JP2013074700A - Liquid transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid transfer device which realizes miniaturization and increased discharge pressure.SOLUTION: A liquid transfer device 1 comprises: a pump chamber 130 having a liquid transfer space 130H-1 which is a through hole in which an output shaft 15a is inserted and a liquid supplying hole 130H-2 for supplying liquid to the liquid transfer space 130H-1; and an ultrasonic motor 160 which contacts a friction contactor 41. The device further comprises: a rotor mechanism part 10 rotatably driven on a central axis as an axis of rotation having elliptic oscillation of an oscillator 40 as a driving source; the output shaft 15a which is a columnar member connected to the rotor mechanism part 10, has a spiral groove 15h formed on an outer circumferential surface thereof, and is rotated with the central axis as the axis of rotation along with the rotation of the rotor mechanism part 10; an oscillator 40 in which longitudinal vibration extending and contracting in the central axis direction and twist vibration with the central axis as a twist axis are excited at the same time; and a friction contactor 41 provided on a surface of the oscillator 40 on which the elliptic oscillation is excited.

Description

  The present invention relates to a liquid transport device used in various fields such as medical treatment and chemical analysis.

  In recent years, for example, in the fields of medical treatment and chemical analysis, an analysis system in which a sensor, an analysis apparatus, and the like are miniaturized is used. In these analysis systems, a micropump is often used as a solution feeding means for reagents and the like. As a technique related to the micropump, for example, Patent Document 1 discloses the following technique.

  The micropump disclosed in Patent Document 1 is a micropump having a liquid feeding capacity in the range of 1 μl / min to 10 ml / min for the flow rate and 10 to 10000 Pa for the pressure. The micropump includes a casing having a liquid supply port and a discharge port and a cylindrical pump chamber therein. In the casing, a screw shaft having a spiral groove formed on the outer periphery is disposed. By comprising in this way, it is unnecessary to provide a check valve independently.

JP 2006-144740 A

  By the way, miniaturization and high discharge pressure are desired for liquid transport devices such as micropumps. However, it is difficult to achieve both miniaturization and high discharge pressure. Patent Document 1 does not specifically describe a driving device (driving means) for rotating the screw shaft. Therefore, it is considered that a general electromagnetic motor is assumed as the driving device (driving means). In this case, in order to realize a high discharge pressure, it is necessary to increase the torque by reducing the size of the motor itself or by using a gear. In any of these cases, it is inevitable to increase the size of the apparatus.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid transport apparatus that achieves both a reduction in size and an increase in discharge pressure.

In order to achieve the above object, a liquid transport apparatus according to an aspect of the present invention includes:
The cross section perpendicular to the central axis has a rectangular shape, the ratio of the short side to the long side constituting the rectangular shape is set to a predetermined value, the vertical vibration that expands and contracts in the central axis direction, and the central axis is twisted. A vibrator whose elliptical vibration is excited by exciting the torsional vibration at the same time, and
A friction contact provided on a surface of the vibrator on which the elliptical vibration is excited;
A rotor mechanism that is in contact with the frictional contact, and is driven to rotate about the elliptical vibration of the vibrator as a drive source, with the central axis as a rotation axis;
A cylindrical member connected to the rotor mechanism portion, an outer peripheral surface of which is formed with a spiral groove portion, and an output shaft that rotates around the central axis as the rotation axis of the rotor mechanism portion;
A pump chamber comprising a liquid transport space which is a through hole into which the output shaft is inserted, and a liquid supply hole for supplying a liquid to the liquid transport space;
A pressing portion that presses the vibrator toward the rotor mechanism portion;
A frame for holding the vibrator together with the rotor mechanism part and the pressing part;
A holder shaft that is a shaft-like member provided on an extension of the torsion shaft of the vibrator on a surface of the vibrator facing the pressing portion;
A holder shaft insertion hole that is provided at a position on the extension of the torsion shaft of the vibrator in the frame and into which the holder shaft is inserted;
On the surface of the vibrator facing the rotor mechanism, a positioning pin provided on an extension of the rotation shaft of the rotor mechanism,
A positioning hole portion provided on a surface of the rotor mechanism portion on the rotating shaft and facing the vibrator, and into which the positioning pin is inserted;
It is characterized by comprising.

  According to the present invention, it is possible to provide a liquid transport apparatus that achieves both miniaturization and high discharge pressure.

FIG. 1 is a perspective view showing a configuration example of a liquid transport apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a configuration example of the pump chamber of the liquid transport device shown in FIG. 3 is a cross-sectional view taken along line AA ′ of the pump chamber shown in FIG. FIG. 4 is an exploded perspective view showing a fixed plate and an ultrasonic motor of the liquid transport device shown in FIG. FIG. 5 is an exploded perspective view of the liquid transport device shown in FIG. FIG. 6 is a perspective view illustrating a configuration example of an ultrasonic motor included in the liquid transfer device illustrated in FIG. 1. FIG. 7 is an exploded perspective view of the vicinity of the rotor mechanism portion of the ultrasonic motor included in the liquid transport device shown in FIG. FIG. 8 is an exploded perspective view of an ultrasonic motor included in the liquid transport device shown in FIG. FIG. 9 is a front sectional view of the vicinity of the rotor mechanism portion of the ultrasonic motor included in the liquid transport device shown in FIG. FIG. 10 is a diagram illustrating a configuration example of a piezoelectric sheet constituting the laminated piezoelectric element. FIG. 11 is a diagram illustrating an example of a laminated structure of the laminated piezoelectric element. FIG. 12 is a diagram illustrating an example of a resonance frequency characteristic in each vibration mode of the laminated piezoelectric element. FIG. 13 is a view showing the outer shape of the first laminated piezoelectric element and the second laminated piezoelectric element. FIG. 14 is a view (side view) of the first laminated piezoelectric element and the second laminated piezoelectric element as seen from the direction indicated by arrow A1 in FIG. FIG. 15 is a view (side view) of the first laminated piezoelectric element and the second laminated piezoelectric element as viewed from the direction indicated by the arrow A2 in FIG.

  Hereinafter, an ultrasonic motor according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration example of a liquid transport apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a configuration example of the pump chamber of the liquid transport device shown in FIG. 3 is a cross-sectional view taken along line AA ′ of the pump chamber shown in FIG. FIG. 4 is an exploded perspective view showing a fixed plate and an ultrasonic motor of the liquid transport device shown in FIG. FIG. 5 is an exploded perspective view of the liquid transport device shown in FIG.

The liquid transport apparatus 1 according to the present embodiment includes a pump chamber 130, an ultrasonic motor 160, and a fixing plate 200 that integrally connects the pump chamber 130 and the ultrasonic motor 160.
The pump chamber 130 has a substantially rectangular parallelepiped shape as shown in FIGS. 1 to 3, and includes a liquid transfer space 130H-1 that is a through hole into which the output shaft 15a of the ultrasonic motor 160 is inserted, and a liquid transfer space 130H-. 1 is formed with a liquid supply hole 130H-2 for supplying the liquid to 1.
The shape of the pump chamber 130 is not limited to a substantially rectangular parallelepiped shape, and may be any other shape as long as it can form a liquid transfer space 130H-1 and a liquid supply hole 130H-2 described later.

  The liquid conveyance space 130H-1 is a substantially cylindrical space, and one opening thereof is a delivery hole for a liquid conveyed in the liquid conveyance space 130H-1, and a tubular member ( A protrusion 130t-1 for mounting a not-shown) is provided. The liquid transfer space 130H-1 is formed so as to penetrate from the inside of the pump chamber 130 to the inside of the protrusion 130t-1 as shown in FIGS.

  The other opening of the liquid transport space 130H-1 is an opening into which the output shaft 15a is inserted as shown in FIGS. 1 to 3, and the other opening is as shown in FIGS. A bearing member 300 through which the output shaft 15a of the ultrasonic motor 160 is inserted is provided. The bearing member 300 also serves as a seal member that prevents the liquid inside the liquid transfer space 130H-1 from flowing into the rotor mechanism 10 of the ultrasonic motor 160. The bearing member 300 may be subjected to a surface treatment such as DLC coating on the contact surface with the output shaft 15a in order to improve slidability and sealing performance.

  The liquid supply hole 130H-2 is a substantially cylindrical space that intersects and is substantially perpendicular to the liquid transport space 130H-1, and is a liquid flow path into the liquid transport space 130H-1. A projection 130t-2 for mounting a tubular member (not shown) is provided at the opening of the liquid supply hole 130H-2. The liquid supply hole 130H-2 is formed so as to penetrate from the inside of the pump chamber 130 to the inside of the protrusion 130t-2 as shown in FIGS.

  The surface of the pump chamber 130 fixed to the fixed plate 200 has a plurality of screw holes sr for screwing to the fixed plate 200 as shown in FIG. 2, and the fixed plate 200 and the ultrasonic motor. A plurality of grooves g for receiving the heads of the screws sr for fixing the screw 160 are formed.

  In addition, it is preferable that the contact portion between the pump chamber 130 and the fixing plate 200 is processed to have an accurate surface roughness, or a so-called O-ring (not shown) or the like is sandwiched. By comprising in this way, it can prevent more reliably that the liquid in the liquid conveyance space 130H-1 of the pump chamber 130 leaks outside.

  Hereinafter, a configuration example of the ultrasonic motor 160 will be described. FIG. 6 is a perspective view illustrating a configuration example of the ultrasonic motor 160 included in the liquid transport device 1 illustrated in FIG. 1. FIG. 7 is an exploded perspective view of the vicinity of the rotor mechanism unit 10 of the ultrasonic motor 160 included in the liquid transfer device 1 shown in FIG. FIG. 8 is an exploded perspective view of the ultrasonic motor 160 included in the liquid conveyance device 1 shown in FIG. 1 (the transmission member is not shown). FIG. 9 is a front cross-sectional view of the vicinity of the rotor mechanism unit 10 of the ultrasonic motor 160 included in the liquid conveyance device 1 shown in FIG.

The ultrasonic motor 160 includes a rotor mechanism unit 10, a pressing mechanism unit 20, a frame 31, and a laminated piezoelectric element 40.
The frame 31 includes a vibrating body housing frame 31P and a rotor mechanism housing frame 31R.
First, the frame 31 will be described in detail.

The vibrator housing frame 31P includes a first plate member 31P1 and a second plate member 31P2 which are a pair of plate members facing each other, and a third plate member 31P3 forming the bottom surface of the vibrator housing frame, Consists of.
The first plate-like member 31P1 is formed with a plurality of screw holes 31P1sh in the thickness direction for screwing a later-described restriction member 51a1, and a plurality of protrusions 51a1t provided on the restriction member 51a1. A plurality of through-holes 31P1th that are respectively inserted are provided.

  Similarly, the second plate-like member 31P2 has a plurality of screw holes (not shown) for screwing a later-described restricting member 51a2 formed in the thickness direction, and is provided in the restricting member 51a2. A plurality of through holes (not shown) through which the plurality of protrusions 51a2t are respectively inserted are provided.

In the third plate-like member 31P3, a pressing shaft insertion hole 31P3h into which a pressing shaft 22a of the holder 22, which will be described later, is inserted has a twisted shaft (twisted vibration) of the laminated piezoelectric element 40 disposed in the vibrator housing frame 31P. (Center axis of the) is provided at a position on the extension.
The rotor mechanism housing frame 31R includes a first U-shaped member 31R1 and a second U-shaped member 31R2, which are a pair of substantially U-shaped members facing each other. The first U-shaped member 31R1 and the second U-shaped member 31R2 are formed in the fixing plate 200 with screw holes 31R1h and 31R2h for screwing the fixing plate 200 to the contact surface with the fixing plate 200. Pins 31t1 and 31t2 to be inserted into the through holes 200ph1 and 200ph2 are provided.

By the way, the rotor mechanism unit 10 includes a bearing 12, a sliding plate 14, and an output member 15.
The bearing 12 includes a first cylindrical portion 12c1 having an outer diameter substantially equal to the inner diameter of the cylindrical portion 200c of the fixing plate 200 (the diameter of the through hole 200H), and an outer diameter substantially equal to the outer diameter of the cylindrical portion 200c. The second cylindrical portion 12c2 is a bearing member. The inner diameter of the bearing 12 is substantially the same as an output shaft 15a of the output member 15 described later, and is inserted through the output shaft 15a.

  Specifically, the bearing 12 is a bearing member configured such that the inner peripheral surface thereof is rotatable, and the outer peripheral surface of the first cylindrical portion 12c1 is fixed to the inner peripheral surface of the cylindrical portion 200c of the fixed plate 200, The lower end surface of the second cylindrical portion 12c2 is in contact with the upper end surface of the output base portion 15b (details will be described later) of the output member 15.

  The sliding plate 14 is arranged so that one surface is in contact with a friction contact 41 provided on the upper end surface of the laminated piezoelectric element 40 and the other surface is against the lower end surface of the output base portion 15 b constituting the output member 15. For example, it is a substantially annular member fixed by bonding or the like. By this sliding plate 14, the vibration of the laminated piezoelectric element 40 is transmitted to the output member 15 as a driving force via the friction contact 41. In other words, the sliding plate 14 and the output member 15 constitute one rotor.

  The output member 15 includes an output shaft 15a and a substantially disk-shaped output base portion 15b connected to one end surface (lower end surface) of the output shaft 15a.

  As described above, the output shaft 15a is a rod-like member that is inserted into the bearing member 300 provided in the opening of the liquid transport space 130H-1 and inserted into the liquid transport space 130H-1, and the output base 15b Rotates with rotation. A spiral groove 15h is formed on the outer peripheral surface of the output shaft 15a. The liquid in the liquid transfer space 130H-1 is transferred by the groove 15h of the rotating output shaft 15a, and discharged from the protrusion 130t-1 to the outside of the pump chamber 130. In other words, the spiral groove portion 15h formed in the output shaft 15a and the inner wall of the pump chamber 130H-1 constitute a liquid flow path, and the liquid in the flow path is caused by the rotation of the output shaft 15a. It is discharged to the outside of 130H-1.

  As will be described in detail later, when a predetermined alternating voltage is applied to the laminated piezoelectric element 40 to excite longitudinal vibration and torsional vibration, elliptical vibration is generated on the surface of the laminated piezoelectric element 40 on which the friction contact 41 is provided. Will occur. As a result, the sliding plate 14 in contact with the friction contact 41 rotates, and the output base 15b and the output shaft 15a also rotate accordingly.

  The output base 15b has a surface (lower end surface) opposite to the surface to which the output shaft 15a is connected fixed to the sliding plate 14 by, for example, adhesion. Specifically, the output base portion 15b is formed with a concave portion 15r having a diameter substantially the same as the outer diameter of the sliding plate 14 on the surface facing the sliding plate 14, and a sliding surface is formed on the surface of the concave portion 15r. The plate 14 is fitted and fixed by, for example, adhesion.

  In the sliding plate 14 and the output base 15b, through holes (positioning pin insertion holes 14h, 15h) into which positioning pins 43 (described later in detail) provided on the upper surface of the laminated piezoelectric element 40 are inserted are respectively laminated piezoelectric elements. It is formed on the 40 side surface. Specifically, the positioning pin insertion holes 14h and 15h are formed at positions corresponding to the central axes of the sliding plate 14 and the output base portion 15b (recessed portion 15r thereof), respectively. Although details will be described later, by assembling the positioning pin 43 into the positioning pin insertion holes 14h and 15h, the positional relationship between these members is necessarily optimized and assembled.

  The fixed plate 200 includes a plate portion 200b and a cylindrical portion 200c provided on one surface of the plate portion 200b. As shown in FIGS. 7 and 9, the fixing plate 200 is formed with a through hole 200H having substantially the same diameter as the outer diameter of the first portion 12c of the bearing 12, as shown in FIGS. The peripheral surface and the outer peripheral surface of the first portion 12c1 of the bearing 12 are fixed by, for example, adhesion. In other words, on this fixed plate 200, a rotor part set composed of the sliding plate 14 and the output member 15 fixed by bonding or the like is rotatably arranged via the bearing 12 as shown in FIG. ing.

  As described above, the plate portion 200b includes through holes 200th1 and 200th2 into which the pins 31t1 and 31t2 provided in the rotor mechanism housing frame 31R are inserted, and the plate portion 200b placed on the rotor mechanism housing frame 31R. Through holes 200ph1 and 200ph2 for screwing the rotor mechanism housing frame 31R to the rotor mechanism housing frame 31R.

Further, through holes 200srh are formed in the plate part 200b at positions (in this example, four corners of the plate part 200b) corresponding to screw holes srh formed in the pump chamber 130 as shown in FIG. These through holes 200srh are through holes through which screws sr for fastening the plate portion 200b and the pump chamber 130 are inserted.
As shown in FIGS. 2 and 5, a plurality of screw holes srh for fastening the fixing plate 200, a fixing plate 200 and an ultrasonic motor are provided on the surface of the pump chamber 130 fixed to the fixing plate 200. A plurality of grooves g that house the heads of the screws sr that fasten 160 (the rotor mechanism housing frame 31R) are formed.

  As described above, the fixing plate 200 is aligned on one side with reference to the pins 31t1 and 31t2 provided on the rotor mechanism housing frame 31R and fixed to the rotor mechanism housing frame 31R by the screw sr. (Fixed to the ultrasonic motor 160). The fixing plate 200 is fixed to the pump chamber 130 by screws sr on the other surface.

  The friction contact 41 provided on the laminated piezoelectric element 40 is pressed against the rotor surface (sliding plate 14 surface) by the pressing force of the spring 21 that pressurizes the laminated piezoelectric element 40 toward the rotor mechanism unit 10. Contact with appropriate pressure (Press contact). Thereby, the elliptical vibration of the laminated piezoelectric element 40 can be transmitted to the rotor mechanism 10 as a driving force.

The pressing mechanism unit 20 includes a spring 21 and a holder 22.
The spring 21 is a member for pressing the laminated piezoelectric element 40 toward the rotor mechanism unit 10 and is positioned by the holder 22. The spring 21 is held in a bent state by the third plate-like member 31P3 of the vibrator housing frame 31P and the laminated piezoelectric element 40. Specifically, the spring 21 is, for example, a plate spring or a coil spring.

The holder 22 includes a pressing shaft 22a and a fixing portion 22f. Specifically, the pressing shaft 22a and the center axis in the longitudinal direction of the laminated piezoelectric element 40 (center axis of torsional vibration) are configured as follows.
The pressing shaft 22a is a shaft member through which the spring 21 is inserted. A fixing portion 22f, which will be described later, is provided at one end of the holder 22, and the other end is inserted into a pressing shaft insertion hole 31P3h formed in the third plate-like member 31P3 of the vibrating body housing frame 31P. As will be described in detail later, since the fixing portion 22f is fixed to the lower surface of the laminated piezoelectric element 40, the pressing shaft 22a of the holder 22 has a pressing shaft insertion hole provided in the third plate-like member 31P3 of the vibrator housing frame 31P. By being inserted into 31P3h, the position of the laminated piezoelectric element 40 is regulated and positioned (the laminated piezoelectric element 40 is regulated to move in a direction perpendicular to the direction of pressing by the spring 21).

  The fixing portion 22f has a pressing shaft 22a connected to one surface and the other surface corresponding to a node position of torsional vibration that is vibration in a direction contributing to driving on the lower surface of the laminated piezoelectric element 40 ( It is a plate-like member fixed by adhesion or the like in the vicinity of the center position in the width direction and the thickness direction.

  The fixing portion 22f is formed integrally with the pressing shaft 22a and is pressed toward the rotor mechanism portion 10 by the laminated piezoelectric element 40 and the spring 21 sandwiched and bent by the fixing portion 22f. Is done. That is, the laminated piezoelectric element 40 is pressed toward the rotor mechanism portion 10 by the spring 21 through the fixing portion 22f.

The holder 22 is made of a material (for example, a resin material) that reduces vibration transmission. Thereby, it is possible to reduce the vibration of the laminated piezoelectric element 40 from being transmitted to the vibrating body housing frame 31P.
The laminated piezoelectric element 40 is a vibrating body formed by laminating piezoelectric sheets, and is provided with a friction contact 41 and a positioning pin 43. Although the details will be described later, the ultrasonic motor is mounted using a holder 22 fixed to the lower end surface in the longitudinal direction of the laminated piezoelectric element 40 by bonding and a positioning pin 43 fixed to the upper end surface by bonding or the like. By assembling, the laminated piezoelectric element 40 is assembled in a state where the center axis (center axis in torsional vibration) and the center axis (rotation axis) of the rotor mechanism unit 10 coincide.

The friction contact 41 is provided in the vicinity of the position where the optimal elliptical vibration is generated for driving on the upper surface of the laminated piezoelectric element 40 (the surface facing the rotor mechanism portion 10). Touching.
The positioning pin 43 protrudes perpendicularly to the upper surface on the center in the long side direction and the short side direction (the rotation axis (center axis) of the rotor mechanism unit 10) of the upper surface of the multilayer piezoelectric element 40. For example, it is fixed to the upper surface by adhesion or the like.

  The positioning pin 43 is inserted into the positioning pin insertion holes 14h and 15h of the sliding plate 14 and the output member 15 described above. When the rotor mechanism 10 (sliding plate 14 and output member 15) is disposed on the laminated piezoelectric element 40, the rotation pin of the rotor mechanism 10 is inserted by inserting the positioning pin 43 into the pin insertion holes 14h and 15h. And the center of the upper surface of the laminated piezoelectric element 40 coincide.

  The restricting member 51a1 is a plate-like member having a plurality (two in this example) of protrusions 51a1t provided in a convex manner in the thickness direction, and through holes 51a1h for screwing are formed in the thickness direction. Similarly, the restricting member 51a2 is a plate-like member in which a plurality of (in this example, two) protrusions 51a2t are provided so as to protrude in the thickness direction, and through holes 51a2h for screwing are formed in the thickness direction. ing.

  These restricting members 51a1 and 51a2 are arranged such that the protrusions 51a1t and 51a2t are in contact with the vicinity of the nodal position of torsional vibration on the main plane of the laminated piezoelectric element 40 (surface facing the vibrating body housing frame 31P). It is applied to the first plate-like member 31P1 and the second plate-like member 31P2 from the outside of the vibrator housing frame 31P, and is screwed and fixed by screws sr using the through holes 51a1h and 51a2h, respectively.

  As described above, the protrusions 51a1t and 51a2t of the regulating members 51a1 and 51a2 are fixed in a state of being in contact with the node position of the torsional vibration of the multilayer piezoelectric element 40 in the main plane of the multilayer piezoelectric element 40. The rotation of the laminated piezoelectric element 40 (the rotation of the rotor mechanism unit 10) and the vibration of the laminated piezoelectric element 40 are not inhibited (the amplitude of the torsional vibration excited on the longitudinal end face of the laminated piezoelectric element 40 is not reduced). Rotation in the same direction, in-plane rotation perpendicular to the direction of the pressing force of the spring 21) is restricted.

  Hereinafter, the piezoelectric sheet constituting the laminated piezoelectric element 40 will be described in detail. FIG. 10 is a diagram illustrating a configuration example of a piezoelectric sheet constituting the laminated piezoelectric element 40. As shown in the figure, the laminated piezoelectric element 40 includes three types of piezoelectric sheets (a first piezoelectric sheet 401, a second piezoelectric sheet 402, and a third piezoelectric sheet 403).

The first piezoelectric sheet 401, the second piezoelectric sheet 402, and the third piezoelectric sheet 403 are rectangular sheet-like piezoelectric elements, for example, a hard lead zirconate titanate piezoelectric ceramic element (PZT). Consists of.
More specifically, on the electrode forming surface of the first piezoelectric sheet 401, a + phase first internal electrode 401a and a + phase second internal electrode 401c are arranged at a substantially central position in the longitudinal direction. They are provided symmetrically with respect to C (a line that bisects the short side).

Similarly, on the electrode formation surface of the second piezoelectric sheet 402, a first internal electrode 402a of a negative phase and a second internal electrode 402c of a negative phase are disposed at a center line C at a substantially central position in the longitudinal direction. They are provided symmetrically with respect to (a line that bisects the short side).
Here, the + phase first internal electrode 401a includes an end portion 401ae extending toward one long side of the first piezoelectric sheet 401 having a rectangular shape and exposed. The + phase second internal electrode 401c includes an end portion 401ce extending toward the other long side of the first piezoelectric sheet 401 having a rectangular shape and exposed.

  Similarly, the negative first internal electrode 402a includes an end portion 402ae that extends toward one long side of the second piezoelectric sheet 402 having a rectangular shape and is exposed. The -phase second internal electrode 402c includes an end portion 402ce extending toward the other long side of the second piezoelectric sheet 402 having a rectangular shape and exposed.

  Here, each of the internal electrodes 401a, 401c, 402a, and 402c described above is made of, for example, a silver palladium alloy having a thickness of 4 μm. The positions where the above-described internal electrodes 401 a, 401 c, 402 a, and 402 c are provided are positions corresponding to positions where the stress of torsional vibration is maximized in the laminated piezoelectric element 40.

The third piezoelectric sheet 403 is a sheet-like member having the same shape as the first piezoelectric sheet 401 and the second piezoelectric sheet 402 and having no internal electrode. That is, the third piezoelectric sheet 403 is a piezoelectric sheet that forms an insulating layer.
FIG. 11 is a diagram illustrating an example of a laminated configuration of the laminated piezoelectric element 40. As shown in the figure, the first laminated portion 411, the second laminated portion 412, the third laminated portion 413, the fourth laminated portion 414, and the fifth laminated portion 415 are formed.

Specifically, the laminated structure of each of these laminated parts (the first laminated part 411, the second laminated part 412, the third laminated part 413, the fourth laminated part 414, and the fifth laminated part 415) It is a part formed by laminating as follows.
<< 1st lamination part 411 >>
The first laminated portion 411 includes at least one third piezoelectric sheet 403 (in the case of a plurality of third piezoelectric sheets 403, the third piezoelectric sheets 403 are stacked in the thickness direction). .
<< 2nd lamination | stacking site | part 412 >>
The second laminated portion 412 is a portion laminated on the first laminated portion 411, and is formed by alternately laminating the first piezoelectric sheets 401 and the second piezoelectric sheets 402 in the thickness direction.
<< 3rd lamination | stacking site | part 413 >>
The third laminated portion 413 is a portion laminated on the second laminated portion 412 and is composed of at least one third piezoelectric sheet 403 (in the case of being composed of a plurality of third piezoelectric sheets 403, 3 piezoelectric sheets 403 are laminated in the thickness direction).
<< 4th lamination | stacking site | part 414 >>
The fourth laminated portion 414 is a portion laminated on the third laminated portion 413, and is formed by alternately laminating the first piezoelectric sheets 401 and the second piezoelectric sheets 402 in the thickness direction.
<< 5th lamination | stacking site | part 415 >>
The fifth laminated portion 415 is a portion laminated on the fourth laminated portion 414, and is composed of at least one third piezoelectric sheet 403 (in the case of being composed of a plurality of third piezoelectric sheets 403, 3 piezoelectric sheets 403 are laminated in the thickness direction).

The dimensions of the multilayer piezoelectric element 40 having the above-described configuration are determined using the following characteristics of the multilayer piezoelectric element. That is, assuming that the height c of the laminated piezoelectric element is constant, the value of (short side length a / long side length b) is taken on the horizontal axis, and the resonance frequency value in each vibration mode is taken on the vertical axis. The characteristics shown in FIG. 12 can be obtained. That is,
The value of the resonance frequency in the longitudinal primary vibration mode does not depend on the value of (a / b) and takes a substantially constant value.
The value of the resonance frequency in the torsional primary vibration mode, the torsional secondary vibration mode, and the torsional tertiary vibration mode increases as the value of (a / b) increases.
The resonance frequency in the torsional primary vibration mode does not coincide with the resonance frequency in the longitudinal primary vibration mode regardless of the value of (a / b).
The resonance frequency in the torsional secondary vibration mode coincides with the resonance frequency in the longitudinal primary vibration mode in the vicinity where the value of (a / b) is 0.6.
The resonance frequency in the torsional tertiary vibration mode coincides with the resonance frequency in the longitudinal primary vibration mode in the vicinity where the value of (a / b) is 0.3.

Due to the above-described characteristics, the value of (a / b) is set as follows in the present embodiment. That is,
When the longitudinal primary vibration mode and the torsional secondary vibration mode are used, the length a of the short side of the multilayer piezoelectric element 40 is set so that the value of (a / b) is 0.6 to 0.7. The long side length b is set.

  That is, in the ultrasonic motor according to the present embodiment, the resonance frequency of the longitudinal primary resonance vibration that expands and contracts in the direction of the center axis 100c of the multilayer piezoelectric element 40 and the torsional secondary resonance vibration that has the center axis 100c as the torsion axis. Are set to a ratio (ratio) between the short side length a and the long side length b in the multilayer piezoelectric element 40. Since the resonance frequency can be adjusted in this way, there is no need for special processing or the like for adjusting the resonance frequency, which is required in the prior art.

  FIG. 13 is a view showing the outer shape of the laminated piezoelectric element 40. 14 is a view (side view) of the laminated piezoelectric element 40 as viewed from the direction indicated by the arrow A1 in FIG. 15 is a view (side view) of the laminated piezoelectric element 40 as viewed from the direction indicated by the arrow A2 in FIG.

  As shown in FIG. 14, on one side surface of the laminated piezoelectric element 40, external electrodes 101B + and 101B- for connecting (short-circuiting) the end portions 401ae and the end portions 402ae at the second laminated portion 412 and the fourth laminated layer, respectively. In the part 414, external electrodes 101A + and 101A− are provided for connecting (short-circuiting) the end portions 401ae and the end portions 402ae, respectively. The external electrode 101A + forms an A + phase external electrode, the external electrode 101A− forms an A− phase external electrode, the external electrode 101B + forms a B + phase external electrode, and the external electrode 101B− forms a B− phase external electrode. An external electrode is formed.

  Further, as shown in FIG. 15, external electrodes 101 </ b> D + and 101 </ b> D− that connect (short-circuit) the end portions 401 ce and the end portions 402 ce in the second laminated portion 412, respectively, on the other side surface of the laminated piezoelectric element 40. External electrodes 101C + and 101C− are provided to connect (short-circuit) the end portions 401ce and the end portions 402ce in the four stacked portions 414, respectively. The external electrode 101C + forms a C + phase external electrode, the external electrode 101C− forms a C− phase external electrode, the external electrode 101D + forms a D + phase external electrode, and the external electrode 101D− forms a D− phase external electrode. An external electrode is formed.

Although not shown, for example, an FPC is fixed to each of these external electrodes, and a driving voltage is applied from a predetermined power source through the FPC.
Here, in the laminated piezoelectric element 40, at least a portion where the + phase first internal electrode 401 a and the − phase first internal electrode 402 a are opposed to each other, and a + phase second internal electrode 401 c and the − phase first internal electrode 401 a. A portion where the second internal electrode 402c faces each other is a piezoelectric activation region activated piezoelectrically. Specifically, there is a high level between the + phase first internal electrode 401a and the − phase first internal electrode 402a and between the + phase second internal electrode 401c and the − phase second internal electrode 402c. A voltage is applied to activate piezoelectrically.

  By the way, alternating voltages having different phases are applied to the internal electrodes of the A phase that is the electrode layer corresponding to the fourth laminated portion 414 and the B phase that is the electrode layer corresponding to the second laminated portion 412. Thus, the longitudinal primary resonance vibration and the torsional secondary resonance vibration are excited in the activation region polarized in the thickness direction (lamination direction) of the multilayer piezoelectric element 40, and the elliptical vibration is excited on the end face of the multilayer piezoelectric element 40. The sliding plate 14 is rotationally driven by the friction contact 41.

  Specifically, longitudinal vibration is excited in the laminated piezoelectric element 40 by applying an alternating voltage having the same phase to the A phase and the B phase. Further, torsional vibration is excited in the laminated piezoelectric element 40 by applying an alternating voltage having a phase difference of 180 degrees (reverse phase) to the A phase and the B phase. Then, by applying an alternating voltage having a phase difference of 90 degrees between the A phase and the B phase, longitudinal vibration and torsional vibration are simultaneously excited in the laminated piezoelectric element 40, and elliptical vibration is excited at its end face. Thus, in the ultrasonic motor according to the present embodiment, driving is performed using the piezoelectric lateral effect of the laminated piezoelectric element 40.

  In addition, about the C phase and D phase of the laminated piezoelectric element 40, the drive force of the said ultrasonic motor can be made larger by applying a drive voltage similarly to A phase and B phase, respectively. Of course, the C phase and the D phase of the multilayer piezoelectric element 40 may be used as a vibration detection phase for detecting the vibration of the multilayer piezoelectric element 40.

  By the way, in the ultrasonic motor according to the present embodiment, the positions where the internal electrodes 401 a, 401 c, 402 a, and 402 c are provided in each piezoelectric sheet correspond to the abdominal portion of the torsional secondary vibration excited by the laminated piezoelectric element 40. It is a position to do. In other words, each internal electrode 401a, 401c, 402a, 402c is provided at a position where the stress of the torsional secondary vibration is maximized.

As described above, according to the present embodiment, it is possible to provide a liquid transport apparatus that realizes miniaturization and high discharge pressure.
The ultrasonic motor 160 included in the liquid transport apparatus 1 according to the present embodiment is a motor that can achieve low speed and high torque, and it is necessary to provide a reduction gear or the like in order to achieve high discharge pressure of the liquid transport apparatus. Absent. That is, according to the present embodiment, the volume occupied by the motor portion of the liquid transport device can be reduced.

  Furthermore, in the liquid transport apparatus 1 according to the present embodiment, the pump chamber 130 and the ultrasonic motor 160 are integrated via the fixed plate 200, and the output shaft 15 a of the ultrasonic motor 160 is in the pump chamber 130. It is used as a member for liquid conveyance. This configuration greatly contributes to downsizing of the entire apparatus. This configuration also contributes to a reduction in the number of parts.

When the torque of the drive unit (motor) is large as in the liquid transport device according to the present embodiment, transport is possible even if the liquid transported by the liquid transport device is a highly viscous liquid. Therefore, even if foreign matter is mixed in the liquid, it can be transported without any problem.
As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to each embodiment mentioned above, A various deformation | transformation and application are possible within the range of the summary of this invention. Of course.

  Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention can be achieved. In the case of being obtained, a configuration from which this configuration requirement is deleted can also be extracted as an invention.

    DESCRIPTION OF SYMBOLS 1 ... Liquid conveying apparatus, 10 ... Rotor mechanism part, 12c1, 12c2 ... Cylindrical part, 13a ... Shaft part, 13g ... Gear part, 13H ... Through-hole, 14 ... Sliding plate, 14h, 15h ... Pin insertion hole, 15a ... Output shaft 15 ... Output member 15b ... Output base 15h ... Groove 15r ... Recessed part 200ph1, 200ph2 ... Through hole 200H ... Through hole 19 ... Spacer 20 ... Pressing mechanism part 21 ... Spring 22 ... Holder, 22a ... Pressing shaft, 22f ... Fixing part, 31 ... Frame, 31P ... Vibrating body housing frame, 31R ... Rotor mechanism housing frame, 31P1, 31P2, 31P3 ... Plate member, 31P1sh ... Screw hole, 31P1th ... Through hole, 31P3h: pressing shaft insertion hole, 31P: vibrator housing frame, 31R1, 31R2: U-shaped member, 1R1h, 31R2h ... screw holes, 31t1, 31t2 ... pins, 31 ... frame, 40 ... laminated piezoelectric element, 41 ... friction contact, 43 ... pins, 51a1t, 51a2t ... projections, 51a1h, 51a2h ... through holes, 51a1, 51a2 ... regulating member, 100c ... center axis, 101A, 101B, 101C, 101D ... external electrode, 130 ... pump chamber, 130t-1, 130t-2 ... protrusion, 130H-1 ... liquid transfer space, 130H-2 ... liquid supply Hole: 160 ... Ultrasonic motor, 200 ... Fixed plate, 200c ... Cylindrical part, 200b ... Plate part, 300 ... Bearing member.

Claims (3)

The cross section perpendicular to the central axis has a rectangular shape, the ratio of the short side to the long side constituting the rectangular shape is set to a predetermined value, the vertical vibration that expands and contracts in the central axis direction, and the central axis is twisted. A vibrator whose elliptical vibration is excited by exciting the torsional vibration at the same time, and
A friction contact provided on a surface of the vibrator on which the elliptical vibration is excited;
A rotor mechanism that is in contact with the frictional contact, and is driven to rotate about the elliptical vibration of the vibrator as a drive source, with the central axis as a rotation axis;
A cylindrical member connected to the rotor mechanism portion, an outer peripheral surface of which is formed with a spiral groove portion, and an output shaft that rotates around the central axis as the rotation axis of the rotor mechanism portion;
A pump chamber comprising a liquid transport space which is a through hole into which the output shaft is inserted, and a liquid supply hole for supplying a liquid to the liquid transport space;
A pressing portion that presses the vibrator toward the rotor mechanism portion;
A frame for holding the vibrator together with the rotor mechanism part and the pressing part;
A holder shaft that is a shaft-like member provided on an extension of the torsion shaft of the vibrator on a surface of the vibrator facing the pressing portion;
A holder shaft insertion hole that is provided at a position on the extension of the torsion shaft of the vibrator in the frame and into which the holder shaft is inserted;
On the surface of the vibrator facing the rotor mechanism, a positioning pin provided on an extension of the rotation shaft of the rotor mechanism,
A positioning hole portion provided on a surface of the rotor mechanism portion on the rotating shaft and facing the vibrator, and into which the positioning pin is inserted;
A liquid conveying apparatus comprising: Including a fixed plate that is a plate-like member in which a through-hole through which the output shaft is inserted is formed;
The liquid transport apparatus according to claim 1, wherein the rotor mechanism is fixed to one surface of the fixed plate, and the pump chamber is fixed to the other surface of the fixed plate. A bearing member through which the output shaft is inserted is provided in the vicinity of the opening on the rotor mechanism portion side in the liquid transfer space of the pump chamber,
The liquid conveying apparatus according to claim 1, wherein the bearing member seals the opening on the rotor mechanism unit side together with the output shaft.

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