion where the distances cannot be made the same, the area may be made different in order to compensate for the difference in parasitic capacitance caused by the difference. Similarly, in order to compensate for the difference in parasitic capacitance caused by the difference in parasitic capacitance, the distance may be different for the portions that cannot be made to have the same area.

In the case of the piezoelectric actuator 4 shown in fig. 3, the area of the terminal 82c provided on the end portion of the second vibrating portion wiring 82a is larger than the area of the terminal 81c provided on the end portion of the first vibrating portion wiring 81 a. This is a measure in accordance with the case where the distance of the fourth electrode 606 from the substrate 61 is larger than the distance of the third electrode 604 from the substrate 61 as shown in fig. 5. By making the area of the terminal 82c larger than the area of the terminal 81c in this way, the parasitic capacitances between the first and third vibrating portion wires 81a and 604 and the substrate 61 and between the second and fourth vibrating portion wires 82a and 606 and the substrate 61 can be made to be equal to each other in a value close to each other, and the noise component can be more favorably cancelled and reduced in the differential amplifier 73A.

The area of the terminal 82c is appropriately set according to the difference in parasitic capacitance or the area of the terminal 81c, and is preferably larger than 100% and not more than 1000%, and more preferably 105% or more and not more than 800%, of the area of the terminal 81c, for example.

Second embodiment

Fig. 16 is a perspective view showing a robot according to a second embodiment of the present invention.

The robot 1000 shown in fig. 16 can perform operations such as feeding, removing, transporting, and assembling of precision equipment or its constituent components. The robot 1000 is a six-axis robot, and includes: a base 1010 fixed to a floor or a ceiling, an arm 1020 rotatably connected to the base 1010, an arm 1030 rotatably connected to the arm 1020, an arm 1040 rotatably connected to the arm 1030, an arm 1050 rotatably connected to the arm 1040, an arm 1060 rotatably connected to the arm 1050, an arm 1070 rotatably connected to the arm 1060, and a control device 1080 for controlling driving of the arms 1020, 1030, 1040, 1050, 1060, 1070.

Further, the arm 1070 is provided with a hand connecting portion to which an end effector 1090 corresponding to a work to be performed by the robot 1000 is attached. A piezoelectric motor 1 is mounted on all or a part of each joint, and the arms 1020, 1030, 1040, 1050, 1060, 1070 are rotated by driving the piezoelectric motor 1. The piezoelectric motor 1 may be mounted on the end effector 1090 and used to drive the end effector 1090.

The control device 1080 is a computer, and includes, for example, a processor (CPU), a memory, an I/F (interface), and the like. The processor executes a predetermined program (code string) stored in the memory, thereby controlling the driving of each unit of the robot 1000. Further, the program may be downloaded from an external server via an I/F. Further, all or a part of the configuration of the control device 1080 may be provided outside the robot 1000 and may be connected via a communication network such as a LAN (local area network).

As described above, such a robot 1000 includes the piezoelectric motor 1. That is, the robot 1000 includes the piezoelectric actuator 4 (vibrating unit) and the control device 7 (control unit) that controls the vibration of the piezoelectric actuator 4, and includes the piezoelectric driving device 3 that drives the rotor 2 (driven member) in contact with the piezoelectric actuator 4 by vibrating the piezoelectric actuator 4. The piezoelectric actuator 4 includes: a piezoelectric body 602 having a lower surface 6021 (first surface) and an upper surface 6022 (second surface) in a front-back relationship; a driving electrode which has a first electrode 601 disposed on the lower surface 6021 and a second electrode 603 disposed on the upper surface 6022, and vibrates the piezoelectric body 602 by inputting a driving signal Sd from the control device 7 to the second electrode 603; and a detection electrode that has a third electrode 604 disposed on the lower surface 6021 and a fourth electrode 606 disposed on the upper surface 6022, and outputs a detection signal Ss corresponding to the vibration of the piezoelectric body 602 to the control device 7 (control unit) via the fourth electrode 606. Further, on the lower surface 6021, the first electrode 601 is separated from the third electrode 604, and, on the upper surface 6022, the second electrode 603 is separated from the fourth electrode 606. According to the robot 1000, the detection signal Ss with high accuracy can be obtained in the piezoelectric driving device 3. Therefore, by performing the driving based on the detection signal Ss, the piezoelectric driving device 3 capable of performing the driving stably can be realized. This makes it possible to obtain the robot 1000 that can be stably driven.

Third embodiment

Fig. 17 is a schematic diagram showing the overall configuration of a printer according to a third embodiment of the present invention.

The printer 3000 shown in fig. 17 includes an apparatus main body 3010, a printing mechanism 3020, a paper feed mechanism 3030, and a control device 3040 provided inside the apparatus main body 3010. The apparatus main body 3010 is provided with a tray 3011 on which the recording paper P is set, a paper discharge port 3012 through which the recording paper P is discharged, and an operation panel 3013 such as a liquid crystal display.

The printing mechanism 3020 includes a magnetic head unit 3021, a carriage motor 3022, and a reciprocating mechanism 3023 that reciprocates the magnetic head unit 3021 by the driving force of the carriage motor 3022. The head unit 3021 includes a magnetic head 3021a as an ink jet recording head, an ink cartridge 3021b for supplying ink to the magnetic head 3021a, and a carriage 3021c on which the magnetic head 3021a and the ink cartridge 3021b are mounted.

The reciprocating mechanism 3023 includes a carriage guide shaft 3023a that supports the carriage 3021c so as to be capable of reciprocating, and a timing belt 3023b that moves the carriage 3021c on the carriage guide shaft 3021a by the driving force of a carriage motor 3022. The paper feeding mechanism 3030 includes a driven roller 3031 and a driving roller 3032 which are pressed against each other, and a piezoelectric motor 1 which drives the driving roller 3032.

In the printer 3000, the paper feed mechanism 3030 intermittently feeds the recording paper P one by one to the vicinity of the lower portion of the magnetic head unit 3021. At this time, the magnetic head unit 3021 reciprocates in a direction substantially orthogonal to the transport direction of the recording paper P, and performs printing on the recording paper P.

The control device 3040 is configured by a computer, and includes, for example, a processor (CPU), a memory, an I/F (interface), and the like. The processor executes a predetermined program (code string) stored in the memory, thereby controlling the driving of each unit of the printer 3000. Such control is executed based on print data input from a host computer such as a personal computer via an I/F, for example. Further, the program may be downloaded from an external server via an I/F. Further, all or a part of the configuration of the control device 1080 may be provided outside the printer 3000 and may be connected via a communication network such as a LAN (local area network).

As described above, the printer 3000 includes the piezoelectric motor 1. That is, the printer 3000 includes a piezoelectric actuator 4 (vibrating unit) and a control device 7 (control unit) that controls the vibration of the piezoelectric actuator 4, and includes a piezoelectric driving device 3 that vibrates the piezoelectric actuator 4 and drives a rotor 2 (driven member) in contact with the piezoelectric actuator 4. The piezoelectric actuator 4 includes: a piezoelectric body 602 having a lower surface 6021 (first surface) and an upper surface 6022 (second surface) that are in a front-back relationship with each other; a driving electrode which has a first electrode 601 disposed on the lower surface 6021 and a second electrode 603 disposed on the upper surface 6022, and vibrates the piezoelectric body 602 by inputting a driving signal Sd from the control device 7 to the second electrode 603; and a detection electrode that has a third electrode 604 disposed on the lower surface 6021 and a fourth electrode 606 disposed on the upper surface 6022, and outputs a detection signal Ss corresponding to the vibration of the piezoelectric body 602 to the control device 7 (control unit) via the fourth electrode 606. Further, on the lower surface 6021, the first electrode 601 is separated from the third electrode 604, and, on the upper surface 6022, the second electrode 603 is separated from the fourth electrode 606. According to the printer 3000, the detection signal Ss can be obtained with high accuracy in the piezoelectric driving device 3. Therefore, by performing the driving based on the detection signal Ss, the piezoelectric driving device 3 capable of performing the driving stably can be realized. This makes it possible to obtain the printer 3000 which can be stably driven.

In the present embodiment, the piezoelectric motor 1 drives the driving roller 3032 for paper feeding, but may drive the carriage 3021c, for example, in addition to this.

The piezoelectric driving device, the robot, and the printer according to the present invention have been described above based on the illustrated embodiments, but the present invention is not limited thereto, and the configuration of each part may be replaced with any configuration having the same function. In addition, other arbitrary components may be added to the present invention. In addition, the embodiments may be appropriately combined.