JP2005073341A - Piezoelectric actuator and device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric actuator along with a device equipped with it for improved durability. <P>SOLUTION: A piezoelectric element 52 is pasted on both surfaces of a reinforcing plate 51 to constitute a piezoelectric actuator 5. An abutting member 54, composed of materials whose hardness is higher than the reinforcing plate 51, is provided independent of the reinforcing plate 51. The abutting member 54 is made to abut with a moving body. When an piezoelectric element 52 is applied with a voltage to vibrate the piezoelectric actuator 5, the abutting member 54 repeatedly pressurizes the moving body for movement. Since the reinforcing plate 51 is separate from the abutting member 54, with the abutting member 54 having higher hardness than that of the reinforcing plate 51, the vibration of the piezoelectric element 52 is transmitted well to the reinforcing plate 51, while wearing of the abutting member 54 is prevented, resulting in improved durability of the piezoelectric actuator 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a piezoelectric actuator that vibrates by repeatedly displacing a piezoelectric element and moves a moving body by the vibration, and an apparatus including the piezoelectric actuator.

  Conventionally, a so-called piezoelectric actuator has been developed in which a piezoelectric element is vibrated by repeatedly applying a voltage to the piezoelectric element, and a moving body is moved by the vibration. As such a piezoelectric actuator, there is one in which a protrusion is provided on a side surface of the piezoelectric element (for example, Patent Document 1). In this piezoelectric actuator, a protrusion is bonded to the side surface of the plate-like piezoelectric element, the protrusion is brought into contact with the moving body, and the moving body is moved by the frictional force between the moving body and the protrusion. According to such a configuration, since the protrusion comes into contact with the moving body, wear of the piezoelectric element is prevented, and the shape change of the piezoelectric element can be prevented even when used for a long period of time, and stable vibration can be obtained. .

  However, on the other hand, since the piezoelectric element is made of a brittle material such as ceramics, it has a drawback of being inferior in impact resistance. Therefore, in recent years, in order to reinforce the brittleness of the piezoelectric element, a structure in which a diaphragm is fixed to the piezoelectric element has been proposed (for example, Patent Document 2). In this piezoelectric actuator, a diaphragm made of phosphor bronze or the like is fixed to a plate-like piezoelectric element. The diaphragm is integrally formed with a protrusion protruding in the planar direction of the piezoelectric element, and the moving body is moved by the frictional force between the moving body and the protrusion by contacting the protrusion with the moving body. According to such a configuration, the vibration plate transmits vibrations of the piezoelectric element to the protrusion while reinforcing the brittleness of the piezoelectric element, so that the protrusion vibrates well and moves the moving body.

JP 7-184382 A (Pages 5 and 6) JP 2000-188882 A (page 6)

  However, in such a piezoelectric actuator, the vibration plate is made of a relatively soft material such as phosphor bronze in order to transmit the vibration to the protrusion without hindering the vibration of the piezoelectric element. For this reason, the protrusion integrally formed on the diaphragm is worn by friction with the moving body, and the durability of the piezoelectric actuator cannot be improved.

  The objective of this invention is providing the piezoelectric actuator which can improve durability, and an apparatus provided with the same.

The piezoelectric actuator of the present invention is a piezoelectric actuator that includes a piezoelectric element and a vibration member fixed to the piezoelectric element, and moves the moving body by the vibration of the piezoelectric element. The vibration member is in contact with the moving body. A separate contact member is provided, and at least a contact surface of the contact member that contacts the moving body is configured to have higher hardness than the vibration member.
According to this invention, since the vibration member is fixed to the piezoelectric element, the brittleness of the piezoelectric element is reinforced and the impact resistance is improved. Further, since the vibration member and the contact member are provided separately, the vibration member and the contact member can be made of different materials. At this time, since at least the contact surface of the contact member to the moving body is configured to be harder than the vibration member, the piezoelectric element can be used as the vibration member while ensuring good strength of the contact surface of the contact member. It is possible to select a material that does not hinder the vibrations. Therefore, since the vibration member reinforces the piezoelectric element, the vibration of the piezoelectric element is transmitted to the contact member well, and the contact member is prevented from being worn on the contact surface with the moving body. Durability is improved.

In the present invention, the abutting member is provided so as to protrude from the piezoelectric element, and a part of the abutting member is fixed to a surface substantially parallel to the protruding direction of the abutting member among the surfaces of the piezoelectric element and / or the vibration member. It is desirable that
According to this invention, since the contact member is provided so as to protrude from the piezoelectric element, the piezoelectric element contacts the moving body even when the piezoelectric actuator is arranged at an angle with respect to the moving body. Without contact, the contact member contacts the moving body. Therefore, the degree of freedom of arrangement of the piezoelectric actuator is increased.
In addition, since a part of the contact member is fixed to the piezoelectric element surface and / or the vibration member surface substantially parallel to the protruding direction, the fixed area of the contact member to the piezoelectric element and / or the vibration member is widened. Accordingly, the fixing force necessary for the contact member is ensured, and this also improves the durability of the piezoelectric actuator.
Here, the surface substantially parallel to the protruding direction means that the angle formed between the protruding direction and the surface direction of the piezoelectric element and / or the vibration member is about 0 °, for example, within ± 30 ° with respect to the protruding direction. And more preferably within ± 15 °, and even more preferably within ± 10 °. Therefore, for example, when the piezoelectric element is formed in a block-shaped rectangular parallelepiped and the abutting member protrudes at a right angle from an arbitrary surface, the protruding direction is a direction perpendicular to the arbitrary surface, and the protruding direction The substantially parallel surface of the piezoelectric element refers to a surface adjacent to the one arbitrary surface.

In the present invention, it is desirable that at least one of the piezoelectric element, the vibration member, and the contact member is provided with positioning means for positioning the contact member with respect to the piezoelectric element.
According to the present invention, since the positioning means is provided, the abutting member is reliably positioned with respect to the piezoelectric element, and even if the abutting member is repeatedly abutted against the movable body, the abutting member is displaced. Is prevented. Further, since the positioning member easily positions the contact member with respect to the piezoelectric element, the assembling property of the piezoelectric actuator is improved, the variation in the assembly position of the contact member is suppressed, and the quality is stabilized.

In the present invention, it is desirable that the thickness dimension of the contact surface of the contact member to the moving body is larger than the thickness dimension of the vibration member.
According to this invention, since the thickness dimension of the contact surface of the contact member is formed larger than the thickness dimension of the vibration member, while ensuring an appropriate thickness of the vibration member that does not hinder the vibration of the piezoelectric element, In addition, the thickness of the contact surface can be increased. As a result, the contact area of the contact member with the moving body is increased, the drive of the moving body is stabilized, wear of the contact member is reduced, and the durability of the piezoelectric actuator is improved.
Here, the thickness dimension of the contact member and the vibration member means a dimension in a direction orthogonal to the surface of the vibration member fixed to the piezoelectric element.

In the present invention, it is desirable that the thickness dimension of the contact member is uniform.
According to this invention, since the thickness dimension of the contact member is uniform, the shape of the contact member is simplified, and therefore the manufacture of the contact member is simplified. Further, in order to process the shape of the abutting member, it is only necessary to simply cut out from a material having a uniform thickness, or to cut a bar-shaped member having the same shape to a desired thickness. .

In the present invention, it is preferable that the contact member is made of ceramics, cemented carbide, steel material subjected to nitriding treatment, or steel material subjected to carburizing treatment.
According to this invention, since the material of the contact member is set appropriately, the wear of the contact surface to the moving body is satisfactorily prevented, and the durability of the piezoelectric actuator is improved. Here, since these materials have a relatively high Young's modulus, they are materials that cannot normally transmit the vibration of the piezoelectric element when used as a vibration member. Therefore, these materials can be selected by providing the contact member and the vibration member separately.

In the present invention, it is desirable that the contact member and the vibration member are fixed to each other by any one of adhesion, brazing, and caulking, or a combination thereof.
According to this invention, since the contact member and the vibration member are fixed to each other by an appropriate method, the contact member and the vibration member are securely joined, and the vibration of the vibration member is transmitted to the contact member satisfactorily. The In addition, for example, even when the driving force necessary for moving the moving body is large and the frictional force of the abutting member against the moving body is large, the abutting member is securely fixed to the vibration member. The movable body is brought into contact with the movable body without being damaged, and the vibration of the vibrating member is transmitted to the movable body satisfactorily to move the movable body.

In the present invention, the piezoelectric element and the vibration member are formed in a plate shape, the piezoelectric element is fixed to both surfaces of the vibration member, and the thickness dimension of the vibration member is the thickness of the portion of the contact member disposed between the piezoelectric elements. Desirably larger than the dimensions.
According to this invention, since the piezoelectric element and the vibration member are formed in a plate shape, the piezoelectric element and the vibration member vibrate in the plane direction. Therefore, when the contact member vibrates in the plane direction of the piezoelectric element, the moving body can be moved in the plane direction.

In addition, since the piezoelectric elements are fixed on both surfaces of the vibration member, if the piezoelectric elements on both surfaces are simultaneously vibrated, the vibration behavior of the piezoelectric elements becomes symmetrical across the vibration member, and the entire piezoelectric actuator is in the plane direction of the piezoelectric elements. Draw a vibration trajectory in a parallel plane. Therefore, the contact member vibrates in a plane parallel to the plane direction of the piezoelectric element, and the driving force transmission efficiency in the direction becomes good.
Furthermore, since the piezoelectric elements are disposed on both surfaces of the plate-like vibration member, the contact member is also disposed so as to be sandwiched between the piezoelectric elements on both surfaces. At this time, since the thickness dimension of the vibration member is larger than the thickness dimension of the contact member disposed between the piezoelectric elements, the piezoelectric element is satisfactorily connected to the vibration member without being obstructed by the contact member. Therefore, the vibration of the piezoelectric element is satisfactorily transmitted to the vibration member, the contact member vibrates well, and the driving efficiency of the moving body is improved.

In the present invention, it is desirable that traction oil be interposed between the contact member and the moving body.
According to this invention, since the traction oil is interposed between the abutting member and the moving body, the abutting member and the moving body are in contact with each other in this oil, and the mutual contact area is reduced. Therefore, the frictional force of the contact member is reduced and wear is further prevented, so that the durability of the piezoelectric actuator is further improved.
Here, the traction oil is a lubricant having an increased traction coefficient. The pressure-viscosity coefficient is high, and it has the property of hardening when pressure is applied and softening when pressure is released.

The apparatus of the present invention includes the above-described piezoelectric actuator.
According to this invention, since the apparatus includes the above-described piezoelectric actuator, the same effects as described above can be obtained, and the durability of the piezoelectric actuator and the apparatus can be improved. Such a device can be applied to various devices such as a liquid discharge device, a drive device, a toy, a watch, and the like, and is particularly suitable for application as a device that requires downsizing.

  Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In the second embodiment and later described below, the same reference numerals are given to the same components and components having the same functions as those in the first embodiment described below, and description thereof will be simplified or omitted.

[First embodiment]
FIG. 1 is a plan view of a liquid ejection device (device) 11 according to the first embodiment, and FIG. 2 is a side sectional view of the liquid ejection device 11.
In these FIG. 1 and FIG. 2, the liquid ejection device 11 includes a tube 31 through which liquid flows, a ball 32 that presses the tube 31, and a rotor 4 that moves the ball 32 on the tube 31 (movement) Body), a piezoelectric actuator 5 that rotationally drives the rotor 4, and a retainer 33 that defines a rolling trajectory of the ball 32. These components, that is, a part of the tube 31, the ball 32, the rotor 4, the piezoelectric actuator 5, and the retainer 33 are housed in the case member 2.

  The case member 2 includes a base portion 21 on which the tube 31 is disposed and a lid member 22 (FIG. 2) that covers an opening portion of the base portion 21. Holes 213 and 221 are formed in the base 21 and the lid member 22 at a plurality of locations (four locations in the present embodiment) near the outer periphery, respectively. A pin 23 is passed through these holes 213 and 221, whereby the lid member 22 is attached to the base 21. Here, the four pins 23 are fitted into the holes 221 of the lid member 22, and these pins 23 are fitted into the two diagonal holes 213 of the holes 213 of the base portion 21. Accordingly, the base portion 21 and the lid member 22 are defined by the two pins 23 at positions on the diagonal line in the in-plane direction of the mutual contact surfaces, and displacement of these relative positions is prevented. Further, a notch 216 is formed at the end of the base 21 in the vicinity of the two holes 213 fitted to the pin 23 on the surface facing the lid member 22. The notch 216 forms a gap between the base 21 and the lid member 22 when they contact each other.

In the base 21, a tube guide groove 211 in which the tube 31 is disposed is formed at the approximate center of the surface facing the lid member 22. The tube guide groove 211 includes an arc-shaped portion and two straight portions formed in parallel to each other from both ends of the arc-shaped portion toward the end portion of the base portion 21. A hole 211B is formed in the cross-sectional direction of the base portion 21 in the middle of the straight line portion, and a groove 211A is formed from the side surface of the hole 211B along the back surface of the base portion 21 to the end portion of the base portion 21.
The tube 31 is disposed along the groove 211A from the outside of the case member 2 and enters the inside of the case member 2 through the hole 211B. And the tube 31 is arrange | positioned along the tube guide groove | channel 211, and is again arrange | positioned outside through the other hole 211B and the groove | channel 211A. A stopper 212 is attached to each of the two grooves 211A so that the tube 31 is set along the tube guide groove 211 without slack. These stoppers 212 can adjust the tension so that the tube 31 is disposed in the tube guide groove 211 with an appropriate tension. The material of the tube 31 can employ silicone rubber, polyurethane, or other elastic materials.
A plurality of balls 32 (two in the present embodiment) are provided, and come into contact with the tube guide groove 211 of the tube 31 at equal intervals along the arcuate portion of the tube guide groove 211, that is, 180 ° in the present embodiment. It is arranged on the opposite side to the side.

The rotor 4 is made of polycarbonate or any other material and is formed in an annular shape, and a ring 4A made of a high hardness material such as alumina is press-fitted to the outer periphery. A concave portion 43 having an arcuate cross section is formed on the outer periphery of the ring 4A. An annular bush 41 made of a material having a low coefficient of friction such as Delrin or polytetrafluoroethylene (PTFE) is press-fitted on the inner peripheral side of the rotor 4. The bush 41 is rotatably supported on the rotor shaft 25 by a rotor shaft 25 fixed to the lid member 22 and a rotor pressing member 251 screwed to the rotor shaft 25.
Further, a claw portion 252 having a substantially triangular cross section is formed on the inner periphery of the rotor shaft 25. The claw portion 252 is engaged with a hole 215 formed in the base portion 21 and a quadrant pin 24 penetrating the rotor pressing member 251 at a claw portion at the tip. The base 21 and the lid member 22 are positioned in close proximity by the quadrant pin 24.
A pressing rubber 42 is provided on the surface of the rotor 4 that faces the ball 32, and is in contact with the ball 32. Here, the distance between the rotor 4 and the tube guide groove 211 is set smaller than the sum of the diameter of the ball 32 and the diameter of the tube 31. As a result, the ball 32 is pressed against the tube 31 side by the pressing rubber 42 of the rotor 4, and the tube 31 is crushed along the shape of the tube guide groove 211.

FIG. 3 shows an exploded perspective view of the piezoelectric actuator 5. In FIG. 3, the piezoelectric actuator 5 includes a reinforcing plate (vibrating member) 51 formed in a substantially rectangular flat plate shape, a substantially rectangular flat plate-like piezoelectric element 52 fixed on both front and back surfaces of the reinforcing plate 51, and a piezoelectric element. An abutting member 54 that protrudes from 52 and abuts against the rotor 4 and a support plate 53 that supports the piezoelectric element 52 so as to vibrate are provided. The piezoelectric actuator 5 includes an application device (not shown) that applies a voltage having a predetermined frequency to the piezoelectric element 52.
The reinforcing plate 51 is made of SUS301EH having a Vickers hardness of 500 HV and a Young's modulus of 210 GPa, and is formed in a plate shape having a thickness of about 0.1 mm (tolerance ± 0.01 mm). A substantially rectangular convex portion 511 protruding in the longitudinal direction of the reinforcing plate 51 is integrally formed at the end in the width direction on the short side of the reinforcing plate 51. In the reinforcing plate 51, a substantially semicircular concave portion 512 is formed on the opposite side diagonally to the convex portion 511. In addition, arm portions 51 </ b> A and 51 </ b> B that protrude from the reinforcing plate 51 are integrally formed at substantially the center in the length direction of the reinforcing plate 51.

  The piezoelectric element 52 is provided in a substantially rectangular portion on both surfaces of the reinforcing plate 51. The material of the piezoelectric element 52 is not particularly limited, and various materials such as lead zirconate titanate (PZT (registered trademark)), crystal, and lithium niobate can be used. In addition, on both surfaces of the piezoelectric element 52, nickel, gold, and the like are formed by a method such as plating, sputtering, and vapor deposition to form electrodes. Of these two electrodes, the electrode on the surface facing the reinforcing plate 51 is formed over the entire surface of the piezoelectric element 52 and is electrically connected to the reinforcing plate 51 by being bonded to the reinforcing plate 51. Further, the electrodes on the surface of the piezoelectric element 52 are electrically insulated at the corresponding portions by providing substantially L-shaped grooves on both ends of the diagonal line, and a substantially Z-shaped electrode (drive electrode) 520 is formed at the center. Yes. The drive electrode 520 and the reinforcing plate 51 are connected to the above-described applying device by a lead wire (not shown).

  Here, dimensions, thicknesses, electrode divisions, and the like of the piezoelectric element 52 include so-called longitudinal vibration in which the piezoelectric element 52 expands and contracts in the longitudinal direction when a voltage is repeatedly applied to the piezoelectric element 52, and the piezoelectric element 52. Are appropriately set so that a so-called bending vibration that bends in a direction orthogonal to the longitudinal vibration in the plane appears at the same time with respect to the plane center. At this time, the resonance frequency of the longitudinal vibration and the resonance frequency of the bending vibration are preferably set to be close to each other, and the ratio of the resonance frequency of the bending vibration to the resonance frequency of the longitudinal vibration is larger than 1.00. 1.03 or less is desirable. Further, the length ratio of the long side to the short side of the piezoelectric element 52 is preferably 0.274 or more when the long side is 1.

When the short side of the piezoelectric element 52 is smaller than 0.274, the resonance frequency of the longitudinal vibration becomes higher than the resonance frequency of the bending vibration, and a good elliptical orbit cannot be drawn. At this time, the ratio of the resonance frequency of the bending vibration to the resonance frequency of the longitudinal vibration is 1.00 or less. In addition, when the ratio of the resonance frequency of the bending vibration to the resonance frequency of the longitudinal vibration is larger than 1.03, the resonance point of the longitudinal vibration and the resonance point of the bending vibration are separated from each other, and the amplitudes of both vibrations are simultaneously improved. I can't.
The frequency of the voltage applied to the piezoelectric element 52 is such that both vibrations appear favorably between the resonance frequency of the longitudinal vibration and the resonance frequency of the bending vibration, more preferably between the anti-resonance frequency and the resonance frequency of the bending vibration. Select the frequency as appropriate. In addition, the waveform of the voltage applied to the piezoelectric actuator 5 is not specifically limited, For example, a sine wave, a rectangular wave, a trapezoidal wave, etc. are employable.

The contact member 54 is made of alumina having a Vickers hardness of 1600 HV and a Young's modulus of 350 to 380 GPa, and includes a contact portion 541 that contacts the rotor, and a fixing portion 542 that is fixed to the reinforcing plate 51 and the piezoelectric element 52. ing.
The contact portion 541 is formed in a semi-cylindrical shape with a radius of 0.5 mm, and is formed with a thickness of 0.3 mm, which is thicker than the thickness dimension of the reinforcing plate 51. The fixing portion 542 is formed in a semi-cylindrical shape having a radius of 0.5 mm so as to be engaged with the concave portion 512 of the reinforcing plate 51, and is formed with a thickness of 0.09 mm (tolerance +0, −0.01 mm). Yes. That is, the fixing portion 542 is set to be equal to or less than the thickness of the reinforcing plate 51 in consideration of dimensional tolerances.

FIG. 4 shows a partial side sectional view of the piezoelectric actuator 5. As shown in FIG. 4, the fixing portion 542 is interposed between the two piezoelectric elements 52, and is positioned with respect to the planar direction of the piezoelectric elements 52 by being guided by the concave portions 512 of the reinforcing plate 51. ing. That is, in the present embodiment, the recess 512 serves as a positioning unit that positions the contact member 54 with respect to the piezoelectric element 52. The piezoelectric element 52, the reinforcing plate 51, and the contact member 54 are bonded and fixed to each other with a room temperature curing type epoxy resin or the like.
The contact portion 541 is curved in a substantially arc shape protruding toward the rotor 4 with respect to the thickness direction (the direction parallel to the thickness direction of the reinforcing plate 51 and the piezoelectric element 52), and this curved surface is the ring 4A. The contact surface 543 is in contact with the recess 43. As described above, when the contact surface 543 is formed in a substantially arc-shaped cross section and the concave portion 43 is formed in a substantially arc-shaped cross section as described above, when either one is displaced in the rotation axis direction of the rotor 4. However, the engagement between the two is prevented from being disengaged.

The support plate 53 screws the arm portions 51A and 51B of the reinforcing plate 51 with three screws 531, 532 and 533. The support plate 53 is rotatably supported on the lid member 22 by a fixture 534, whereby the piezoelectric actuator 5 is fixed to the lid member 22. Further, a substantially U-shaped elastic portion 535 is interposed between the arm portion 51 </ b> A and the support plate 53. One end of the elastic portion 535 is fixed to the screws 532 and 533 and the fixture 534, and the other end is locked to the lid member 22 by a locking member 536. The elastic portion 535 urges the piezoelectric actuator 5 around the fixture 534, whereby the contact member 54 of the piezoelectric actuator 5 is pressed against the concave portion 43 of the ring 4A with an appropriate urging force.
In FIG. 1, the piezoelectric actuator 5 is supported by the lid member 22. However, for simplicity of explanation, the illustration of the lid member 22 is omitted, and only the piezoelectric actuator 5 and the support plate 53 are illustrated. .

  The retainer 33 is provided between the rotor 4 and the base 21 and is formed in a ring shape. The inner peripheral side of the retainer 33 is brought into contact with a protrusion 26 provided in an annular shape on the base portion 21, thereby preventing displacement in the plane direction. A plurality of (six in the present embodiment) ball holding portions 331 are formed at equal intervals along the periphery of the retainer 33. Of these ball holding portions 331, the balls 32 are arranged on two opposite sides. Further, a convex portion 332 is formed on the outer periphery of the retainer 33, and a rotation detecting means 333 that detects passage of the convex portion 332 is provided on the side surface of the retainer 33.

Such a liquid ejection device 11 operates as follows.
First, when a voltage is applied between the drive electrode 520 and the reinforcing plate 51 by an application device (not shown), a portion of the piezoelectric element 52 where the drive electrode 520 is formed expands and contracts in the longitudinal direction, so-called longitudinal vibration is excited. At this time, since the drive electrode 520 is formed in a substantially Z shape, the piezoelectric element 52 expands and contracts asymmetrically with respect to the center line along the longitudinal direction. As a result, the piezoelectric element 52 excites bending vibration that bends in a direction perpendicular to the longitudinal vibration in the plane, symmetrically with respect to the plane center of the piezoelectric element 52. By these longitudinal vibration and bending vibration, the contact member 54 of the piezoelectric actuator 5 draws a substantially elliptical orbit. When the contact surface 543 of the contact member 54 presses the concave portion 43 of the ring 4A in a part of this elliptical orbit, the rotor 4 rotates in the direction of arrow R in FIG. By repeating this operation at an appropriate frequency, the rotor 4 is rotated at a desired rotational speed.

When the rotor 4 rotates, the ball 32 pressed by the pressing rubber 42 rolls while crushing the tube 31 by friction. As a result, the liquid sandwiched between the two balls 32 in the tube 31 moves, and the liquid is discharged from the tube 31. By repeating this at a predetermined number of revolutions, the liquid in the tube 31 is continuously discharged.
As the ball 32 rolls, the ball holding portion 331 is pushed, whereby the retainer 33 rotates. At this time, the rotation detecting means 333 detects the passage of the convex portion 332 of the retainer 33 and detects the rotation speed (number of rotations) of the ball 32.
When the liquid discharge device 11 is not used, the tube 31 is released from the pressure closure. In this case, the lid member 22 is separated from the base portion 21 together with the rotor 4 and the piezoelectric actuator 5 when the tips of the quadrant pins 24 are retracted to disengage from the claw portions 252. Thereby, the pressing force of the ball 32 against the tube 31 is released, and the pressure closing of the tube 31 is released. At this time, it is possible to easily separate the cover member 22 and the base portion 21 by applying a nail or a driver to the notch 216 to separate the cover member 22 and the base portion 21.

According to such a liquid ejecting apparatus 11, the following effects can be obtained.
(1) Since the reinforcing plate 51 and the contact member 54 are provided separately, materials suitable for each function can be selected separately. That is, the reinforcing plate 51 is made of SUS301EH, whereas the contact member 54 is made of alumina having a hardness higher than that of the reinforcing plate 51. Thereby, the reinforcing plate 51 does not hinder the vibration of the piezoelectric element 52 while compensating for the brittleness of the piezoelectric element 52, and the contact member 54 can ensure good wear resistance with respect to the concave portion 43 of the rotor 4. Therefore, the reinforcing plate 51 can satisfactorily transmit the vibration of the piezoelectric element 52 to the contact member 54, and the impact resistance of the piezoelectric actuator 5 can be improved. Moreover, since the wear of the contact member 54 can be prevented, the durability of the piezoelectric actuator 5 can be improved.

 (2) Since the piezoelectric element 52 and the reinforcing plate 51 are formed in a plate shape, and the piezoelectric element 52 is provided on both surfaces of the reinforcing plate 51, the piezoelectric element 52 vibrates similarly on both sides of the reinforcing plate 51. Therefore, the entire piezoelectric actuator 5 vibrates in a direction parallel to the plane of the reinforcing plate 51. At this time, since the piezoelectric actuator 5 is arranged in a direction parallel to the rotation plane of the rotor 4, the contact member 54 can press the rotor 4 in a direction parallel to the rotation plane, and the rotor 4 is driven with good driving efficiency. can do.

(3) Since the fixing portion 542 of the contact member 54 is disposed and bonded between the two piezoelectric elements 52, the fixing portion 542 can be fixed to the plane of the piezoelectric element 52. Therefore, unlike the case where the protrusion is bonded to the side surface of the conventional piezoelectric element, the fixing area of the fixing portion 542 to the piezoelectric element 52 can be increased. Therefore, the holding force of the contact member 54 can be improved, and the contact member 54 can be stably fixed.
(4) Since the thickness dimension of the fixing portion 542 is set to be smaller than the thickness dimension of the reinforcing plate 51 in consideration of tolerances, the piezoelectric elements 52 are pasted on both surfaces of the reinforcing plate 51. In addition, the piezoelectric element 52 can be satisfactorily adhered to the entire pasting surface of the reinforcing plate 51 without floating from the reinforcing plate 51 by the fixing portion 542. Therefore, vibration can be transmitted favorably from the piezoelectric element 52 to the reinforcing plate 51, and the rotor 4 can be driven efficiently.

(5) Since the reinforcing plate 51 includes positioning means for the contact member 54 by the recess 512, the contact member 54 can be reliably positioned with respect to the piezoelectric element 52 and the reinforcing plate 51. At this time, since the concave portion 512 is formed in a substantially semicircular concave shape, the contact member 54 can be positioned also in the width direction of the piezoelectric element 52 in the contact member 54. Further, the holding force in the direction can be increased by restricting the position of the contact member 54 in the width direction.
Furthermore, since the abutting member 54 can be easily positioned by simply placing it in contact with the recess 512, the assembling property of the piezoelectric actuator 5 can be improved.

(6) Since the thickness dimension of the contact portion 541 is formed larger than the thickness dimension of the reinforcing plate 51, the contact area of the contact surface 543 with respect to the rotor 4 can be increased. Therefore, the frictional force on the contact surface 543 is reduced, and the durability of the piezoelectric actuator 5 can be further improved.
(7) Since the contact member 54 is made of alumina, appropriate hardness can be secured, wear resistance of the contact surface 543 can be improved, and durability of the piezoelectric actuator 5 can be improved. .
In addition, since the contact member 54 and the reinforcing plate 51 are fixed to each other by bonding, an appropriate fixing force of the contact member 54 to the reinforcing plate 51 can be ensured.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
FIG. 5 shows a plan view of the drive device 12 according to the second embodiment. In FIG. 5, a driving device (device) 12 includes a piezoelectric actuator 5 including a piezoelectric element 52, a rotating body (moving body) 100 that rotates by vibration of the piezoelectric actuator 5, and a contact force of the piezoelectric actuator 5 on the rotating body 100. And a contact force adjusting means 6 for adjusting. The piezoelectric actuator 5 and the abutting force adjusting means 6 are fixed to a disk-shaped fixed body 7, and a plurality of balls 71 in which an annular rotating body 100 is arranged on the outer periphery of the fixed body 7 at equal intervals in the circumferential direction. It is provided so that it can rotate through.

FIG. 6 is a perspective view of the piezoelectric actuator 5. As shown in FIG. 6, the piezoelectric actuator 5 includes a reinforcing plate (vibrating member) 51 formed in a substantially rectangular flat plate shape, and flat plate piezoelectric elements 52 provided on both the front and back surfaces of the reinforcing plate 51. I have.
The reinforcing plate 51 is made of SUS301EH similar to the first embodiment, but unlike the first embodiment, the convex portion 511 is not formed. A recess 512 is formed at the approximate center in the width direction of the short side of the reinforcing plate 51.
The abutting member 54 is made of cemented carbide H1 having a Vickers hardness of 1500 HV and a Young's modulus of 700 GPa (a cemented carbide alloy having a WC particle diameter of 1 μm and a Co content of 10%), and has a thickness of 0.09 mm (tolerance +0, −0. 01 mm), and is formed in a disk shape having a diameter of 1.0 mm. For example, the contact member 54 cuts a rod having a diameter of 1.0 mm with an appropriate thickness (about 0.09 mm) and polishes it in the thickness direction, thereby removing the flash generated by the cutting and also against the rotating body 100. The contact surface 543 is formed to have a circular arc shape toward the rotating body 100 in the thickness direction.

FIG. 7 shows a partial side sectional view of the piezoelectric actuator 5. As shown in FIG. 7, a part of the abutting member 54 is interposed between the two piezoelectric elements 52 and held by adhesion as in the first embodiment. At this time, the substantially semicircular portion of the abutting member 54 is disposed in the recess 512, thereby forming a fixed portion 542 that is positioned and fixed with respect to the piezoelectric element 52. A substantially semicircular portion on the opposite side to the fixed portion 542 is a contact portion 541 that protrudes from the piezoelectric element 52.
The contact portion 541 is in contact with the inner periphery of the rotating body 100 at the contact surface 543, and the longitudinal direction of the piezoelectric actuator 5 is substantially perpendicular to the tangential direction of the inner periphery (that is, along the radial direction of the rotating body 100). Is arranged). In addition, arm portions 51 </ b> A are integrally formed on both sides in the width direction at substantially the center in the longitudinal direction of the reinforcing plate 51. The arm portions 51A protrude from the reinforcing plate 51 at a substantially right angle, and holes 513 are formed in these end portions.

  The electrodes on the surface of the piezoelectric element 52 are electrically insulated from each other by a groove, and a plurality of electrodes are formed symmetrically about a center line along the longitudinal direction. That is, two grooves 55A are formed so as to divide the width direction of the piezoelectric element 52 into approximately three equal parts, and among the three electrodes divided by these grooves 55A, the longitudinal direction is further approximately divided into two equal parts. Thus, a groove 55B is formed. By these grooves 55A and 55B, an electrode 52A is formed in the center on the surface of the piezoelectric element 52, and electrodes 52B and 52C having pairs on opposite ends on the diagonal line are formed on both sides of the electrode 52A. The electrodes 52A, 52B, 52C and the reinforcing plate 51 are connected to the application device on the opposite side of the fixed body 7 through holes (not shown) formed in the fixed body 7 by lead wires or the like. These electrodes 52A, 52B, and 52C are similarly provided on both the front and back piezoelectric elements 52 provided with the reinforcing plate 51 interposed therebetween. For example, an electrode 52A is formed on the back side of the electrode 52A. .

The contact force adjusting means 6 includes a support member 56 that supports the piezoelectric actuator 5, a spring 57 having one end fixed to the support member 56, and an eccentric pin 58 that adjusts the biasing force of the spring 57.
The support member 56 is made of hard plastic or other material, and as shown in FIG. 6, the pair of fixing portions 561 to which the piezoelectric actuator 5 is fixed and the fixing portions 561 are integrally formed. And a slide portion 562 that is slidably supported by the fixed body 7. A screw portion 563 is formed in the fixing portion 561 at a position corresponding to the hole 513 of the arm portion. The piezoelectric actuator 5 is fixed to the fixing portion 561 by screwing the screw 564 through the hole 513 into the screw portion 563.
FIG. 8 shows a cross-sectional view taken along the line VIII-VIII in FIG. As shown in FIG. 8, the slide portion 562 is disposed in a slide groove 72 formed in a concave shape in the fixed body 7, and the support member 56 is located with respect to the rotating body 100 at the substantially center in the width direction. A plurality of long holes 565 (two in the present embodiment) are formed so as to be parallel to the approaching and separating directions. A screw 721 passes through these elongated holes 565 and is screwed into the fixed body 7. Thereby, the support member 56 can slide in the longitudinal direction of the long hole 565, that is, in the proximity and separation direction with respect to the rotating body 100.

  9 shows a cross-sectional view taken along the line IX-IX in FIG. As shown also in FIG. 9, one end of a spring 57 is attached to the side surface of the fixed portion 561 on both sides of the support member 56 on the side of the end portion far from the contact member 54 of the piezoelectric actuator 5. The spring 57 is arranged so that its expansion / contraction direction is parallel to the approaching / separating direction of the piezoelectric actuator 5, and a cylindrical contact pin 571 is inserted at the other end. The contact pin 571 is supported so as to be slidable parallel to the plane direction of the fixed body 7, and the tip thereof is in contact with the side surface of the eccentric pin 58. The eccentric pin 58 is rotatably supported by being screwed to the fixed body 7. Thus, one end of the spring 57 is brought into contact with the support member 56, and the contact pin 571 at the other end of the spring 57 is brought into contact with the side surface of the eccentric pin 58, whereby the spring 57 causes the support member 56 to rotate. It is energized in the direction approaching 100. Therefore, the contact member 54 of the piezoelectric actuator 5 is pressed against the rotating body 100 with an appropriate contact force.

The rotating body 100 is made of martensitic stainless steel SUS440C, and a concave portion (contacted portion) 101 having an arc-shaped cross section is formed in the inner peripheral portion. The contact member 54 of the piezoelectric actuator 5 is in contact with the recess 101. Traction oil is interposed between the recess 101 and the contact surface 543 of the contact member 54. Here, the traction oil is a lubricant having an increased traction coefficient. The pressure-viscosity coefficient is high, and it has the property of hardening when pressure is applied and softening when pressure is released. As the traction oil, SANTOTRAC # 100 (manufactured by Nippon Mining Oil Co., Ltd.), ITF32 (manufactured by Idemitsu Kosan Co., Ltd.) or the like can be employed.
A plurality of balls 71 arranged at equal intervals along the inner periphery of the rotating body 100 includes a groove 102 formed on the inner periphery of the rotating body 100, an inclined portion formed on the outer periphery of the fixed body 7, and the fixed body 7. Are held in the groove 102 by being sandwiched between the inclined portions of the annular pressing plate 711 fixed to the ring. Further, an annular ball holding portion 712 is interposed between the fixed body 7 and the pressing plate 711. The ball holding portion 712 has substantially the same number of semicircular cutout portions as the balls 71 on the outer periphery, and the balls 71 are arranged in the cutout portions, so that a predetermined interval is maintained on the outer periphery of the fixed body 7. .

Such a driving device 12 operates as follows.
An AC voltage is applied to the piezoelectric element 52 of the piezoelectric actuator 5 by an applying device to vibrate the piezoelectric actuator 5. At this time, by selectively applying a voltage only to the electrode 52A and the electrode 52C, the piezoelectric actuator 5 vibrates while drawing an elliptical orbit combined with longitudinal vibration and bending vibration as in the first embodiment. The contact member 54 is pressed against the concave portion 101 of the rotating body 100 at a part of the elliptical orbit and intermittently rotates the rotating body 100 in the circumferential direction by a frictional force with the rotating body 100. By repeating this at a predetermined frequency, the rotating body 100 rotates in one direction at a predetermined rotation speed.
When changing the rotation speed of the rotating body 100, the contact force adjusting means 6 is operated. That is, for example, when the rotational speed of the rotating body 100 is decreased, the eccentric pin 58 is operated to rotate the spring 57 in a longer direction. As a result, the urging force of the spring 57 to the support member 56 is relaxed, and the contact force of the contact member 54 of the piezoelectric actuator 5 to the rotating body 100 is weakened. Therefore, the range in which the contact member 54 contacts the rotating body 100 on the elliptical track and the rotating body 100 can be driven by the frictional force is narrowed, and the transmitted rotational torque is weakened. As a result, the rotational speed of the rotating body 100 is reduced. Becomes slower.

On the other hand, when the rotational speed of the rotating body 100 is increased, the eccentric pin 58 is rotated to adjust the spring 57 in the contracting direction. Then, the contact force of the contact member 54 with respect to the rotating body 100 is increased, and the transmitted rotational torque is increased, so that the rotation speed of the rotating body 100 is increased.
Further, when rotating the rotating body 100 in the opposite direction, the electrode of the voltage applied to the piezoelectric element 52 is switched symmetrically about the center line along the longitudinal direction. That is, when a voltage having a predetermined frequency is applied to the electrodes 52A and 52B of the piezoelectric element 52, the contact member 54 vibrates in an elliptical orbit in the opposite direction. Thereby, the rotating body 100 is driven in the opposite direction.

  Therefore, according to such a second embodiment, the following effects can be obtained in addition to the same effects as the effects (1) to (5) of the first embodiment.

(8) Since the contact member 54 is formed in a simple disk shape having a uniform thickness, it can be manufactured inexpensively and easily, for example, by cutting a round bar into a predetermined thickness. Therefore, the manufacturing cost of the drive device 12 can be reduced.
(9) Since the traction oil is interposed between the contact member 54 and the recess 101, the contact area where both contact directly can be reduced. Therefore, the wear of the contact member 54 and the recess 101 can be prevented more favorably, and the durability of the piezoelectric actuator 5 can be further improved.
(10) Since the contact member 54 is made of a cemented carbide, it is possible to ensure an appropriate hardness, improve the wear resistance of the contact member 54, and thus improve the durability of the piezoelectric actuator 5. be able to.
Further, since the contact member 54 and the reinforcing plate 51 are fixed to each other by bonding, an appropriate fixing force of the contact member 54 to the reinforcing plate 51 can be ensured as in the first embodiment.

The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the material of the vibration member is not limited to SUS301EH, and may be made of other stainless steel, aluminum, amorphous, rubber metal, or the like that easily vibrates with a low Young's modulus and does not hinder the vibration of the piezoelectric element 52. . The material of the contact member is not limited to alumina or cemented carbide, but may be a ceramic such as silicon nitride, zirconia, or silicon carbide, or a steel material subjected to nitriding, carburizing, or carbonitriding. In short, the material of the contact member may be selected so that at least the contact surface to the moving body has higher hardness than the vibration member.

The shape of the contact member and the fixing structure to the piezoelectric actuator are not limited to the above-described embodiments, and may be structures as shown in FIGS. 10 to 16, for example.
10 and 11, the recess 512 of the reinforcing plate 51 is formed in a substantially V shape. The contact member 54 is set so that the thickness dimension thereof is equal to or less than the thickness dimension of the reinforcing plate 51 in consideration of manufacturing tolerances, and the base end side is substantially V-shaped corresponding to the recess 512. Is formed. The front end side of the contact member 54 is formed in a substantially rectangular shape, and is seen in a plan view (a state viewed from a direction orthogonal to the plane direction of the piezoelectric element 52, that is, a state shown in FIG. 10) and a side view (a view from the plane direction of the piezoelectric element 52). In this state, that is, the state of FIG. 11, the corners are formed in an arc shape. According to such a structure, the contact member 54 can be positioned in the planar direction by the concave portion 512, and deviation in the direction can be prevented. Further, since the substantially V-shaped portion of the contact member 54 is sandwiched between the piezoelectric elements 52, the contact member 54 can be reliably held.

  12 and 13, the contact member 54 is formed in a substantially spherical shape having a diameter larger than the thickness dimension of the reinforcing plate 51. The recess 512 of the reinforcing plate 51 is formed in a substantially semicircular shape in a plan view (state shown in FIG. 12) so as to correspond to the shape of the contact member, and also in a side view (state shown in FIG. 13). It is formed in a substantially arc concave shape along the surface shape of 54. Concave surfaces 521 are formed on the surfaces of the piezoelectric elements 52 facing each other at substantially the center of the short side, and the distance between the facing concave portions 521 is set to be approximately equal to the thickness dimension of the contact member 54. The contact member 54 is held by the recess 512 of the reinforcing plate 51 and the recess 521 of the piezoelectric element 52. Therefore, the recesses 512 and 521 serve as positioning means for positioning the contact member 54 with respect to the piezoelectric element 52. Yes. According to such a structure, the contact member 54 can be reliably held by the recesses 512 and 521.

In FIG. 14 and FIG. 15, the concave portion 512 of the reinforcing plate 51 is formed in a substantially rectangular shape, and a protruding portion 512 </ b> A protruding in a direction approaching each other is formed at the end portion. On the other hand, the contact member 54 includes a contact portion 541 and a fixed portion 542 as in the first embodiment, and the contact portion 541 is formed thicker than the fixed portion 542. The contact part 541 is formed in a substantially rectangular parallelepiped. Further, on the base end side of the fixed portion 542, that is, the side adjacent to the contact portion 541, an engaging portion 541A to which the protruding portion 512A is engaged is formed on both sides in the plane direction. The contact members 54 are fixed to each other by the fixing portion 542 being disposed in the concave portion 512 and the protruding portion 512A being engaged with the engaging portion 541A. According to such a structure, since the contact member 54 is held by the reinforcing plate 51 by engaging the protrusion 512A with the engagement portion 541A, the contact member 54 extends in the longitudinal direction of the piezoelectric element 52. Failures such as falling off can be reliably prevented.
In addition, the distance of the protrusion part 512A which opposes may be formed smaller than the width dimension of the engaging part 541A. In this case, the protruding portion 512A is engaged so as to bite into the engaging portion 541A, and the contact member 54 and the reinforcing plate 51 are fixed by caulking, so that the fixing force of both can be improved.

In FIG. 16, the contact member 54 is formed in a substantially rectangular plate shape. A substantially trapezoidal recess 512 is formed in the reinforcing plate 51. The dimension in the width direction of the recess 512 at the end of the reinforcing plate 51 is set to be larger than the dimension in the width direction of the contact member 54 (in the shape indicated by the two-dot chain line in FIG. 16). After the contact member 54 is disposed in the recess 512, the contact members 54 are fixed by the recess 512 of the reinforcement plate 51 by caulking the reinforcing plates 51 on both sides of the contact member 54 in the direction approaching each other. According to such a structure, since the reinforcing plate 51 holds the contact member 54 by caulking, the contact member 54 can be reliably held.
As described above, the contact member 54 and the reinforcing plate 51 may be fixed by adhesion, brazing, or the like in the above-described embodiment.

The piezoelectric elements are not limited to those provided on both sides of the vibration member, and may be provided only on one side of the reinforcing plate 51 as shown in FIGS. 17 and 18, for example. 17 and 18, the contact member 54 includes a contact portion 541 and a fixing portion 542, and the contact portion 541 is formed to protrude only on the side where the piezoelectric element 52 is disposed in the thickness direction. . Such an abutting member 54 is fixed to the piezoelectric element 52 by bonding or the like only on one side while being positioned by the recess 512 of the reinforcing plate 51. Even in such a structure, since the fixing portion 542 of the contact member 54 is fixed to the plane of the piezoelectric element 52, the fixed area can be increased, and the contact member 54 can be reliably held.
In FIG. 10 to FIG. 18 described above, the contact member is not limited to the one provided in the approximate center of the short side of the piezoelectric element and the vibration member. For example, as in the first embodiment, the contact member is provided at the end in the short side width direction. It may be provided. Alternatively, the contact member may be provided on the long sides of the piezoelectric element and the vibration member. Further, the shapes of the piezoelectric element and the vibration member are not limited to a substantially rectangular shape or a plate shape, and can be arbitrarily set depending on applications and use conditions.

The abutting member is not limited to the one fixed to the plate-like plane of the piezoelectric element, and may be one fixed to the side surface of the piezoelectric element and / or the vibration member, for example, as shown in FIGS.
In FIG. 19 and FIG. 20, the contact member 54 is formed in a substantially L shape having a substantially semicircular contact portion 541 and a substantially rectangular fixing portion 542, and is a plate having the same thickness as the reinforcing plate 51. It is comprised by the shape member. In the contact member 54, the surface opposite to the contact surface 543 of the contact portion 541 is fixed to the short side surface of the reinforcing plate 51, and the fixed portion 542 side surface is fixed to the long side surface of the diaphragm 51. Accordingly, the contact portion 541 is disposed so as to protrude in the longitudinal direction at the end portion in the width direction of the piezoelectric element 52. According to such a fixing structure of the abutting member 54, the fixing portion 542 is fixed with a predetermined area on the side surface of the reinforcing plate 51, so that a necessary fixing force can be ensured. In addition, since the contact member 54 is formed in a substantially L shape and is fixed to the side surface of the reinforcing plate 51, there is no need to form a recess or the like for positioning the contact member 54 in the reinforcing plate 51. The shape can be simplified.

  In FIG. 21 and FIG. 22, the contact member 54 has a substantially C-shape including a contact portion 541 formed over the entire width of the piezoelectric element 52 and fixing portions 542 formed on both sides of the contact portion 541 in the width direction. Is formed. The contact member 54 is formed with a thickness dimension substantially equal to the combined thickness dimension of the reinforcing plate 51 and the two piezoelectric elements 52, and the surface of the contact portion 541 opposite to the contact surface 543 is the piezoelectric element 52. Further, the side surface of the fixing portion 542 is fixed to the long side surface of the piezoelectric element 52 and the reinforcing plate 51. Even in such a structure, since the fixing portion 542 is fixed to the long side surfaces of the piezoelectric element 52 and the reinforcing plate 51, the piezoelectric element 52 and the reinforcing plate can be adjusted by adjusting the dimension of the fixing portion 542 with respect to the direction. The fixing area to 51 can be adjusted, and a required fixing force can be secured.

Alternatively, the contact member may be fixed to the outer surface of the piezoelectric element 52 as shown in FIGS.
In FIG. 23 and FIG. 24, the contact member 54 is disposed substantially in the center in the width direction of the piezoelectric element 52, and the contact portion 541 having a thickness dimension obtained by combining the thickness dimensions of the reinforcing plate 51 and the two piezoelectric elements 52; The contact portion 541 is formed in a substantially C shape including fixed portions 542 formed at both ends in the thickness direction. The surface of the contact portion 541 opposite to the contact surface 543 is fixed to the short side surface of the piezoelectric element 52 and the reinforcing plate 51, and the fixing portion 542 is provided with the reinforcing plate 51 out of the plane of the piezoelectric element 52. It is fixed on the surface opposite to the side. With such a structure, the fixing force necessary for the contact member 54 can be secured by adjusting the shape and size of the fixing portion 542.
In short, if a part of the contact member is fixed to a surface substantially parallel to the protruding direction from the piezoelectric element and / or the vibration member, the fixed area can be increased by increasing the dimension in the surface direction. Therefore, the fixing force of the contact member to the piezoelectric element and / or the vibration member can be improved.

The best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations.
Therefore, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

  The piezoelectric actuator of the present invention can be applied to various devices such as a timepiece and a toy in addition to a liquid ejection device and a driving device, and is particularly suitable for application to a device that needs to be reduced in size and thickness.

FIG. 3 is a plan view showing the liquid ejection device according to the first embodiment of the present invention. FIG. 4 is a side sectional view showing a liquid ejection device. The disassembled perspective view which shows a piezoelectric actuator. A side sectional view showing a part of a piezoelectric actuator. The top view which shows the drive device concerning 2nd embodiment of this invention. The disassembled perspective view which shows the piezoelectric actuator concerning 2nd embodiment. A side sectional view showing a part of a piezoelectric actuator. VIII-VIII sectional drawing of FIG. IX-IX sectional drawing of FIG. The top view which shows the modification of the piezoelectric actuator of this invention. FIG. 11 is a side sectional view of FIG. 10. The top view which shows the modification of the piezoelectric actuator of this invention. FIG. 13 is a side sectional view of FIG. 12. The top view which shows the modification of the piezoelectric actuator of this invention. FIG. 15 is a side sectional view of FIG. 14. The top view which shows the modification of the piezoelectric actuator of this invention. The top view which shows the modification of the piezoelectric actuator of this invention. FIG. 18 is a side sectional view of FIG. 17. The top view which shows the modification of the piezoelectric actuator of this invention. The side view of FIG. The top view which shows the modification of the piezoelectric actuator of this invention. FIG. 22 is a side sectional view of FIG. 21. The top view which shows the modification of the piezoelectric actuator of this invention. FIG. 24 is a side sectional view of FIG. 23.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 4 ... Rotor (moving body), 5 ... Piezoelectric actuator, 11 ... Liquid discharge apparatus (apparatus), 12 ... Drive apparatus (apparatus), 51 ... Reinforcement plate (vibration member), 52 ... Piezoelectric element, 54 ... Contact member, DESCRIPTION OF SYMBOLS 100 ... Rotating body (moving body), 512 ... Recessed part (positioning means), 521 ... Recessed part (positioning means), 541 ... Contact part, 542 ... Fixed part, 543 ... Contact surface.

Claims (10)

A piezoelectric actuator comprising a piezoelectric element and a vibration member fixed to the piezoelectric element, wherein the moving body is moved by vibration of the piezoelectric element,
The vibration member is provided with a separate contact member that contacts the moving body,
The piezoelectric actuator according to claim 1, wherein at least a contact surface of the contact member that contacts the moving body is configured to have a higher hardness than the vibration member. The piezoelectric actuator according to claim 1,
The contact member is provided to protrude from the piezoelectric element,
A part of the contact member is fixed to a surface of the piezoelectric element and / or the vibration member that is substantially parallel to the protruding direction of the contact member. The piezoelectric actuator according to claim 1 or 2,
At least one of the piezoelectric element, the vibration member, and the contact member is provided with positioning means for positioning the contact member with respect to the piezoelectric element. The piezoelectric actuator according to any one of claims 1 to 3,
The piezoelectric actuator according to claim 1, wherein a thickness dimension of a contact surface of the contact member with respect to the movable body is larger than a thickness dimension of the vibration member. The piezoelectric actuator according to any one of claims 1 to 4,
A piezoelectric actuator characterized in that a thickness dimension of the contact member is uniform. The piezoelectric actuator according to any one of claims 1 to 5,
The contact member is made of ceramics, cemented carbide, steel material that has been subjected to nitriding treatment, or steel material that has been subjected to carburizing treatment. The piezoelectric actuator according to any one of claims 1 to 6,
The piezoelectric actuator, wherein the contact member and the vibration member are fixed to each other by any one of adhesion, brazing, and caulking, or a combination thereof. The piezoelectric actuator according to any one of claims 2 to 7,
The piezoelectric element and the vibration member are formed in a plate shape,
The piezoelectric element is fixed to both surfaces of the vibration member,
The piezoelectric actuator according to claim 1, wherein a thickness dimension of the vibration member is larger than a thickness dimension of a portion of the contact member disposed between the piezoelectric elements. The piezoelectric actuator according to any one of claims 1 to 8,
A piezoelectric actuator, wherein traction oil is interposed between the contact member and the movable body.   An apparatus comprising the piezoelectric actuator according to claim 1.

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