JP2008131669A - Friction drive actuator - Google Patents

Abstract

A friction drive actuator having a simple structure for pressing a vibrator against a mover is provided.
The friction drive actuator includes a rubber 129 that pulls the ultrasonic vibrator 1200 so as to press the ultrasonic vibrator 1200 against a rotor 122. The rubber 129 is taken up by the take-up mechanism 500.
[Selection] Figure 1

Description

  The present invention relates to a friction drive actuator in which a vibrator causes a movable element to perform a predetermined motion by a frictional force, and particularly relates to a structure for adjusting a force for pressing the vibrator against the movable element.

  Conventionally, a friction drive actuator that drives a mover by minute vibration of a vibrator has been used. Since this friction drive actuator can operate at high speed, it is used in many industrial fields. As an example of this friction drive actuator, there is one that generates a vibration by applying a voltage to a piezoelectric element, and transmits this vibration to a mover by a frictional force. Among them, in particular, those whose vibration has an ultrasonic frequency are called ultrasonic actuators (or ultrasonic motors). In particular, ring-shaped ultrasonic actuators are widely used for a camera focus adjustment mechanism and the like. Further, the ultrasonic actuator has high energy efficiency, can be positioned minutely, has a holding torque when not energized, and does not emit electromagnetic waves. For these reasons, ultrasonic actuators are expected as an alternative to ordinary electromagnetic motors, particularly stepping motors.

  The ultrasonic actuator generates a minute vibration in the vibrator and transmits the minute vibration to the mover (rotor or the like) by friction, and thus requires a mechanism for applying a pressing force from the ultrasonic vibrator to the mover. In addition, since the contact portion between the ultrasonic transducer and the mover is worn by friction and the pressing force changes, the ultrasonic actuator requires a mechanism for adjusting the pressing force.

For example, Japanese Unexamined Patent Application Publication No. 2002-262587 discloses a mechanism for adjusting the pressing force using a link and cam mechanism.
Japanese Patent Laid-Open No. 2002-262587

  The displacement of the ultrasonic transducer in the ultrasonic actuator is on the order of microns. Therefore, the mechanism for adjusting the pressing force requires a link mechanism that can adjust the displacement on the micron order. Such a link mechanism has a problem that the mass becomes very large.

  For example, a link mechanism for adjusting the pressing force disclosed in Japanese Patent Application Laid-Open No. 2002-262587 has components such as an adjusting screw, a cantilever, and a cam. This link mechanism converts displacement caused by human work into displacement on the order of microns. However, according to this link mechanism, it is difficult to reduce the weight of the ultrasonic actuator because the mass of the surrounding components is extremely large as compared with the ultrasonic vibrator that generates the driving force. Such a problem is a problem that may also occur in friction drive actuators other than ultrasonic actuators.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a lightweight friction drive actuator.

  The friction drive actuator of the present invention includes a movable element, a vibrator that contacts the movable element and causes the movable element to perform a predetermined movement, a support shaft that movably supports the vibrator, and a vibrator that is attached to the vibrator. And a rubber that pulls the vibrator and presses it against the mover, and a winding mechanism that winds the rubber so as to increase the force pressing the vibrator against the mover. According to this, the structure for pressing the vibrator against the mover can be reduced in weight.

  The rubber may include one conductive rubber, the other conductive rubber, and an intermediate insulating rubber sandwiched between them. They constitute a three-layer structure extending along the direction of pulling the vibrator. In this case, if the friction drive actuator further includes a variable voltage source that can adjust the deformation amount of the rubber by applying a voltage between the one conductive rubber and the other conductive rubber, the vibrator can be moved. It is possible to make fine adjustments to the force pressing on the child.

  Also, the rubber is one conductive rubber having a columnar shape extending along the direction of pulling the vibrator and a cylinder provided on the outer peripheral surface of the one conductive rubber and extending along the direction of pulling the vibrator. An intermediate insulating rubber having a shape, and the other conductive rubber having a cylindrical shape provided on the outer peripheral surface of the intermediate insulating rubber and extending along the direction of pulling the vibrator may be included. Also in this case, if the friction drive actuator further includes a variable voltage source capable of adjusting the deformation amount of the rubber by applying a voltage between the one conductive rubber and the other conductive rubber, the vibrator It is possible to make fine adjustments to the force that presses against the mover.

  The rubber may be an annular rubber hooked on each of the vibrator and the winding mechanism. According to this, it becomes easy to assemble the rubber for driving the vibrator against the movable element to the friction drive actuator.

  The above-described vibrator is provided on each surface of the diaphragm having conductive pressing protrusions protruding sideways, one and the other piezoelectric elements sandwiching the diaphragm, and one and the other piezoelectric elements. A plurality of electrodes may be included. Further, the winding mechanism described above may include an insulating pressing force adjusting shaft that can rotate around the shaft, and a conductive pulling protrusion that protrudes laterally from the pressing force adjusting shaft. In this case, the annular rubber is attached to the pressing protrusion and the pulling protrusion so that one conductive rubber is in contact with the pressing protrusion and the other conductive rubber is in contact with the pulling protrusion. It is desirable.

  According to this, it is not necessary to attach wiring for realizing electrical connection between them and the power supply to either one or the other conductive rubber. Therefore, the possibility of occurrence of a problem of disconnection of the wiring is reduced. Further, the structure of the electric circuit for applying a voltage to the rubber becomes simple.

  Further, if the intermediate insulating rubber contains a piezoelectric polymer material, it is possible to realize both increase and decrease of the force for pressing the vibrator against the mover. On the other hand, if the intermediate insulating rubber contains an electrostrictive polymer material, it is possible to finely adjust the force for pressing the mover against the vibrator in a considerably wide range.

  Hereinafter, a friction drive actuator according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
The friction drive actuator according to the first embodiment of the present invention will be described with reference to FIGS. An object of the present invention is to improve a mechanism for adjusting a frictional force between a vibrator and a mover (for example, a rotor). Therefore, in the following, an ultrasonic vibrator is shown as a typical example of the structure of the vibrator. However, the structure of the vibrator itself is not limited as long as the object of the present invention can be achieved. The vibrator may be a piezoelectric vibrator or a magnetic vibrator other than the ultrasonic vibrator.

[Overall configuration and drive principle]
First, the overall configuration of the ultrasonic actuator according to the present embodiment will be described with reference to FIGS. 1 and 2.

(overall structure)
As shown in FIG. 1, the ultrasonic actuator as an example of the friction drive actuator in the present embodiment includes an ultrasonic vibrator 1200 as an example of a vibrator and a rotor 122 as an example of a mover. Yes. The contact portion 1215 of the ultrasonic vibrator 1200 is in contact with the rotor 122. The rotor 122 is fixed to an annular bearing 123. A fixed shaft 124 is inserted into the bearing 123. The bearing 123 is slidable with respect to the fixed shaft 124.

  When the ultrasonic vibrator 1200 starts to vibrate, the contact portion 1215 performs a minute elliptical motion. As a result, the rotor 122 rotates around the fixed shaft 124. The fixed shaft 124 is fixed to a substrate not shown.

  The ultrasonic vibrator 1200 has a conductive pressing protrusion 1224 protruding from the side surface thereof. The pressing protrusion 1224 has a U-shaped notch 1224a. One end of an annular rubber 129 is hooked on the notch 1224a. Therefore, the ultrasonic vibrator 1200 is pulled by the rubber 129. As a result, the ultrasonic vibrator 1200 rotates around the support shaft 127. The support shaft 127 is inserted into the through hole 1214 a of the support protrusion 1214. The support protrusion 1214 can be rotated around the axis of the support shaft 127, but movement along the axial direction of the support shaft 127 is a member (see FIG. (Not shown).

  The ultrasonic vibrator 1200 is pressed against the rotor 122 by the traction force of the rubber 129. Thereby, a frictional force is generated between the rotor 122 and the ultrasonic vibrator 1200. Therefore, the elliptical vibration of the ultrasonic vibrator 1200 is transmitted to the rotor 122 more reliably.

  The support shaft 127 is fixed to the substrate (not shown). Therefore, the positional relationship between the ultrasonic transducer 1200 and the rotor 122 is maintained in a substantially constant relationship.

  The other end of the rubber 129 is hooked on a pulling protrusion 113 protruding from the peripheral surface of the pressing force adjusting shaft 112. The pressing force adjusting shaft 112 is an insulator, and the pulling protrusion 113 is a conductor, so that one conductive rubber 1291 and the other conductive rubber 1293 are insulated. However, since the surface of the pressing force adjusting shaft 112 is covered with an insulating material, each of the one conductive rubber 1291 and the other conductive rubber 1293 is insulated from the pressing force adjusting shaft 112. As a result, one conductive rubber 1291 and the other conductive rubber 1293 may be insulated.

[Ultrasonic transducer]
(Main composition)
As shown in FIG. 3, the ultrasonic vibrator 1200 has a substantially rectangular diaphragm 1211. A rectangular upper piezoelectric element 1212 and a rectangular lower piezoelectric element 1213 are provided on one main surface and the other main surface of the diaphragm 1211, respectively.

  An upper electrode 1216 is provided on the outer surface of the upper piezoelectric element 1212. The upper electrode 1216 is divided into upper electrodes 1216a, 1216b, 1216c, and 1216d. Upper electrodes 1216a, 1216b, 1216c, and 1216d each have the same rectangular shape. The upper electrode 1216a and the upper electrode 1216d are electrically connected by wiring. The upper electrode 1216b and the upper electrode 1216c are electrically connected by wiring.

  A lower electrode 1217 is provided on the outer surface of the lower piezoelectric element 1213. The lower electrode 1217 is divided into upper electrodes 1217a, 1217b, 1217c, and 1217d. The upper electrodes 1217a, 1217b, 1217c, and 1217d have the same rectangular shape. The lower electrode 1217a and the lower electrode 1217d are electrically connected by wiring. The lower electrode 1217b and the lower electrode 1217c are electrically connected by wiring.

  Each of the upper piezoelectric element 1212 and the lower piezoelectric element 1213 is a piezoelectric element that is polarized in the thickness direction and is deformed by a piezoelectric effect with respect to an electric field in the thickness direction.

In the present embodiment, the size of the rectangular portion of diaphragm 1211 is 9 mm in length and 2 mm in width. The sizes of the upper piezoelectric element 1212 and the lower piezoelectric element 1213 are 8 mm in length and 2 mm in width. The thicknesses of the diaphragm 1211, the upper piezoelectric element 1212, and the lower piezoelectric element 1213 are all 0.2 mm. The diaphragm 1211 is made of stainless steel, and specifically, a PZT element is used as the above-described piezoelectric element. The PZT element is made of a material generally called lead zirconate titanate Pb (Ti · Zr) O ₃ / hard system.

  However, the above-described configuration is merely an example of a vibrator manufactured by the present inventors, and the configuration of the present invention is not limited to the above-described configuration. The friction drive actuator of the present invention can be applied to all friction drive actuators that drive a mover by using a frictional force generated when a vibrator is pressed against the mover.

(Drive principle)
The ultrasonic vibrator 1200 includes a longitudinal primary vibration mode (hereinafter referred to as “longitudinal vibration”) shown in FIG. 4 and a bending (bending) tertiary vibration mode (hereinafter referred to as “flexural vibration”) shown in FIG. Two types of vibration modes. In the present embodiment, both of the resonance frequencies in the longitudinal vibration and the flexural vibration are 240 kHz, which coincide with each other.

  Longitudinal vibration occurs when the same potential is applied to all of the upper electrodes 1216a, 1216b, 1216c, and 1216d and the lower electrodes 1217a, 1217b, 1217c, and 1217d. On the other hand, flexural vibration occurs when the polarity of the potential applied to the upper electrodes 1216a and 1216d and the lower electrodes 1217a and 1217d is opposite to the polarity of the potential applied to the upper electrodes 1216b and 1216c and the lower electrodes 1217b and 1217c.

  For example, when a positive potential is applied to the upper electrodes 1216a and 1217d and the lower electrodes 1217a and 1217d, and a negative potential is applied to the upper electrodes 1216b and 1216c and the lower electrodes 1216b and 1216c, flexural vibration occurs. In addition, when a negative potential is applied to the upper electrodes 1216a and 1216d and the lower electrodes 1217a and 1217d, flexural vibration is also generated when a positive potential is applied to the upper electrodes 1216b and 1216c and the lower electrodes 1216b and 1216c. Arise.

  In the present embodiment, electrodes positioned on a rectangular diagonal line are electrically connected to each other by wiring, but adjacent electrodes are insulated from each other. Hereinafter, the voltage applied to one of the two electrodes insulated from each other is assumed to be φA. A voltage applied to the other of the two electrodes insulated from each other is φB.

  That is, if the voltages φA and φB are in-phase AC voltages (for example, 240 kHz), the longitudinal vibration shown in FIG. 4 occurs, and if the voltages φA and φB are opposite-phase AC voltages (for example, 240 kHz), The flexural vibration shown in FIG.

  When the flexural vibration is generated by shifting the phase by ± 90 ° with respect to the above-described longitudinal vibration, the resultant vibration becomes an elliptical motion. Therefore, as shown in FIGS. 6 and 7, the contact portion 1215 of the ultrasonic transducer 1200 moves to draw an elliptical orbit. Here, for convenience of explanation, each of the voltages φA and φB is a sine wave, but the voltage applied to the ultrasonic actuator of the present invention is not limited to a sine wave, It may be a square wave or a triangular wave (sawtooth wave).

[Rubber for pressing]
Next, the configuration and driving principle of the rubber 129 will be described with reference to FIGS.

(Constitution)
FIG. 8 is a cross-sectional view of the rubber 129, and is a cross-sectional view taken along the line VIII-VIII in FIG. As shown in FIG. 8, the rubber 129 includes one conductive rubber 1291, the other conductive rubber 1293, and an intermediate insulating rubber 1292 sandwiched between them. Note that the above-described one conductive rubber 1291 and the other conductive rubber 1293 are interchangeable.

  As shown in FIG. 1, the conductive rubber 1293 is in contact with the pressing protrusion 1224. Therefore, the potential of the diaphragm 1211 and the potential of the other conductive rubber 1293 are the same. That is, the other conductive rubber 1293 and the pressing protrusion 1224 are electrically connected. In addition, since the insulating members 1224b are provided on the opposite side surfaces of the notch 1224a, one conductive rubber 1291 and the other conductive rubber 1293 are not short-circuited.

  As shown in FIG. 1, the rubber 129 is twisted by a half rotation (180 °) in the twisted portion 2000 and hooked on the pulling protrusion 113 as shown in FIG. 2. Therefore, one conductive rubber 1291 and the pulling protrusion 113 are electrically connected. Therefore, the potential of the diaphragm 1211 and the potential of the conductive rubber 1291 are the same.

  As shown in FIG. 1, when the ultrasonic actuator is driven, a predetermined voltage is applied between the pressing protrusion 1224 and the pulling protrusion 113 by the variable voltage source 114. Therefore, a predetermined voltage is applied between one conductive rubber 1291 and the other conductive rubber 1293.

(Operating principle)
Next, the principle of operation of the ultrasonic actuator according to the present embodiment will be described.

  As shown in FIG. 9, when a voltage is applied between one conductive rubber 1291 and the other conductive rubber 1293, an electrostatic force Q is generated between them, and the intermediate insulating rubber 1292 has a thickness direction. Is compressed. Accordingly, the intermediate insulating rubber 1292 expands in the direction indicated by the arrow F3 in FIG. 9, that is, in the direction parallel to the main surface, in other words, in the in-plane direction. Thereby, an expansion force is generated in a direction parallel to the direction of the traction force F1 of the rubber 129 shown in FIG. As a result, the traction force F1 decreases. Therefore, the force with which the ultrasonic vibrator 1200 is pressed against the rotor 122, that is, the pressing force F2, is reduced.

  In the present embodiment, the pressing force F2 is set to be slightly stronger by rotating the pressing force adjusting shaft 112 around the axis. In addition, a voltage is applied in advance between one conductive rubber 1291 and the other conductive rubber 1293 by the variable voltage source 114. In this case, if the voltage of the variable voltage source 114 is increased, the traction force F1 is decreased, and thereby the initial value of the pressing force F2 is adjusted. In addition, as the pressing force F2 decreases due to wear between the contact portion 1215 of the ultrasonic vibrator 1200 and the contact portion of the rotor 122, a voltage applied between one conductive rubber 1291 and the other conductive rubber 1293. The pressing force F2 can be kept constant by decreasing the.

  The adjustment of the pressing force F2 is performed by reducing the voltage applied to one conductive rubber 1291 and the other conductive rubber 1293. Therefore, the power consumption increases due to the adjustment of the pressing force F2. The amount is very small.

  Further, as described above, one conductive rubber 1291 in the rubber 129 is electrically connected to the pulling protrusion 113, and the other conductive rubber 1293 is electrically connected to the pressing protrusion 1224. Therefore, it is not necessary to connect a wiring to the rubber 129 in order to apply a voltage between the one conductive rubber 1291 and the other conductive rubber 1293.

(Other)
If one conductive rubber 1291 and the other conductive rubber 1293 of the rubber 129 are exposed, an electrical failure may occur between them and other components. In order to avoid the occurrence of this problem, one conductive rubber 1291 and the other conductive rubber 1293 may be covered with an insulating coating layer 1294 as shown in FIG. However, the insulating coating layer 1294 needs to be removed at a position where one conductive rubber 1291 and the other conductive rubber 1293 are connected to the pulling protrusion 113 and the pressing protrusion 1224, respectively.

  As the intermediate insulating rubber 1292, a piezoelectric polymer material polarized in the direction perpendicular to the main surface thereof, that is, in the thickness direction may be used. Examples of such a material include polyvinylidene fluoride, a polyvinylidene fluoride polymer, and porous polytetrafluoroethylene. When such a material is used, an attractive force and a repulsive force corresponding to the polarity of voltage and the polarity of polarization can be generated between one conductive rubber 1291 and the other conductive rubber 1293. Therefore, it is possible to increase and decrease the pressing force F2 by decreasing and increasing the voltage of the variable voltage source 114. That is, both expansion and contraction along the direction of the traction force F1 of the rubber 129 can be realized.

  Further, as the intermediate insulating rubber 1292, a material generally referred to as an electrostrictive polymer material such as a dielectric elastomer may be used. In this material, an electrostrictive phenomenon based on Maxwell stress occurs. If the electrostrictive molecular material is used, the displacement is very large, so that the adjustment range of the increase and decrease of the pressing force F2 can be increased.

[Rubber winding mechanism]
FIG. 11 shows a winding mechanism 500 for winding the rubber 129. The winding mechanism 500 includes a pressing force adjusting shaft 112, a traction protrusion 113 protruding perpendicular to the pressing force adjusting shaft 112, and a base portion 3000 into which a lower end portion of the pressing force adjusting shaft 112 is inserted. . As indicated by a dotted line in FIG. 11, a drive mechanism 4000 that rotates the pressing force adjusting shaft 112 around the axis may be provided. However, in the present embodiment, drive mechanism 4000 may not be provided. In this case, the tip of a driver (not shown) is inserted into the driver recess 112a provided on the upper end surface of the pressing force adjusting shaft 112, and the force for pressing the ultrasonic vibrator 1200 against the rotor 122 by human power is adjusted. Shall be.

  Therefore, the lower end of the pressing force adjusting shaft 112 is semi-fixed to the base portion 300. That is, a static frictional force is generated between the contact surfaces of the pressing force adjusting shaft 112 and the base portion 3000 so that the pressing force adjusting shaft 112 does not rotate around the shaft due to the torque based on the traction force F1 of the rubber 129. ing. The adjustment of the pressing force F2 is performed by rotating the pressing force adjusting shaft 112 and applying a torque higher than the static friction force to the pressing force adjusting shaft 112. As a result, the pressing force adjusting shaft 112 rotates and the rubber 129 is wound around the pressing force adjusting shaft 112 as shown in FIG. As a result, the traction force F1 increases and the pressing force F2 also increases.

(Embodiment 2)
Next, the ultrasonic actuator according to the second embodiment of the present invention will be described with reference to FIGS. The ultrasonic actuator according to the present embodiment is different from the ultrasonic actuator according to the first embodiment in the structure of the annular rubber 129. Therefore, in the following description, only the annular rubber is described. The description of the structure will not be repeated.

(Other forms of rubber for pressing)
FIG. 12 shows an example of rubber 129 having different cross-sectional shapes. The rubber 129 of the present embodiment has an annular shape as a whole, like the rubber 129 of the first embodiment. The outer shape of the cross section of the rubber 129 is circular. The rubber 129 includes one conductive rubber 1391, the other conductive rubber 1393, and an intermediate insulating rubber 1392 sandwiched therebetween. Each of the other conductive rubber 1393 and intermediate insulating rubber 1392 has a donut shape. That is, each of the other conductive rubber 1393 and intermediate insulating rubber 1392 has a cylindrical shape. One conductive rubber 1391 has a circular cross-sectional shape. That is, one conductive rubber 1391 has a cylindrical shape. One conductive rubber 1391, the other conductive rubber 1393, and the intermediate insulating rubber 1392 are formed so as to have a concentric cross section.

  Note that portions of the other conductive rubber 1393 and intermediate insulating rubber 1392 in the vicinity of the pulling protrusion 113 are removed. Accordingly, one conductive rubber 1391 is electrically connected to the pulling protrusion 113.

  When a voltage is applied between one conductive rubber 1391 and the other conductive rubber 1393, the intermediate insulating rubber 1392 tends to deform so that its diameter in the cross section becomes large. However, according to the rubber 139 of the present embodiment, the one conductive rubber 1391, the intermediate insulating rubber, and the other conductive rubber 1393 are formed concentrically. 1393. Therefore, the intermediate insulating rubber 1392 does not deform so as to expand in the diametrical direction in its cross section, but deforms so as to extend in the direction parallel to the traction force F1 (the direction in which the rubber 129 extends). As a result, the traction force F1 is reduced.

  According to this, the rubber 129 can be contracted only by reducing the voltage applied between the one conductive rubber 1391 and the other conductive rubber 1393. Therefore, the pressing force F2 can be increased only by reducing the voltage. That is, the rubber 129 of the present embodiment can be adjusted in the same manner as the adjustment of the pressing force F2 of the ultrasonic actuator of the first embodiment.

  As shown in FIG. 13, the rubber 129 may be covered with an insulating coating layer 1394 in order to prevent leakage between the rubber 129 and other components.

  The insulating coating layer 1394 is removed at a position where the pressing protrusion 1224 and the rubber 129 are electrically connected, and the insulating coating layer 1394 is connected to the other conductive rubber at a position where the pulling protrusion 113 and the rubber 129 are electrically connected. 1393 and intermediate insulating rubber 1392 are removed. Further, unlike the rubber 129 of the first embodiment, the rubber 129 of the present embodiment does not need to be twisted by a half rotation.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic diagram illustrating an overall configuration of an ultrasonic actuator according to a first embodiment. FIG. 3 is a diagram for explaining a state of twisting of rubber according to the first embodiment. FIG. 2 is a schematic diagram illustrating an ultrasonic transducer that is a constituent element of the ultrasonic actuator according to the first embodiment. FIG. 5 is a diagram for explaining one vibration mode of an ultrasonic transducer that is a constituent element of the ultrasonic actuator of the first embodiment. FIG. 6 is a diagram for explaining another vibration mode of the ultrasonic transducer that is a constituent element of the ultrasonic actuator according to the first embodiment. FIG. 3 is a diagram for explaining an operation principle of an ultrasonic transducer that is a constituent element of the ultrasonic actuator according to the first embodiment. FIG. 3 is a diagram for explaining an operation principle of an ultrasonic transducer that is a constituent element of the ultrasonic actuator according to the first embodiment. It is a schematic sectional drawing of the rubber | gum of Embodiment 1, Comprising: It is the VIII-VIII sectional view taken on the line of FIG. FIG. 6 is a diagram for explaining the operation of the rubber according to the first embodiment. 6 is a schematic view showing another example of rubber according to Embodiment 1. FIG. 3 is a perspective view of a winding mechanism that is a component of the ultrasonic actuator according to Embodiment 1. FIG. 4 is a schematic cross-sectional view of a rubber according to Embodiment 2. FIG. FIG. 5 is a schematic view showing another example of rubber according to the second embodiment.

Explanation of symbols

  1200 Ultrasonic vibrator, 1211 Diaphragm, 1212, 1213 Piezoelectric element, 1216 Upper electrode, 1217 Lower electrode, 122 Rotor, 129 Rubber, 112 Pushing force adjusting shaft, 113 Pulling projection, 114 Variable voltage source, 127 Supporting axis.

Claims (7)

A mover,
A vibrator that contacts the movable element and causes the movable element to perform a predetermined motion;
A support shaft for movably supporting the vibrator;
A rubber attached to the vibrator, extending along a predetermined direction, pulling the vibrator and pressing it against the mover;
A friction drive actuator comprising: a winding mechanism that winds up the rubber so as to increase a force for pressing the vibrator against the mover. The rubber includes one conductive rubber, the other conductive rubber, and an intermediate insulating rubber sandwiched therebetween, which constitutes a three-layer structure extending along the direction of pulling the vibrator,
2. The friction drive actuator according to claim 1, further comprising a variable voltage source capable of adjusting a deformation amount of the rubber by applying a voltage between the one conductive rubber and the other conductive rubber. Friction drive actuator. The rubber is
One conductive rubber having a cylindrical shape extending along the direction of pulling the vibrator;
An intermediate insulating rubber provided on an outer peripheral surface of the one conductive rubber and having a cylindrical shape extending along a direction of pulling the vibrator;
The other conductive rubber having a cylindrical shape provided on the outer peripheral surface of the intermediate insulating rubber and extending along the direction of pulling the vibrator,
2. The friction drive actuator according to claim 1, further comprising a variable voltage source capable of adjusting a deformation amount of the rubber by applying a voltage between the one conductive rubber and the other conductive rubber. Friction drive actuator.   The friction drive actuator according to claim 1, wherein the rubber is an annular rubber hooked on each of the vibrator and the winding mechanism. The vibrator is
A diaphragm having conductive pressing protrusions protruding laterally;
One and the other piezoelectric element sandwiching the diaphragm,
A plurality of electrodes provided on the respective surfaces of the one and the other piezoelectric elements,
The winding mechanism is
An insulating pressing force adjusting shaft that can rotate around the shaft;
A conductive traction protrusion protruding laterally from the pressing force adjusting shaft,
The annular rubber includes the pressing protrusion, the traction protrusion, and the traction protrusion so that the one conductive rubber contacts the pressing protrusion and the other conductive rubber contacts the traction protrusion. The friction drive actuator of claim 1, attached to the friction drive actuator.   The friction drive actuator according to claim 1, wherein the intermediate insulating rubber includes a piezoelectric polymer material.   The friction drive actuator according to claim 1, wherein the intermediate insulating rubber includes an electrostrictive polymer material.

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