JP2011067002A - Ultrasonic motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic motor in which a stacked piezoelectric element is easily fixed to an elastic body without using a jig or a device for fixing the stacked piezoelectric element to the elastic body. <P>SOLUTION: The ultrasonic motor 1 is equipped with: a bar-like elastic body 12 having a groove portion 14, a pair of stacked piezoelectric elements 18 having both ends held on the bar-like elastic body 12, disposed on a front surface 12a and a rear surface 12b in a state of having an acute angle as an angle between the displacement direction and the longitudinal direction of the bar-like elastic body 12 and arranged on the bar-like elastic body 12 so as to be inclined in the opposite direction to each other when viewed face to face in the longitudinal direction of the bar-like elastic body 12, and a frictional piece 26 bonded to the front end of the bar-like elastic body 12. In the ultrasonic motor 1, alternating voltages different in phase are applied to the pair of stacked piezoelectric elements 18 respectively, thereby simultaneously exciting longitudinal vibration and torsional vibration to cause the frictional piece 26 to excite an ultrasonic elliptic movement. The ultrasonic motor 1 has a pressurizing mechanism 60 for pressurizing the stacked piezoelectric element 18 in order to closely fix the stacked piezoelectric element 18 to the bar-like elastic body 12. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ultrasonic motor that drives a driven member using an electromechanical transducer as a driving source.

  In recent years, ultrasonic motors have attracted attention as new motors that replace electromagnetic motors. Ultrasonic motors use vibrations of vibrators such as piezoelectric elements. Compared to conventional electromagnetic motors, ultrasonic motors produce low rotation and high torque without gears, large holding power, high resolution, quietness, and magnetic noise. In addition, there are advantages such as not being affected by magnetic noise.

  Such an ultrasonic motor has an electromechanical conversion element (laminated piezoelectric element) and a driven member that uses the electromechanical conversion element as a drive source. The driven member is driven by the vibration of the electromechanical transducer.

  For example, Patent Document 1 discloses an ultrasonic motor that has a simple configuration, can be driven at a low voltage, and can stably obtain a resonance frequency.

  The ultrasonic motor includes a prismatic elastic body provided with a groove at a predetermined position on the outer periphery, a plurality of stacked piezoelectric elements inclined on at least two opposing side surfaces of the prismatic elastic body, and a prismatic elastic body. And by applying alternating voltages with different phases to the plurality of stacked piezoelectric elements, the resonance longitudinal vibration and the resonance torsional vibration are simultaneously excited. An ultrasonic elliptical vibration is generated on the surface.

JP 08-317669 A

  In the ultrasonic motor described in Patent Document 1 described above, the multilayered piezoelectric element is prevented from being damaged, and the prismatic elastic body and the multilayered piezoelectric element are integrated to form the same vibrating body. In order to integrate the body and the multilayer piezoelectric element, it is necessary to fix the multilayer piezoelectric element to the prismatic elastic body while applying pressure to the multilayer piezoelectric element.

  However, fixing by such pressure includes a jig for fixing the prismatic elastic body, and a holding elasticity for pressing the stacked piezoelectric element against the prismatic elastic body in order to fix the stacked piezoelectric element to the prismatic elastic body. A jig for holding the body and a jig for pressing the holding elastic body toward the prismatic elastic body are required. When such a jig is used, it is difficult to assemble the ultrasonic motor.

  Further, since the laminated piezoelectric element is disposed at an inclination, the pressing force by the holding elastic body is not easily transmitted to the laminated piezoelectric element, that is, fixing by pressing is not easy.

  The present invention has been made in view of these circumstances, and it is possible to easily fix the multilayer piezoelectric element to the elastic body without using a jig or apparatus for fixing the multilayer piezoelectric element to the elastic body. An object is to provide a sonic motor.

  In order to achieve the object, the present invention provides a rod-shaped elastic body having a groove formed on the entire circumference on the outer periphery, and both ends are held by the rod-shaped elastic body, and a displacement direction and a longitudinal direction of the rod-shaped elastic body The rod-like elastic bodies are disposed on two opposing side surfaces of the rod-like elastic body with an acute angle between them, and are inclined in opposite directions when viewed from the longitudinal direction of the rod-like elastic body. A pair of laminated piezoelectric elements disposed on the body and a friction element joined to the tip of the rod-like elastic body, and applying alternating voltages having different phases to the pair of laminated piezoelectric elements, respectively. An ultrasonic motor that simultaneously excites longitudinal vibration and torsional vibration to excite an ultrasonic elliptical motion in the friction element, wherein the laminated piezoelectric element is fixed to the rod-shaped elastic body. Piezoelectric element Having a pressurizing mechanism for pressurizing a to provide an ultrasonic motor according to claim.

  ADVANTAGE OF THE INVENTION According to this invention, even if it does not use the jig and apparatus for fixing a laminated piezoelectric element to an elastic body, the ultrasonic motor which can fix a laminated piezoelectric element to an elastic body easily can be provided.

FIG. 1 is a top view of an ultrasonic transducer constituting the ultrasonic motor according to the first embodiment of the present invention. FIG. 2 is a diagram (front view) of the ultrasonic transducer viewed from the α direction shown in FIG. 1. FIG. 3 is a view (back view) of the ultrasonic transducer viewed from the β direction shown in FIG. 1. 4 is a diagram (right side view) of the ultrasonic transducer viewed from the γ direction shown in FIG. 5 is a view (left side view) of the ultrasonic transducer viewed from the δ direction shown in FIG. FIG. 6 is an exploded view of the ultrasonic transducer when the ultrasonic transducer is viewed from the α direction shown in FIG. 1. FIG. 7 is a side view of an ultrasonic motor using an ultrasonic transducer. FIG. 8 is an exploded view of an ultrasonic motor using an ultrasonic transducer. FIG. 9 is an exploded view of the ultrasonic transducer when the ultrasonic transducer according to the second embodiment of the present invention is viewed from the α direction shown in FIG. 1. FIG. 10 is an exploded view of the ultrasonic transducer when the ultrasonic transducer of the modification according to the second embodiment is viewed from the α direction shown in FIG. 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The first embodiment will be described with reference to FIGS.
The ultrasonic motor 1 includes an ultrasonic transducer 10 that generates ultrasonic vibrations as illustrated in FIGS. 1 to 6, a rotor 53 that is a driven member that is driven when the vibrations of the ultrasonic transducer 10 are transmitted, In a basic elastic body 12 to be described later, a pressurizing mechanism 60 that pressurizes the laminated piezoelectric element 18 to tightly fix the laminated piezoelectric element 18 to the basic elastic body 12, a driven member (rotor 53), and an ultrasonic transducer 10 and a pressing mechanism 70 that applies a pressing force to.

  The ultrasonic vibrator 10 is a laminated type that is an electromechanical conversion element that is excited by applying an alternating voltage by a drive source (not shown) and a prismatic (rod-shaped) basic elastic body 12 made of, for example, a brass material (O material of C2801P). The piezoelectric element 18 is disposed at the upper end in the longitudinal direction of the basic elastic body 12 so as to oppose the driven member (rotor 53), and the sliding drive that transmits the vibration caused by the laminated piezoelectric element 18 to the driven member (rotor 53). And a child 26. The basic elastic body 12 has a groove portion 14 having a depth of approximately 1 mm to approximately 2 mm formed (recessed) over the entire circumference on the outer periphery at a position of, for example, 11 mm from the lower end. By changing the length dimension below the groove 14 (on the side opposite to the laminated piezoelectric element 14) and setting the relative position of the groove 14 to an appropriate (desired) position, the resonance frequency of the resonance longitudinal vibration mode and the resonance torsional vibration is obtained. Almost match.

  The basic elastic body 12 has a recess 16a on the front surface 12a of the basic elastic body 12, and has a recess 16b on the back surface 12b of the basic elastic body 12 facing the front surface 12a. The recesses 16a and 16b are not necessarily limited to the front surface 12a and the back surface 12b, and may be disposed on the side surfaces 12c and 12d facing the basic elastic body 12.

  The concave portion 16 a is disposed on the front surface 12 a in a state where it is inclined by a desired angle with respect to the height (longitudinal) direction of the basic elastic body 12. Similarly to the recess 16a, the recess 16b is disposed on the back surface 12b while being inclined by the same desired angle as the recess 16a with respect to the height (longitudinal) direction of the basic elastic body 12. In this case, the recesses 16a and 16b are attached in the opposite direction when viewed from the front. The inclination angles of the recesses 16a and 16b are acute angles between the height (longitudinal) direction of the basic elastic body 12 and the longitudinal direction of the recesses 16a and 16b.

  In the recesses 16a and 16b, laminated piezoelectric elements 18 which are vibration main bodies that generate vibrations by ultrasonic waves and are electromechanical transducers are respectively inserted. Therefore, the laminated piezoelectric element 18 inserted into the recesses 16a and 16b is also arranged in a state inclined by a desired angle. The laminated piezoelectric element 18 inserted into the recesses 16a and 16b is mounted in the opposite direction on the front surface 12a and the back surface 12b in the same manner as the recesses 16a and 16b. That is, the laminated piezoelectric element 18 is disposed on the basic elastic body 12 so as to be inclined in directions opposite to each other when viewed in the longitudinal direction of the basic elastic body 12.

  The inclination angle of the multilayer piezoelectric element 18 is an acute angle between the height direction of the basic elastic body 12 and the longitudinal direction of the multilayer piezoelectric element 18, as in the case of the recesses 16 a and 16 b. Therefore, as shown in FIGS. 4 and 5, the side surfaces of the multilayer piezoelectric element 18 are projected at the same position in the longitudinal direction on both the front and back surfaces. That is, the laminated piezoelectric element 18 has two front sides 12a and 12b, which are the two opposite sides of the basic elastic body 12, with an acute angle between the displacement direction and the longitudinal direction of the basic elastic body 12, respectively. Arranged. Further, these laminated piezoelectric elements 18 are disposed on the basic elastic body 12 so as to be inclined in directions opposite to each other when viewed in the longitudinal direction of the basic elastic body 12.

  The multilayer piezoelectric element 18 disposed in the recess 16a and the multilayer piezoelectric element 18 disposed in the recess 16b sandwich the basic elastic body 12. These laminated piezoelectric elements 18 are held at both ends by the basic elastic body 12 (the recesses 16a and 16b and the holding elastic body 20).

  In addition, the electrical terminals extending from the laminated piezoelectric element 18 inserted into the recess 16a are an A terminal and a GND terminal, respectively. In addition, the electrical terminals extending from the laminated piezoelectric element 18 inserted into the recess 16b are a B terminal and a GND terminal, respectively.

  The ultrasonic motor 1 has a pressurizing mechanism 60 that pressurizes the laminated piezoelectric element 18 in the basic elastic body 12 in order to tightly fix the laminated piezoelectric element 18 to the basic elastic body 12. This pressurization means that the laminated piezoelectric element 18 is closely fixed to the basic elastic body 12 without a gap, and a pressure higher than the atmospheric pressure is applied to the laminated piezoelectric element 18. When the pressurizing mechanism 60 pressurizes the multilayer piezoelectric element 18 and the multilayer piezoelectric element 18 is closely fixed to the basic elastic body 12, the vibration of the multilayer piezoelectric element 18 is transmitted to the basic elastic body 12.

  The pressurizing mechanism 60 applies pressure to the stacked piezoelectric element 18 in parallel to the stacking direction (thickness direction, longitudinal direction) of the stacked piezoelectric element 18. The pressurizing mechanism 60 is disposed inside the distal end portion of the basic elastic body 12, and in the longitudinal direction of the basic elastic body 12, the pressing mechanism 70 side and the sliding drive element 26 side described later than the laminated piezoelectric element 18. And disposed on the rotor 53 side. The pressurizing mechanism 60 individually pressurizes the laminated piezoelectric element 18 on the front surface 12a side inserted into the concave portion 16a and the laminated piezoelectric element 18 on the back surface 12b side inserted into the concave portion 16b. And the back surface 12b side.

  The pressurizing mechanism 60 is a groove portion that is disposed in parallel with the stacking direction (thickness direction, longitudinal direction) of the multilayer piezoelectric element 18 from the upper surface 12f of the basic elastic body 12 toward the upper surface 18a of the multilayer piezoelectric element 18. 64 and the groove 64 are fitted (tightened) to pressurize the laminated piezoelectric element 18 in parallel to the laminating direction from the upper surface 18a side, and the laminated piezoelectric element 18 is firmly fixed to the basic elastic body 12. And a pressurizing fixing screw 62.

  The inclination angle of the groove 64 is the same as the inclination angle of the recesses 16 a and 16 b, and is an acute angle between the height (longitudinal) direction of the basic elastic body 12 and the longitudinal direction of the groove 64. The groove 64 is disposed inside the tip of the basic elastic body 12, is formed obliquely with respect to the upper surface 12f of the basic elastic body 12, and the length of the basic elastic body 12 is between the upper surface 12f and the upper surface 18a. It is arranged obliquely with respect to the direction. The groove portion 64 faces a sliding driver 26 described later.

  When the pressurizing fixing screw 62 is tightened in the groove portion 64, it is integrated with the basic elastic body 12. At this time, since the groove portion 64 is disposed in parallel to the stacking direction of the multilayer piezoelectric element 18, the pressurizing fixing screw 62 is arranged along the stacking direction of the multilayer piezoelectric element 18. 18 is pressurized from the upper surface 18a side. At this time, the pressurizing direction in which the pressurizing fixing screw 62 pressurizes and the stacking direction of the multilayer piezoelectric element 18 are the same direction.

  As a result, the laminated piezoelectric element 18 is tightly fixed to the basic elastic body 12 in the recesses 16a and 16b, and the pressurizing fixing screw 62 and the basic elastic body 12 are integrated. Therefore, the pressurizing fixing screw 62, the laminated piezoelectric element 18, and the basic elastic body 12 are the same vibrating body.

  As described above, the pressurizing fixing screw 62 pressurizes the laminated piezoelectric element 18 when it is tightened into the groove 64.

  As described above, the pressurizing fixing screw 62 is a pressurizing portion that pressurizes the multilayer piezoelectric element 18, and is a fixing portion that fixes the multilayer piezoelectric element 18 to the basic elastic body 12.

  For example, a frictional element made of a grindstone in which alumina ceramic abrasive grains are dispersed in an annular phenol resin or a sliding drive element 26 made of a composite resin is joined to the tip (upper surface 12f, upper end) of the basic elastic body 12. ing. The sliding driver 26 is the upper end portion of the ultrasonic transducer 10.

  A through hole 30 is formed on the central axis of the basic elastic body 12. A female screw 32 is threaded at the longitudinal vibration node position of the ultrasonic transducer 10 on the central axis of the through hole 30 (see FIG. 6).

  A shaft 51 is fitted in the through hole 30. The shaft 51 has a length protruding from the upper end portion of the ultrasonic motor 1 as shown in FIG.

The shaft 51 is threaded with a male screw 58 and a male screw 59.
The male screw 58 is arranged on the shaft 51 so as to correspond to the arrangement position of the female screw 32 (vertical vibration node position of the ultrasonic transducer 10). The male screw 58 is screwed into the female screw 32 and then fixed by adhesion. As a result, the shaft 51 is bonded and fixed at the longitudinal vibration node of the basic elastic body 12.
The male screw 59 is disposed at the tip of the shaft 51 protruding from the upper end of the ultrasonic transducer 10. The male screw 59 is disposed on the shaft 51 so as to correspond to the position where the nut 57 is disposed. A nut 57 is fitted to the male screw 59.

  An annular rotor 53 that is driven by the sliding driver 26 is disposed on the sliding driver 26 that is the upper end of the ultrasonic transducer 10. Specifically, a sliding material 53 a made of, for example, an annular ceramic is attached to the lower surface of the rotor 53 facing the sliding driver 26. The cross-sectional shape of the rotor 53 and the cross-sectional shape of the sliding member 53a are the same, and the rotor 53 is driven by being brought into contact with the sliding driver 26 via the sliding member 53a.

  A radial bearing 54 is disposed inside the rotor 53. A spring holding body 55 is disposed on the rotor 53. The spring holder 55 positions and holds the coil spring 56.

  A shaft 51 is inserted through the rotor 53, the sliding member 53 a, the radial bearing 54, and the spring holder 55.

  The rotor 53 is pressed and fixed by a coil spring 56 so as to be rotatable toward the sliding drive element 26 via a spring holder 55 and a radial bearing 54. More specifically, the sliding member 53 a is pressed and fixed to the sliding driver 26.

  The coil spring 56 is held by a spring holder 55 and is prevented from coming off from the spring holder 55 (shaft 51) by a nut 57. The nut 57 adjusts the pressing force of the coil spring 56.

  That is, the coil spring 56 surrounds the shaft 51 in a spiral shape, is held by the spring holding body 55, and is disposed so as not to be detached from the shaft 51 by the nut 57. The pressing force of the coil spring 56 is adjusted by the nut 57. The coil spring 56 presses the rotor 53 against the sliding driver 26 via the spring holder 55 and the radial bearing 54 by the pressing force of the coil spring 56.

  Thus, the nut 57, the coil spring 56, the spring holder 55, and the radial bearing 54 are a pressing mechanism 70 that presses the rotor 53 against the sliding driver 26.

Next, the operation method of the present invention will be described.
First, a method for manufacturing the ultrasonic transducer 10 will be described.
As shown in FIG. 6, the laminated piezoelectric element 18 is inserted into the recesses 16a and 16b. Next, when the pressurizing fixing screw 62 is tightened into the groove portion 64 from the upper surface 12 f side, the pressurizing fixing screw 62 is integrated with the basic elastic body 12. At this time, since the pressurizing direction and the stacking direction are the same direction, the pressurizing fixing screw 62 pressurizes the stacked piezoelectric element 18 from the upper surface 18 a side in parallel along the stacking direction of the stacked piezoelectric element 18. Then, the multilayer piezoelectric element 18 is closely fixed to the basic elastic body 12 in the recesses 16a and 16b without a gap. Thereby, the laminated piezoelectric element 18 is integrated with the pressurizing fixing screw 62 and the basic elastic body 12, and the pressurized fixing screw 62, the laminated piezoelectric element 18 and the basic elastic body 12 are the same vibrating body. Thereafter, the sliding driver 26 is joined to the tip (upper surface 12 f) of the basic elastic body 12. The sliding driver 26 may be bonded to the tip of the basic elastic body 12 with an adhesive or the like. Thereby, the ultrasonic transducer | vibrator 10 is formed.

Next, the operation of the ultrasonic transducer 10 will be described.
In the ultrasonic transducer 10, the primary resonance longitudinal vibration of the size of the ultrasonic transducer 10 and the primary (secondary) resonance torsional vibration are excited at substantially the same frequency Fr. It can be done.
Resonant longitudinal vibration is vibration in the direction of arrow Z shown in FIG. The primary resonance torsional vibration is vibration in the direction of arrow ω shown in FIG. 1, and is vibration with the vibration direction of resonance longitudinal vibration (direction of arrow Z) as the axis of torsion. In the vicinity of this frequency, it is formed in such a shape that there is no natural vibration of resonance bending vibration.

First, when an alternating voltage with the frequency Fr and amplitude Vr is applied to the A terminal and an alternating voltage with the same frequency and amplitude and phase is applied to the B terminal, the resonance longitudinal vibration is excited. The node position of the resonance longitudinal vibration is present at substantially the center on the central axis of the basic elastic body 12.
Next, when an alternating voltage having the frequency Fr and amplitude Vr is applied to the A terminal and an alternating voltage having the same frequency and the same amplitude and opposite phase is applied to the B terminal, the resonant torsional vibration is excited. In resonant torsional vibration, there is a node position on the central axis of the basic elastic body 12.
Furthermore, when an alternating voltage with frequency Fr and amplitude Vr is applied to the A terminal, and an alternating voltage with the same frequency and the same amplitude and a phase different by 90 degrees is applied to the B terminal, resonant longitudinal vibration and resonant torsional vibration are synthesized, Ultrasonic elliptical vibration is excited at the position of the sliding driver 26.

  Next, an operation method of the ultrasonic motor 1 of this embodiment using the ultrasonic transducer 10 will be described with reference to FIGS. 7 and 8. 7 and 8, a shaft 51 is fitted in the through hole 30 (see FIG. 6) of the ultrasonic transducer 10. The male screw 58 is bonded and fixed after being screwed into the female screw 32. Thus, the shaft 51 is bonded and fixed to the longitudinal vibration node of the basic elastic body 12.

  A rotor 53 is pressed and fixed to the sliding driver 26 (upper end portion of the ultrasonic transducer 10) by a coil spring 56 via a radial bearing 54 and a spring holder 55. The pressing force of the coil spring 56 is adjusted by a nut 57. The rotor 53 abuts on the sliding driver 26 via the sliding member 53a. Thereby, the pressing mechanism 70 is formed.

As described above, an alternating voltage having a frequency Fr, an amplitude Vr, and a phase difference of +90 degrees or −90 degrees is applied to the A terminal and the B terminal of the ultrasonic transducer 10. Then, the rotor 53 rotates clockwise or counterclockwise with respect to the sliding driver 26.
Thus, in the present embodiment, in order to tightly fix the laminated piezoelectric element 18 to the basic elastic body 12 by the pressurizing mechanism 60, the jig for fixing the basic elastic body 12 is not used, and the laminated piezoelectric element is used as the basic elastic body. The holding elastic body held by 12 is not used, and therefore a jig for pressing the holding elastic body toward the basic elastic body 12 is not used. In the present embodiment, the laminated piezoelectric element 18 can be easily pressurized from the upper surface 18a in parallel along the laminating direction by tightening the pressurizing fixing screw 62 into the groove portion 64 without using such a jig. The laminated piezoelectric element 18 can be easily fixed to the basic elastic body 12 by this pressurization. Moreover, in this embodiment, since a jig and an apparatus are not used for fixation, since it can fix by pressurization, the ultrasonic motor 1 can be assembled easily.

  In the present embodiment, in order to pressurize the multilayer piezoelectric element 18 in parallel along the stacking direction, the multilayer piezoelectric element 18 is fixed to the basic elastic body 12 in a state where external factors other than pressurization are reduced. The force can be directly transmitted to the laminated piezoelectric element 18. Therefore, in the present embodiment, the pressurization can be efficiently transmitted directly to the multilayer piezoelectric element 18, the transmission efficiency of the pressurization can be improved, and the fixing efficiency can be improved. That is, in this embodiment, even if the multilayer piezoelectric element 18 is inclined, the force for fixing the multilayer piezoelectric element 18 to the basic elastic body 12 can be directly transmitted to the multilayer piezoelectric element 18 without waste.

  In the present embodiment, a jig for fixing the laminated piezoelectric element 18 to the basic elastic body 12 by pressing the laminated piezoelectric element 18 against the recesses 16 a and 16 b by tightening the pressurizing fixing screw 62 into the groove 64. For example, since the holding elastic body becomes unnecessary, the ultrasonic motor 1 can be made inexpensive.

  Further, in the present embodiment, in order to individually pressurize the laminated piezoelectric elements 18 inserted into the recesses 16a and 16b by the pressurizing fixing screws 62, it is possible to adjust the preload for each of the laminated piezoelectric elements 18. As a result, it is possible to easily adjust the degree of fixation of each of the laminated piezoelectric elements 18 with respect to the basic elastic body 12, to adjust the preload more precisely, and to finely adjust the pressure.

  Further, in this embodiment, the pressurizing fixing screw 62 is tightened into the groove portion 64, the pressurizing fixing screw 62 is integrated with the basic elastic body 12, and the laminated piezoelectric element 18 is connected to the basic elastic body 12 by the pressurizing fixing screw 62. It is firmly fixed to. Therefore, in this embodiment, the pressurizing fixing screw 62, the laminated piezoelectric element 18, and the basic elastic body 12 are integrated to form the same vibrating body. Therefore, in this embodiment, the vibration of the laminated piezoelectric element 18 can be transmitted to the basic elastic body 12 without waste.

Next, a second embodiment will be described with reference to FIGS. About the same structure as 1st Embodiment, description is abbreviate | omitted by attaching | subjecting the same referential mark as 1st Embodiment.
The pressurizing mechanism 60 of the present embodiment is disposed inside the base end portion of the basic elastic body 12, and in the longitudinal direction of the basic elastic body 12, the pressing mechanism 70 and the sliding mechanism are sandwiched between the stacked piezoelectric elements 18. The drive element 26 and the rotor 53 are disposed on the opposite side. In the basic elastic body 12 of the present embodiment, one pressurizing mechanism 60 is disposed for one stacked piezoelectric element 18 as in the first embodiment.

  The pressurizing mechanism 60 applies pressure to the stacked piezoelectric element 18 in parallel to the stacking direction (thickness direction, longitudinal direction) of the stacked piezoelectric element 18.

  The pressurizing mechanism 60 is disposed in parallel with the stacking direction (thickness direction, longitudinal direction) of the multilayer piezoelectric element 18, and is arranged from the lower surface 12 g of the basic elastic body 12 toward the lower surface 18 b of the multilayer piezoelectric element 18. By being fastened to the groove portion 64 and the groove portion 64, the laminated piezoelectric element 18 is pressurized in parallel to the lamination direction from the lower surface 18 b side, and the laminated piezoelectric element 18 is fixed to the basic elastic body 12. And a pressure fixing screw 62.

  The groove portion 64 is disposed inside the base end portion of the basic elastic body 12, is formed obliquely with respect to the lower surface 12g of the basic elastic body 12, and is elongated between the lower surface 12g and the lower surface 18b. It is arranged obliquely with respect to the direction.

Next, the operation method of the present invention is substantially the same as that of the first embodiment except that the pressurizing fixing screw 62 pressurizes the laminated piezoelectric element 18 from the lower surface 18b side in parallel to the lamination direction of the laminated piezoelectric element 18. Since it is the same, detailed description is abbreviate | omitted.
As described above, in the present embodiment, the pressurizing mechanism 60 is disposed on the side opposite to the pressing mechanism 70, the sliding driver 26, and the rotor 53. Therefore, in this embodiment, even after the pressing mechanism 70 is assembled, the ultrasonic motor 1 is assembled, and the pressing force of the coil spring 56 is adjusted by the nut 57, the stacked piezoelectric element 18 inserted into the recesses 16a and 16b is pressurized and fixed. The pressure can be individually applied by the screws 62, and the preload for each of the stacked piezoelectric elements 18 can be adjusted by the pressure fixing screws 62. As a result, it is possible to easily adjust the fixing state of the laminated piezoelectric element 18 with respect to the basic elastic body 12.

  As a modification of the present embodiment, the pressurizing mechanism 60 may use an eccentric screw 66 instead of the pressurizing fixing screw 62 as shown in FIG.

  Further, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Ultrasonic motor, 10 ... Ultrasonic vibrator, 12 ... Basic (bar-shaped) elastic body, 12a ... Front, 12b ... Back, 12c, 12d ... Side, 12f ... Upper surface, 12g ... Lower surface, 14 ... Groove part, 16a, 16b ... concave portion, 18 ... stacked piezoelectric element, 18a ... upper surface, 18b ... lower surface, 26 ... sliding drive element (friction element), 30 ... through hole, 32 ... female screw, 60 ... pressurizing mechanism, 62 ... pressure fixing Screws, 64 ... groove, 70 ... pressing mechanism.

Claims (4)

A rod-like elastic body having a groove formed over the entire circumference on the outer periphery;
Both ends are held by the rod-shaped elastic body, and are respectively disposed on two opposing side surfaces of the rod-shaped elastic body with an acute angle between the displacement direction and the longitudinal direction of the rod-shaped elastic body, A pair of stacked piezoelectric elements disposed in the rod-shaped elastic body so as to be inclined in opposite directions as viewed in the longitudinal direction of the rod-shaped elastic body;
A friction member joined to the tip of the rod-shaped elastic body;
Comprising
An ultrasonic motor that simultaneously excites longitudinal vibration and torsional vibration by applying alternating voltages having different phases to the pair of laminated piezoelectric elements, and excites ultrasonic elliptical motion in the friction element,
An ultrasonic motor comprising a pressurizing mechanism that pressurizes the multilayer piezoelectric element to tightly fix the multilayer piezoelectric element to the rod-shaped elastic body.   The ultrasonic motor according to claim 1, wherein the pressurizing mechanism applies pressure to the multilayer piezoelectric element in parallel to a stacking direction of the multilayer piezoelectric element.   The pressurizing mechanism is arranged on the opposite side of the friction element with the multilayer piezoelectric element interposed therebetween in the longitudinal direction of the rod-shaped elastic body. Ultrasonic motor.   The ultrasonic motor according to claim 1, wherein the pressurizing mechanism pressurizes each of the stacked piezoelectric elements individually.

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