JP2014140271A - Driving device using measuring worm type deformation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device capable of allowing an object to operate by employing an elastic member for a piezoelectric element to increase the expansion/contraction amount of the element, thus gaining required driving force regardless of downsized configuration.SOLUTION: A driving device 10 includes: first fixing means 1; a first piezoelectric element 2: a stator 5 having a tabular elastic member 3 and second fixing means 4 coupled in this order; and a movable section 6 operated by mutual action with the tabular elastic member 3 of the stator 5. In the stator 5, the distance between an edge of the tabular elastic member 3 side of the first piezoelectric element 2 and the second fixing means 4 can be increased or decreased by expanding or contracting the first piezoelectric element 2 with the first fixing means 1 serving as a fixed-end. As a result, with the decrease of the distance between the edge of the tabular elastic member 3 side of the first piezoelectric element 2 and the second fixing means 4, the deflection of the tabular elastic member 3 can be increased.

Description

  The present invention relates to a drive device using expansion and contraction of a piezoelectric element.

  One of driving devices using a piezoelectric element is an ultrasonic motor. Ultrasonic motors are friction-driven actuators that rotate and linearly move equipment by bringing a stator excited by mechanical vibrations in the ultrasonic region into contact with a rotor and slider. In addition, it is used in various fields such as security cameras and multi-dimensional motors incorporated in surgical equipment.

  For example, in Patent Document 1, a bimorph piezoelectric element is connected to both ends of an elastic body, the elastic body is deformed by the movement of the bimorph piezoelectric element, and an operating point on the elastic body is brought into contact with the moving main body. A piezoelectromechanical drive is disclosed that can be moved. However, in the drive device disclosed in Patent Document 1, the displacement amount of the operating point is small, and in order to increase the operation amount and the drive amount of the moving main body, the drive device such as enlarging the bimorph piezoelectric element is used. Must be enlarged. For this reason, it has been difficult to incorporate into a small device such as a surgical device.

  Alternatively, Patent Document 2 includes a plurality of piezoelectric elements arranged so that the expansion and contraction directions are on the same plane, a base for fixing the piezoelectric elements, and a dome-shaped elastic body fixed to the expansion and contraction ends of the piezoelectric elements. An ultrasonic vibrator is disclosed, and a driving device such as an ultrasonic motor can be configured by the vibrator. However, in the ultrasonic transducer disclosed in Patent Document 2, it is necessary to prepare a plurality of piezoelectric elements, and it is assumed that a dome-shaped elastic body is used. That is, a large space is required to install the piezoelectric element and the elastic body, and the drive device is also increased in size, so that it is difficult to incorporate the device into a small device such as a surgical device.

Japanese Patent No. 445275 Japanese Patent Laid-Open No. 5-191988

  The present invention has been made in view of the above-mentioned problems of the prior art, and by expanding the amount of expansion and contraction of the piezoelectric element with an elastic member, the object can be operated while obtaining a required driving force while being downsized. It is an object of the present invention to provide a drive device that can be used.

In order to solve the above problems, the present invention adopts the following configuration. That is, the present invention
A stator comprising a first fixing means, a first piezoelectric element, a plate-like elastic member, and a second fixing means connected in this order, and a movable part that operates by interaction with the plate-like elastic member of the stator. The first piezoelectric element expands and contracts with the first fixing means as a fixed end, whereby the distance between the end of the first piezoelectric element on the plate-like elastic member side and the second fixing means increases or decreases, and the first piezoelectric element plate The driving device is configured such that the bending generated in the plate-like elastic member increases as the distance between the end portion on the side of the elastic member and the second fixing means decreases.

  In the present invention, “being connected in this order” means not only a form in which the respective parts are directly connected in order but also a form in which the respective parts are indirectly connected in order through some member other than each part. It is a concept that includes. “Piezoelectric element” refers to an expansion-contraction type piezoelectric element, which mainly corresponds to a laminated piezoelectric element. The “plate-like” of the “plate-like elastic member” means a shape having no curvature in a state where bending is most eliminated. However, as long as the amount of expansion and contraction of the first piezoelectric element can be increased by the plate-like elastic member, the plate-like elastic member is somewhat curved when the distance between the end of the first piezoelectric element and the second fixing means is maximum. It may be. This is because it is easy to be deformed into a worm-like shape in a desired direction by curving a little.

  In the present invention, it is preferable that the plate-like elastic member is bent so as to protrude in a direction orthogonal to the expansion / contraction direction of the first piezoelectric element. This is because the amount of bending of the plate-like elastic member can be maximized. In the present application, the “direction orthogonal to the expansion / contraction direction of the first piezoelectric element” does not need to be a direction completely orthogonal to the expansion / contraction direction of the first piezoelectric element, and is acceptable as long as it is a deformation that drives an object. It is. For example, when the angle between the expansion / contraction direction of the first piezoelectric element and the convex direction of the deformation of the plate-like elastic member is 75 ° or more and 105 ° or less, the error range is “a direction orthogonal to the expansion / contraction direction of the first piezoelectric element”. Shall be included.

  In the present invention, the plate-like elastic member and the second fixing means may be coupled via a second piezoelectric element different from the first piezoelectric element. In other words, the first piezoelectric element and the second piezoelectric element may be provided at both ends of the plate-like elastic member. By providing a plurality of piezoelectric elements, it is possible to introduce off-the-shelf elements and to precisely control the amount and deformation of the plate-like elastic member.

  In the present invention, a plurality of stators may be provided. That is, the movable part can be more efficiently operated by increasing or decreasing the number of stators installed according to the form of the movable part. Further, by providing a plurality of stators, for example, the movable part can be operated in a multidimensional manner.

  In the present invention, a plurality of plate-like elastic members may be connected to one second fixing means, and the first piezoelectric element and the first fixing means may be connected to each plate-like elastic member. In other words, a plurality of plate-like elastic members and the like can be connected while providing a predetermined interval in the circumferential direction around the second fixing means. In such a form, for example, by installing a sphere as a movable part in the vicinity of the second fixing means, each of the plurality of plate-like elastic members is bent by an arbitrary amount of bending, and brought into contact with the sphere. The sphere can be moved in multiple dimensions by increasing or decreasing the deflection of the plate-like elastic member.

  In this invention, it is preferable to further provide the control means which controls the direction of bending of a plate-shaped elastic member. This is because by providing the restricting means, the control of the bending of the plate-like elastic member becomes more precise, and the movable part can be operated efficiently.

  According to the present invention, the piezoelectric element and the plate-like elastic member are connected between the fixing means to constitute the stator, and the expansion / contraction amount of the piezoelectric element can be expanded to the bending amount (deformation amount) of the elastic member. The structure is taken. Therefore, even when a small piezoelectric element is used or there are restrictions on the types of piezoelectric elements that can be arranged, a large amount of deformation can be obtained by bending the elastic member. Further, it is possible to minimize the installation space of the stator by using the plate-like elastic member. For example, when a drive device is desired to be installed in a pipe, a stator can be installed in the pipe longitudinal direction or pipe circumferential direction along the inner wall surface of the pipe, and the installation space in the pipe radial direction can be minimized. As described above, according to the present invention, there is provided a driving device capable of operating a body while obtaining a necessary driving force while being downsized by enlarging the expansion / contraction amount of the piezoelectric element with an elastic member. be able to.

It is the schematic for demonstrating the operation | movement aspect of the drive device 10 of this invention which concerns on 1st Embodiment. FIG. 4 is a diagram for explaining the relationship between the expansion / contraction amount x of the first piezoelectric element 2 and the deflection amount y of the plate-like elastic member 3. FIG. 4 is a diagram illustrating an example of a waveform of a voltage applied to the first piezoelectric element 2 when operating the driving device 10. It is the schematic for demonstrating the other operation | movement aspect of the drive device 10 of this invention which concerns on 1st Embodiment. It is the schematic for demonstrating the stator 15 provided in the drive device 20 of this invention which concerns on 2nd Embodiment. It is the schematic for demonstrating the drive device 30 of this invention which concerns on 3rd Embodiment. It is the schematic for demonstrating the drive device 30 of this invention which concerns on 3rd Embodiment. It is the schematic for demonstrating the stator 35 provided in the drive device 40 of this invention which concerns on 4th Embodiment. It is the schematic for demonstrating the control means 7a. It is the schematic for demonstrating the control means 7b. It is the schematic for demonstrating the drive device which concerns on an Example.

1. First Embodiment A driving apparatus 10 according to a first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the driving device 10 includes a stator 5 in which a first fixing means 1, a first piezoelectric element 2, a plate-like elastic member 3 and a second fixing means 4 are connected in this order, and a plate of the stator 5. The movable part 6 which operates by interaction with the elastic member 3 is provided. In addition, although the movable part 6 shown in FIG. 1 is a rotor disc, this invention is not limited to the said form, You may use a linear moving body like a slider as a movable part.

1.1. First fixing means 1
In the driving device 10, the first fixing means 1 is a means for fixing the one end 2 a of the first piezoelectric element 2. The form of the 1st fixing means 1 will be specifically limited if the end 2a of the 1st piezoelectric element 2 is fixed and the 1st piezoelectric element 2 is a form which can be expanded-contracted using the said 1st fixing means 1 as a fixed end. is not. For example, a metal piece, a plastic piece, a ceramic piece, or the like fixed at a location (not shown) where the drive device 10 is installed can be used as the first fixing means 1.

1.2. First piezoelectric element 2
In the driving device 10, the first piezoelectric element 2 is an element whose one end 2 a is fixed to the first fixing means 1 and expands and contracts with the first fixing means 1 as a fixed end. The first piezoelectric element 2 is not particularly limited as long as it is an expandable piezoelectric element, and for example, a stacked piezoelectric element in which a plurality of piezoelectric elements are stacked in the expansion / contraction direction can be applied. The extension amount of the first piezoelectric element 2 can be determined in accordance with the shape and size of the plate-like elastic member 3 and the movable portion 6. For example, when the driving device 10 is operated, it is preferable that the amount of deformation (deformation amount) of the plate-like elastic member 3 is about several microns (about 0.1 μm to 30 μm). As will be described later, in the driving device 10, since the expansion / contraction amount by the first piezoelectric element 2 is enlarged and converted into the deflection amount of the plate-like elastic member 3, efficient driving is possible even if the expansion / contraction amount of the first piezoelectric element 2 is small. Is possible.

1.3. Plate-like elastic member 3
In the driving device 10, the plate-like elastic member 3 is a member whose one end 3 a is connected to the end 2 b of the first piezoelectric element 2, and bending is generated and eliminated as the first piezoelectric element 2 expands and contracts. There is a change in the amount of deflection depending on the distance between the end 2 b of the first piezoelectric element 2 and the second fixing means 4. The constituent material of the plate-like elastic member 3 may be any material having elasticity, and may be made of, for example, metal or plastic. The shape of the plate-like elastic member 3 may be a shape without bending in a state where the bending is eliminated. For example, in a state in which the bending is eliminated, the shape can be a shape along a straight line connecting the end 2b of the first piezoelectric element 2 and the second fixing means 4. However, as described later, the bending direction of the plate-like elastic member 3 may be regulated by slightly bending the plate-like elastic member 3. The thickness and size of the plate-like elastic member 3 can be determined in accordance with the shape and size of the movable portion 6. As described above, it is preferable that the first piezoelectric element 2 bend (deforms) about several microns (0.1 μm to 30 μm) by extension.

1.4. Second fixing means 4
In the driving device 10, the second fixing means 4 is a means for fixing one end (end opposite to the first piezoelectric element 2) 3 b of the plate-like elastic member 3. If the form of the 2nd fixing means 4 is the form which fixes the end 3b of the plate-shaped elastic member 3, and can restrain the plate-shaped elastic member 3 between the 1st piezoelectric element 2 and the 2nd fixing means 4, It is not particularly limited. For example, a metal piece, a plastic piece, a ceramic piece, or the like fixed at a location (not shown) where the driving device 10 is installed can be used as the second fixing means 4.

1.5. Stator 5
In the driving device 10, the stator 5 is formed by connecting the first fixing means 1, the first piezoelectric element 2, the plate-like elastic member 3, and the second fixing means 4 in this order. Accordingly, the first piezoelectric element 2 expands and contracts with the first fixing means 1 as a fixed end, whereby the distance between the end 2b of the first piezoelectric element 2 on the plate-like elastic member 3 side and the second fixing means 4 increases or decreases. As the distance between the end 2b of the first piezoelectric element 2 on the plate-like elastic member 3 side and the second fixing means 4 decreases, the bending that occurs in the plate-like elastic member 3 can be increased.

  Here, in the driving device 10, the expansion / contraction amount by the first piezoelectric element 2 is enlarged and converted into the deflection amount of the plate-like elastic member 3. The relationship between the amount of expansion / contraction of the first piezoelectric element 2 and the amount of deflection of the plate-like elastic member 3 will be described with reference to FIG.

The relationship between the amount of expansion / contraction of the first piezoelectric element 2 and the amount of deflection of the plate-like elastic member 3 in the driving device 10 can be considered by approximating a triangle as shown in FIG. As a result of applying a voltage to the first piezoelectric element 2, it is assumed that the distance between the end 2b of the first piezoelectric element 2 and the second fixing means 4 is reduced by x. Assuming that the length of the plate-like elastic member 3 (the length in a state in which the bending is eliminated) is a, the amount of bending y when bent into a worm-shaped type is y = (2ax−x ² ) ^1/2. / 2. For example, when a = 10 mm and x = 5 μm, y = 158 μm, and the expansion / contraction amount of the first piezoelectric element 2 is expanded to about 32 times the deflection amount of the plate-like elastic member 3. Actually, since the plate-like elastic member 3 is bent and deformed, the enlargement ratio is reduced depending on the material and shape of the plate-like elastic member 3, but in any case, the expansion / contraction amount of the first piezoelectric element 2 can be increased. (Hereinafter, this effect may be referred to as “displacement amount expansion effect”). In particular, in a region where the expansion / contraction amount x of the first piezoelectric element 2 is small, the displacement amount expansion effect due to the bending of the plate-like elastic member 3 becomes large. Specifically, the first piezoelectric element 2 is preferably used in a region where the extension amount of the first piezoelectric element 2 is enlarged by about 2 to 10 times by the bending of the plate-like elastic member 3.

  In the driving device 10, the plate-like elastic member 3 is on the extension of the first piezoelectric element 2 in the expansion / contraction direction and substantially on the same plane in the state where the bending is eliminated. By setting it as such a structure, the plate-shaped elastic member 3 can be bent so that it may become convex in the direction orthogonal to the expansion-contraction direction of the 1st piezoelectric element 2, and the displacement amount expansion effect becomes the maximum. That is, it leads to further miniaturization of the driving device 10, which is preferable.

1.6. Movable part 6
In this way, the expansion and contraction of the first piezoelectric element 2 is converted into the worm-shaped bend of the plate-like elastic member 3 so that the movable part of the driving device 10 is operated by the interaction with the plate-like elastic member 3. Can be made. The form of the movable part 6 may be a form generally used in a drive device, for example, a rotary body such as a rotor or a sphere, a linear moving body such as a slider that can be operated in one or two dimensions, It can be a rod-like body, a flat plate or the like. Hereinafter, the operation of the stator 5 and the movable portion (rotor) 6 in the drive device 10 will be described with reference to FIG.

  As shown in FIG. 1A, in the driving device 10, the stator 5 and the movable portion 6 are installed so that the movable portion 6 is in the vicinity of the plate-like elastic member 3. When a voltage is applied to the first piezoelectric element 2 in such a state, the distance between the end 2b of the first piezoelectric element 2 and the second fixing means 4 decreases depending on the applied voltage, and the plate-like elastic member 3 Is pushed up and bends into a worm type. As the distance between the end 2b of the first piezoelectric element 2 and the second fixing means 4 decreases, the deflection generated in the plate-like elastic member 3 increases, and eventually the plate-like elasticity is obtained as shown in FIG. A bent portion of the member 3 comes into contact with the movable portion 6. By further increasing the bending of the plate-like elastic member 3 from here, the movable portion 6 can be rotated by friction between the plate-like elastic member 3 and the movable portion 6.

  Here, in the driving device 10, the movable portion 6 can be continuously rotated by adjusting the waveform of the voltage applied to the first piezoelectric element 2. For example, the waveform of the applied voltage is preferably a sine waveform, a trapezoidal waveform, or a sawtooth waveform as shown in FIG. That is, when the voltage applied to the first piezoelectric element 2 is gradually increased, the plate-like elastic member 3 is slowly bent into a worm shape and comes into contact with the movable portion 6. Thereafter, when the voltage is further increased gradually, the movable portion 6 rotates in the direction indicated by the arrow in FIG. Then, by rapidly reducing the applied voltage so that the first piezoelectric element 2 contracts rapidly, the movable part 6 is made to slide with the plate-like elastic member 3 while applying almost no reverse friction force to the movable part 6. For example, the state shown in FIG. 1A can be restored while rotating in the direction of the arrow in FIG. Thus, the movable part 6 can be continuously rotated by applying a voltage to the 1st piezoelectric element 2 periodically with a predetermined waveform. Note that low-speed driving can be realized by thinning out the driving waveform.

  The magnitude of the voltage applied to the first piezoelectric element 2 is determined according to the characteristics of the first piezoelectric element 2 and the device configuration, and is not particularly limited. Further, the frequency of the voltage is not particularly limited. For example, the frequency of the voltage can be set to about 100 Hz to about 20 kHz, and the frequency of the voltage is set to an ultrasonic frequency of about 20 kHz or more. It can also be used as a so-called ultrasonic motor. If the frequency is changed during driving, the rotational speed of the movable part can be changed.

  In the above description, in the driving device 10, when the elastic plate member 3 and the movable portion 6 are not in contact with each other, the bending portion of the elastic plate member 3 is brought into contact with the movable portion 6, thereby moving the movable portion 6. Although the case where it makes it operate | move was demonstrated, the operation | movement in the drive device 10 is not limited to this aspect. For example, the following aspects are also possible. That is, as shown in FIG. 4A, in the driving device 10, a predetermined voltage is applied to the first piezoelectric element 2, and the plate-like elastic member 3 is bent according to the same principle as described above, so that the movable portion 6 Keep in contact with. In such a state, when the voltage applied to the first piezoelectric element 2 is gradually changed, the distance between the end 2b of the first piezoelectric element 2 and the second fixing means 4 gradually depends on the applied voltage. It increases and the bending of the plate-like elastic member 3 decreases. When the bending of the plate-like elastic member 3 is reduced, a frictional force is generated between the plate-like elastic member 3 and the movable portion 6, and the movable portion can be rotated as shown in FIG.

  Or in the said description, the form (FIG. 1 (B)) which rotates the movable part 6 counterclockwise by making the plate-shaped elastic member 3 with respect to the movable part 6 into a contact state from a non-contact state, plate-like elasticity Although the mode (FIG. 4B) in which the movable portion 6 is rotated clockwise by changing the member 3 from the contact state to the non-contact state has been described, the rotation direction of the movable portion 6 is not limited to these. By adjusting the waveform of the drive voltage, for example, the movable part 6 can be rotated clockwise by changing the elastic elastic member 3 from the non-contact state to the contact state with respect to the movable part 6. The rotation direction can be appropriately changed.

2. 2nd Embodiment In this invention, the form of the stator with which a drive device is equipped is not limited to a form like the said stator 5. FIG. FIG. 5 schematically shows the stator 15 provided in the drive device 20 of the present invention according to the second embodiment. In FIG. 5, description of the movable part is omitted. In FIG. 5, the same components as those of the driving device 10 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 5, the stator 15 includes a first fixing means 1, a first piezoelectric element 2, a plate-like elastic member 3, and a second fixing means 4 connected in this order. The second fixing means 4 is characterized in that it is connected via a second piezoelectric element 12 different from the first piezoelectric element 2. In other words, in the stator 15, both ends of the plate-like elastic member 3 are connected so as to be sandwiched between the two piezoelectric elements 2 and 12. About the 2nd piezoelectric element 12, it is preferable to set it as an expansion-contraction type piezoelectric element, For example, it can be set as the same form as the above-mentioned 1st piezoelectric element.

  As shown in FIGS. 5A to 5D, according to the stator 15, the voltage applied to the first piezoelectric element 2 and the second piezoelectric element 12 is adjusted to adjust the plate-like elastic member 3. It is possible to arbitrarily adjust the amount of bending and the position of the bending, and it is possible to precisely control the operation of the movable portion 6 with more variations as compared with a configuration in which only one piezoelectric element is provided. Is possible.

3. Third Embodiment In the drive device according to the present invention, a plurality of stators may be provided. 6 and 7 schematically show a drive device 30 according to the third embodiment of the present invention. 6 and 7, the same components as those of the driving device 10 are denoted by the same reference numerals and description thereof is omitted.

  In the driving device 30, a plurality of plate-like elastic members 3, 3, 3 are connected to one second fixing means 4, and the first piezoelectric element 2 and the first fixing means 1 are connected to each plate-like elastic member 3. It is characterized by being connected. In the illustrated form, the stators 5, 5, 5 are provided in the circumferential direction at 120 ° intervals with the second fixing means 4 as the center. With such a configuration, for example, it is possible to operate the sphere in a multidimensional manner using the sphere 26 as the movable portion. That is, in the stators 5, 5, and 5, the rotation direction of the sphere can be changed in a multidimensional manner by changing the applied voltage and adjusting the amount of deflection of the plate-like elastic member 3.

4). Fourth Embodiment In the driving devices 10 to 30, the first piezoelectric element 2 is extended to reduce the distance between the end 2 b of the first piezoelectric element 2 and the second fixing means 4, and the plate-like elastic member 3. The form in which the bending is caused has been described. However, the present invention is not limited to this form. FIG. 8 schematically shows a stator 35 provided in the drive device 40 of the present invention according to the fourth embodiment. In FIG. 8, description of the movable part is omitted. In FIG. 8, the same components as those of the driving device 10 are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 8, the stator 35 includes a fixing means 36 (first fixing means 1), a first piezoelectric element 2, a connecting means 37, a plate-like elastic member 3, and a fixing means 36 (second fixing means 4) connected in this order. It becomes. In other words, in the stator 35, the fixing means 36 functions as both the first fixing means 1 and the second fixing means 4, and the first piezoelectric element 2 and the plate-like elastic member 3 are connected via the connecting means 37. Are different from the stator 5 in that they are connected together. In FIG. 8A, the first piezoelectric element 2 is in an expanded state when a voltage is applied thereto.

  In the stator 35, the connecting means 37 can connect the first piezoelectric element 2 and the plate-like elastic member 3, and the plate-like elastic member 3 follows the expansion and contraction of the first piezoelectric element 2. The form is not particularly limited as long as it causes bending. For example, a metal piece, a plastic piece, a ceramic piece, or the like can be used. The connection method of the connection means 37, the 1st piezoelectric element 2, and the plate-shaped elastic member 3 is not specifically limited, The connection using an adhesive agent, the connection by welding, etc. are employable.

  In the stator 35, the plate-like elastic member 3 is bent as the first piezoelectric element 2 is reduced from the extended state. That is, the stator 35 is fixed to the end of the first piezoelectric element 2 (the end on the plate-like elastic member 3 side via the connecting means 37) by reducing the first piezoelectric element 2 from the extended state with the fixing means 36 as a fixed end. Part) 2b and the fixing means 36 are decreased, and as the distance between the end portion 2b of the first piezoelectric element 2 and the fixing means 36 is decreased, the bending generated in the plate-like elastic member 3 is increased. ing.

  Also with such a stator 35, the plate-like elastic member 3 can be bent into a worm-like shape, and the above-described displacement amount expansion effect can be obtained. However, in the stator 35, when the first piezoelectric element 2 is contracted from the extended state, a repulsive force acting in a direction away from the first piezoelectric element 2 may act on the connecting means 37 in order to eliminate the bending of the plate-like elastic member 3. There is. Therefore, there is a possibility that the connection between the first piezoelectric element 2 and the plate-like elastic member 3 is disconnected due to aging. Further, since the stator 35 is provided so that the first piezoelectric element 2 and the plate-like elastic member 3 are overlapped as shown in the drawing, the stator 35 is more space than the stators 5 and 15 configured as a substantially planar body. There may be significant inhibition.

5. Other Configurations As described above, the drive device according to the present invention obtains the displacement amount expansion effect by deflecting the plate-like elastic member into a worm-like shape and bringing the plate-like elastic member into contact with the movable portion. , Moving the moving part. Therefore, it is preferable to provide the driving device with a restricting means for restricting the bending direction (convex direction) of the plate-like elastic member to the movable portion side.

  FIG. 9 schematically shows a form in which a restricting means 7 a for restricting the direction of bending of the plate-like elastic member 3 is provided in the driving device 10. The regulating means 7 a is a means provided separately from the stator 5, so as to come into contact with the plate-like elastic member 3 in a state where the bending of the plate-like elastic member 3 is eliminated, or of the plate-like elastic member 3. It is provided to be in the vicinity. When the plate-like elastic member 3 is bent, the plate-like elastic member 3 is always bent so as to protrude toward the opposite side of the restricting means 7a due to the presence of the restricting means 7a.

  Or you may regulate the direction of bending of the plate-shaped elastic member 3 by adding a device to the plate-shaped elastic member 3 itself. As an example, FIG. 10 schematically shows regulating means 7b and 7b provided on the plate-like elastic member 3. As shown in FIG. In addition, in FIG. 10, the thickness direction sectional drawing of the plate-shaped elastic member 3 is shown roughly. As shown in FIG. 10, by providing convex portions as restricting means 7b and 7b at the end of the plate-like elastic member 3, the direction of bending of the plate-like elastic member 3 is restricted in the direction of the arrow shown.

  In addition, by bending the plate-like elastic member 3 to some extent in advance within a range that does not impair the displacement amount expansion effect according to the present invention, the direction of bending of the plate-like elastic member 3 when operating the drive device according to the present invention. Can also be regulated in a desired direction.

  As described above, in the drive device according to the present invention, the stator is configured by connecting the first piezoelectric element and the plate-like elastic member between the fixing means, and the plate-like elastic member is formed by expansion and contraction of the first piezoelectric element. In this way, the first piezoelectric element can be expanded and contracted to the bending amount (deformation amount) of the plate-like elastic member. Therefore, even when only one first piezoelectric element is used as the piezoelectric element and it is a small piezoelectric element, a large amount of deformation can be obtained by bending the plate-like elastic member. Moreover, it is also possible to omit the installation space of a stator by making an elastic member into plate shape. By providing a plurality of piezoelectric elements or a plurality of stators, the movable part can be operated in a multidimensional manner. As described above, according to the driving device of the present invention, the expansion and contraction amount of the first piezoelectric element is expanded by the plate-like elastic member, thereby obtaining the necessary driving force while reducing the size and operating the object. Is possible.

  In the above description, in the driving devices 10 to 30, the first fixing means 1, the first piezoelectric element 2, the plate-like elastic member 3 (second piezoelectric element 12), and the second fixing means 4 are on one plane. However, the present invention is not limited to this form. Depending on the shape of the installation location, for example, it can be installed while being partially curved.

  In the above description, the plate-like elastic member 3 provided in the driving devices 10 to 30 is exemplified by an elastic member having a rectangular planar shape, but the present invention is not limited to this form. Various planar shapes such as a trapezoidal shape and a triangular shape can be employed. However, it is preferable to use a plate-like elastic member having a rectangular planar shape from the viewpoint of bending the plate-like member equally from both ends and deforming it so that it is convex at the approximate center.

  Further, in the above description, the case where the second piezoelectric element 12 is provided between the plate-like elastic member 3 and the second fixing means 4 in the case where a plurality of piezoelectric elements are provided in one stator is exemplified. The form is not limited. Depending on the shape of the plate-like elastic member, three or more piezoelectric elements may be provided in one stator. However, from the viewpoint of reducing the size of the driving device, the number of piezoelectric elements for one plate-like elastic member is preferably small, and preferably 1 or 2.

  Further, in the above description, in the case where a plurality of stators are provided, a mode in which three stators 5 are provided at intervals of 120 ° with the second fixing means 4 as the center is illustrated, but the present invention is not limited to this mode. About the number of stators and the installation form of a stator, it can determine according to the shape of a movable part, the location which installs a drive device, etc.

  In the above description, only the form in which the restricting means 7a and 7b or the plate-like elastic member is slightly curved is illustrated as the restricting means, but the form of the restricting means is not limited to these. Any means capable of regulating the bending of the plate-like elastic member 3 is included in the present invention.

  Hereinafter, the effect of the drive device according to the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following specific modes.

<Configuration of drive device>
The drive device shown in FIG. 11 was produced and performance evaluation was performed. In the manufactured drive device, the length of the laminated piezoelectric element (NEC TOKIN, AE0203D16F) was 20 mm, the length of the plate-like elastic member (phosphor bronze) was 20 mm, and the thickness of the plate-like elastic member was 0.5 mm.

<Confirmation of displacement expansion effect>
With respect to the stator configured as described above, as a result of applying a voltage of 140 V to the multilayer piezoelectric element, the extension amount of the multilayer piezoelectric element (length x in FIG. 2) was 13 μm, and the amount of deflection of the plate-like elastic member (see FIG. The length y) of 2 was 50 μm. That is, a displacement amount expansion effect of about 3.8 times was obtained. In addition, it is thought that this magnification rate can further be improved by changing the shape dimension of a plate-shaped elastic member.

<Operation experiment of drive device>
As shown in FIG. 11, the rotor with a diameter of 30 mm was rotated by interacting with the above stator. As a result of applying a trapezoidal wave voltage of about 1 kHz to the laminated piezoelectric element, the rotor could be continuously rotated. The rotor could be continuously rotated at other frequencies.

  As described above, a driving device capable of obtaining a large driving force while being miniaturized by deforming the elastic member into a worm-like shape by expansion and contraction of the piezoelectric element and expanding the expansion and contraction amount of the piezoelectric element by the elastic member. Could be provided.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. However, the invention can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and a drive device that includes such a change is also included in the technical scope of the present invention. Must be understood.

  The drive device according to the present invention can be used as a friction drive type actuator in which a stator excited by mechanical vibration is brought into contact with a movable part such as a rotor or a slider to rotate or linearly move. In addition to the XY stage, it can be suitably used in various fields such as a security camera, a surgical device, a multi-dimensional motor incorporated in an automobile door mirror, or the like.

DESCRIPTION OF SYMBOLS 10 Drive apparatus 1 1st fixing means 2 1st piezoelectric element 3 Plate-shaped elastic member 4 2nd fixing means 5 Stator 6 Movable part (rotor)
7a, 7b Restricting means 20 Driving device 12 Second piezoelectric element 15 Stator 30 Driving device 26 Movable part (sphere)
40 Driving device 35 Stator 36 Fixing means 37 Connecting means

Claims (6)

A stator in which a first fixing means, a first piezoelectric element, a plate-like elastic member, and a second fixing means are connected in this order, and a movable portion that operates by interaction of the stator with the plate-like elastic member. ,
In the stator, the distance between the end of the first piezoelectric element on the plate-like elastic member side and the second fixing means increases or decreases as the first piezoelectric element expands and contracts with the first fixing means as a fixed end. The driving device is configured such that as the distance between the end of the first piezoelectric element on the plate-like elastic member side and the second fixing means decreases, the deflection generated in the plate-like elastic member increases. .   2. The drive device according to claim 1, wherein the plate-like elastic member is bent so as to protrude in a direction orthogonal to an expansion / contraction direction of the first piezoelectric element.   3. The drive device according to claim 1, wherein the plate-like elastic member and the second fixing unit are connected via a second piezoelectric element different from the first piezoelectric element.   The drive device according to claim 1, wherein a plurality of the stators are provided.   5. The plurality of plate-like elastic members are connected to one second fixing means, and the first piezoelectric element and the first fixing means are connected to each plate-like elastic member. The drive apparatus in any one of.   The drive device according to any one of claims 1 to 5, further comprising a restricting unit that restricts a direction of bending of the plate-like elastic member.