JP2010246249A - Rotary drive using piezoelectric element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary drive in which a design position of a node line is hard to change carelessly. <P>SOLUTION: A diaphragm 10 has a piezoelectric element 20 where conduction layers 14 and 16 are arranged on a piezoelectric plate 12 in the rotary drive. A body to be driven is rotated around a central axis which passes through a superficial centroid position and is orthogonal to the diaphragm while friction force is operated on the confronted body to be driven 50 by driving projections 40 arranged on a plate face of the diaphragm with plate bending vibration generating node lines N1 and N2, which radially extend from the planar centroid position O of the diaphragm by bending of the diaphragm in a direction orthogonal to the plate face of the diaphragm. An outer shape of the diaphragm is polygonal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rotary drive device using a piezoelectric element, and can be used for a so-called ultrasonic motor or the like.

In an ultrasonic motor having a structure in which a driving claw is provided on the spreading surface of a vibrator to rotate a driven body (rotor), a plate bending vibration extending radially from the planar center of gravity (center) of the vibrator The stability of the node line (immovable line) is important. That is, by providing the driving claw on the spreading surface of the vibrator, the node line is shifted from the design position in the state where the driving claw is not provided. When such a deviation occurs, the frictional driving force against the driven body on which the driving claw provided on the vibrator acts during plate bending vibration changes, and in a severe case, the driven body moves in the opposite direction due to the relationship with the position of the driving claw. It is also possible to rotate. Thus, it becomes unstable as a rotation drive device. In order to eliminate such instability, the present applicants and others disclose a structure in which a dummy dummy claw for balancing is provided in the following Patent Document 1.
JP 2003-324981 A

However, in Patent Document 1, it is necessary to provide a dummy dummy claw for balancing on the spreading surface of the vibrator. In an actual structure, the dummy claw is set to an accurate height so that it does not act on the driven body. In addition, it is necessary to provide the drive claw so as to have an exact symmetry with respect to the node line as a boundary, but because there is a difference in height, perfect symmetry is impossible, and if it was formed with high accuracy However, the instability of the node line due to the material non-uniformity of the vibrator remains.
Therefore, the problem to be solved is to provide a rotary drive device in which the design position of the node line is unlikely to change carelessly.

In view of the above problems, the first invention is that a diaphragm including a piezoelectric element provided with an energization layer on a piezoelectric plate is bent in a direction perpendicular to the plate surface of the diaphragm so that the planar center of gravity of the diaphragm is Due to the plate bending vibration that generates radially extending node lines, the driving convex portion provided on the plate surface of the diaphragm causes a frictional force to act on the driven body facing, and the planar gravity center position is determined. A rotary drive device that rotates a driven body about a central axis perpendicular to the diaphragm, and the diaphragm has a polygonal outer shape or a circular outer shape, and the planar Provided is a rotary drive device using a piezoelectric element, characterized in that a concave portion, a through hole or a convex region having a polygonal outer periphery is provided around the center of gravity.
The planar center of gravity position of the diaphragm is the center in a flat manner and is on the central axis of rotation (rotation) of the driven body. The term “polygon” in the present application is used in a broad sense, and includes, for example, one in which each corner of a quadrangle is removed and cut by a straight line or an arc. Further, the star shape is also included in the polygon, and the star shape corner portion is removed and cut.

In the second invention, the surfaces of two plate-like piezoelectric elements are bonded to each other, and the current-carrying layer region facing by the bonding has the entire region in a conductive connection state (short state). Each of the piezoelectric plates has a plurality of regions with different polarization directions on each spreading surface, and each region of one piezoelectric plate is located at a position vertically opposite to each region of the other piezoelectric plate. The diaphragm according to the first aspect of the invention is configured such that the polarization directions of adjacent regions in the plate are opposite to each other, and that the corresponding directions of both piezoelectric plates are also opposite to each other. To do.
In the present application, the polarization states in opposite directions are referred to as parallel polarization as described above. Conversely, a polarization state in the same direction as in the next third invention is called series polarization.

  In the third invention, each of the two plate-like piezoelectric elements is provided with a non-divided energization layer on the back surface of each piezoelectric plate, and a divided energization layer divided into a plurality of regions is provided on the surface. , There is a correspondence relationship in which each region of each piezoelectric element is electrically connected to one region of the divided energization layer of one piezoelectric element and one region of the separation energization layer of the other piezoelectric element. The vibrators are formed by pasting the back surfaces of the piezoelectric elements so that the areas are positioned vertically opposite to each other, and the piezoelectric plates are all polarized in the same direction in each area of the piezoelectric elements. At the same time, the diaphragm of the first invention is configured so that the polarization directions of the piezoelectric plates are the same as each other even in the bonded state.

  In the first invention, when the outline shape of the diaphragm is a polygon, the length from the center of the diaphragm to the outline gradually changes around the center, that is, the resistance value of the bending of the diaphragm gradually changes. Therefore, the radial node line passing through the center of the diaphragm cannot be carelessly changed around this center. In other words, the fact that the outer shape is not a circle but a polygon is a mechanical restriction means against fluctuations around the center of the node line. Even if the outer shape is circular, a concave portion with a polygonal outer periphery is provided on the front surface or back surface of the diaphragm, a polygonal hole penetrating from the front surface to the back surface, or a polygonal convex region is provided. The same applies to the case where there is.

  In the second invention, the diaphragm of the first invention does not have a base material other than the piezoelectric element, such as a base metal plate or a base glass plate for attaching the piezoelectric element, and therefore piezoelectric distortion is not caused. It can be taken out efficiently as it is, and can be made thinner, smaller, and less expensive during mass production. Even in such a case, as in the second invention, when the polarization direction is alternately changed for each adjacent region, the connection to the alternating voltage generator becomes simple. That is, it is not necessary to electrically connect (short) the front and back surfaces of the bonded diaphragm as a whole, and each of the current-carrying layers corresponding to each polarization direction on both the front and back surfaces. All of them are in a conductive connection state without distinguishing the areas of the electrodes, but it is only necessary to connect the front and back surfaces of the vibrator in this state to the respective terminals of the alternating voltage generator, making the electrical connection work very easy. Become.

  In the third invention, as in the second invention, the diaphragm does not have a base material other than the piezoelectric element such as a base metal plate or a base glass plate for attaching the piezoelectric element, and the piezoelectric strain Can be taken out sufficiently efficiently, and it is possible to reduce the thickness, size and cost of mass production. However, although the present invention has the same polarization direction (series polarization) and the polarization work is simple, it is necessary to conduct conductive connection between the front and back surfaces for each corresponding region of the entire bonded diaphragm. The electrical connection itself is simpler in the second invention.

  Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a rotary drive device according to the present invention. (A) is a top view, (b) is a sectional view taken along line N2-N2 in (a), and (c) is a bottom view. FIG. 2 is an electrical wiring diagram thereof. Current-carrying layers 14 and 16 are formed on the front and back surfaces of a substantially square plate-shaped piezoelectric body, that is, the piezoelectric plate 12, and only the surface current-carrying layer 14 is evenly divided by two vertical and horizontal dividing grooves 22 as shown in the figure. The piezoelectric element 20 is formed by dividing into substantially square areas A, B, C, and D.

  The planar center of gravity position of the piezoelectric element, that is, the center O is bonded and fixed together with the center of the substantially square base plate 30 to constitute the diaphragm 10. An electric wiring, which will be described later, is performed on the diaphragm to form a rotary drive device. As a material of the base plate 30, in addition to a metal plate such as stainless steel, Pyrex (registered trademark) glass or the like may be used. Four drive protrusions 40 are fixed at appropriate positions on the back side of the base plate in this example, but two drive protrusions 40 may be provided. When the base plate is a metal, it can be integrally formed by welding or the like, and when it is glass or the like, it can be integrally formed when the base plate is formed. The dividing groove line of the piezoelectric element of the present application is a radial line passing through the center O.

  The straight lines N1-N1 and N2-N2 passing through the above-described center O are the center of the width of the dividing groove, and are node lines during plate bending vibration of the diaphragm. According to FIG. 1C when the diaphragm 10 is viewed from the back side, the four drive protrusions 40 are provided at angular positions separated from each node line in the clockwise direction by the same angle θ. In this case, the piezoelectric element 20 has four regions A, B, C, and D, and the region angle between the node lines N1-N1 and N2-N2 is 90 degrees. Therefore, the angle θ is preferably 22.5 degrees, which is ¼ of the region angle, and is also used in this example.

  In addition, the center of the drive convex portion is positioned at a position of 35 to 40 percent of the length of the radiation line from the center O until the radiation line passing through the center O and the drive convex portion 40 intersects the outline of the diaphragm. It is preferable to make it.

  When the polarization direction of the piezoelectric plate 12 is the same in each of the regions A, B, C, and D, the regions A and C are electrically connected, the regions B and D are electrically connected, and each is a self-excited oscillator. Etc., and connected to each terminal of the alternating voltage generator 60. Thereby, the regions A and C have the same phase vibration, and the regions B and D have the same phase vibration, but the regions A and C have the opposite phase. Accordingly, when the areas A (and C) are convex on the front side, the areas B (and D) are concave. As a result of the vibration, the rotor 50 which is a driven body is driven in the direction of the arrow (counterclockwise direction) around the center O in the direction view of FIG. If each drive projection is provided at a position symmetrical to the position of FIG. 5C with respect to the adjacent node line, the rotation of the rotor is in the opposite direction.

  As described above, the positional relationship between the position of the node line and the driving convex portion is important in terms of the driving force and the driving direction with respect to the rotor, and it is inconvenient if the node line is not positioned as designed. The node line in this embodiment is a radial line that passes through the center O and passes through the center of each side of the diaphragm 10 or the base plate 30. If the radial node line is somewhat displaced from the center position of each side, the line length on the diaphragm that the node line crosses is obviously longer. That is, since the thickness of the base plate 30 is substantially constant, each region divided by the elongated line to the left and right has a greater resistance (bending rigidity) to plate bending vibration than the original region before shifting. Change. Accordingly, even if there is material non-uniformity of the base plate 30 other than the influence of the driving convex portion 40, the position of the node line is at the design position because it does not cause a large change in the vibration resistance. On the other hand, it does not change substantially.

  Even if the outer shape of the base plate 30 is circular, the outer shape is an appropriate polygon as depicted by a two-dot chain line 30M in FIG. 1C, and the center is made to coincide with the center O described above. If the position of the node line is changed, a difference in the plate thickness change along the node line is caused. The resistance will change greatly. These changes are unlikely to occur. Therefore, the change from the design position of the node line can also be regulated by the presence of such a polygon in the diaphragm.

  FIG. 3 can be said to correspond to FIG. 2 of a modification of the embodiment shown in FIGS. As shown in FIG. 3, the energization layer on the surface of the piezoelectric element 20 is divided into four right triangle regions A, B, C, and D so that the dividing groove line passes through the center O and each corner. When the polarization direction of the piezoelectric plate is the same in each of the areas A, B, C, and D, the areas A and C are electrically connected as shown in the figure, the areas B and D are electrically connected, It is connected to each terminal of an alternating voltage generator such as a self-excited oscillator (not shown). Thereby, the regions A and C have the same phase vibration, and the regions B and D have the same phase vibration, but the regions A and C have the opposite phase. The node lines in this case are diagonal lines N1-N1 and N2-N2 of the diaphragm 10.

  Even when the outer shape of the diaphragm is an even regular polygon other than a square, the node line may be located diagonally or may be located at the center of each side. FIG. 4 shows an example in which the diaphragm 10 (or the base plate 30) is a regular hexagon and the piezoelectric element 30 is circular. The energization layer on the surface of the piezoelectric element is divided into six uniform fan-shaped regions every 60 degrees by radial lines passing through the center O. Each dividing groove line passes through the center position of each side of the outline. The polarization directions of the piezoelectric plates are the same in each region, the regions A, C, and E jumping in the circumferential direction are electrically connected, and the remaining regions B, D, and F are electrically connected. Connect to the omitted alternating voltage generator. In this case, the node line passes through the center O and the center of each side. Regions A, C, and E and regions B, D, and F exhibit vibrations that are concave and convex opposite to each other.

  FIG. 5 shows an example in which the diaphragm 10 (or the base plate 30) is a regular octagon and the piezoelectric element 30 is circular. The energization layer on the surface of the piezoelectric element is divided into eight equal fan-shaped regions every 45 degrees with radial lines passing through the center O. Each dividing groove line passes through each corner. In each region, the polarization direction of the piezoelectric plate is the same, the regions A, C, E, and G jumping in the circumferential direction are electrically connected, and the remaining regions B, D, F, and H are electrically connected. These are connected to an alternating voltage generator (not shown). In this case, the node lines are radial passing through the center O and each corner. Regions A, C, E, and G and regions B, D, F, and H have vibrations that are concave and convex opposite to each other.

4 and 5, a circular hole H is provided in the center of the diaphragm 10. This is provided in order to insert a rotating shaft of a rotor (not shown).
In the above embodiment, the outer shape of the diaphragm 10 is an even regular polygon, but if it is an even polygon, the driven body can be rotated even if it is not a regular polygon. A regular polygon is good for efficient rotation. Moreover, even if it is an odd-numbered polygon, although it is inefficient, it can be rotated. Further, although the polarization direction of the piezoelectric plate 12 is the same in each region, the polarization direction may be changed for each adjacent region (parallel polarization). Becomes easier.

  For example, even when the outer shape is a square, in an actual product, it is preferable to cut the corners of the square because the actual vibration is stabilized. Assuming that the length of one side of the square is 20, the amount of this cut is about 3 at each end of each side (2 to 4, ie, 10 to 20% of the side length). Therefore, even though the square is the basic shape, it can also be said to be an octagon. Further, the cut is not limited to a straight line and may be rounded. The same applies to other arbitrary polygons such as a hexagon, and if each corner is cut, vibration is likely to be stabilized. This arbitrary polygon includes a polygon whose outer shape is uneven like a star.

Hereinafter, examples of regular triangles and regular pentagons will be described as examples of odd-numbered polygons. FIG. 6 shows a case of an equilateral triangle, and the energization layer is divided into six identical right triangles by three lines passing through the center of the diaphragm and each vertex. The piezoelectric plate is polarized in the same direction in each region, the regions A, C, and E of the conductive layer are electrically connected and short-circuited, and the remaining ones are also connected and short-circuited, and each is connected to each terminal of the alternating voltage generator.
FIG. 7 shows a case of a regular pentagon, and the current-carrying layer is divided into ten identical right triangles by five lines passing through the center of the diaphragm and each vertex. The piezoelectric plate is polarized in the same direction in each region, the connection layers A, C, E, G, and I are electrically connected and short-circuited, and the remaining ones are connected and short-circuited, and each is connected to each terminal of the alternating voltage generator. Connect.

  Further, for example, when the polarization directions of the piezoelectric plates are all the same in the form of FIG. 5, the regions A and B, C and D, E and F, G and H are electrically conductively connected, and two adjacent regions are connected. Can be treated as four individual regions having the same shape. Further, if the drive convex portion is located at the central angular position of the circumferential angle of the regions B, D, F, and H, that is, the intermediate angular position between the line N2-N2 and the line N3-N3, and the line N1-N1. In the case where the regions B and C, D and E, F and G, and H and A are integrated, respectively, in the middle angle position of the line N4-N4. It can be rotated in the opposite direction to the former case. That is, in the former, since the driving convex portion is close to the node lines N3-N3 and N1-N1, if the driving convex portion is provided so as to project on the plane of FIG. The body is rotated in the clockwise direction as viewed in the direction of FIG. Moreover, in the latter, since a drive convex part is close to node line N2-N2 and N4-N4, a drive force is made to act counterclockwise.

  Moreover, if the piezoelectric elements 20 and 20 of FIG. 2 and FIG. 3 are used for the front and back of the base plate 30, and the driving convex portion is set at 22.5 degrees in FIG. When the energization to the piezoelectric element is switched by a switch, the node lines at the time of vibration change from N1 and N2 in FIG. 1 to N1 and N2 in FIG. That is, since the node line adjacent to each driving projection moves and changes to the opposite side with respect to each driving projection, the driving direction can be reversed.

  In the following, the vibration plate 10 is not formed by using a separate member base plate such as a metal plate or a glass plate other than the piezoelectric body, but by attaching two piezoelectric elements 20 and 20 ′ together. An example of the formed structure will be described. FIG. 8 is a plan view thereof, but the dividing groove line 22 is not visible on the upper surface side in the case of FIG. 9 in the form of FIG. 9 and the form of FIG. Think of it as a figure. 9 and 11 are cross-sectional views of the C region and D region of the diaphragm 10, but the same applies to the remaining regions. There are regions A, B, C, and D corresponding to four divisions of the conductive layer of the upper piezoelectric element 20. On the other hand, each of the four corresponding regions of the lower piezoelectric element 20 ′ is A ′, B ′, C ′, D ′. It is in.

  The embodiment shown in FIG. 9 uses parallel polarization in which the polarization direction of each region of the piezoelectric plate 12 of the piezoelectric element 20 is different for each adjacent region. In addition, the piezoelectric plate 12 ′ of the lower piezoelectric element 20 ′ is similarly parallel-polarized, and is configured in such a direction as to be polarized in opposite directions in each of the upper and lower corresponding regions (for example, C and C ′). ing. Furthermore, the entire opposing conductive layer including the divided surface conductive layer 14 of the upper piezoelectric element 20 and the non-divided back conductive layer 16 ′ of the lower piezoelectric element 20 ′ is electrically conductive. It is joined to. As an example of the conductive adhesive used for the joining, there is Ablebond (trade name) 84-1LMI of Nippon Able Stick Co., Ltd.

  As shown in the schematic circuit diagram of FIG. 10, each terminal of the alternating voltage generator 60 is connected to the front and back surfaces 16 and 14 ′ of the diaphragm 10. Each region of the piezoelectric plate is represented by two parallel lines, and the direction of polarization is indicated by an arrow. Specifically, one end (a clip) of the alternating voltage generator 60 is (pressed) connected to the upper surface conductive layer 16 of FIG. 9, and the divided conductive layer 14 ′ on the lower surface of the diaphragm in which the four regions are conductively connected to each other. And the other end (the clip) need only be (pressed) connected. Therefore, the electrical wiring itself after forming the diaphragm having the structure shown in FIG. 9 is very simple and suitable for mass production.

  As can be seen from the circuit diagram of FIG. 10, in reality, the energizing layers 14 and 14 ′ of FIG. 9 do not require the dividing groove line 22, and both energizing layers are in a conductive connection state between the adjacent regions. That is, it may be integrated like the energization layers 16 and 16 '.

In order to manufacture the diaphragm 10 having the structure shown in FIG. 9, first, an energization layer is formed on the front and back surfaces of a piezoelectric plate as a material plate having a size corresponding to a plurality of vibrators (in reality, a large number). . One surface (front surface) has a divided groove line 22 and a plurality of patterns including a contour of each divided energization layer and a vibrator outer shape line to be cut later as an individual vibrator by screen printing or the like. Baking print formation. Polarize it. The material plate forming the piezoelectric element 20 and the other material plate forming the piezoelectric element 20 ′ are bonded to each other in a conductive connection state in a positional relationship in which the polarization directions are opposite to each other. Then, it cut | disconnects with a diamond saw etc., and forms the diaphragm 10 of the form of FIG.
Thereafter, each region of the energization layer 14 ′ is conductively connected, and clip-like terminals connected to the respective terminals of the alternating voltage generator are brought into contact with the front surface 16 and the rear surface 14 ′ of the diaphragm, and wiring is simple. Yes, it can be mass-produced at low cost.

  Further, as is apparent from FIG. 10 of the circuit diagram, each region A ′, B ′, C ′, D ′ of the divided energization layer 14 of the piezoelectric element 20 ′ is made of a conductive member so as to be short-circuited. In this case, the driving convex portion 40 can be freely provided on the upper surface conductive layer 16 or the lower surface conductive layer 14 'of FIG. 8 is provided on the upper surface conductive layer 16 at an angular position in FIG. 8 (provided in a region B at a position of 22.5 degrees counterclockwise from the horizontal dividing groove line 22 in FIG. When the regions A and C extend and the regions A and C (and regions A ′ and C ′) protrude upward, the regions B ′ and D ′ extend and the regions B ′ and D ′ (And regions B and D) are vibrations that protrude downward, and the driven body can be driven clockwise as indicated by an arrow in the viewing direction of FIG. 8 (top view of FIG. 9).

  In the embodiment shown in FIG. 11, the polarization direction of each region of the piezoelectric plate 12 of the piezoelectric element 20 is the same in all regions. Further, the piezoelectric plate 12 ′ of the lower piezoelectric element 20 ′ is similarly polarized and joined so as to have the same polarization direction as that of the upper piezoelectric element. In this example, they are joined so as to be electrically conductive, and the wiring in this case is shown in FIG. In the case of this series polarization, a diaphragm can be formed even if the junction of two piezoelectric elements is insulated.

One method of manufacturing the diaphragm 10 having the structure shown in FIG. 11 is not first divided into the front and back surfaces of a piezoelectric plate as a material plate having a size corresponding to a plurality of vibrators (in reality, many). An energization layer is formed and polarized in the same direction over the entire material plate. Prepare two of them and paste them together so that the polarization directions are the same. Thereafter, each divided energization layer contour is formed while forming the dividing groove line 22, and a plurality of diaphragms 10 in the form of FIG. 11 are formed by cutting with a diamond saw or the like along the vibrator outer shape line.
Thereafter, on the front and back surfaces of the vibrator 10, the corresponding regions (all combinations such as the region C and the region C ′) are conductively connected to obtain the circuit diagram of FIG. 12.

  As another method, an energization layer is formed on the front and back surfaces of a piezoelectric plate as a material plate having a size corresponding to a plurality of vibrators (in reality, a large number). One surface (front surface) has a divided groove line 22 and a plurality of patterns including a contour of each divided energization layer and a vibrator outer shape line to be cut later as an individual vibrator by screen printing or the like. Baking print formation. It is polarized, but the material plate to be the upper piezoelectric element 20 and the material plate to be the lower piezoelectric element 20 ′ are polarized in the opposite directions as viewed from the surfaces of the divided conductive layers 14 and 14 ′. Let Each of the material plates is joined to the integrated energization layers 16 and 16 'in which the energization layers are not divided. Thereafter, the diaphragm 10 is cut along a contour line of the vibrator with a diamond saw or the like to form a plurality of diaphragms 10 having the form shown in FIG.

In the electrical wiring after the diaphragm 10 is formed, it is necessary to perform wiring as shown in FIG. 12, and the upper and lower sides of each region of the conductive layer 14 of the piezoelectric element 20 and each region of the conductive layer 14 ′ of the piezoelectric element 20 ′ are arranged. It is necessary to electrically connect the energization layers of the regions corresponding to the above. It is troublesome to make this connection with a print pattern or with a cord line.
The matters described with reference to FIGS. 8 to 12 are the same for various polygons other than the case where the diaphragm 10 is substantially square. Particularly, for a small diaphragm, the side of the square is about 10 mm. The mass productivity of the type in which the energization layer is divided into two by the dividing groove line passing through the center and the center is good.

  As a diaphragm that enables the driven body to be driven to rotate in the opposite direction, there is a diaphragm in which the configuration shown in FIG. 13 is electrically connected as shown in FIG. Specifically, the piezoelectric element 20 in the form of FIG. 13 in plan view and the piezoelectric element 20 ′ having the same shape in the top view are joined together by series polarization as in the case of FIG. 11. The region of the piezoelectric element 20 ′ is not shown, but is represented by a symbol with “′” added to the symbol of the region of the piezoelectric element 20. A straight line that bisects the angle 45 degrees formed by the diagonal line N1′-N1 ′ and the side center line N1-N1 passing through the center of the side is divided into a region A or D (A ′ or D ′) and a region B or E ( B ′ or E ′), and regions A and D (A ′, D ′) are symmetrical with respect to the diagonal line N1′-N1 ′. The regions B and E (B ′, E ′) are symmetric with respect to the diagonal line N1-N1.

  The areas C and F of the upper piezoelectric element 20 and the areas C 'and F' of the lower piezoelectric element 20 'are always energized during use. The upper piezoelectric element 20 uses the areas A and D, and the lower piezoelectric element 20 'uses the areas B' and E '. Regions corresponding to the upper and lower positions are also used correspondingly. When the alternating voltage generator 60 is energized and applied to the areas A and D (A ′, D ′) at predetermined times by switching the switch 70, vibrations with the two side center lines N1-N1 and N2-N2 as node lines are applied. Occurs. On the other hand, when energization is applied to the regions B ′ and E ′ (B, E) of the lower piezoelectric element, vibration is generated with two diagonal lines N1′-N1 ′ and N2′-N2 ′ as node lines. If the driving convex portion 40 is at the position of one contour line (the boundary line described above) of the regions A and D as shown in the figure, the node lines adjacent to the driving convex portion are connected to each other by switching the connection by the switch 70. Since it is located on the opposite side, the rotational drive direction with respect to the driven body is reversed.

  The diaphragm in the case where the outer shape is a regular hexagon or a regular octagon can be driven reversely according to the configuration described with reference to FIGS. FIG. 15 illustrates division in the case of a regular hexagon. Regions A, B, and C are configured in units of 3 units (circular angle is 120 degrees). Regions A and B are symmetrical with respect to the radial lines of the diaphragm. As is apparent from the description of the square shape in FIG. 13, the dividing groove line 22 and the node line in the region do not necessarily match.

  FIGS. 16 and 17 are examples of a motor using the diaphragm 10 of the rotary drive device according to the present invention, which is characterized in that the entire motor is made thin. FIG. 17 is an enlarged cross-sectional view of a main part of the driven body 50 shown in FIG. Although a plan view of the motor is not drawn, it is circular and the casing 100 is a thin cylinder. The diaphragm 10 is supported on the casing 100 via a damper member 80 such as a sponge material. The driven member 50 that is rotationally driven around the rotation center axis O is pressed and supported by the lower lid member of the casing 100 via a rotatable ball 90 by the driving convex portion 40 provided on the diaphragm. The member 58 is a driving force extraction member attached to the driven body 50, and is drawn out through the peripheral wall surface of the casing. Here, the rotation angle of the driven body is smaller than 360 degrees, for example, 90 degrees. It is rotationally driven in both positive and negative directions within this angle range and can be used for driving a robot arm or the like.

  The driven body 50 is formed by joining a sliding plate 52 to a substrate 56 via a buffer material 54. Examples of the buffer material include double-sided tape, and examples of the sliding plate include glass fiber reinforced synthetic resin (glass epoxy resin) in which glass fiber is impregnated with epoxy resin. The driven body may be made of Teflon (registered trademark). This is because the partially spherical groove 50 </ b> H at the center receives the ball 90. Due to the presence of the buffer material 54, the vibration of the driving projection 40 hitting the driven body 50 is absorbed, and the presence of the damper member 80 absorbs the vibration noise of the diaphragm 10 hitting the casing, thereby reducing the noise. it can.

  FIG. 18 shows another embodiment of the motor using the diaphragm 10 of the rotary drive device according to the present invention. The rotary shaft 59 extends coaxially with the central axis O of the driven body 50 like a normal motor. ing. FIG. 19 is a plan view of the main components of FIG. Although a plan view of the motor is not drawn, it is circular and the casing 100 is cylindrical. The diaphragm 10 is supported on the casing 100 via a damper member 80 such as a sponge material. The driven body 50 has a supporting spring plate 110 formed by a leaf spring member and a peripheral portion thereof fixed. The driven body 50 is pressed in the direction of the diaphragm and is driven against the driving convex portion 40 provided on the lower surface of the diaphragm. The upper surface is pressed. A hole 50H for receiving the ball 90 is provided at the center of the support spring plate 110, and an appropriate number of holes are provided in the outer region circumferential direction to increase the degree of freedom of deformation of the support spring plate. A rotating shaft 59 is fixedly erected at the center of the support spring plate.

  A bearing 120 is disposed at an appropriate position of the rotating shaft. The support spring plate 110 has a role of pressing the driven body (preloading role) and a role of eliminating wobbling of the rotating shaft 59. Further, the bearing 120 prevents wobbling in the upper part of the rotating shaft. The role of the damper member 80 is the same as that in the above-described embodiment. For the preload, the driven body can be attracted to the vibration plate side using a magnet, and may be used in combination with a leaf spring member.

As a modified example of the motor, the diaphragm 10 can be provided on both sides of the driven body, and the driving force of both diaphragms can be applied simultaneously. In this case, the driving force increases. In this case, the connection to the alternating voltage generator such as a self-excited oscillator may be a serial electrical connection or a parallel electrical connection.
In a manufacturing method in which a titanium material is used as a base member and a piezoelectric material is formed on the surface by a so-called hydrothermal synthesis method, the film can be formed even when the surface of the base member is a curved surface. Suitable for mass production of high-precision and small microactuators.

Alternatively, a driving convex portion may be provided on each of the front and back surfaces of one diaphragm, and each driven body that is disposed on both sides of the diaphragm and faces each driving convex portion may be rotationally driven. In this case, the two driven bodies may be rotated in the same direction, or may be rotated in different directions by energization control.
Furthermore, the vibrator according to the present invention may be mounted on the outside of the bottom wall of a cylinder or a rectangular tube, and the flow rate control may be performed by rotating the driven body in the cylinder.
If the height of the driving convex portion is formed high, the driven body can be rotated quickly, and if it is formed low, the driven body can be rotated slowly, but the rotational speed of the driven body in use can be controlled by intermittent energization. Good.

  The present invention can be used for ultrasonic motors, driving of robot arms, various measuring instrument related devices, and the like.

FIG. 1 is a diagram showing an embodiment of a rotary drive device according to the present invention. FIG. 2 is an electrical wiring diagram of the apparatus of FIG. FIG. 3 is a wiring diagram of a modification of the embodiment of FIG. FIG. 4 shows an example in which the diaphragm is a regular hexagon and the piezoelectric element is circular. FIG. 5 shows an example in which the diaphragm is a regular octagon and the piezoelectric element is circular. FIG. 6 shows an example in which the diaphragm and the piezoelectric element are equilateral triangles. FIG. 7 shows an example in which the diaphragm and the piezoelectric element are regular pentagons. FIG. 8 is a plan view of another form of rotary drive device. 9 is a cross-sectional view of one embodiment of FIG. FIG. 10 is an electrical wiring circuit diagram corresponding to the embodiment of FIG. FIG. 11 is a cross-sectional view of another embodiment of FIG. FIG. 12 is an electrical wiring circuit diagram corresponding to the embodiment of FIG. FIG. 13 is a plan view of the modified example of FIG. FIG. 14 is an electrical wiring circuit diagram of the form of FIG. FIG. 15 is a plan view of another modified example of FIG. FIG. 16 is a cross-sectional view of a motor as an application example of the present rotary drive device. FIG. 17 is a partially enlarged view of parts using the motor of FIG. FIG. 18 is a cross-sectional view of another motor as an application example of the present rotary drive device. FIG. 19 is a plan view of parts using the motor of FIG.

DESCRIPTION OF SYMBOLS 10 Diaphragm 12 Piezoelectric plate 14,16 Current-carrying layer 20,20 'Piezoelectric element 22 Divided groove line which divided | segmented piezoelectric plate into several area | region 30 Base plate 40 Drive convex part 50 Driven body A, B, C, D, A' , B ', C', D 'Divided conductive layer and piezoelectric plate area

Claims (3)

A plate bending in which a diaphragm having a piezoelectric element provided with an energization layer on a piezoelectric plate is bent in a direction perpendicular to the plate surface of the diaphragm to generate a node line extending radially from the planar center of gravity of the diaphragm. Due to the vibration, the driving convex portion provided on the plate surface of the diaphragm causes a frictional force to act on the driven body facing the same, and passes around the planar center of gravity position around the central axis perpendicular to the diaphragm. A rotary drive device that rotates a driven body,
The diaphragm has a polygonal outer shape or a circular outer shape, and is provided with a concave portion, a through-hole, or a convex region having a polygonal outer periphery around the planar gravity center position. A rotary drive device using a piezoelectric element characterized by the above.   The surfaces of two plate-like piezoelectric elements are bonded together, and the conductive layer region facing by the bonding makes the entire region conductively connected, and the piezoelectric plate of each piezoelectric element is polarized on each spreading surface. It has a plurality of regions with different directions, and each region of one piezoelectric plate is in a position opposite to each region of the other piezoelectric plate, and adjacent regions in each piezoelectric plate are in the polarization direction The rotation drive device using a piezoelectric element according to claim 1, wherein the directions of the piezoelectric elements are opposite to each other, and further, the polarization directions are opposite to each other in the corresponding regions of both piezoelectric plates.   Each of the two plate-like piezoelectric elements is provided with a non-divided current-carrying layer on the back surface of each piezoelectric plate, and on the surface with a divided current-carrying layer divided into a plurality of regions. There is a correspondence relationship for electrically connecting one region of the divided energization layer and one region of the separation energization layer of the other piezoelectric element for each region of each piezoelectric element, and the corresponding regions are vertically The vibrators are configured by bonding the back surfaces of the respective piezoelectric elements so that they face each other, and the piezoelectric plates are all polarized in the same direction in each region of each piezoelectric element, and are bonded together. 2. The rotation drive device using a piezoelectric element according to claim 1, wherein the polarization directions of the piezoelectric plates are the same in each state.

Images