JP4150056B2 - Ultrasonic motor and electronic device with ultrasonic motor - Google Patents

Description

    The present invention relates to an ultrasonic motor that generates a large torque and stabilizes the torque, and an electronic apparatus with an ultrasonic motor.

    Recently, in the field of micro motors, ultrasonic motors using the piezoelectric effect of piezoelectric elements have attracted attention because of their advantages of high conversion efficiency from electrical energy to mechanical energy and downsizing of the device configuration. In particular, an ultrasonic motor of a type that obtains a driving force by two-mode vibration of the piezoelectric vibrator itself is widely used from the viewpoint of miniaturization (FIG. 14: Non-Patent Document 1).

  This ultrasonic motor 100 performs a predetermined polarization process and generates a bending vibration and a stretching vibration, and a support member that is a central part of the piezoelectric vibrator 101 and supports the bending vibration and the stretching vibration by sandwiching the node. 102, a pressing member 103 fixed to the periphery of the support member 102, and a moving body 104 in which the end face of the piezoelectric vibrator 101 is pressed.

The piezoelectric vibrator 101 simultaneously excites bending vibration and expansion vibration and elliptically vibrates on the peripheral surface, while the applied pressure is applied to the central portion of the piezoelectric vibrator 101 via the pressurizing member 103 and the support member 102. The piezoelectric vibrator 101 and the moving body 104 are periodically pressed against each other to generate a frictional force between them. Then, the moving body 104 is rotated in one direction.
Manabu Aoyagi, Yoshiro Tomikawa Ultrasonic Motor Using Longitudinal-Bending Coupled Vibration of Obliquely Symmetrical Piezoelectric Plate Proceedings of 6th Dynamics Symposium on Electromagnetic Force P355-360

    However, in the ultrasonic motor 100 according to the prior art, the piezoelectric vibrator 101 and the moving body 104 are directly brought into contact with each other and converted into the rotational force of the moving body 104. Therefore, the wear resistance of the piezoelectric vibrator 101 made of a piezoelectric element is low. The output (torque) of the ultrasonic motor 100 is small and unstable. Therefore, a structure may be adopted in which protrusions made of a highly wear-resistant material are provided on the piezoelectric vibrator 101 and brought into contact with the moving body 104. In this case, however, the balance of vibration is lost above and below the piezoelectric vibrator 101. I have.

  The unstable vibration state and the fluctuation of the frictional force described above cause a problem that a large torque cannot be generated and the torque is fluctuated.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an ultrasonic motor and an electronic apparatus with an ultrasonic motor that generate large torque and stabilize torque and moving speed.

    Therefore, in order to solve the above problems, the ultrasonic motor of the present invention includes a plate-like piezoelectric vibrator having a piezoelectric element, and a relative movement with the piezoelectric vibrator due to the vibration of the piezoelectric vibrator. A structure having a moving body, a protrusion provided on the piezoelectric vibrator and in contact with the moving body, and a balance protrusion on a side surface opposite to the side surface of the piezoelectric vibrator provided with the protrusion. And

  According to this, the vibration balance of the piezoelectric vibrator is stabilized. This also keeps the node of the piezoelectric vibrator at the center of the piezoelectric vibrator, so that the piezoelectric vibrator can be supported without suppressing vibration. Therefore, a large torque can be stably taken out from the ultrasonic motor.

    According to the present invention, an ultrasonic motor that can stably extract a large torque can be realized.

Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to FIGS.

(Embodiment 1)
FIG. 1 shows an ultrasonic motor according to a first embodiment to which the present invention is applied. FIG. 1 (a) shows a front structure, and FIG. 1 (b) shows a bottom structure.

  This ultrasonic motor includes a piezoelectric vibrator 11, a vibration expanding member 12 of the present invention provided on the bottom surface of the piezoelectric vibrator 11, a low elastic modulus member 13 provided on the top surface of the piezoelectric vibrator 11, A guide case 14 as a node guide member of the present invention disposed around the piezoelectric vibrator 11, a pressure member 15 provided on the upper surface of the guide case 14, and a guide plate 16 in which the side portions of the guide case 14 are fitted together. The tip of the vibration expansion projection 12 is in pressure contact with the moving body 17.

  2 and 3 are diagrams showing the structure and vibration state of the piezoelectric vibrator.

  The piezoelectric vibrator 11 includes a first piezoelectric vibrator 111 and a second piezoelectric vibrator 112 laminated on the first piezoelectric vibrator 111. Each of the piezoelectric vibrators 111 and 112 is manufactured using a piezoelectric material such as barium titanate, lead zirconate titanate, lithium niobate, or lithium tantalate.

  In the first piezoelectric vibrator 111, the entire surface is polarized in the thickness direction with the front side in the figure as (−) and the back side as (+) to form a polarization part 111a. Further, electrodes are formed on the entire front side and the entire back side.

  The second piezoelectric vibrator 112 divides a rectangular body into four parts, and a first polarization part 112a that is polarized in the thickness direction with the front side in the figure as (+) and the back side as (-) for each divided part, It has the 2nd polarization part 112b, the 3rd polarization part 112c, and the 4th polarization part 112d. In addition, electrodes are formed on the front side of each polarization portion 112a... 112d, while electrodes are formed on the entire back surface of the second piezoelectric vibrator 112 as a counter electrode. In addition, the electrode of the first polarization unit 112a and the electrode of the second polarization unit 112b are electrically connected by a conducting wire, and the electrode of the third polarization unit 112c and the fourth polarization unit 112d are electrically conducted by a conducting wire.

  When a drive signal is input to the polarization unit 111a of the first piezoelectric vibrator 111 and the first polarization unit 112a and the second polarization unit 112b of the second piezoelectric vibrator 112, as shown in FIG. The vibration V1 is generated in the first piezoelectric vibrator 111, the bending vibration V2 and the stretching vibration (not shown) are generated in the second piezoelectric vibrator 112, and the elliptical vibration V3 rotating in one direction is the bending vibration V2 and the stretching vibration V1. Is generated on each peripheral surface of the piezoelectric vibrator 11.

  As described above, since the stretching vibration V1 and the bending vibration V2 are generated in each of the first piezoelectric vibrator 111 and the second piezoelectric vibrator 112, the elliptical vibration V3 of the piezoelectric vibrator 11 is greatly displaced and a large torque is generated. Give rise to

  On the other hand, when a drive signal is input to the third polarization part 112c and the fourth polarization part 112d of the second piezoelectric vibrator 112 and the polarization part 111a of the first piezoelectric vibrator 111, as shown in FIG. A bending vibration V4 and a stretching vibration (not shown) that are 180 ° out of phase with the vibration V1 are generated in the second piezoelectric vibrator 112, and an elliptical vibration V5 that rotates in the opposite direction to the elliptical vibration V3 is generated in the piezoelectric vibrator 11.

  Note that only the second piezoelectric vibrator 112 may be used, and elliptical vibration may be generated in the piezoelectric vibrator 11 by the bending vibrations V2 and V4 and the expansion and contraction vibration generated thereby.

  FIG. 4 shows the positions of nodes of stretching vibration and bending vibration generated in the piezoelectric vibrator.

  When expansion / contraction vibration V1 occurs in the rectangular piezoelectric vibrator 11 shown in FIG. 10A, the center of the long side of the rectangular body becomes a node N1, as shown in FIG. On the other hand, when flexural vibrations V2 and V4 occur, three locations become nodes N2, N3, and N4 at equal intervals along the long side of the rectangular body. In the present embodiment, the position of the node N1 of the stretching vibration V1 and the position of the node N3 of the bending vibrations V2 and V4 are the same.

    Further, as shown in FIG. 1, the vibration enlarging member 12 is fixed to a pressure contact portion 11 a with the moving body 17 of the piezoelectric vibrator 11, that is, a substantially central portion of a short side. Then, the elliptical vibrations V <b> 3 and V <b> 5 of the piezoelectric vibrator 11 are expanded and pressed against the moving body 17 with a large vibration displacement, thereby generating a large frictional force with the moving body 17.

  The low elastic modulus member 13 is made of a material having a lower elastic modulus than the piezoelectric vibrator 11, for example, resin, rubber, or plastic, and does not transmit the stretching vibration V 1, bending vibration V 2, V 4 of the piezoelectric vibrator 11 to the guide case 14. The stretching vibration V1 and the like are not attenuated.

  The guide case 14 includes a front U-shaped main body, and first node guide portions 14a and 14a projecting from both arms of the U-shaped main body in the drawing toward the piezoelectric vibrator 11, and a second node guide. It consists of the parts 14b and 14b and the protrusion part 14c which protrudes toward the piezoelectric vibrator 11 from the main body upper part. Here, the guide case 14 is made of a material having a lower elastic modulus than that of the piezoelectric vibrator 11, for example, a resin such as plastic or rubber, from the viewpoint of not transmitting bending vibration and stretching vibration and not attenuating bending vibration.

  As shown in FIG. 1B, the first node guide portions 14a and 14a are located at the bending vibration node N2 of the piezoelectric vibrator 11, and are the node N2 of the piezoelectric vibrator 11, and include a pressure member. 15 abuts on both opposing parts in the width direction perpendicular to the direction of pressurization and both opposing parts in the thickness direction. Since the piezoelectric vibrator 11 does not move in the direction perpendicular to the pressurizing direction but is guided in the pressurizing direction, the bending vibration and the stretching vibration are stable, and the piezoelectric vibrator 11 and the movable body 17 are pressed against each other. The part is not displaced.

  The second node guide portions 14b and 14b are located at the bending vibration node N4 of the piezoelectric vibrator 11 and are the node N4 of the piezoelectric vibrator 11 and in the width direction perpendicular to the direction in which the pressing member 15 is pressed. 2, the two parts facing each other and the two parts facing each other in the thickness direction perpendicular to the pressing direction.

  In addition, a sheet having a low elastic modulus made of a resin having a lower elastic modulus than that of the piezoelectric vibrator 11, such as rubber or plastic, is interposed between the first node guide portion 14 a and the second node guide portion 14 b and the piezoelectric vibrating body 11. It may be interposed.

  The projecting portion 14 c is provided at a pressure contact portion 11 a with the movable body 17 of the piezoelectric vibrator 11, that is, a portion corresponding to the side opposite to the portion where the vibration enlarging member 12 is provided. The applied pressure is transmitted to the piezoelectric vibrator 11.

  The pressurizing member 15 uses, for example, a coil spring, and a corresponding portion on the opposite side to the press contact portion 11a with the moving body 17 of the piezoelectric vibrator 11 through the protruding portion 14c of the guide case 14 and the low elastic modulus member 13. To the pressure contact area. Since all the applied pressure is applied to the moving body 17 via the vibration expanding member 12, the frictional force generated between the vibration expanding member 12 and the moving body 17 is increased. The pressing member 15 may be an elastic member such as rubber or a leaf spring.

  The guide plate 16 forms a guide groove 16a into which the side portion of the guide case 14 is inserted along the pressing direction of the pressing member 15, and guides the guide case 14 in the pressing direction.

  Next, a method for using the ultrasonic motor will be described with reference to FIGS.

  When the moving body 17 is moved in one direction, drive signals are input to the polarization unit 111a of the first piezoelectric vibrator 111, the first polarization unit 112a of the second piezoelectric vibrator 112, and the second polarization unit 112b. That's fine.

  The stretching vibration V1 is generated in the first piezoelectric vibrator 111, the bending vibration V2 is generated in the second piezoelectric vibrator 112, and the elliptical vibration V3 is generated on the peripheral surface of the piezoelectric vibrator 11. The elliptical vibration V3 is magnified by the vibration enlarging member 12. On the other hand, the pressurizing member 15 is configured so that the corresponding portion of the piezoelectric vibrator 11 opposite to the press contact portion 11a with the moving body 17 is pressed through the protrusion 14c of the guide case 14 and the low elastic modulus member 13 to the press contact portion 11a. The vibration enlarging member 12 is brought into pressure contact with the moving body 17.

  At this time, all of the applied pressure is applied to the pressure contact portion 11a between the piezoelectric vibrator 11 and the moving body 17, and the guide case 14 also moves the piezoelectric vibrator 11 in the pressurizing direction against bending vibration and stretching vibration. Since it is guided only in the pressurizing direction without moving in the vertical direction, the bending vibration and expansion / contraction vibration generated in the piezoelectric vibrator 11 are stable, and the press contact portion 11a with the moving body 17 of the piezoelectric vibrator 11 does not slip. A large pressure is applied between the piezoelectric vibrator 11 and the moving body 17.

  And a big frictional force arises between the vibration expansion member 12 and the moving body 17, and the moving body 17 moves to one direction at high speed.

  On the other hand, when the moving body 17 is moved in the opposite direction, the drive signal is sent to the polarization unit 111a of the first piezoelectric vibrator 111, the third polarization unit 112c of the second piezoelectric vibrator 112, and the fourth polarization unit 112d. You can enter.

  The stretching vibration V1 is generated in the first piezoelectric vibrator 111, the bending vibration V4 is generated in the second piezoelectric vibrator 112, the reversely rotating elliptical vibration V5 is generated in the peripheral surface of the piezoelectric vibrator 11, and the elliptical vibration V5 is It is enlarged by the vibration enlarging member 12. On the other hand, the pressurizing member 15 has a part of the piezoelectric vibrator 11 opposite to the press contact part 11a facing the press contact part 11a toward the press contact part 11a via the protrusion 14c of the guide case 14 and the low elastic modulus member 13. The vibration enlarging member 12 is brought into pressure contact with the moving body 17. And the mobile body 17 receives the frictional force of a reverse direction, and moves to the direction opposite to one direction.

  As described above, according to the present embodiment, all the applied pressure is applied to the pressure contact portion 11 a between the vibration expanding projection 12 provided on the piezoelectric vibrator 11 and the moving body 17 by the pressing portion member 15, so that a large torque is applied. generate.

  In addition, the guide case 14 guides the piezoelectric vibrator 11 only in the pressurizing direction without moving the piezoelectric vibrator 11 in the direction perpendicular to the pressurizing direction even with respect to bending vibration and expansion / contraction vibration. Bending vibration and stretching vibration are stable. Accordingly, the pressure contact portion 11a of the piezoelectric vibrator 11 with the moving body 17 does not slip, so that a large pressing force is applied between the vibration expanding member 12 provided at the pressure contact portion 11a of the piezoelectric vibrator 11 and the moving body 17, and a large pressure is applied. Generates torque and stabilizes torque.

  In addition, since the first piezoelectric vibrator 111 and the second piezoelectric vibrator 112 are laminated to generate the stretching vibration V1 and the bending vibration V2, respectively, the elliptical vibration V3 of the piezoelectric vibrator 11 is greatly displaced, It produces a larger torque.

  Further, the vibration enlarging member 12 expands the elliptical vibrations V3 and V5 of the piezoelectric vibrator 11 and generates a large frictional force with the moving body 17, thereby generating a large torque and moving the moving body 17 at a high speed. Let

  Further, since the low elastic modulus member 13 is interposed between the pressure member 15 and the piezoelectric vibrator 11, the transmission of bending vibration and expansion / contraction vibration is prevented, and bending vibration or the like is not attenuated.

  Further, since the guide case 14 is made of a material having a lower elastic modulus than the piezoelectric vibrator 11, it prevents the transmission of flexural vibrations and stretching vibrations and does not attenuate the flexural vibrations.

  If a sheet having a low elastic modulus lower than that of the piezoelectric vibrator 11 is interposed between the first node guide portion 14a, the second node guide portion 14b, and the piezoelectric vibrator 11, bending vibration and Prevents transmission of stretching vibration and does not attenuate bending vibration.

(Embodiment 2)
5A and 5B show an ultrasonic motor according to Embodiment 2 to which the present invention is applied. FIG. 5A shows a front structure, and FIG. 5B shows a bottom structure.

  The ultrasonic motor includes a piezoelectric vibrator 11, a vibration enlarging member 12 provided below the piezoelectric vibrator 11, a balance protrusion 21 provided on the opposite side of the piezoelectric vibrator 11 to the vibration enlarging member 12, and a balance. The pressure member 15 is in pressure contact with the upper surface of the projection 21 and the guide case 22 as the node guide member of the present invention is in contact with the expansion / contraction vibration node of the piezoelectric vibrator 11. The same members as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  Here, the balance protrusion 21 is the same as the vibration enlarging member 12, and is provided in a corresponding portion of the piezoelectric vibrator 11 on the opposite side to the vibration enlarging member 12. Then, the vibration balance of the piezoelectric vibrator 11 is maintained, and the bending vibration and the stretching vibration are stabilized.

  As shown in FIG. 5 (b), the guide case 22 forms a substantially cross-shaped space 22 a inside a rectangular body, and the piezoelectric vibrator 11 is inserted into the cross-shaped space 22 a, so that the inner surface of the guide case 22 is formed. Are brought into contact with both parts facing each other in the width direction of the piezoelectric vibrator 11 and both parts facing each other in the thickness direction. The piezoelectric vibrator 11 is guided in the pressurizing direction without moving in the direction perpendicular to the pressurizing direction.

  Next, the operation of this ultrasonic motor will be described.

  A bending vibration and a stretching vibration are generated in the piezoelectric vibrator 11, an elliptical vibration is generated on the peripheral surface, and the displacement of the elliptical vibration is expanded by the vibration expanding member 12. On the other hand, the pressurizing member 15 pressurizes the piezoelectric vibrator 11 via the balance protrusion 21 and presses the vibration enlarging member 12 and the movable body 17 together.

  At this time, the guide case 22 does not move the piezoelectric vibrator 11 in the direction perpendicular to the pressurizing direction, stabilizes the bending vibration and the expansion / contraction vibration, and sets the pressure contact portion with the moving body 17 of the vibration expanding member 12. Does not displace.

  Further, the balance protrusion 21 equalizes the moments of inertia and rigidity of the upper and lower portions of the piezoelectric vibrator 11 and maintains the balance of the piezoelectric vibrator 11, so that the bending vibration and the like are stabilized and formed around the node.

  A frictional force is generated between the moving body 17 and the vibration enlarging member 12, and the moving body 17 moves in one direction.

  As described above, according to the present embodiment, the guide case 22 does not move the piezoelectric vibrator 11 in the direction perpendicular to the pressurizing direction, but guides only in the pressurizing direction, thereby stabilizing the bending vibration and the stretching vibration. In addition, since the pressure contact portion between the vibration enlarging member 12 and the moving body 17 is not slid, a large pressure is applied between the piezoelectric vibrator 11 and the moving body 17. As a result, a large torque is generated and the torque is stabilized as in the first embodiment.

  In addition, since the balance of the piezoelectric vibrator 11 is maintained by the balancing protrusions 21, the bending vibration and the stretching vibration are stabilized.

(Embodiment 3)
FIG. 6 shows an ultrasonic motor according to the third embodiment to which the present invention is applied, in which (a) shows a front structure and (b) shows a bottom structure.

  This ultrasonic motor includes a piezoelectric vibrator 11, a vibration expanding member 23 provided on the lower surface of the piezoelectric vibrator 11, and a guide case 24 as a node guide member of the present invention provided around a vibration node of the piezoelectric vibrator 11. The low elastic modulus member 13 provided on the upper surface of the piezoelectric vibrator 11 and the pressurizing member 15 pressed against the upper surface of the low elastic modulus member 13.

  Here, the low elastic modulus member 13 does not transmit bending vibration and expansion / contraction vibration from the piezoelectric vibrator 11 to the pressing member 15, and does not attenuate bending vibration or the like.

  The vibration enlarging member 23 has a curved surface 23 a at a pressure contact portion with the moving body 17. This curved surface 23a makes the friction generated between the movable body 17 uniform when the vibration enlarging member 23 is brought into pressure contact with the pressurizing direction, and does not vigorously wear a specific portion. Then, a constant pressure is applied to the moving body 17 to move the moving body 17 at a constant speed.

  The guide case 24 includes first and second node guide portions 24a and 24a and second node guide portions 24b and 24b that protrude toward a bending vibration node of the piezoelectric vibrator 11 in a rectangular parallelepiped having a hollow inside. The piezoelectric vibrator 11 has third node guide portions 24c, 24c, and 24c protruding toward the expansion and contraction vibration nodes.

  The first node guide portions 24a and 24a and the second node guide portions 24b and 24b are nodes of the flexural vibration of the piezoelectric vibrator 11, and are in contact with both opposing portions in the width direction perpendicular to the pressing direction. . The third node guide portions 24c, 24c, and 24c are nodes of the stretching vibration of the piezoelectric vibrator 11, and abut on opposite sides in the thickness direction perpendicular to the pressing direction.

  The first node guide portions 24a and 24a and the second node guide portions 24b and 24b of the guide case 24 do not move the piezoelectric vibrator 11 in the width direction perpendicular to the pressurizing direction. The three node guide portions 24c, 24c, and 24c do not move the piezoelectric vibrator 11 in the thickness direction perpendicular to the pressing direction. That is, the piezoelectric vibrator 11 is guided in the pressing direction without moving in the direction perpendicular to the pressing direction.

  As described above, according to the present embodiment, the guide case 24 guides the piezoelectric vibrator 11 in the pressurizing direction without moving the piezoelectric vibrator 11 in the direction perpendicular to the pressurizing direction. The effect is obtained.

  In addition, since the pressure contact portion of the vibration expanding member 23 with the moving body 17 is a curved surface 23a to prevent uneven wear caused by friction with the moving body 17, the moving body 17 applies a certain pressure. Torque is constant.

(Embodiment 4)
FIG. 7 shows an ultrasonic motor according to Embodiment 4 to which the present invention is applied, in which (a) shows a front structure and (b) shows a bottom structure.

  This ultrasonic motor includes a piezoelectric vibrator 11, a vibration expanding member 12 provided on the lower surface of the piezoelectric vibrator 11, a node guide member of the present invention disposed around the piezoelectric vibrator 11, and a guide case 25 as a guide member. And fixing members 26 and 26 fixed to the nodes of the expansion and contraction vibration of the piezoelectric vibrator 11 and a pressurizing member 15 that presses against a portion of the piezoelectric vibrator 11 opposite to the vibration enlarging member 12.

  Here, the guide case 25 is a rectangular parallelepiped with a hollow inside, and the first node guide portions 25a and 25a and the second node guide portion 25b projecting inward at the position of the bending vibration node of the piezoelectric vibrator 11. 25b, and guide grooves 25c and 25c are formed along the pressing direction on both inner surfaces of the rectangular parallelepiped.

  The first node guide portions 25a and 25a and the second node guide portions 25b and 25b are bending vibration nodes of the piezoelectric vibrator 11, and both of them are opposed in the width direction perpendicular to the pressing direction. Abuts the site.

  The end faces of the fixing members 26 and 26 are in contact with the guide grooves 25c and 25c in the thickness direction perpendicular to the pressing direction of the piezoelectric vibrator 11, as shown in FIG.

  The first node guide portions 25a and 25a and the second node guide portions 25b and 25b of the guide case 25 do not move the piezoelectric vibrator 11 in the width direction perpendicular to the pressure direction, and the pressure direction. To guide. The fixing members 26 and 26 and the guide grooves 25c and 25c guide the piezoelectric vibrator 11 in the pressing direction without moving the piezoelectric vibrator 11 in the thickness direction perpendicular to the pressing direction. That is, the piezoelectric vibrator 11 does not move in the direction perpendicular to the pressurizing direction, but is guided in the pressurizing direction, so that the expansion and contraction vibration and the bending vibration are stable, and the vibration expanding member provided in the piezoelectric vibrator 11 The press-contact portion between 12 and the moving body 17 is not displaced.

  As described above, according to the present embodiment, the guide case 25 guides the piezoelectric vibrator 11 in the pressurizing direction without moving the piezoelectric vibrator 11 in the direction perpendicular to the pressurizing direction. In addition, a large torque is obtained and the torque is stabilized.

(Embodiment 5)
FIG. 8 shows a front structure of an ultrasonic motor according to the fifth embodiment to which the present invention is applied.

  This ultrasonic motor includes a piezoelectric vibrator 11, a vibration expanding member 12 provided on the lower surface of the piezoelectric vibrator 11, and a guide as a node guide member and an end guide member of the present invention provided around the piezoelectric vibrator 11. The case 27, the pressure member 15 that press-contacts the upper surface of the guide case 27, and the guide plate 16 that fits the side portion of the guide case 26, and the tip of the vibration expanding member 12 press-contacts the disc-shaped moving body 28. is doing.

  Here, the guide case 27 includes node guide portions 27a and 27a projecting from both arms of the U-shaped guide case body toward the expansion and contraction vibration nodes of the piezoelectric vibrator 11, and piezoelectric waves from the corner portions of the guide case body. An end guide part 27 b that protrudes toward the vibrator 11 is provided.

  The node guide portions 27a and 27a are nodes of expansion and contraction vibration in the piezoelectric vibrator 11 and have thicknesses perpendicular to both the portions facing each other in the width direction perpendicular to the pressing direction of the pressing member 15 and the pressing direction. It abuts against both parts facing each other in the direction (see FIG. 1B).

  The end guide portions 27b and 27b are ends of the piezoelectric vibrator 11 on the side opposite to the vibration enlarging member 12, and are opposed to each other in the width direction perpendicular to the pressurizing direction of the pressurizing member 15 and the additional portions. In the thickness direction perpendicular to the pressure direction, the two portions that face each other and the end surface opposite to the pressure contact portion with the moving body 27 are brought into contact with each other.

  The node guide portions 27a and 27a and the end guide portions 27b and 27b guide the piezoelectric vibrator 11 in the pressing direction without moving the piezoelectric vibrator 11 in the direction perpendicular to the pressing direction. The pressurizing member 15 pressurizes the guide case 27 in a direction connecting the corresponding part of the piezoelectric vibrator 11 opposite to the vibration enlarging member 12 and the vibration enlarging member 12, and the vibration enlarging member 12 and the moving body 28, all the applied pressure is applied.

  Next, the operation of this ultrasonic motor will be described.

  Stretching vibration and bending vibration are generated in the piezoelectric vibrator 11, and the piezoelectric vibrator 11 is pressurized by the pressurizing member 15 through the guide case 27, and the vibration enlarging member 12 is brought into pressure contact with the moving body 27.

  At this time, the node guide portions 27a and 27a and the end guide portions 27b and 27b guide the piezoelectric vibrator 11 in the pressurizing direction without moving the piezoelectric vibrator 11 in the direction perpendicular to the pressurizing direction. The vibration is stable and the pressure contact portion of the piezoelectric vibrator 11 with the moving body 28 is not displaced. Then, the moving body 28 rotates in one direction.

  As described above, according to the present embodiment, the node guide portions 27a and 27a and the end guide portions 27b and 27b of the guide case 27 do not move the piezoelectric vibrator 11 in the direction perpendicular to the pressurizing direction. Since it is guided in the pressurizing direction to stabilize bending vibration and expansion / contraction vibration, and the pressure contact portion of the piezoelectric vibrator 11 with the moving body 28 is not displaced, a large pressure is applied to the pressure expanding portion of the vibration expanding member 12 and the moving body 28. Generates a large torque and stabilizes the torque.

  Furthermore, since the pressing member 15 pressurizes the vibration expanding member 12 from the corresponding part on the opposite side to the vibration expanding member 12, all the pressure is applied between the vibration expanding member 12 and the moving body 28. Join and generate a large torque.

(Embodiment 6)
FIG. 9 shows an ultrasonic motor according to the sixth embodiment to which the present invention is applied. FIG. 9A shows a side structure, FIG. 9B shows a rear structure, and FIG. 9C shows a structure observed from the bottom. This ultrasonic motor includes a laminated piezoelectric vibrator 31, a vibration expanding member 12 provided on the bottom surface of the piezoelectric vibrator 31, a fixing member 32 fixed to a bending vibration node of the piezoelectric vibrator 31, and piezoelectric vibration. The vibration expanding member 12 is in pressure contact with the moving body 17 and includes a pressure member 15 that presses the upper surface of the child 31 and a guide plate 33 as a guide member of the present invention fitted to the fixing member 32.

  FIG. 10 is a diagram showing a laminated structure of piezoelectric vibrators.

  The piezoelectric vibrator 31 includes a first piezoelectric vibrator 311, a second piezoelectric vibrator 312, a third piezoelectric vibrator 313, and a fourth piezoelectric vibrator shown in FIGS. It is a structure in which 314 is laminated and baked.

  As shown in FIGS. 4A and 4B, the first piezoelectric vibrator 311 and the second piezoelectric vibrator 312 are polarized on substantially the entire surface with the front side (+) and the back side (−). To obtain polarization portions 311a and 312a. In addition, electrodes are formed on the front side corresponding to the polarization portions 311a and 312a. In addition, two through holes 311b, 311b, 312b, and 312b through which the fixing member 32 penetrates are formed at the bending vibration nodes.

  As shown in FIGS. 3C and 3D, the third piezoelectric vibrator 313 and the fourth piezoelectric vibrator 314 have a (+) front side and a back side for each divided portion obtained by dividing the rectangular body into four parts. (−) Is applied to the polarization process to form first polarization portions 313a and 314a, second polarization portions 313b and 314b, third polarization portions 313c and 314c, and fourth polarization portions 313d and 314d. Further, through holes 313e, 313e, 314e, and 314e through which the fixing member 32 penetrates are formed in the bending vibration nodes.

  Further, on the back side of the first piezoelectric vibrator 311, the second piezoelectric vibrator 312, the third piezoelectric vibrator 313, and the fourth piezoelectric vibrator 314, as shown in FIG. An electrode is formed on the front electrode as a counter electrode of the front electrode.

  Further, as shown in FIG. 5G, a first side electrode 31a, a second side electrode 31b, and a third side electrode 31c are formed in the thickness direction on one side surface of the piezoelectric vibrator 31, A fourth side electrode and a fifth side electrode are formed on the opposite side surfaces.

The first side electrode 31 a conducts an electrode formed on the polarization part 311 a of the first piezoelectric vibrator 311 and an electrode formed on the polarization part 312 a of the second piezoelectric vibrator 312. The second side electrode 31b conducts the electrode formed on the first polarization part 313a of the third piezoelectric vibrator 313 and the electrode formed on the first polarization part 314a of the fourth piezoelectric vibrator 314. The third side surface electrode 31 c conducts the electrode formed on the fourth polarization portion 313 d of the third piezoelectric vibrator 313 and the electrode formed on the fourth polarization portion 314 d of the fourth piezoelectric vibrator 314. The fourth side electrode conducts the electrode formed on the second polarization portion 313b of the third piezoelectric vibrator 313 and the electrode formed on the second polarization portion 314b of the fourth piezoelectric vibrator 314. The fifth side electrode electrically connects the electrode formed on the third polarization portion 313c of the third piezoelectric vibrator 313 and the electrode formed on the third polarization portion 314c of the fourth piezoelectric vibrator 314.

  In addition, in the same figure (f), as shown, for example using the 1st piezoelectric vibrator 311, the through-hole 311b, each piezoelectric vibrator 311, 312, 313, 314 which penetrates the fixed shafts 321 and 321 mentioned later, The electrode 311c having a larger diameter than 312b, 313e, and 314e may be formed, and annular insulating spaces 311d and 311d may be provided between the electrode 311c and the fixed shafts 321 and 321. In this way, the fixed shafts 321 and 321 and the electrode 311c are insulated, and a short circuit between them is prevented.

  As shown in FIG. 9, the fixing member 32 includes a fixed shaft 321 penetrating the piezoelectric vibrator 31, and rubber sheets 322 and 322 around the fixed shaft 321 and in contact with the piezoelectric vibrator 31. And a plate 323 fixed with a fixed shaft 321 and screws, and nuts 324 and 324 disposed between the plate 323 and the piezoelectric vibrator 31.

  The fixed shafts 321 and 321 are formed with screws on the peripheral surface of the portion where the nut 324 and the plate 323 are fixed. Since the rubber sheet 322 has an elastic modulus lower than that of the piezoelectric vibrator 31, vibration leakage from the piezoelectric vibrator 31 is prevented. The plate 323 is formed in a trapezoidal cross section along the pressing direction, as shown in FIG.

  In this assembling method of the fixing member 32, the fixed shaft 321 is passed through the through holes 311b... 314e provided in the bending vibration nodes of the piezoelectric vibrator 31, and then both surfaces of the piezoelectric vibrator 31 along the fixed shaft 321. The nut 324 and 324 are passed through the fixed shaft 321 while the rubber sheet 322 is in contact with the plate 323, and the fixed shaft 321 is rotated to tighten the nuts 324 and 324 to fix the piezoelectric vibrator 31.

  The guide plate 33 is provided along the pressurizing direction of the piezoelectric vibrator 31. A guide groove 33a having a trapezoidal cross section is formed along the pressurizing direction, and the plate 323 is fitted into the guide groove 33a. Then, paired with the plate 323, the fixing member 32 is guided in the pressurizing direction, and the lower side and the oblique side of the guide groove 33a having a trapezoidal cross section are in contact with the plate 323. Do not move in the direction perpendicular to the pressure direction.

  The pressurizing member 15 pressurizes a portion of the piezoelectric vibrator 31 opposite to the vibration enlarging member 12 to the vibration enlarging member 12. The pressurizing member 15 may pressurize the fixed shaft 321 of the fixed member 32 in the pressurizing direction described above, or pressurize the end surface of the plate 323.

  Next, the operation of this ultrasonic motor will be described.

  Stretching vibration is generated in the first piezoelectric vibrator 311 and the second piezoelectric vibrator 312, bending vibration is generated in the third piezoelectric vibrator 313 and the fourth piezoelectric vibrator 314, and the vibration enlarging member 12 is elliptical. Vibrate. On the other hand, the pressurizing member 15 pressurizes the vibration enlarging member 12 at a corresponding portion on the opposite side to the vibration enlarging member 12.

  At this time, the guide plate 33 guides the fixing member 32 in the pressurizing direction together with the plate 323, and does not move the fixing member 32 in the direction perpendicular to the pressurizing direction. The piezoelectric vibrator 31 fixed to the fixing member 32 is also guided in the pressurizing direction and does not move in a direction perpendicular to the pressurizing direction. Therefore, bending vibration and expansion / contraction vibration are stable, and the press contact portion of the piezoelectric vibrator 31 with the moving body 17 is not displaced.

  And a big frictional force arises between the vibration expansion member 12 and the moving body 17, and the moving body 17 moves at high speed.

  As described above, according to the present embodiment, the fixing member 32 and the guide plate 33 guide the piezoelectric vibrator 31 in the pressurizing direction and prevent the piezoelectric vibrator 31 from moving in the direction perpendicular to the pressurizing direction. In addition, since the expansion and contraction vibration is stabilized and the pressure contact portion between the vibration enlarging member 12 and the moving body 17 is not slid, a large pressure is applied to the piezoelectric vibrator 31 to generate a large torque and to stabilize the torque. Let

  Moreover, since the insulating space 311d is provided between the fixed shaft 321 and the electrode 311c, the fixed shaft 321 and the electrode 311c are insulated from each other, and a short circuit between the electrode 311c and the fixed shaft 321 is prevented.

  In addition, the piezoelectric vibrator 31 causes stretching vibration in the first piezoelectric vibrator 311 and the second piezoelectric vibrator 312, and bending vibration is caused by the third piezoelectric vibrator 313 and the fourth piezoelectric vibrator 314. As a result, a larger torque is generated.

(Embodiment 7)
11A and 11B show an ultrasonic motor according to Embodiment 7 to which the present invention is applied. FIG. 11A shows a front structure, and FIG. 11B shows a side structure.

  This ultrasonic motor is provided in a piezoelectric vibrator 31, vibration expansion members 12 and 12 provided on the bottom surface of the piezoelectric vibrator 31, and corresponding portions of the piezoelectric vibrator 31 on the opposite side to the vibration expansion members 12 and 12. The balance protrusions 21, 21, the pressure members 15, 15 that pressurize the upper surfaces of the balance protrusions 21, the fixing member 36 fixed in the thickness direction of the piezoelectric vibrator 31, and the fixing member 36 It is comprised from the guide member 37 which touches.

  Here, the fixing member 36 is a spacer provided between the piezoelectric vibrator 31 and the guide member 37, and a fixed shaft 36a that penetrates the expansion / contraction vibration node of the piezoelectric vibrator 31 in a direction perpendicular to the pressing direction. 36b, 36b.

  The guide member 37 has guide grooves 37a and 37a extending in the pressurizing direction of the piezoelectric vibrator 31 at each of the U-shaped tip portions. Each side surface of the guide grooves 37a and 37a abuts on both end surfaces facing each other in the thickness direction of the piezoelectric vibrator 31 perpendicular to the pressurizing direction of the fixed shaft 36a, and pressurizes the fixed shaft 36a. In the longitudinal direction of the piezoelectric vibrator 31 perpendicular to the direction, the piezoelectric vibrator 31 is in contact with both opposing portions.

  The guide member 37 does not move the fixed shaft 36a in the direction perpendicular to the pressurizing direction, but only guides in the pressurizing direction, and the piezoelectric vibrator 31 to which the fixed shaft 36a is fixed is also perpendicular to the pressurizing direction. It does not move in any direction, but is guided in the pressurizing direction.

  As described above, according to the present embodiment, the guide member 37 and the fixing member 36 guide the piezoelectric vibrator 31 in the pressurizing direction without moving the piezoelectric vibrator 31 in the direction perpendicular to the pressurizing direction. Since the vibration is stabilized and the pressure contact portion between the vibration expanding members 12 and 12 and the moving body 17 is not displaced, a large pressing force is applied between the moving body 17 and the vibration expanding members 12 and 12, and a large torque is applied. Generates and stabilizes torque.

  In addition, the pressurizing members 15 and 15 pressurize the portion of the piezoelectric vibrator 31 opposite to the vibration enlarging members 12 and 12 toward the vibration enlarging members 12 and 12. A large torque is generated by applying to the pressure contact portion between the vibration enlarging members 12 and 12 and the moving body 17.

  Further, since the balance protrusions 21 and 21 are provided on the opposite side of the piezoelectric vibrator 31 with respect to the vibration enlarging members 12 and 12, the upper and lower moments of inertia of the piezoelectric vibrator 31 are equal, and the piezoelectric vibrator 31 is piezoelectric. The balance of the vibrator 31 is maintained, and bending vibration and stretching vibration are stabilized.

(Embodiment 8)
12A and 12B show an ultrasonic motor according to an eighth embodiment to which the present invention is applied. FIG. 12A shows a front structure, and FIG. 12B shows a side structure.

  In this ultrasonic motor, the piezoelectric vibrator 31, the vibration expansion members 12 and 12 provided on the bottom surface of the piezoelectric vibrator 31, the fixing member 41 fixed to the piezoelectric vibrator 31, and the fixing member 41 are brought into contact with each other. It consists of guide members 42 and 42 and a pressure member 15 brought into pressure contact with the fixed member 41.

  Here, the fixing member 41 is a U-shaped member that fixes the fixed shafts 41a and 41a penetrating the node of the bending vibration of the piezoelectric vibrator 31 in the direction perpendicular to the pressing direction, and both ends of the fixed shafts 41a and 41a. 41c, spacers 41b and 41b provided in a space between the U-shaped member 41c and the piezoelectric vibrator 31, and a cylindrical member 41d protruding upward from the upper surface of the U-shaped member 41c in parallel with the pressing direction. , 41d.

  The guide members 42, 42 have an annular cross section and extend in the pressurizing direction of the piezoelectric vibrator 31. Further, the cylindrical members 41d and 41d of the fixing member 41 are brought into contact with the inner peripheral surface to make the cylindrical members 41d and 41d slidable.

  The guide members 42 and 42 guide the columnar members 41d and 41d in the pressurizing direction without moving them in the direction perpendicular to the pressurizing direction. That is, the piezoelectric vibrator 31 fixed to the fixing member 41 does not move in a direction perpendicular to the pressing direction, but guides in the pressing direction.

  As described above, according to the present embodiment, the piezoelectric member 31 is not moved in the direction perpendicular to the pressurizing direction by the fixing member 41 and the guide member 42, but is guided in the pressurizing direction. Since the expansion and contraction vibration is stabilized and the pressure contact portion between the vibration expanding members 12 and 12 and the moving body 17 is not displaced, a large pressure is applied between the vibration expanding members 12 and 12 and the moving body 17. Generates a large torque and stabilizes the torque.

(Embodiment 9)
FIG. 13 is a block diagram of an electronic apparatus with an ultrasonic motor according to a ninth embodiment to which the present invention is applied.

  The electronic apparatus 50 with an ultrasonic motor includes the above-described piezoelectric vibrator 51, a moving body 52 that is moved by the piezoelectric vibrator 51, a pressurizing mechanism 53 that pressurizes the moving body 52 and the piezoelectric vibrator 51, and a moving body. This is realized by including a transmission mechanism 54 that moves in conjunction with the transmission mechanism 52 and an output mechanism 55 that moves based on the operation of the transmission mechanism 54.

  Here, for the transmission mechanism 54, for example, a transmission wheel such as a gear or a friction wheel is used. As the output mechanism 55, for example, a shutter driving mechanism and a lens driving mechanism are used in a camera, a pointer driving mechanism and a calendar driving mechanism are used in an electronic timepiece, and a cutting tool feeding mechanism and a machining member feeding mechanism are used in a machine tool.

  The electronic device 50 with an ultrasonic motor is applied to, for example, an electronic timepiece, a measuring instrument, a camera, a printer, a printing machine, a machine tool, a robot, and a moving device.

  Note that if the output shaft is attached to the moving body 52 and a power transmission mechanism for transmitting torque from the output shaft is provided, a drive mechanism can be realized by a single ultrasonic motor.

    The ultrasonic motor of the present invention is a stage that requires precise positioning, driving a reading head and a writing head in an information recording device, driving a lens in a digital camera, a video camera, etc. It can also be used to drive various driving units (calendars, hands, etc.) in a wristwatch that requires power consumption, and can be applied as a driving source for various electronic devices.

The ultrasonic motor concerning Embodiment 1 to which this invention is applied is shown, (a) is a front structure, (b) is explanatory drawing which shows the structure of a bottom face. FIG. 2 is an explanatory diagram illustrating the structure and vibration state of the piezoelectric vibrator according to FIG. 1. FIG. 2 is an explanatory diagram illustrating the structure and vibration state of the piezoelectric vibrator according to FIG. 1. FIG. 2 is an explanatory diagram illustrating the positions of nodes of stretching vibration and bending vibration generated in the piezoelectric vibrator according to FIG. 1. The ultrasonic motor concerning Embodiment 2 to which this invention is applied is shown, The figure (a) is a front structure, The figure (b) is explanatory drawing which shows the structure of a bottom face. The ultrasonic motor concerning Embodiment 3 to which this invention is applied is shown, (a) is a front structure, (b) is explanatory drawing which shows the structure of a bottom face. The ultrasonic motor concerning Embodiment 4 to which this invention is applied is shown, (a) is a front view structure, (b) is explanatory drawing which shows a bottom face structure. The structure of the front of the ultrasonic motor concerning Embodiment 5 to which this invention is applied is shown. The ultrasonic motor concerning Embodiment 6 to which this invention is applied is shown, (a) is a side structure, (b) is a back surface structure, (c) is explanatory drawing which shows the structure observed from the bottom face. FIG. 10 is an explanatory diagram illustrating a laminated structure of piezoelectric vibrators according to FIG. 9. The ultrasonic motor concerning Embodiment 7 to which this invention is applied is shown, (a) is a front structure, (b) is explanatory drawing which shows the structure of a side. The ultrasonic motor concerning Embodiment 8 to which this invention is applied is shown, (a) is a front structure, (b) is explanatory drawing which shows the structure of a side. It is explanatory drawing which shows the block diagram of the electronic device with an ultrasonic motor concerning Embodiment 9 to which this invention is applied. The structure of the ultrasonic motor concerning a prior art is shown.

Explanation of symbols

Ultrasonic motor 10
Piezoelectric vibrator 11
Vibration expansion member 12
Low modulus member 13
Information case 14
Pressure member 15
Balance projection 21
Information case 22
Vibration expansion projection 23
Information case 24
Information case 25
Fixing member 26
Information case 27
Piezoelectric vibrator 31
Insulation space 311c
Fixing member 32
Guide board 33
Fixing member 36
Guide member 37
Fixing member 41
Guide member 42

Claims (8)

A plate-like piezoelectric vibrator having a piezoelectric element;
A moving body that moves relative to the piezoelectric vibrator by the vibration of the piezoelectric vibrator;
A protrusion provided on the piezoelectric vibrator and in contact with the moving body;
In the ultrasonic motor consisting of
2. An ultrasonic motor according to claim 1, wherein a balance protrusion is provided on a side surface opposite to the side surface of the piezoelectric vibrator provided with the protrusion. The ultrasonic motor according to claim 1, wherein the protrusion has a shape in which an area of a boundary portion with the piezoelectric vibrator is larger than a contact area with the moving body. The ultrasonic motor according to claim 2, wherein the protrusion has a curved surface portion provided in a relative motion direction of the piezoelectric vibrator and the moving body. 4. The superstructure according to claim 1, wherein a balance protrusion is provided on a side surface opposite to the side surface of the piezoelectric vibrator on which the protrusion is provided. 5. Sonic motor. 5. The piezoelectric vibrator according to claim 1, wherein the piezoelectric vibrator has a rectangular shape, and the vibration excited by the piezoelectric vibrator is a combined vibration of a bending vibration and a stretching vibration. The described ultrasonic motor. 2. A guide member that guides the piezoelectric vibrator so as to be movable in a contact direction with the movable body, and a pressurizing member that applies a contact pressure between the protrusion and the movable body. The ultrasonic motor according to claim 5. The ultrasonic motor according to any one of claims 1 to 6, wherein a pressing force of the pressing member is applied to the balancing protrusion. An electronic apparatus with an ultrasonic motor, comprising the ultrasonic motor according to any one of claims 1 to 7.

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