JP2012235586A - Ultrasonic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic motor that realizes a simple configuration and, even when being driven to obtain high torque, prevents abrasion of a frictional contactor from advancing.SOLUTION: The ultrasonic motor using a longitudinally and torsionally vibrating piezoelectric device comprises: a first laminated piezoelectric device 40-1 and a second laminated piezoelectric device 40-2 that are serially arranged along the direction of longitudinal vibration so as to hold a rotor structure section 13 therebetween; a frictional contactor 41-1 disposed in the first laminated piezoelectric device 40-1; a frictional contactor 41-2 disposed in the second laminated piezoelectric device 40-2; a positioning pin 43-1 disposed on the extended portion of a rotation axis at the rotor structure section 13 in the first laminated piezoelectric device 40-1; a positioning pin 43-2 disposed on the extended portion of a rotation axis at the rotor structure section 13 in the second laminated piezoelectric device 40-2; and the rotor structure section 13 that includes a bearing 13b, to which the positioning pins 43-1 and 43-2 are inserted, and is driven by rotation.

Description

  The present invention relates to an ultrasonic motor that uses vibration of a vibrator such as a piezoelectric element.

  In recent years, ultrasonic motors using vibrations of vibrators such as piezoelectric elements have attracted attention as new motors that replace electromagnetic motors. Compared with conventional electromagnetic motors, this ultrasonic motor is capable of obtaining low speed and high thrust without gears, high holding force, long stroke and high resolution, quietness, and magnetism. This has the advantage of not generating noise.

In an ultrasonic motor, a friction force is applied between the friction contact and the driven member by pressing (pressing) an ultrasonic vibrator against the driven member that is a relative motion member via the friction contact. The driven member is slid (driven by friction) by this frictional force.
As such an ultrasonic motor, for example, by causing a longitudinal vibration and a torsional vibration to be simultaneously generated in an ultrasonic vibrator, an elliptical vibration in which these vibrations are synthesized is generated in the ultrasonic vibrator, and the elliptical vibration is generated. An ultrasonic motor that drives the driven member by using it is known. Specifically, for example, Patent Document 1 discloses the following technique.

  That is, in Patent Document 1, longitudinal vibration and torsional vibration are simultaneously excited in the rod-shaped elastic body by utilizing the stretching vibration of two laminated piezoelectric elements arranged opposite to each other on the side surface of the rod-shaped elastic body. An ultrasonic motor is disclosed in which an elliptical motion is excited by a driver provided on an end face of the rod-like elastic body, and a rotor is rotated by the driver.

In this ultrasonic motor, a groove is provided in the rod-shaped elastic body in order to make the frequency of longitudinal vibration and the frequency of torsional vibration substantially coincide with each other. Then, by adjusting the position of the groove, the resonance frequency of the longitudinal vibration frequency and the torsional vibration frequency are substantially matched.
Furthermore, a through hole is provided in the central portion of the rod-like elastic body along the length direction, and a shaft is inserted and fixed in the through hole. And the rotor supported on the basis of this shaft is rotated by the driver that has obtained the driving force from the above-described elliptical vibration.

JP-A-9-117168

By the way, it is difficult to say that the ultrasonic motor disclosed in Patent Document 1 is easy to assemble for the following reasons.
That is, in the ultrasonic motor disclosed in Patent Document 1, the laminated piezoelectric element and the rod-shaped elastic body must be bonded and fixed, and the frequency of longitudinal vibration and the frequency of torsional vibration are substantially matched. The fact that the groove portion must be formed in the rod-shaped elastic body reduces the ease of assembly. Such a poor assembling property may lead to variations or deterioration in the motor performance of the ultrasonic motor.

  By the way, in order to increase the torque of the ultrasonic motor, it is necessary to increase the frictional force between the driven body and the friction contact. That is, it is necessary to increase the force (pressing force) for pressing the ultrasonic transducer against the driven body. When such a drive is performed, the wear of the friction contact is naturally promoted.

  The present invention has been made in view of the above-described circumstances, and realizes a simple configuration, and even when driven so as to obtain a high torque, the wear of the friction contact is hardly promoted. An object is to provide a sonic motor.

In order to achieve the above object, an ultrasonic motor 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. An ultrasonic motor that rotationally drives a rotor mechanism unit using the elliptical vibration of a vibrator whose elliptical vibration is excited by simultaneously exciting torsional vibration as an axis,
A first vibrator that is a pair of vibrators arranged in series along the longitudinal vibration direction so as to sandwich the rotor mechanism portion from one direction side and the other direction side in the longitudinal vibration direction; A second vibrator;
A first friction contact provided on a surface of the first vibrator facing the rotor mechanism,
A second friction contact provided on a surface of the second vibrator facing the rotor mechanism,
A first positioning pin provided on the surface of the first vibrator facing the rotor mechanism portion, substantially perpendicular to the surface on an extension of the rotation shaft of the rotor mechanism portion;
A second positioning pin provided on the surface of the second vibrator that faces the rotor mechanism portion, substantially perpendicular to the surface on the extension of the rotation shaft of the rotor mechanism portion;
A bearing portion into which the first positioning pin and the second positioning pin are inserted, a first friction contact surface that contacts the first friction contact, and the second friction contact And a driven body having a second frictional contact surface in contact with each other, and rotationally driven with the elliptical vibration of the first vibrator and the second vibrator as a drive source and the central axis as a rotation axis A rotor mechanism portion to be
A first pressing portion that presses the first vibrator toward the rotor mechanism portion;
A second pressing portion that presses the second vibrator toward the rotor mechanism portion;
A frame for holding the first vibrator and the second vibrator together with the rotor mechanism section, the first pressing section, and the second pressing section,
It is characterized by comprising.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where it implement | achieves a simple structure and it drives when obtaining a high torque, it can provide the ultrasonic motor with which abrasion of a friction contact is hard to be accelerated | stimulated.

FIG. 1 is a perspective view showing a configuration example of an ultrasonic motor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the ultrasonic motor shown in FIG. FIG. 3 is an exploded perspective view of the vicinity of the first portion of the ultrasonic motor according to the embodiment of the present invention. FIG. 4 is an exploded perspective view of the vicinity of the rotor mechanism portion of the ultrasonic motor according to the embodiment of the present invention. FIG. 5 is a perspective view showing an example of the assembly process of the rotor mechanism in the ultrasonic motor according to the embodiment of the present invention. FIG. 6A is a perspective view showing an example of the assembly process of the second portion in the ultrasonic motor according to the embodiment of the present invention. FIG. 6B is a perspective view showing an example of the assembly process of the second portion in the ultrasonic motor according to the embodiment of the present invention. FIG. 7A is a perspective view showing a vibration state of the first laminated piezoelectric element and the second laminated piezoelectric element in a longitudinal primary vibration mode by a broken line. FIG. 7B is a perspective view showing a vibration state of the first laminated piezoelectric element and the second laminated piezoelectric element in a torsional secondary vibration mode by a broken line. FIG. 8A is a diagram illustrating a configuration example of a piezoelectric sheet constituting the first laminated piezoelectric element and the second laminated piezoelectric element. FIG. 8B is a diagram illustrating an example of a laminated structure of the first laminated piezoelectric element and the second laminated piezoelectric element. FIG. 9 is a diagram illustrating an example of a resonance frequency characteristic in each vibration mode of the laminated piezoelectric element. FIG. 10A is a diagram showing the outer shape of the first laminated piezoelectric element and the second laminated piezoelectric element. FIG. 10B is a side view of the first laminated piezoelectric element and the second laminated piezoelectric element as viewed from the direction indicated by the arrow A1 in FIG. 10A. FIG. 10C is a side view of the first laminated piezoelectric element and the second laminated piezoelectric element as seen from the direction indicated by the arrow A2 in FIG. 10A. FIG. 11 is a diagram schematically showing the first laminated piezoelectric element, the second laminated piezoelectric element, and the rotor mechanism unit.

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 an ultrasonic motor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the ultrasonic motor shown in FIG. FIG. 3 is an exploded perspective view of the vicinity of the first portion of the ultrasonic motor according to the embodiment of the present invention. FIG. 4 is an exploded perspective view of the vicinity of the rotor mechanism portion of the ultrasonic motor according to the embodiment of the present invention. FIG. 5 is a perspective view showing an example of the assembly process of the rotor mechanism in the ultrasonic motor according to the embodiment of the present invention. 6A and 6B are perspective views showing an example of the assembly process of the second portion in the ultrasonic motor according to the embodiment of the present invention.

The ultrasonic motor according to this embodiment includes a frame 31, a first laminated piezoelectric element 40-1, a second laminated piezoelectric element 40-2, a rotor mechanism unit 13, and a first pressing mechanism unit 20-1. And a second pressing mechanism unit 20-2.
The frame 31 includes a first vibrating body housing frame 31P-1, a second vibrating body housing frame 31P-2, and a rotor mechanism housing frame 31R.

First, the first vibrator housing frame 31P-1 and the members assembled to the first vibrator housing frame 31P-1 will be described in detail.
The first vibrating body housing frame 31P-1 is a main plane opposing plate shape which is a pair of plate-like members facing the main plane (surface having the largest area) of the first laminated piezoelectric element 40-1 having a substantially rectangular parallelepiped shape. It consists of members 31P1-1 and 31P2-1 and a bottom plate-like member 31P3 that forms the bottom surface of the first vibrator housing frame 31P-1.

  A plurality of screw holes 31P1sh-1 for screwing the restricting member 51a1-1 are formed in the main plane opposing plate member 31P1-1 in the thickness direction as shown in FIG. 3, and the restricting member A plurality of through holes 31P1th-1 are formed through which the plurality of protrusions 51a1t-1 provided in 51a1-1 are respectively inserted.

  Similarly, a plurality of screw holes (not shown) are formed in the thickness direction in the main plane opposing plate-like member 31P2-1 for screwing a later-described restricting member 51a2-1, and the restricting member A plurality of through holes (not shown) through which the plurality of protrusions 51a2t-1 provided in 51a2-1 are respectively inserted are provided.

  As shown in FIG. 2, the bottom plate-like member 31P3 has a pressing shaft insertion hole 31P3h-1 into which the pressing shaft 22a-1 is inserted, and is disposed in the first vibrator housing frame 31P-1. The laminated piezoelectric element 40-1 is provided at a position on the extension of the torsion axis (center axis of torsional vibration).

  The restriction member 51a1-1 is a plate-like member in which a plurality (two in this example) of protrusions 51a1t-1 are provided so as to protrude in the thickness direction, and screw holes 51a1h-1 are formed in the thickness direction. . Similarly, the restriction member 51a2-1 is a plate-like member in which a plurality (two in this example) of protrusions 51a2t-1 are provided so as to protrude in the thickness direction, and screw holes 51a2h-1 are formed in the thickness direction. Has been.

  Then, as shown in FIG. 3, the restricting member 51a1-1 has a protrusion 51a1t-1 inserted into the through hole 31P1th-1 of the main plane opposing plate-like member 31P1-1, so that the first laminated piezoelectric element 40-1 The main plane opposing plate-like member 31P1-1 is brought into contact with the vicinity of the nodal position of the torsional vibration of the main plane, and is screwed and fixed by the screw Sr using the screw holes 51a1h-1. Has been.

  Similarly, the restricting member 51a2-1 has a protrusion 51a2t-1 inserted into a through-hole (not shown) of the main plane facing plate-like member 31P2-1 and out of the main plane of the first laminated piezoelectric element 40-1. It is applied to the main plane facing plate-like member 31P2-1 so as to come into contact with the vicinity of the node position of torsional vibration, and is screwed and fixed by the screw Sr using the screw holes 51a2h-1.

  As described above, the protrusions 51a1t-1 and 51a2t-1 of the regulating members 51a1-1 and 51a2-1 are fixed in a state of being in contact with the node position of the torsional vibration on the main plane of the first laminated piezoelectric element 40-1. Thus, the vibration of the first laminated piezoelectric element 40-1 is not inhibited (the amplitude of the torsional vibration excited on the end surface in the longitudinal direction of the first laminated piezoelectric element 40-1 is not reduced). The rotation of the single laminated piezoelectric element 40-1 (the rotation in the same direction as the rotation of the gear 13g, the rotation in the plane perpendicular to the direction of the pressing force of the pressing spring 21-1) is restricted.

The first pressing mechanism 20-1 includes a pressing spring 21-1 and a pressing shaft 22a-1.
The pressing spring 21-1 is a member for pressing the first laminated piezoelectric element 40-1 toward the rotor mechanism unit 13, and is positioned by the pressing shaft 22a-1. The pressing spring 21-1 is sandwiched between the bottom plate member 31P3 of the first vibrating body housing frame 31P-1 and the first laminated piezoelectric element 40-1 in a bent state. Specifically, the pressing spring 21-1 is, for example, a leaf spring or a coil spring.

  The pressing shaft 22a-1 is a shaft member through which the pressing spring 21-1 is inserted. As shown in FIGS. 1 and 2, one end of the pressing shaft 22a-1 is fixed to the lower end surface of the first laminated piezoelectric element 40-1, and the other end is the bottom of the first vibrator housing frame 31P1-1. It is inserted through the pressing shaft insertion hole 31P3h-1 formed in the face plate member 31P3.

  Thus, one end of the pressing shaft 22a-1 is fixed to the lower end surface of the first multilayer piezoelectric element 40-1, and the other end of the pressing shaft 22a-1 is provided on the bottom plate-like member 31P3. By being inserted into the pressing shaft insertion hole 31P3h-1, the positioning (position regulation) of the first laminated piezoelectric element 40-1 is performed (the first laminated piezoelectric element 40-1 is pressed by the pressing spring 21-1). Movement in a direction perpendicular to the direction of With the above-described configuration, the pressing shaft 22a-1 and the central axis in the longitudinal direction of the first laminated piezoelectric element 40-1 (the central axis of torsional vibration) coincide.

  The first laminated piezoelectric element 40-1 is a vibrating body formed by laminating piezoelectric sheets (details of the laminated structure will be described later), and is provided with a friction contact 41-1 and a positioning pin 43-1. ing. By assembling using the pressing shaft 22a-1 disposed on the lower end surface in the longitudinal direction of the first laminated piezoelectric element 40-1 and the positioning pin 43-1 fixed to the upper end surface by adhesion or the like, The first laminated piezoelectric element 40-1 is assembled in a state where the center axis (center axis in torsional vibration) and the center axis (rotation axis) of the rotor mechanism portion 13 coincide with each other.

  The friction contact 41-1 is located near the position where the longitudinal vibration and the torsional vibration are maximum on the upper end surface (the surface facing the rotor mechanism portion 13) of the first laminated piezoelectric element 40-1 (the elliptical vibration optimal for driving is present). It is provided in the vicinity of the generated position) and is in contact with the sliding plate 13f of the rotor mechanism section 13.

  Specifically, the friction contact 41-1 is, for example, the outermost peripheral portion in the width direction (long side b direction shown in FIG. 7A) and the thickness direction (short side shown in FIG. 7A) of the first multilayer piezoelectric element 40-1. (a direction) is arrange | positioned in the position applicable to the center site | part. The friction contact 41-1 frictionally drives the sliding plate 13f of the rotor mechanism unit 13 using the vibration of the first laminated piezoelectric element 41-1 (elliptical vibration generated on the upper end surface) as a drive source.

The positioning pin 43-1 is disposed on the upper end surface of the upper end surface of the first multilayer piezoelectric element 40-1 on the center in the long side direction and the short side direction (the rotation axis (center axis) of the rotor mechanism unit 13). On the other hand, it is fixed to the upper end surface by adhesion or the like so as to be vertically convex.
The positioning pin 43-1 is inserted into an inner diameter hole of a bearing 13b described later. When the rotor mechanism 13 (bearing 13b, sliding plate 13f, gear 13g) is disposed on the first laminated piezoelectric element 40-1, the positioning pin 43-1 is inserted into the inner diameter hole of the bearing 13b. The rotation center of the rotor mechanism unit 13 coincides with the center of the upper end surface of the first laminated piezoelectric element 40-1.

Hereinafter, the rotor mechanism housing frame 31R and the rotor mechanism unit 13 will be described in detail.
As shown in FIG. 2, the rotor mechanism housing frame 31 </ b> R includes a pair of first U-shaped members 31 </ b> R <b> 1 that are opposed to each other and a second U-shaped member 31 </ b> R <b> 2. The first U-shaped member 31 </ b> R <b> 1 and the second U-shaped member 31 </ b> R <b> 2 are disposed so that the hollow portions are opposed to each other, and the hollow portions define one space region in which the rotor mechanism unit 13 is accommodated. It is composed. As shown in FIGS. 1 and 2, the first vibrating body housing frame 31P-1 described above is connected to one side (lower side) of the rotor mechanism housing frame 31R, and the other side (upper side). Is connected to a second vibrator housing frame 31P-2 described later.

As shown in FIG. 4, the rotor mechanism unit 13 includes a bearing 13b, a sliding plate 13f, and a gear 13g.
As shown in FIG. 2, the bearing 13b is provided on a positioning pin 43-1 provided on the upper end surface of the first laminated piezoelectric element 40-1, and on a lower end surface of a second laminated piezoelectric element 40-2 described later. This is a bearing member into which the positioning pin 43-2 is inserted. Specifically, the bearing 13b is a bearing member whose outer peripheral surface is configured to be rotatable or a sliding bearing having a small friction coefficient on the inner peripheral side.

  The sliding plate 13f is a member having a substantially annular shape, and one surface (lower end surface) is in contact with the friction contact 41-1 provided on the upper end surface of the first laminated piezoelectric element 40-1, and the other. The direction (upper end surface) is disposed so as to contact the friction contact 41-2 provided on the lower end surface of the second laminated piezoelectric element 40-2. The outer peripheral surface of the sliding plate 13f is fixed to the inner peripheral surface of the gear 13g, while the inner peripheral surface of the sliding plate 13f is fixed to the outer peripheral surface of the bearing 13b.

The gear 13g is a gear having a substantially annular shape, and a sliding plate 13f is inserted into a hollow portion thereof, and an outer peripheral surface of the sliding plate 13f is fixed to an inner peripheral surface of the gear 13g. Yes.
Hereinafter, the second vibrator housing frame 31P-2 and members assembled to the second vibrator housing frame 31P-2 will be described in detail.

  As shown in FIGS. 6A and 6B, the second vibrating body housing frame 31P-2 is a main plane that is a pair of plate-like members facing the main plane of the second laminated piezoelectric element 40-2 having a substantially rectangular parallelepiped shape. It consists of opposing plate-like members 31P1-2 and 31P2-2. The main plane opposing plate-like members 31P1-2 and 31P2-2 are connected to the above-described rotor mechanism housing frame 31R on one side, and a fixing plate 27 described later is assembled to the other side.

  A plurality of screw holes 31P1sh-2 for screwing the regulating member 51a1-2 are formed in the main plane opposing plate-like member 31P1-2 in the thickness direction, and are provided in the regulating member 51a1-2. A plurality of through holes 31P1th-2 through which the plurality of protrusions 51a1t-2 are respectively inserted are formed.

Further, a screw hole 31P1sh for screwing the fixing plate 27 as shown in FIG. 6B is formed in a contact portion of the main plane opposing plate-like member 31P1-2 with a plate-like portion 27P1 of the fixing plate 27 described later. -2 is formed.
Similarly, a plurality of screw holes 31P2sh-2 for screwing the restriction member 51a2-2 are formed in the main plane opposing plate member 31P2-2 in the thickness direction, and the restriction member 51a2-2 is formed. A plurality of through-holes 31P2th-2 are provided through which the plurality of protrusions 51a2t-2 provided in the respective holes are inserted.

Further, a screw hole 31P2sh for screwing the fixing plate 27 as shown in FIG. 6B is provided at a contact portion of the main plane facing plate-like member 31P2-2 with a plate-like portion 27P2 of the fixing plate 27 described later. -2 is formed.
The fixing plate 27 is a member having a substantially U-shaped cross section, and a pair of plate-like portions that abut on the main plane opposing plate-like members 31P1-2 and 31P2-2 of the second vibrating body housing frame 31P-2. 27P1 and 27P2 and a mounting portion 27P3 mounted on the upper end surfaces of the main plane opposing plate-like members 31P1-2 and 31P2-2.

  As shown in FIGS. 2 and 6B, when the fixed plate 27 is assembled to the second vibrating body housing frame 31P-2, the plate-like portion 27P1 includes a screw of the main plane facing plate-like member 31P1-2. A screw hole 27P1sh that forms one screw hole integrally with the hole 31P1sh-2 is formed.

  Similarly, as shown in FIGS. 2 and 6B, when the fixed plate 27 is assembled to the second vibrating body housing frame 31P-2, the plate-like portion 27P2 has a main plane facing plate-like member 31P2-. A screw hole 27P2sh that forms one screw hole is formed integrally with the two screw holes 31P2sh-2.

As shown in FIGS. 2 and 6B, the placement portion 27P3 includes a pressing shaft insertion hole 27P3h into which the pressing shaft 22a-2 is inserted, and the first stacked piezoelectric element 40-1 of the placement portion 27P3. It is provided at a position on the extension of the torsion axis (the center axis of torsional vibration).
The restriction member 51a1-2 is a plate-like member in which a plurality (two in this example) of protrusions 51a1t-2 are provided so as to protrude in the thickness direction, and screw holes 51a1h-2 are formed in the thickness direction. . Similarly, the regulating member 51a2-2 is a plate-like member in which a plurality (two in this example) of protrusions 51a2t-2 are provided so as to protrude in the thickness direction, and screw holes 51a2h-2 are formed in the thickness direction. Has been.

  As shown in FIG. 2 and FIG. 6A, the restricting member 51a1-2 has its protrusion 51a1t-2 inserted into the through hole 31P1th-2 of the main plane opposing plate member 31P1-2, so that the second laminated piezoelectric element 40-2 is abutted against the main plane opposing plate member 31P1-2 so as to be in contact with the vicinity of the node position of the torsional vibration of the main plane of 40-2, and by the screw Sr using the screw hole 51a1h-2. Screwed and fixed.

  Similarly, the restricting member 51a2-2 is twisted in the main plane of the second laminated piezoelectric element 40-2 by the protrusion 51a2t-2 being inserted into the through hole of the main plane opposing plate member 31P2-2. It is applied to the main plane facing plate-like member 31P2-2 so as to be in contact with the vicinity of the vibration node position, and is screwed and fixed by the screw Sr using the screw holes 51a2h-2.

  As described above, the protrusions 51a1t-2 and 51a2t-2 of the regulating members 51a1-2 and 51a2-2 are twisted of the second laminated piezoelectric element 40-2 in the main plane of the second laminated piezoelectric element 40-2. By being fixed in contact with the node position of the vibration, the vibration of the second laminated piezoelectric element 40-2 is not hindered (torsional vibration excited on the end surface in the longitudinal direction of the second laminated piezoelectric element 40-2) Rotation of the second laminated piezoelectric element 40-2 (rotation in the same direction as the rotation of the gear 13g, rotation in a plane perpendicular to the direction of the pressing force of the pressing spring 21-2). ) Is regulated.

The second pressing mechanism 20-2 includes a pressing spring 21-2 and a pressing shaft 22a-2 as shown in FIGS. 6A and 6B.
The pressing spring 21-2 is a member for pressing the second laminated piezoelectric element 40-2 toward the rotor mechanism portion 13, and is positioned by a pressing shaft 22a-2 inserted through the pressing spring 21-2. The The pressing spring 21-2 is sandwiched from above and below by the mounting portion 27P3 of the fixed plate 27 and the second laminated piezoelectric element 40-2, and is held in a bent state. Specifically, the pressing spring 21-2 is, for example, a leaf spring or a coil spring.

The pressing shaft 22a-2 is a shaft member through which the pressing spring 21-2 is inserted. One end of the pressing shaft 22a-2 is fixed to the upper end surface of the second laminated piezoelectric element 40-2, and the other end is inserted into a pressing shaft insertion hole 27P3h formed in the mounting portion 27P3 of the fixing plate 27.
In this way, one end of the pressing shaft 22a-2 is fixed to the upper end surface of the second multilayer piezoelectric element 40-2, and the other end of the pressing shaft 22a-2 is placed on the mounting portion 27P3 of the fixing plate 27. The second laminated piezoelectric element 40-2 is positioned (position regulation) by being inserted into the formed pressing shaft insertion hole 27P3h (the second laminated piezoelectric element 40-2 is pressed by the pressing spring 21-2). Movement in a direction perpendicular to the direction of With the above-described configuration, the pressing shaft 22a-2 and the central axis in the longitudinal direction of the second laminated piezoelectric element 40-2 (the central axis of torsional vibration) coincide with each other.

The second laminated piezoelectric element 40-2 is a vibrating body (details of the laminated structure will be described later) formed by laminating piezoelectric sheets, and is provided with a friction contact 41-2 and a positioning pin 43-2. ing.
The friction contact 41-2 is provided in the vicinity of the position where the elliptical vibration optimal for driving occurs in the lower end surface of the second laminated piezoelectric element 40-2 (the surface facing the rotor mechanism portion 13). The portion 13 is in contact with the sliding plate 13f.

The positioning pin 43-2 is arranged on the lower end surface of the lower end surface of the second laminated piezoelectric element 40-2 on the center in the long side direction and the short side direction (the rotation axis (center axis) of the rotor mechanism unit 13). On the other hand, it is fixed to the lower end surface by adhesion or the like so as to be vertically convex.
The positioning pin 43-2 is inserted into an inner diameter hole of a bearing 13b described later. When the rotor mechanism unit 13 (bearing 13b, sliding plate 13f, gear 13g) is disposed on the second laminated piezoelectric element 40-2, the positioning pin 43-2 is inserted into the bearing 13b, whereby the rotor mechanism unit 13 and the center of the upper end surface of the second laminated piezoelectric element 40-2 coincide with each other.

By assembling using the pressing shaft 22a-2 and the positioning pin 43-2, the center axis (center axis in torsional vibration) of the second laminated piezoelectric element 40-2 and the center axis (rotation) of the rotor mechanism unit 13 are rotated. Assemble with the axis aligned.
Hereinafter, an assembly process of the ultrasonic motor according to the present embodiment will be described.

  First, as shown in FIG. 3, the pressing shaft 22a-1 of the first pressing mechanism portion 20-1 is inserted into the pressing shaft insertion hole 31P3h formed in the bottom plate-like member 31P3 of the first vibrating body housing frame 31P-1. Further, the pressing spring 21-1 is inserted into the pressing shaft 22a-1, and the first laminated piezoelectric element 40-1 is placed on the pressing shaft 22a-1 and fixed by adhesion or the like. Specifically, the pressing shaft 22a-1 is fixed to a position corresponding to the central axis of the torsional vibration on the lower end surface of the first laminated piezoelectric element 40-1.

  Subsequently, the protrusions 51a1t-1 of the restricting member 51a1-1 are inserted into the through holes 31P1th-1 of the main plane opposing plate member 31P1-1, and the screw holes 51a1h-1 of the restricting member 51a1-1 and the main plane are opposed to each other. Screws Sr are screwed into the screw holes 31P1sh-1 of the plate-like member 31P1-1 and fastened, and the first laminated piezoelectric element 40-1 is projected from the main plane side of the protrusion 51a1t-1 of the regulating member 51a1-1. Position with pinch.

  Similarly, the protrusion 51a2t-1 of the restricting member 51a2-1 is inserted into the through hole 31P2th-1, and the screw hole 51a2h-1 of the restricting member 51a2-1 and the screw hole 31P2sh− of the main plane opposing plate-like member 31P2-1. The screw Sr is screwed into 1 and fastened, and the first laminated piezoelectric element 40-1 is sandwiched and positioned by the protrusions 51a2t-1 of the regulating member 51a2-1 from the main plane side.

Further, as shown in FIG. 5, the rotor mechanism portion 13 is disposed from the side surface (opening side) in the rotor mechanism housing frame 31R, and the positioning pins 43-1 of the first laminated piezoelectric element 40-1 are connected to the rotor mechanism. It is inserted into the inner diameter hole of the bearing 13 b of the portion 13.
Thereafter, as shown in FIG. 6A, the second laminated piezoelectric element 40-2 is inserted into the second vibrating body housing frame 31P-2 from the upper side (opening side) of the second laminated piezoelectric element 40-2. The positioning pin 43-2 on the lower end surface is inserted into the inner diameter hole of the bearing 13b of the rotor mechanism unit 13.

  Subsequently, as shown in FIG. 6A, the protrusions 51a1t-2 of the regulating member 51a1-2 are inserted into the through holes 31P1th-2, and the screw holes 51a1h-2 of the regulating member 51a1-2 and the main plane opposing plate member 31P1 are inserted. -2 screw holes 31P1sh-2 are screwed and fastened, and the second laminated piezoelectric element 40-2 is sandwiched by the protrusions 51a1t-2 of the regulating member 51a1-2 from the main plane side. Position.

  Similarly, as shown in FIG. 6A, the protrusions 51a2t-2 of the restricting member 51a2-2 are inserted into the through holes 31P2th-2, and the screw holes 51a2h-2 of the restricting member 51a2-2 and the main plane opposing plate member 31P2 are inserted. -2 screw holes 31P2sh-2 are screwed in and fastened, and the second laminated piezoelectric element 40-2 is sandwiched by the projecting portions 51a2t-2 of the regulating member 51a2-2 from the main plane side. Position.

  Here, the protrusions 51a1t-1, 51a2t-1, 51a1t-2, and 51a2t-2 of the above-described regulating members 51a1-1, 51a2-1, 51a1-2, and 51a2-2 are respectively connected to the laminated piezoelectric elements 40-1. 40-2 is in contact with “near position of torsional vibration” (contacting so as not to inhibit torsional vibration).

  Finally, as shown in FIG. 6B, the pressing shaft 22a-2 is fixed to the position corresponding to the central axis of the torsional vibration of the upper end surface of the second laminated piezoelectric element 40-2 by bonding or the like, and the pressing shaft 22a- 2 is inserted through the pressing spring 21-2. Then, the pressing shaft 22a-2 is inserted into the pressing shaft insertion hole 27P3h formed in the mounting portion 27P3 of the fixed plate 27, and the fixed plate 27 is mounted on the second vibrator housing frame 31P-2. The screw holes 27P1sh and 27P2sh formed in the plate-like portions 27P1 and 27P2 and the screw holes 31P1sh formed in the main plane opposing plate-like members 31P1-2 and 31P2-2 of the second vibrator housing frame 31P-2. The screw Sr is screwed into -2, 31P2sh-2, and the fixing plate 27 is fixed to the second vibrating body housing frame 31P-2.

Hereinafter, the vibration modes of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 will be described in detail.
FIG. 7A is a perspective view showing a vibration state of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 in a vertical primary vibration mode by a broken line. FIG. 7B is a perspective view showing a vibration state of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 in a torsional secondary vibration mode by a broken line. 7A and 7B, the states (shapes) of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 before vibration are indicated by solid lines, and the laminated piezoelectric element 40 during vibration in each vibration mode is shown. The state (shape) is indicated by a broken line.

Here, as shown in FIGS. 7A and 7B, the length of the short side constituting the cross section orthogonal to the central axis 100c of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 having a substantially rectangular parallelepiped shape. Is a, the length of the long side is b, and the height along the central axis 100c is c. However, the size relationship between the short side a, the long side b, and the height c is
a <b <c
Suppose that In the following description, the height c direction is defined as the vibration direction of the longitudinal primary vibration mode and the torsional axial direction of the torsional vibration.

  In the ultrasonic motor according to the present embodiment, the values of the dimensions of the short side a, the long side b, and the height c of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 are appropriately set. By doing so, the resonance frequency of the longitudinal primary vibration mode and the resonance frequency of the torsional secondary vibration mode or the torsional tertiary vibration mode are substantially matched.

In FIGS. 7A and 7B, p1 and p2 indicate directions of torsional vibration, q indicates a direction of longitudinal vibration, and N indicates a vibration node.
In the longitudinal primary vibration shown in FIG. 7A, one node N exists at the center position in the height c direction of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2. In the torsional secondary vibration shown in FIG. 7B, the node N exists at two positions in the height c direction and the position of the central axis 100c.

  Hereinafter, the piezoelectric sheets constituting the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 will be described in detail. FIG. 8A is a diagram illustrating a configuration example of a piezoelectric sheet constituting the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2. As shown in the figure, the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 include three types of piezoelectric sheets (first piezoelectric sheet 401, second piezoelectric sheet 402, third piezoelectric element). 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. Further, the positions where the above-described internal electrodes 401a, 401c, 402a, and 402c are provided are positions corresponding to positions where the stress of torsional vibration is maximized among the laminated piezoelectric elements 40-1 and 40-2. .

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. 8B is a diagram illustrating an example of a laminated structure of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2. 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 first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 adopting the above-described configuration are determined using the following characteristics of the laminated 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. 9 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.

  FIG. 10A is a diagram showing the outer shape of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2. FIG. 10B is a side view of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 as viewed from the direction indicated by the arrow A1 in FIG. 10A. FIG. 10C is a side view of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 as viewed from the direction indicated by the arrow A2 in FIG. 10A.

  As shown in FIG. 10B, on one side surface of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2, an external electrode 101B + that connects (short-circuits) the end portions 401ae at the second laminated portion, The external electrode 101B− that connects (short-circuits) the end portions 402ae at the second stacked portion, the external electrode 101A + that connects (short-circuit) the end portions 401ae at the fourth stacked portion, and the end portions 402ae at the fourth stacked portion. Is connected (short-circuited).

Here, the external electrode 101A + constitutes an A + phase external electrode, the external electrode 101A− constitutes an A− phase external electrode, and the external electrode 101B + constitutes a B + phase external electrode. The external electrode 101B- constitutes a B-phase external electrode.
Further, as shown in FIG. 10C, the external electrode 101 </ b> C + that connects (short-circuits) the end portions 401 ce at the second laminated portion is provided on one side surface of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2. And an external electrode 101C− that connects (short-circuits) the end portions 402ce in the second stacked portion, an external electrode 101D + that connects (short-circuits) the end portions 401ce in the fourth stacked portion, and an end portion in the fourth stacked portion. An external electrode 101D- that connects (short-circuits) 402ce is provided.

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. − Represents a D-phase external electrode.
Although not shown, for example, an FPC is fixed to each of these external electrodes, and a driving voltage is applied to each external electrode from the predetermined power source via the FPC.

  Here, of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2, at least a portion where the + phase first internal electrode 401a and the − phase first internal electrode 402a face each other, and The portion where the + phase second internal electrode 401c and the − phase second internal electrode 402c face each other is a piezoelectrically activated region activated piezoelectrically. That is, a high voltage is applied 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. Applied, each electrode is polarized and piezoelectrically activated.

FIG. 11 is a diagram schematically showing the first laminated piezoelectric element 40-1, the second laminated piezoelectric element 40-2, and the rotor mechanism unit 13.
In the ultrasonic motor according to this embodiment, as described above, two laminated piezoelectric elements (the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2) having the same configuration are arranged in the longitudinal direction of each piezoelectric element. Along the direction (vertical direction), the rotor mechanism unit 13 is interposed in series. In order to arrange in this manner, the rotational driving direction of the rotor mechanism unit 13 by these two laminated piezoelectric elements (the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2) is set to be the same direction. In FIG. 11, the drive voltages applied to the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 must be voltages having opposite polarities as shown in FIG.

  That is, the drive voltage applied to each phase (A + phase, A− phase, B + phase, B− phase) of the first multilayer piezoelectric element 40-1 and the second multilayer piezoelectric element 40-2 corresponding to each phase. The phase difference from the drive voltage applied to each phase (A + phase, A− phase, B + phase, B− phase) must be approximately 180 degrees.

Specifically, in the example shown in FIG. 11, the drive voltage is applied as follows.
A driving voltage having the same polarity is applied to the A-phase of the first laminated piezoelectric element 40-1 and the A + phase of the second laminated piezoelectric element 40-2 by the driving voltage source VA-1.
The drive voltage source VA-2 has the same polarity for the A + phase (external electrode 101A +) of the first multilayer piezoelectric element 40-1 and the A-phase (external electrode 101A-) of the second multilayer piezoelectric element 40-2. Apply drive voltage.
The drive voltage source VB-1 has the same polarity for the B + phase (external electrode 101B +) of the first multilayer piezoelectric element 40-1 and the B-phase (external electrode 101B-) of the second multilayer piezoelectric element 40-2. Apply drive voltage.
The drive voltage source VB-2 has the same polarity for the B-phase (external electrode 101B-) of the first multilayer piezoelectric element 40-1 and the B + phase (external electrode 101B +) of the second multilayer piezoelectric element 40-2. Apply drive voltage.

In this way, by setting the wiring configuration for applying the drive voltage in parallel, the rotor mechanism section 13 can be formed by the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 with a small number of wires. Can be rotated in a desired direction.
By the way, the drive voltage may be applied to the C-phase and D-phase external electrodes of the laminated piezoelectric elements 40-1 and 40-2 in the same manner as in the case of the A-phase and B-phase external electrodes. Thereby, the driving force of the ultrasonic motor can be further increased. The C-phase and D-phase external electrodes of the multilayer piezoelectric elements 40-1 and 40-2 are used as vibration detection electrodes for detecting the vibration of the multilayer piezoelectric elements 40-1 and 40-2. Of course, it does not matter if it is not used at all.

As described above, according to the present embodiment, it is possible to provide an ultrasonic motor that realizes a simple configuration and that is less likely to promote frictional contact wear even when driven to obtain a high torque. Can do. Specifically, according to the ultrasonic motor according to the present embodiment, for example, the following effects can be obtained.
-By using two vibrators (first laminated piezoelectric element 40-1 and second laminated piezoelectric element 40-2), without increasing the pressing force per vibrator (acceleration of friction contact wear) The torque of the ultrasonic motor can be increased. In other words, high torque is achieved and durability is not deteriorated.
-Since the structure which clamps the rotor mechanism part 13 with two vibrator | oscillators (1st laminated piezoelectric element 40-1 and 2nd laminated piezoelectric element 40-2) is taken, static holding force improves.
-At the time of assembly, since the positioning between the members is automatically performed by the positioning pins 43-1 and 43-2 and the pressing shafts 22a-1 and 22a-2, the rotation center of the rotor mechanism unit 13 A simple configuration includes three axes: an axis, an axis of torsional vibration of the first laminated piezoelectric element 40-1, an axis of torsional vibration of the second laminated piezoelectric element 40-2, and a rotation axis of the rotor mechanism 13 ( Can be easily matched). That is, the ease of assembly and the accuracy of assembly are improved.
The movement of the first laminated piezoelectric element 40-1 and the second laminated piezoelectric element 40-2 in the rotation direction of the rotor mechanism unit 13 has a simple configuration (regulating members 51a1-1, 51a2-1, 51a1-2, 51a2 -2).
As described above, the number of assembly processes can be reduced and the cost can be reduced by a simple assembly process. Furthermore, by reducing the number of assembly processes, it is possible to reduce the variation in motor performance and improve the stability of performance.

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.
For example, on each side surface of each of the laminated piezoelectric elements 40-1 and 40-2, the same-polarity electrodes of the A-phase external electrode 101A and the D-phase external electrode 101D are short-circuited (the external electrode 101A + and the external electrode 101D + are connected to each other). By short-circuiting and short-circuiting the external electrode 101A- and the external electrode 101D-) and short-circuiting the same-polarity electrodes of the B-phase external electrode 101B and the C-phase external electrode 101C (external Wiring can be reduced by short-circuiting the electrode 101B + and the external electrode 101C + and short-circuiting the external electrode 101B- and the external electrode 101C-). In each of the piezoelectric sheets 401 and 402, the internal electrodes are formed in a pattern that enables such a short circuit between the external electrodes. With this configuration, normally, eight wirings (lands) are required for the positive electrode and the negative electrode, but driving with four driving electrodes is possible with the four wirings (lands).

  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 be extracted as an invention.

    DESCRIPTION OF SYMBOLS 13 ... Rotor mechanism part, 13f ... Sliding plate, 13g ... Gear, 20-1, 20-2 ... Pressing mechanism part, 21-1, 21-2 ... Pressing spring, 22a-1, 22a-2 ... Pressing shaft, 27 ... fixed plate, 27P1, 27P2 ... plate-like portion, 27P3 ... mounting portion, 27P1sh, 27P2sh ... screw hole, 27P3h ... pressing shaft insertion hole, 31 ... frame, 31P ... vibrator housing frame, 31R ... rotor mechanism housing frame 31P1, 31P2 ... Main plane facing plate member, 31P3 ... Bottom plate member, 31P1sh, 31P2sh ... Screw hole, 31P1th, 31P2th ... Through hole, 31P3h ... Press shaft insertion hole, 31R1, 31R2 ... U-shaped member, 40 -1 ... 1st laminated piezoelectric element, 40-2 ... 2nd laminated piezoelectric element, 41-1, 41-2 ... Friction contact, 43-1, 43 2 ... Positioning pins, 51a1, 51a2 ... Restriction members, 51a1t, 51a2t ... Projections, 51a1h, 51a2h ... Screw holes, 100c ... Center axis, 101A, 101B, 101C, 101D ... External electrodes, 401a, 401c, 402a, 402c ... Internal electrode, 401ae, 401ce, 402ae, 402ce ... end, 401 ... first piezoelectric sheet, 402 ... second piezoelectric sheet, 403 ... third piezoelectric sheet, 411 ... first layered part, 412 ... second layered Site, 413 ... 3rd lamination site, 414 ... 4th lamination site, 415 ... 5th lamination site.

Claims (8)

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. An ultrasonic motor that rotationally drives a rotor mechanism unit using the elliptical vibration of a vibrator whose elliptical vibration is excited by simultaneously exciting torsional vibration as an axis,
A first vibrator that is a pair of vibrators arranged in series along the longitudinal vibration direction so as to sandwich the rotor mechanism portion from one direction side and the other direction side in the longitudinal vibration direction; A second vibrator;
A first friction contact provided on a surface of the first vibrator facing the rotor mechanism,
A second friction contact provided on a surface of the second vibrator facing the rotor mechanism,
A first positioning pin provided on the surface of the first vibrator facing the rotor mechanism portion, substantially perpendicular to the surface on an extension of the rotation shaft of the rotor mechanism portion;
A second positioning pin provided on the surface of the second vibrator that faces the rotor mechanism portion, substantially perpendicular to the surface on the extension of the rotation shaft of the rotor mechanism portion;
A bearing portion into which the first positioning pin and the second positioning pin are inserted, a first friction contact surface that contacts the first friction contact, and the second friction contact And a driven body having a second frictional contact surface in contact with each other, and rotationally driven with the elliptical vibration of the first vibrator and the second vibrator as a drive source and the central axis as a rotation axis A rotor mechanism portion to be
A first pressing portion that presses the first vibrator toward the rotor mechanism portion;
A second pressing portion that presses the second vibrator toward the rotor mechanism portion;
A frame for holding the first vibrator and the second vibrator together with the rotor mechanism section, the first pressing section, and the second pressing section,
An ultrasonic motor comprising: The ultrasonic wave according to claim 1, wherein the torsion axis of the first vibrator, the torsion axis of the second vibrator, and the rotation axis of the rotor mechanism unit are coaxial. motor. The first pressing part presses the vicinity of the node position of the torsional vibration of the first vibrator toward the rotor mechanism part,
2. The ultrasonic motor according to claim 1, wherein the second pressing portion presses the vicinity of the node position of the torsional vibration of the second vibrator toward the rotor mechanism portion. The first pressing portion includes a first pressing shaft that contacts the vicinity of the node position of the torsional vibration of the first vibrator, and a first pressing portion that presses the first pressing shaft toward the rotor mechanism portion. 1 elastic member,
The second pressing portion includes a second pressing shaft that is close to a node position of the torsional vibration of the second vibrator, and a second pressing portion that presses the second pressing shaft toward the rotor mechanism portion. The ultrasonic motor according to claim 3, further comprising: an elastic member. The first positioning pin is provided in the vicinity of the torsional vibration node position of the first vibrator, and the second positioning pin is the torsional vibration node of the second vibrator. The ultrasonic motor according to claim 1, wherein the ultrasonic motor is provided near a position. The first vibrator and the second vibrator have a substantially rectangular parallelepiped shape,
A first restricting member that contacts a node position of the torsional vibration of the main plane of the first vibrator and restricts the rotation of the first vibrator in the same direction as the rotation direction of the rotor mechanism; ,
A second regulating member that contacts a node position of the torsional vibration of the main plane of the second vibrator and regulates the rotation of the second vibrator in the same direction as the rotation direction of the rotor mechanism; ,
The ultrasonic motor according to claim 1, further comprising: The ultrasonic motor according to claim 1, wherein the drive voltage applied to the first vibrator and the drive voltage applied to the second vibrator have opposite polarities. Provided with a two-phase drive electrode comprising at least an A phase and a B phase, provided on each of the first vibrator and the second vibrator;
The two-phase drive electrodes are:
A first A-phase voltage that applies the same drive voltage to the positive electrode of the A-phase drive electrodes of the first vibrator and the negative electrode of the A-phase drive electrodes of the second vibrator. The source,
A second A-phase voltage that applies the same drive voltage to the negative electrode of the A-phase drive electrodes of the first vibrator and the positive electrode of the A-phase drive electrodes of the second vibrator. The source,
A first B-phase voltage that applies the same drive voltage to the positive electrode of the B-phase drive electrodes of the first vibrator and the negative electrode of the B-phase drive electrodes of the second vibrator. The source,
A second B-phase voltage that applies the same drive voltage to the negative electrode of the B-phase drive electrode of the first vibrator and the positive electrode of the B-phase drive electrode of the second vibrator. The source,
The ultrasonic motor according to claim 1, further comprising:

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