Patent Abstract:
To provide a highly versatile piezoelectric actuator module that can be made thinner and is easy to handle.  
     A piezoelectric actuator module I0 includes a piezoelectric actuator main body  21  having electrodes, a plurality of signal input terminals  18 A to  18 D whereby a drive signal is inputted from the exterior and supplied to the electrodes, a rotating body  22  that is disposed in substantially the same plane as the piezoelectric actuator main body  21  and is driven and rotatably moved by the piezoelectric actuator main body  21,  a casing  15  for accommodating the piezoelectric actuator main body electrically connected to the rotating body  22  and the signal input terminals, and an output shaft  12  which is exposed from the casing  15  and by which the rotational movement transmitted directly or indirectly by the rotating body  22  is outputted to the exterior.

Full Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a piezoelectric actuator module, an electric motor module, and an apparatus using the same.  
       DESCRIPTION OF THE RELATED ART  
       [0002]     Piezoelectric actuators based on the use of piezoelectric elements are known in conventional practice (for example, see Japanese Patent No. 3241688).  
       SUMMARY OF THE INVENTION  
       [0000]     Problems the Invention is Intended to Solve  
         [0003]     However, when piezoelectric actuators are configured in the manner described in the above-mentioned Japanese Patent No. 3241688, problems arise in the sense that the actuators themselves are thick and that it is difficult to reduce the thickness of the apparatus containing these piezoelectric actuators. In view of this, an object of the present invention is to provide a highly versatile, thin, and easy-to-handle piezoelectric actuator module, electric motor module, and apparatus equipped with the piezoelectric actuator module and the electric motor module.  
         [0000]     Means for Solving the Problems  
         [0004]     In order to solve the problems described above, a piezoelectric actuator module is provided having a piezoelectric actuator main body with electrodes, a signal input terminal to input a drive signal from the exterior and to supply the drive signal to the electrodes, a rotating body that is disposed in substantially the same plane as the piezoelectric actuator main body in contact with part of the piezoelectric actuator main body and is rotatably driven by the piezoelectric actuator main body, a casing to accommodate the piezoelectric actuator main body electrically connected to the rotating body and the signal input terminal, and an output shaft which is exposed from the casing and by which the rotational movement transmitted directly or indirectly by the rotating body is outputted to the exterior.  
         [0005]     In this case, a slider to support the piezoelectric actuator main body is included, wherein the piezoelectric actuator main body may be pressed against the rotating body by rotating or translating the slider. Also, an urging member to urge the slider toward the rotating body may be included. Furthermore, the urging member may be configured to be replaceable. Furthermore, an urging force varying part to vary the urging force applied to the slider by the urging member may be included.  
         [0006]     Also, the casing may include a lid unit and a casing main body, wherein the lid includes a first lid unit to cover the portions corresponding to the rotating body and the output shaft, and a second lid unit to cover the portion corresponding to the piezoelectric actuator main body. Furthermore, the first lid unit and the second lid unit may be designed to be able to be assembled in a partially overlapped state. Furthermore, an observation window or transparent member than allows the state of contact to be observed from the exterior of the casing may be provided to the casing.  
         [0007]     Also, the rotating body may have an axle, and a bearing part to support the axle may be extended from the peripheral surface of the casing. Furthermore, the output shaft may be connected to the axle, and a drive force transmission part may be connected via the output shaft. Furthermore, the drive force transmission part may have a gear or a cam, and the gear or cam may be either fixed or detachably disposed.  
         [0008]     Also, the output shaft may have a substantially cylindrical shape. Furthermore, the ground electric potential of the driving power source of the piezoelectric actuator main body may be the same as the electric potential of the casing. Furthermore, the piezoelectric actuator module may be designed such that the piezoelectric actuator main body includes a substrate in which piezoelectric elements are layered over a plurality of regions on the surface thereof, a fixing part to fix the substrate to the slider, and a contact portion provided to the longitudinal end of the substrate, and the piezoelectric elements are stretched and contracted by supplying a drive signal to the piezoelectric elements to create longitudinal oscillation whereby the oscillating plate expands and contracts in the longitudinal direction, and to create curved oscillation in a direction intersecting with the longitudinal direction, and the rotating body is rotatably driven by the displacement of the contact portion that accompanies a combined oscillation obtained by combining these oscillations.  
         [0009]     In another arrangement, a supporting slider is provided to press the piezoelectric actuator main body against the rotating body, and a flexible substrate designed to supply driving electric power to the piezoelectric actuator main body from an external connecting terminal and electrically connected to the electrodes of the piezoelectric actuator main body, wherein the flexible substrate includes a casing support part supported by the casing, a slider support part supported by the slider, and a damper part disposed in the middle portion between the casing support part and the slider support part and designed to reduce stress or to suppress oscillation transmission between the two support parts. In yet another arrangement, the piezoelectric actuator main body includes a substrate in which piezoelectric elements are layered on the surface thereof, and a contact portion that is configured separately from the substrate supported by the substrate, and pressed against the rotating body; and at least the portion of the contact portion pressed against the rotating body is configured with a higher degree of hardness than that of the substrate. In still another arrangement, one end of the contact portion protrudes from the end surface of the substrate in a specific direction, and the other end is fixed in place and supported in a concavity provided to one end of the substrate. Also, the contact portion may be configured from ceramics, cemented carbide, nitrided steel, or cemented steel. Also, a plurality of electrodes and signal input terminals may be provided.  
         [0010]     Also, provided is an electric motor module having a piezoelectric actuator main body with electrodes, a plurality of signal input terminals to input a drive signal and to supply the drive signal to the electrodes, a rotating body that is disposed in substantially the same plane as the piezoelectric actuator main body in contact with part of the piezoelectric actuator main body and that is driven and rotatably moved by the piezoelectric actuator main body, a casing to accommodate the piezoelectric actuator main body electrically connected to the rotating body and the signal input terminals, an output shaft which is exposed from the casing and by which the rotational movement transmitted directly or indirectly by the rotating body is outputted to the exterior, and a drive circuit that creates a drive signal on the basis of the electric power supplied from the exterior and outputs the signal to the signal input terminal.  
         [0011]     Also provided is an apparatus having a piezoelectric actuator main body with electrodes, a plurality of signal input terminals to input a drive signal and to supply the drive signal to the electrodes, a rotating body that is disposed in substantially the same plane as the piezoelectric actuator main body in contact with part of the piezoelectric actuator main body and that is driven and rotatably moved by the piezoelectric actuator main body, a casing to accommodate the piezoelectric actuator main body electrically connected to the rotating body and the signal input terminals, an output shaft which is exposed from the casing and by which the rotational movement transmitted directly or indirectly by the rotating body is outputted to the exterior, a driven part that is connected to and driven by the output shaft, a power source to supply electric power, and a drive circuit to create a drive signal on the basis of the electric power supplied from the power source and outputting the signal to the signal input terminals. In this case, the driven body may be a gear, a propeller, or a tool attachment.  
         [0000]     Effects of the Invention  
         [0012]     According to the present invention, it is possible to configure a highly versatile piezoelectric actuator module that is easy to handle and that can be made thinner, and a device in which the piezoelectric actuator module is installed can therefore be made thinner and more compact. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is an external perspective view of a piezoelectric actuator module of a first embodiment;  
         [0014]      FIG. 2  is a top view of the piezoelectric actuator module of the first embodiment;  
         [0015]      FIG. 3  is a top view of the piezoelectric actuator main body (oscillator);  
         [0016]      FIG. 4  is a side view of the piezoelectric actuator main body (oscillator);  
         [0017]      FIG. 5  is a top perspective view of the piezoelectric actuator main body not yet fixed to a slider;  
         [0018]      FIG. 6  is a top perspective view of the piezoelectric actuator main body that has been fixed to a slider;  
         [0019]      FIG. 7  is a bottom perspective view of the piezoelectric actuator main body already fixed to a slider;  
         [0020]      FIG. 8  is an external perspective view of the slider and piezoelectric actuator main body of  FIG. 7  incorporated in a casing main body;  
         [0021]      FIG. 9  is an external perspective view of a flexible substrate;  
         [0022]      FIG. 10  is a top view of the flexible substrate;  
         [0023]      FIG. 11  is a side view of the flexible substrate;  
         [0024]      FIG. 12  is a front view of the flexible substrate;  
         [0025]      FIG. 13  is a connection diagram of the flexible substrate;  
         [0026]      FIG. 14  is a top view of the piezoelectric actuator module of a first modification;  
         [0027]      FIG. 15  is a top view of the piezoelectric actuator module of a third modification;  
         [0028]      FIG. 16  is a side view of the piezoelectric actuator module of the third modification;  
         [0029]      FIG. 17  is a front view of the piezoelectric actuator module of the third modification;  
         [0030]      FIG. 18  is a top view of the slider of a fifth modification;  
         [0031]      FIG. 19  is an external perspective view of the slider and piezoelectric actuator main body in  FIG. 18  incorporated into a casing main body;  
         [0032]      FIG. 20  is a top view of a piezoelectric actuator of a second embodiment;  
         [0033]      FIG. 21  is a top view of a piezoelectric actuator module of a third embodiment;  
         [0034]      FIG. 22  is a side view of the piezoelectric actuator module of the third embodiment;  
         [0035]      FIG. 23  is a front view of the piezoelectric actuator module of the third embodiment;  
         [0036]      FIG. 24  is a side view taken along a cross section A-A of the piezoelectric actuator module  10 Y;  
         [0037]      FIG. 25  is a diagram for describing a modification of the third embodiment;  
         [0038]      FIG. 26  is a top view of a piezoelectric actuator module of a fourth embodiment;  
         [0039]      FIG. 27  is a side cross-sectional view of the piezoelectric actuator module of the fourth embodiment;  
         [0040]      FIG. 28  is a front cross-sectional view of the piezoelectric actuator module of the fourth embodiment;  
         [0041]      FIG. 29  is an external perspective view of the piezoelectric actuator module of the fourth embodiment;  
         [0042]      FIG. 30  is an external perspective view of a piezoelectric actuator module of a fifth embodiment;  
         [0043]      FIG. 31  is a side view taken along a cross section A-A of the piezoelectric actuator module of the fifth embodiment;  
         [0044]      FIG. 32  is a diagram (part  1 ) for describing a more specific example of applying the fifth embodiment;  
         [0045]      FIG. 33  is a diagram (part  2 ) for describing a more specific example of applying the fifth embodiment;  
         [0046]      FIG. 34  is a main part of the embodiment of a sixth embodiment;  
         [0047]      FIG. 35  is an external perspective view of the actuator module applied to a model airplane (aircraft);  
         [0048]      FIG. 36  is a partial cross-sectional view of a propeller device;  
         [0049]      FIG. 37  is an external perspective view of an electrical tool of an eighth embodiment;  
         [0050]      FIG. 38  is a schematic structural block diagram of an electrical tool of the eighth embodiment;  
         [0051]      FIG. 39  is a schematic structural block diagram of an electric motor module of a ninth embodiment;  
         [0052]      FIG. 40  is an external perspective front view of an oscillating electric motor module of the tenth embodiment;  
         [0053]      FIG. 41  is an explanatory diagram of a state in which the oscillating electric motor module is incorporated into a portable phone;  
         [0054]      FIG. 42  is a top view of the piezoelectric actuator main body (oscillator) of an eleventh embodiment;  
         [0055]      FIG. 43  is a top view of a piezoelectric actuator main body (oscillator) of a twelfth embodiment;  
         [0056]      FIG. 44  is an external perspective view of the contact portion;  
         [0057]      FIG. 45  is a side view of the piezoelectric actuator main body (oscillator) of the twelfth embodiment;  
         [0058]      FIG. 46  is a top view of a piezoelectric actuator main body (oscillator) of a thirteenth embodiment; and  
         [0059]      FIG. 47  is a side view of the piezoelectric actuator main body (oscillator) of the thirteenth embodiment. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0060]     The embodiments of the present invention will now be described with reference to the diagrams.  
       [1] First Embodiment  
       [0061]     The first embodiment will be described first.  FIG. 1  is an external perspective view of a piezoelectric actuator module of the first embodiment. A piezoelectric actuator module  10  includes a casing (case unit)  11  and an output shaft  12  to transmit drive force that is extended and exposed from the topside of the casing  11 . Furthermore, a flexible substrate  14  provided with an external connection terminal  13  extends from one end of the casing  11  in the longitudinal direction.  
         [0062]     The casing  11  includes a casing main body  15 , and a lid unit  17  fixed to the casing main body  15  by screws  16 . The lid unit protects the piezoelectric actuator main body described hereinafter in conjunction with the casing main body  15 . The size of the casing  11  is such that, for example, the length in the transverse direction of the lid unit  17  is approximately 6 mm, and the length in the longitudinal direction is approximately 13 mm. Also, the casing main body  15  is provided with a fixing screw hole  15 A to fix the piezoelectric actuator module  10  to the device on which it is to be mounted. Furthermore, the external connection terminal  13  is provided with electrodes  18 A to  18 D that are electrically connected to the piezoelectric actuator main body via a connecting wire described hereinafter.  
         [0063]      FIG. 2  is a top view of the piezoelectric actuator module of the first embodiment. A piezoelectric actuator main body  21  is provided inside the casing main body  15 . The piezoelectric actuator main body  21  is supported by a slider  23 . Also, the interior of the casing main body  15  is provided with a rotating body  22  that functions as a driven member driven by the piezoelectric actuator main body  21  and provided with the output shaft  12  exposed from the casing main body  15 . The slider  23  supports the piezoelectric actuator main body  21  at an oscillation node of the piezoelectric actuator main body  21 , or, specifically, at a position where the displacement during oscillation is virtually zero.  
         [0064]     The slider  23  is intended to maintain the supported piezoelectric actuator main body  21  in contact with the rotating body  22 , and is urged toward the rotating body  22  by an urging member  24  interlocked with an interlocking protrusion  23 A of the slider  23 . The urging member  24  is disposed at a position overlapping the piezoelectric actuator main body  21  in the thickness direction (the direction perpendicular to the paper surface of  FIG. 2 ), allowing for a more compact design. Furthermore, the urging member  24  has an easily replaceable structure, and the drive torque of the rotating body  22 , and hence of the output shaft  12 , can be varied by replacing the urging member  24  with one having a different urging force. Furthermore, since a configuration is employed wherein the slider  23  is rotated about an axle  15 A to maintain the piezoelectric actuator main body  21  in contact with the rotating body  22 , a stable urging force (pressure) can be applied with a single elastic member, and the resulting drive torque can be stabilized.  
         [0065]     Also, the piezoelectric actuator main body  21  and the rotating body  22  are disposed such that the centerline in the longitudinal direction passes through the center of rotation of the rotating body  22  when the piezoelectric actuator main body  21  has a substantially rectangular shape. This arrangement is adopted in order to reduce the mounting space and to ensure that the drive force of the piezoelectric actuator main body  21  is set to be substantially equal during direct and reverse rotations of the rotating body  22 . Also, the piezoelectric actuator main body  21  is disposed nearly in the middle in the longitudinal direction of the casing main body  15 , and the mounting surface area can be reduced. A fixing member  25  fixes the flexible substrate  14  to the casing main body  15  on the side of the external connection terminal  13 . The fixing member  25  has a shock preventing spring  26 , and the shock preventing spring  26  urges the slider  23  from the topside of the slider  23  (the side with the lid unit  17 ) toward the bottom (the side with the casing main body  15 ) to prevent shock in the slider  23 . As a result, it is possible to ensure reliably conduction between the piezoelectric actuator main body  21  and the electrodes (overhanging electrodes described hereinafter) of the flexible substrate  14 .  
         [0066]     The components constituting the piezoelectric actuator module will now be described in detail. First, the piezoelectric actuator main body will be described.  FIG. 3  is a top view of the piezoelectric actuator main body (oscillator).  FIG. 4  is a side view of the piezoelectric actuator main body (oscillator). The piezoelectric actuator main body  21  has a structure wherein PZT or other such piezoelectric elements  21 B are affixed to both sides of a substrate (shim)  21 A, which is an elastic member. In this structure, during actual driving, for example, a voltage V− (negative voltage) is applied to the substrate  21 A, and a voltage V+ (positive voltage) is applied to the piezoelectric elements  21 B.  
         [0067]     Fixing units  21 D to fix the piezoelectric actuator main body  21  to the slider  23  are provided to both sides of the substrate  21  A, and the main body is supported with the sections to which the piezoelectric elements  21 B are affixed in a suspended state. These fixing units  21 D are each provided with a positioning hole  21 F and a screw hole  21 E through which a screw is inserted for fixing the main body to the slider  23 . The piezoelectric elements  21 B are provided with five regions A 1  to A 5  per side, and the regions A 1  and A 5  are used as a pair. The regions A 2  and A 4  are similarly used as a pair. Specifically, the same drive signal is applied to the regions used as pairs.  
         [0068]     More specifically, for example, the piezoelectric actuator main body  21  is driven by applying separate drive signals to the regions A 1  and A 5  and to the regions A 2  and A 4 . Initiating longitudinal oscillation in the regions A 1  and A 5 , causing the regions A 2  and A 4  to oscillate, and not oscillating the region A 3  creates an imbalance in stretching and contraction in the longitudinal direction, induces curved oscillation, and creates oscillation along an elliptical orbit in a constant direction in relation to a contact portion  21 C hereinafter described (for example, in a clockwise direction). At this point, the electrode corresponding to the region A 3  serves as a detection electrode. Furthermore, a region C in the middle of the substrate  21 A in the longitudinal direction is equivalent to a so-called node that is not affected by the oscillation of the piezoelectric actuator, and this region is used an electrode connector. Also, the electrodes are disposed in a single row in this region C, which results in an easily mountable structure.  
         [0069]     One end of the piezoelectric actuator main body  21  in the longitudinal direction of the substrate  21 A is provided with the contact portion  21 C pressed against the rotating body  22  to transmit the drive force. A drive voltage is applied to the piezoelectric elements  21 B via the region C, whereby a longitudinal oscillation of expansion and contraction in the longitudinal direction and a curved oscillation in a rough S shape are created in the piezoelectric actuator main body  21 , and the rotating body  22  is driven while these oscillations combine together and cause the tip of the contact portion  21 C to describe an elliptical trajectory. As a result, the rotating body  22  performs rotational movement.  
         [0070]     Next, the slider will be described.  FIG. 5  is a top perspective view of the piezoelectric actuator main body not yet fixed to the slider.  FIG. 6  is a top perspective view of the piezoelectric actuator main body already fixed to the slider.  FIG. 7  is a bottom perspective view of the piezoelectric actuator main body already fixed to the slider. The slider  23  has a profile with a rough H shape in a plan view, and includes an interlocking protrusion  23 A hereinafter described, screw insertion holes  23 B through which are inserted screws  31  to fix the piezoelectric actuator main body  21 , pin insertion holes  23 C through which are inserted interlocking pins  32  to interlock with the flexible substrate  14 , and an axle insertion hole  23 D through which is inserted the axle  15 A (see  FIG. 2 ) provided to the casing main body  15  and used as the center of rotation under urging by the urging member  24 .  
         [0071]      FIG. 8  is an external perspective view of the slider and piezoelectric actuator main body in  FIG. 7  incorporated in a casing main body. The flexible substrate is not shown in FIG. 8  for the sake of simplicity. The slider  23  and the piezoelectric actuator main body  21  are placed along with the rotating body  22  in a holding concavity  15 B in the casing main body  15  in a fixed state. At this time, the contact portion  21 C is disposed to be able to be easily pressed against the peripheral surface of the rotating body  22  by rotation about the axle  15 A.  
         [0072]      FIG. 9  is an external perspective view of the flexible substrate.  FIG. 10  is a top view of the flexible substrate.  FIG. 11  is a side view of the flexible substrate.  FIG. 12  is a front view of the flexible substrate. The flexible substrate  14  is provided with ten overhanging electrodes  35  as shown in the external perspective view in  FIG. 8  and the side view in  FIG. 10  (in  FIG. 2 , only five are visible).  
         [0073]     These overhanging electrodes  35  are soldered to the electrodes of the piezoelectric actuator main body  21 , are electrically connected by deposition or the like while fixed in place, and are used to supply a drive force. More specifically, the overhanging electrodes  35  are classified into three systems: electrodes  35 A, electrodes  35 B, and electrodes  35 C. In this case, the electrodes  35 A are configured to supply the same drive signal to the pair of regions A 1  and A 5  from among the regions Al to A 5  of the piezoelectric elements  21 B shown in  FIG. 3 . Also, the electrodes  35 B are similarly configured so as to supply the same drive signal to the regions A 2  and A 4  used as a pair. Furthermore, the electrodes  35 C are configured to supply a drive signal to the region A 3 . Specifically, the flexible substrate  14  is configured as a multilayered substrate, and the overhanging electrodes  35  are electrically connected to their corresponding electrodes  18 A to  18 D by multilayered wiring.  
         [0074]      FIG. 13  is a connection diagram showing one example of wiring. The electrodes  35 A are connected to the electrode  18 A of the external connection terminal  13  via a connecting wire  19 A, as shown in  FIG. 13 . Also, the electrodes  35 B are connected to the  18 B of the external connection terminal  13  via a connecting wire  19 B. Furthermore, the electrodes  35 C are connected to the electrode  18 C of the external connection terminal  13  via a connecting wire  19 C. Additionally, the electrode  18 D is electrically connected to the substrate  21  A of the piezoelectric actuator main body  21  via a positioning hole  38  hereinafter described.  
         [0075]     Loss during oscillation (during driving) of the piezoelectric actuator main body  21  can be reduced because the electrodes  35 A to  35 C constituting the overhanging electrodes  35  are composed solely from a pattern of conductive material (copper or the like), and not from the base material that constitutes the flexible substrate  14 . Furthermore, the electrodes  35 A to  35 C constituting the overhanging electrodes  35  are made thinner towards the distal end (the side with the connecting parts of the piezoelectric actuator main body). Thus, the flexural stress generated along with the oscillation of the piezoelectric actuator main body  21  is reduced, and the oscillation loss (energy loss) through the overhanging electrodes during oscillation of the piezoelectric actuator main body  21  is reduced to allow for highly efficient driving.  
         [0076]     In this case the distal end section of the flexible substrate  14  containing the overhanging electrodes  35  is curved into a rough U shape by a linking part  36  to allow the piezoelectric actuator main body  21  to be held therebetween, as shown in the side view. Thus, a configuration is provided wherein one flexible substrate  14  is bent into a rough U shape and electric power is supplied to both sides of the piezoelectric actuator main body  21 , making it possible to reduce the number of components and to bring down the cost and size of the device.  
         [0077]     Also, the five overhanging electrodes  35  that face the topside of the piezoelectric actuator main body  21  are bent towards the topside of the piezoelectric actuator main body  21  and are connected to the electrodes on the topside of the piezoelectric actuator main body  21 . The other five overhanging electrodes  35  that face the bottom side of the piezoelectric actuator main body  21  are connected to the electrodes on the bottom side of the piezoelectric actuator main body  21 . Thus, mounting is possible with one flexible substrate  14  on both sides of the piezoelectric actuator main body  21 , resulting in a smaller number of components and improved handling.  
         [0078]     Furthermore, positioning holes  37  to position the device in relation to the slider are provided to the distal end portion of the flexible substrate  14 . Two positioning holes  37  are provided in the present embodiment, and one is a circular hole while the other is an oval hole. Furthermore, positioning holes  38  to position the device in relation to the fixing member  25  are provided to the middle portion of the flexible substrate  14 .  
         [0079]     Therefore, to connect electrically the flexible substrate  14  with the piezoelectric actuator main body  21 , the positioning holes  38  are used to fix completely the flexible substrate  14  in place by fixing the flexible substrate  14  to the casing main body  15  on the side with the external connection terminal  13  by the fixing member  25 . Also, the area between the external connection terminal  13  and the middle portion of the flexible substrate  14 , specifically, the portion provided with the positioning holes  38 , constitutes a damper portion  39  with a damper function to absorb any stress than may be applied, and since the flexible substrate  14  is also fixed to the casing main body by the fixing member  25  with the use of the positioning holes  38 , the drive force is not reduced because even when a tensile force is applied to the external connection terminal  13 , the piezoelectric actuator main body  21  is not directly affected.  
         [0080]     In this state (see  FIG. 2 ), the shock preventing spring  26  of the fixing member  25  urges the slider  23  away from the topside of the slider  23  (the side with the lid unit  17 ) toward the bottom (the side with the casing main body  15 ), and the slider  23  can easily be prevented from undergoing shock even when the piezoelectric actuator main body  21  is in a state of oscillation.  
         [0081]     The piezoelectric actuator module  10  is then completed as shown in  FIG. 1  by fixing the lid unit  17  to the casing main body  15  with the screws  16 . In the piezoelectric actuator module  10  with the configuration described above, a drive voltage is applied to the external connection terminal  13  from the exterior, whereby the piezoelectric actuator main body  21  having a structure in which the piezoelectric elements  21 B is affixed to the substrate  21 A oscillates in a state of being urged toward the rotating body  22  by the urging member  24  interlocked with the interlocking protrusion  23 A of the slider  23 . As a result, a longitudinal oscillation of expansion and contraction in the longitudinal direction, and a curved oscillation in a rough S shape combine together to drive the rotating body  22  and to rotate the rotating body  22   t  while the distal end of the contact portion  21 C describes an elliptical trajectory.  
         [0082]     At this time, the flexible substrate  14  is fixed to the slider  23 , and can be very durable because no stress is generated in the overhanging electrodes  35  of the flexible substrate even when the piezoelectric actuator main body  21  and the slider  23  move. As a result, the rotational movement of the rotating body  22  drives the external driven member via the output shaft  12 .  
       [2] Modifications  
       [0083]     Modifications of the first embodiment will now be described.  
       [2.1] First Modification  
       [0084]     In the above descriptions, to vary the drive torque of the output shaft  12 , the urging member  24 , which has an easily replaceable structure, was replaced with one having a different urging force, but the present first modification is one in which the drive torque of the output shaft  12  can be varied without replacing the urging member  24 .  
         [0085]      FIG. 14  is a top view of the piezoelectric actuator module of the first modification. In  FIG. 14 , the same components as in  FIG. 2  are denoted by the same symbols.  FIG. 2  is a top view of the piezoelectric actuator module of the first embodiment. The piezoelectric actuator main body  21  is provided on the inside of the casing main body  15 . The piezoelectric actuator main body  21  is supported by the slider  23 . The slider  23  is intended to maintain the supported piezoelectric actuator main body  21  in contact with the rotating body  22 , and is urged toward the rotating body  22  by an urging member  24  interlocked with an urging force adjusting cam  41  rotatably fitted over an axle  41 A provided to the slider  23 . At this time, varying the urging force of the urging member  24  by rotating the urging force adjusting cam  41  makes it possible to easily vary the drive torque of the rotating body  22 , and consequently of the output shaft  12  as well.  
       [2.2] Second Modification  
       [0086]     In the above descriptions, the electric potential level of the casing  11  was not described, but the piezoelectric actuator main body is brought to a shielded state and there is no need to take into account the effects of static electricity if the casing  11  is configured from metal or another such conductor and the electric potential level thereof is set at ground level. Furthermore, the grounding can be shared and the circuit configuration can be simplified.  
       [2.3] Third Modification  
       [0087]     In the above descriptions, the lid unit was integrated. However, when the lid unit is integrated, the rotating body and the piezoelectric actuator main body must both be assembled simultaneously and concurrently, and since the positioning relationship between the two is not fixed, adjustment and assembly are difficult as a result. In view of this, the third modification is one in which the lid unit is segmented and assembly can be improved.  
         [0088]      FIG. 15  is a top view of the piezoelectric actuator module of the third modification.  FIG. 16  is a side view of the piezoelectric actuator module of the third modification.  FIG. 17  is a bottom view of the piezoelectric actuator module of the third modification. In  FIGS. 15 through 17 , the same components as in  FIG. 1  are denoted by the same symbols. In the third modification, the lid unit is configured from a first lid unit  17 - 1  fixed in place to cover the section that has the rotating body and the axle thereof, which is the output shaft  12 , and also from a second lid unit  17 - 2  fixed in place to cover the piezoelectric actuator main body, part of the flexible substrate, and other sections thereof.  
         [0089]     In this case, a seam portion  17 X between the first lid unit  17 - 1  and second lid unit  17 - 2  is set such that the thickness of the lid units  17 - 1  and  17 - 2  is about half the other sections, which makes it possible to overlap the two components. As a result, it is possible to prevent debris or the like from penetrating into the completed piezoelectric actuator module from the exterior. As a result of employing such a configuration, any misalignment in the position of the rotating body is removed and assembly steps can be performed with greater ease if first the rotating body is incorporated into the casing main body  15 , and the first lid unit  17 - 1  is fixed with the screws  16 .  
       [2.4] Fourth Modification  
       [0090]     In the above descriptions, the bearing portion of the rotating body was not described in any detail, but it is preferable that a bearing part  16 A protrude from the casing main body  15  as shown in  FIG. 17  while the entire casing  11  (see  FIG. 1 ) is made thinner in order to facilitate positioning and to prevent the output shaft  12  of the rotating body from tilting.  
       [2.5] Fifth Modification  
       [0091]     In the above descriptions, the piezoelectric actuator main body supported by the slider was pressed against the rotating body by the slider and another urging member, but the present modification is one in which the same effects may also be obtained by providing the urging member to the slider itself.  FIG. 18  is a top view of the slider of the fifth modification. In  FIG. 18 , the same components as in  FIG. 5  are denoted by the same symbols. A slider  23 M is configured by integrating together a slider main body  23 MA whose profile is a rough H shape in a plan view, and a roughly U shaped urging part  23 MB on one end of the slider main body  23 MA.  
         [0092]     The slider main body  23 MA includes a screw insertion hole  23 B through which are inserted screws  31  to fix the piezoelectric actuator main body  21 , pin insertion holes  23 C through which are inserted interlocking pins  32  to interlock with the flexible substrate  14 , and an axle insertion hole  23 D through which is inserted an axle  15 A (see  FIG. 19 ) provided to the casing main body  15  and used as the center of rotation upon urging by the urging member  23 MB.  
         [0093]      FIG. 19  is an external perspective view of the slider and piezoelectric actuator main body in  FIG. 18  incorporated in a casing main body. The flexible substrate is not shown in  FIG. 19  for the sake of simplicity. The slider  23 M and the piezoelectric actuator main body  21  are placed along with the rotating body  22  in a holding concavity  15 B in the casing main body  15  in a fixed state. At this time, the urging part  23 MB of the slider  23 M interlocks with an interlocking protrusion  15 M in the holding concavity  15 B in an elastically deformed state, and the slider  23 M is rotated about the axle  15 A by the elastic force thereof, whereby the contact portion  21  C of the piezoelectric actuator main body  21  is pressed against the peripheral surface of the rotating body  22 . Therefore, a stable urging force (pressure) is achieved with one elastic member, and the resulting drive torque is also stabilized in the fifth modification as well.  
       [3] Second Embodiment  
       [0094]     In the first embodiment described above, the contact portion of the piezoelectric actuator main body was pressed against the rotating body by rotating the slider about the axle, but the second embodiment is one in which the contact portion is pressed against the rotating body by sliding the slider toward the rotating body in translating motion.  FIG. 20  is a top view of the piezoelectric actuator of the second embodiment. In  FIG. 20 , the same components as those in  FIG. 2  are denoted by the same symbols. Either a side protuberance  50  or a side sliding part  51  of the slider  23 X is slidably pressed against the sidewall  15 C of the concavity  15 B of the casing main body  15 . Therefore, movement of the slider  23 X only has a degree of freedom in the longitudinal direction of the piezoelectric actuator module.  
         [0095]     In this state, the slider  23 X is intended to maintain the supported piezoelectric actuator main body  21  in contact with the rotating body  22 , and is urged toward the rotating body  22  by an urging member  24 X interlocked with an interlocking protrusion  23 AX of the slider  23 X. If it is assumed at this time that the force vector provided to the interlocking protrusion  23 AX by the urging member  24 X is Al, then the resolved force vector in the transverse direction of the piezoelectric actuator module is A 2 , and the resolved force vector in the longitudinal direction is A 3 .  
         [0096]     However, the resolved force vector A 2  in the transverse direction is only manifested as friction force between the side protuberance  50  and the sidewall  15 C. Specifically, the state of contact of the contact portion  21 C of the piezoelectric actuator main body  21  with the rotating body  22  is substantially maintained due to the resolved force vector A 3  in the longitudinal direction. Therefore, since the contact portion  21 C is pressed against the rotating body  22  from the same direction, it is possible to drive the rotating body  22  in a more stable manner, and the resulting torque is more stable in comparison with the first embodiment.  
       [4] Third Embodiment  
       [0097]     In the embodiments described above, the output shafts were different shafts, but the third embodiment is one in which a gear that functions as an output shaft is provided. [ 0049 ]  FIG. 21  is a top view of the piezoelectric actuator module of the third embodiment.  FIG. 22  is a side view of the piezoelectric actuator module of the third embodiment.  FIG. 23  is a front view of the piezoelectric actuator module of the third embodiment. In  FIGS. 21 through 23 , the same components as those in  FIGS. 15 through 17  are denoted by the same symbols. A piezoelectric actuator module  10 Y includes a casing (lid unit)  11 . The topside of this casing  11  is provided with a gear  60  that functions as an output shaft to transmit drive force. Furthermore, a flexible substrate  14  provided with an external connection terminal  13  extends out from one end in the longitudinal direction of the casing  11 .  
         [0098]     The casing  11  includes a casing main body  15 ; a first lid unit  17 - 1  that is fixed to the casing main body  15  by screws  16 , that protects the piezoelectric actuator main body in conjunction with the casing main body  15 , and that is fixed in place to cover the portion including the rotating body and its rotation shaft, the output shaft  12 ; and a second lid unit  17 - 2  that is fixed in place to cover the piezoelectric actuator main body, part of the flexible substrate, and other portions thereof. In the present embodiment, a gear part  60 A and a rotation shaft  60 B that constitute the gear  60  are configured separately. Therefore, the gear part  60 A can be made detachable. According to this configuration, suitable variations are possible according to the intended use. In the above descriptions, the gear part  60 A and rotation shaft  60 B constituting the gear  60  were configured separately, but they can also be configured integrally.  
         [0099]      FIG. 24  is a side view along a cross section A-A in the piezoelectric actuator module  10 Y. In  FIG. 24 , the same components as those in  FIG. 2  or  FIG. 17  are denoted by the same symbols. The piezoelectric actuator module  10 Y is provided with an observation hole  70  that is formed in the back surface of the casing main body  15 , can be blocked with a blocking plate (not illustrated), and is designed to make it possible to observe the state of contact between the contact portion  21  C of the piezoelectric actuator main body  21  and the rotating body  11 .  
         [0100]     As a result, the state of contact between the contact portion  21 C and the rotating body  1   1  can be observed during manufacture of the piezoelectric actuator module  10 Y, the appropriate adjustments can be made, and the results are easier to inspect. In the above descriptions, the observation hole  70  is blocked by a blocking plate (not shown), but it is possible to obtain the same results by providing a transparent member instead of the observation hole  70  and making the state of contact between the contact portion  21 C and the rotating body  11  visible.  
       [4.1] Modification  
       [0101]      FIG. 25  is a diagram for describing the modification of the third embodiment. In  FIG. 25 , the same components as in  FIG. 24  are denoted by the same symbols. The difference between the third embodiment and the modification of the third embodiment is that a cam  61  is provided instead of the gear  60  that functions as an output shaft. In this case, a cam part  61 A and a rotation shaft  61 B constituting the cam  61  are configured separately. Therefore, the cam part  61 A can be made detachable. According to this configuration, suitable variations can be made according to the intended use. In the above description, the cam part  61 A and rotation shaft  61 B constituting the cam  61  were configured separately, but they can also be configured integrally.  
       [5] Fourth Embodiment  
       [0102]     In the third embodiment described above, the gear part of the gear or the cam part of the cam functioning as the output shaft was configured to be entirely exposed on the casing exterior, but the fourth embodiment is one in which only a part thereof is exposed.  
         [0103]      FIG. 26  is a top view of the piezoelectric actuator module of the fourth embodiment.  FIG. 27  is a side view of the piezoelectric actuator module of the fourth embodiment.  FIG. 28  is a front view of the piezoelectric actuator module of the fourth embodiment.  FIG. 29  is an external perspective view of the piezoelectric actuator module of the fourth embodiment. In  FIGS. 26 through 29 , the same components as in  FIGS. 21 through 23  are denoted by the same symbols.  
         [0104]     A piezoelectric actuator module  10 Z includes a casing (lid unit)  11 , and part of a gear  62  that functions as an output shaft to transmit drive force protrudes from the longitudinal end of the casing  11 . Furthermore, a flexible substrate  14  provided with an external connection terminal  13  extends out from one end in the longitudinal direction of the casing  11 . Employing such a configuration wherein part of the gear  62  that functions as an output shaft to transmit drive force protrudes from the longitudinal end of the casing  11  makes it possible to configure a thinner piezoelectric actuator module than in the third embodiment.  
       [6] Fifth Embodiment  
       [0105]     The fifth embodiment is one in which a cylindrical rotating body is used as the output shaft.  FIG. 30  is an external perspective view of the piezoelectric actuator module of the fifth embodiment. A piezoelectric actuator module  10 Q includes a casing (lid unit)  11 . A cylindrical rotating body  12 B that functions as an output shaft to transmit drive force is accommodated in the casing  11 . Furthermore, an external connection terminal (for surface mounting; not shown) is provided on the rear surface of the casing  11 .  
         [0106]      FIG. 31  is a side view along a cross section A-A of the piezoelectric actuator module of the fifth embodiment. The piezoelectric actuator main body  21  is provided on the inside of the casing main body  15 . The piezoelectric actuator main body  21  is supported by a slider (not shown). The interior of the casing main body  15  is provided with a cylindrical rotating body  12 B as a driven body that functions as an output shaft and is driven by the piezoelectric actuator main body  21 .  
         [0107]     As a result, light can pass through the output shaft portion, making the piezoelectric actuator module suitable for applications such as performing control while transmitting light.  
         [0108]      FIGS. 32 and 33  show a more detailed application example of the fifth embodiment.  FIG. 32  is a cross-sectional view of a specific application example in which a lens is mounted in the hole of the output shaft portion, and the piezoelectric actuator module is used to focus the lens.  FIG. 33  is a side view of a specific example of applying the piezoelectric actuator module in  FIG. 32 .  
         [0109]     A focusing device  80 , which is the device of the present application example, includes a lens  82  having a sliding axle  81 , an internal body tube  83  rotated in conjunction with the cylindrical rotating body  12 B as a result of the cylindrical rotating body  12 B being rotated by the piezoelectric actuator main body  21 , and an external body tube  84  fixed to the casing  11 . In this case, a first guide groove  91  that extends at a slant is provided to the internal body tube  83 , and a second guide groove  92  that extends vertically is provided to the external body tube  84 . The first guide groove  91  and second guide groove  92  are provided so as to intersect with each other.  
         [0110]     The operation will now be described. The internal body tube  83  rotates due to the cylindrical rotating body  12 B being rotatably driven by the piezoelectric actuator main body  21 . At this time, the external body tube  84  does not rotate because it is fixed to the casing  11 .  
         [0111]     Therefore, the sliding axle  81  of the lens  82  slides both along the first guide groove  91  and along the second guide groove  92 . For example, in the case such as is shown in  FIG. 33 , the lens  82  moves downward when the internal body tube  83  turns counterclockwise as seen from above. Similarly, when the internal body tube  83  turns clockwise as seen from above, the lens  82  moves upward as a result. Thus, it is possible to move the lens  84  to the desired position. In the above description, one of possible applications was described, but it is also possible to use the present embodiment in the zoom mechanism of a compact camera or the auto-focus mechanism or the like, including compact digital cameras.  
       [7] Sixth Embodiment  
       [0112]      FIG. 34  shows the main part of an embodiment wherein the actuator module of the embodiments described above is applied to a vehicle (moving body) provided with a wheel device commonly used in toys and the like. A wheel device  100  includes an actuator module  101  as shown in  FIG. 34 . An axle  102  is directly connected to an output shaft  101 A of the actuator module  101 , and the actuator module  101  rotatably drives the axle  102 , which makes it possible to drive the wheels  103  and to move the model automobile or other such vehicle for which the wheel device  100  is provided.  
         [0113]     In the present embodiment, the suspension device is not shown, but mounting the actuator module  101 , the axle  102 , and the wheels  103  on the suspension device can yield a configuration in which the effects of irregularities or the like in the traveled surface can be reduced and the vehicle can run in a satisfactory manner. Also, since the actuator module can be configured to be thin and compact, batteries and other such large components can be easily arranged in a compact model automobile or the like, even in a configuration in which an actuator module is provided separately to each wheel. In the above description, the actuator module  101  directly drives the wheels  103  via the axle  102 , but it is also possible to use a configuration wherein the wheels are driven via a specific deceleration gear train or acceleration gear train.  
       [8] Seventh Embodiment  
       [0114]      FIG. 35  is an external perspective view of a case in which the actuator module of the embodiments described above is applied to a model airplane (aircraft). A model airplane  200  includes a propeller device  201  and is made to fly due to the propulsive force generated by the propeller device  201 . The model airplane  200  also includes main wings  203  extending to the left and right from the vehicle main body  202 , and a tail fin  204  provided to the back part of the vehicle main body  202 . The tail fin  204  is provided with a rudder  205 , and it is possible to adjust the direction in which the model airplane  200  travels by driving the rudder  205 .  
         [0115]     The details of the propeller device  201  will now be described.  FIG. 36  is a partial cross-sectional view of the propeller device. The propeller device  201  has an axle  211  that is rotatably supported and integrated with a propeller  210  on the vehicle main body (supporting body)  202 .  
         [0116]     The axle  211  is integrated with an output shaft  213 A of an actuator module  213 , and when the output shaft  213 A of the actuator module  213  is rotatably driven, propulsive force is generated in the direction of the arrow X in the diagram by the resulting rotation of the propeller  210 , and the model airplane  200  is caused to fly. As described above, according to the present embodiment, it is easy to make the actuator module compact and lightweight, so the actuator module can be reduced in weight and it is possible to fly a larger model airplane over a longer period of time compared to a model airplane in which a coil motor is installed. In the above description, the actuator module  213  directly drives the propeller  210 , but it is also possible to use a configuration wherein the propeller is driven via a specific deceleration gear train or acceleration gear train.  
       [9] Eighth Embodiment  
       [0117]      FIG. 37  is an external perspective view of an electric tool of the ninth embodiment.  FIG. 38  is a schematic structural block view of an electric tool of the ninth embodiment. An electrical tool  300  includes a casing  301 , a lid unit  303  constituting the casing  301  and accommodating a battery  302  as a fuel source in its interior, an actuator module  304 , an attachment (the cross-shaped driver pin in  FIG. 36 )  305  detachably affixed to the output shaft of the actuator module  304  installed in the casing  301 , an operating switch  306  to switch the direction of rotation and changing the stops, and a drive circuit  307  mounted in the casing  301  and used to drive the actuator module  304  by the supply of power from the battery  302  in accordance with the operating state of the operating switch  306 .  
         [0118]     According to the configuration described above, the output shaft of the actuator module  304 , and hence the attachment  305  affixed to the output shaft, are rotatably driven by the drive circuit  307  according to user&#39;s operation of the operating switch  306  to attach or to remove a screw  310 . In this case, the actuator module  304  can yield a greater torque than a coil motor of the same volume, and it is possible to configure a compact electrical tool with a wide range of applications. As described above, according to the present embodiment, the actuator module can be used to configure a compact electrical tool with a high torque.  
       [10] Ninth Embodiment  
       [0119]      FIG. 39  is a schematic structural block diagram of the electric motor module of the tenth embodiment. An electric motor module  400  includes an actuator module  401 , a drive circuit  403  to drive the actuator module  401  due to a supply of power from the exterior via a power source supply terminal  402 , and a casing  404  to accommodate the actuator module  401  and the drive circuit  403 , wherein the power source supply terminal  402  is exposed to the exterior. According to the ninth embodiment, the output shaft (not shown) of the actuator module  401  can be rotated merely by connecting an external power source to the power source supply terminal  402 , and the electric motor module can be handled in the same manner as a regular coil motor.  
       [11] Tenth Embodiment  
       [0120]      FIG. 40  is an external front view of the oscillating electric motor module of the tenth embodiment. In  FIG. 40 , the same components as those in the modification of the third embodiment in  FIG. 25  are denoted by the same symbols. The tenth embodiment is comparable to the third embodiment, and is configured as an oscillating electric motor module  500  to handle incoming information in a portable phone, wherein an eccentric counterweight  71  is provided instead of the gear  60  that functions as an output shaft. In this case, a counterweight part  71 A and an axle  71 B constituting the eccentric counterweight  71  are configured separately. Because of the need to maintain high oscillation, metal material with a high specific gravity, for example, tungsten, is used as the counterweight part  71 A. In this case, the counterweight part  71 A can be made detachable and can be varied according to the required oscillation or the like.  
         [0121]      FIG. 41  is an explanatory diagram of a state in which the oscillating electric motor module  500  is incorporated into a portable phone  501 . The oscillating electric motor module  500  can be formed to be extremely small as shown in  FIG. 41 , and there is enough space to hold the module even in a compact portable phone  501 . When the portable phone  501  receives a signal, the counterweight part  71 A rotates in the direction of the arrow in  FIG. 41 , for example, and the phone oscillates due to a counterweight imbalance in the axle  71 B of the counterweight part  71 A, whereby the user can be informed of the incoming signal by the oscillation.  
       [12] Eleventh Embodiment  
       [0122]      FIG. 42  is a top view of the piezoelectric actuator main body (oscillator) of the eleventh embodiment. A piezoelectric actuator main body  21 X has a structure wherein PZT or other such piezoelectric elements  21 B are affixed to both sides of a substrate (shim)  21 A, which is an elastic member. In this structure, during actual driving, for example, a voltage V− (negative voltage) is applied to the substrate  21 A, and a voltage V+ (positive voltage) is applied to the piezoelectric elements  21 B.  
         [0123]     Fixing units  21 D to fix the piezoelectric actuator main body  21  to the slider  23  are provided on both sides of the substrate  21  A, and the main body is supported by the sections to which the piezoelectric elements  21 B are affixed in a suspended state. These fixing units  21 D are each provided with a positioning hole  21 F and a screw hole  21 E through which a screw is inserted to fix the main body to the slider  23 . The piezoelectric elements  21 B are provided with a single region A 11  wherein a drive signal is applied.  
         [0124]     More specifically, the piezoelectric actuator main body  21 X is driven by applying a drive voltage to the region A 11 . Longitudinal oscillation is then induced, but since the contact portion  21 Z is provided to a position asymmetrical to the substrate  21 A, an imbalance occurs in the longitudinal expansion and contraction, curved oscillation is induced, and oscillation is created along an elliptical orbit in a constant direction in relation to the contact portion  21 Z (for example, in a clockwise direction). Specifically, the piezoelectric actuator main body  21 X of the present embodiment makes it possible to configure a piezoelectric actuator capable of rotating in one direction merely by providing one electrode. In order to make oscillation more reliable, a balancing part  21 Z 1  with the same shape as the contact portion  21 Z may be provided at a position that is substantially asymmetrical to the position at which the contact portion  21 Z is provided in relation to the center of the rectangular substrate.  
       [13] Twelfth Embodiment  
       [0125]      FIG. 43  is a top view of the piezoelectric actuator main body (oscillator) of the twelfth embodiment.  FIG. 44  is an external perspective view of the contact portion.  FIG. 45  is a side view of the piezoelectric actuator main body (oscillator) of the twelfth embodiment. The substrate  21 A is formed, for example, from SUS301EH with a Vickers hardness of 500 HV and a Young&#39;s modulus of 210 GPa.  
         [0126]     The contact portion  21 M, however, is configured from alumina with a Vickers hardness of 1600 HV and a Young&#39;s modulus of 350 to 380 GPa, and includes a contact end part  21 MA having a contact surface  21 MA 1  that is pressed against the rotating body, and a fixed part  21 MB that is fixed in place and supported in a concavity  21 K provided to one end of the substrate in order to support the contact end part  21 MA. The contact end part  21 MA is formed into a half cylinder as shown in  FIG. 44 , for example, and has a thickness commensurate with the thickness obtained by adding the piezoelectric elements  21 B (two layers) to the thickness of the substrate  21 A, as shown in  FIG. 45 .  
         [0127]     Also, the fixed part  21 MB is formed into a half cylinder with the same shape as the concavity  21 K provided on one end of the substrate  21  A, and the thickness thereof is commensurate with that of the substrate  21 A. The fixed part  21 MB is in a state of being fixed to the substrate  21 A and held from both sides by the two piezoelectric elements  21  B. The piezoelectric elements  21 B, the substrate  21 A, and the contact portion  21 M are bonded and fixed to each other with a cured epoxy resin adhesive at room temperature. Because of the configuration described above, the substrate  21 A and the contact portion  21 M can be configured from materials suitable for their respective functions.  
         [0128]     As described above, the substrate  21 A is configured from SUS301EH, and it compensates for the brittleness of the piezoelectric elements  21 B while not impeding the oscillation of the piezoelectric elements  21 B. Also, since the contact portion  21 M is configured from alumina, the abrasion resistance of the contact surface  21 MA 1  in contact with the rotating body can be improved, so the durability of the piezoelectric actuator module is also improved.  
       [14] Thirteenth Embodiment  
       [0129]      FIG. 46  is a top view of the piezoelectric actuator main body (oscillator) of the thirteenth embodiment.  FIG. 47  is a side view of the piezoelectric actuator main body (oscillator) of the thirteenth embodiment. The substrate  21 A constituting the piezoelectric actuator main body  21 Z if formed, for example, from SUS301EH with a Vickers hardness of 500 HV and a Young&#39;s modulus of 210 GPa.  
         [0130]     The contact portion  21 N, however, is configured from strong steel alloy H 1  (WC particle diameter 1 μm, Co content 10%) with a Vickers hardness of 1500 HV and a Young&#39;s modulus of 700 GPa, and includes a contact end part  21 NA having a contact surface  21 NA 1  that is pressed against the rotating body, and a fixed part  21 NB that is fixed in place and supported in a concavity  21 K provided to one end of the substrate  21 A to support the contact end part  21 NA. The entire contact portion  21 N is formed into a disc shape.  
         [0131]     The contact portion  21 N is made, for example, by cutting a rod of cemented carbide H 1  down to an appropriate thickness and grinding the rod in the thickness direction to remove burrs resulting from cutting. The portion is formed such that a cross sectional shape in which the contact surface  21 NA 1  is cut in the direction parallel to the paper surface in  FIG. 47  forms an arc-shaped convexity in relation to the rotating body.  
         [0132]     Also, the fixed part  21 NB is formed into a half cylinder with the same shape as the concavity  21 K provided on one end of the substrate  21 A, and the thickness thereof is commensurate with the substrate  21 A. The fixed part  21 NB is fixed to the substrate  21 A and is sandwiched between the two piezoelectric elements  21 B; and the piezoelectric elements  21 B, the substrate  21 A, and the contact portion  21 N are bonded and fixed to each other with a cured epoxy resin adhesive at room temperature. Because of the configuration described above, the substrate  21 A and the contact portion  21 N can be configured from materials suitable for their respective functions.  
         [0133]     As described above, the substrate  21 A is configured from SUS301EH, and it compensates for the brittleness of the piezoelectric elements  21 B while not impeding the oscillation of the piezoelectric elements  21 B. Also, since the contact portion  21 N is configured from cemented carbide H 1 , the abrasion resistance of the contact end surface  21 NA 1  in contact with the rotating body can be improved, so the durability of the piezoelectric actuator module is also improved.  
       [15] Modifications of the Embodiments  
       [0134]     In the above description, SUS301EH was used as the material for the substrate  21 A, but the material is not limited thereto and other types of stainless steel may also be used. Alternatively, the substrate may be configured from aluminum, amorphous metal, rubber metal, or another such material that has a low Young&#39;s modulus, oscillates readily, and does not impede the oscillation of the piezoelectric elements  21 B.  
         [0135]     In the above description, alumina or cemented carbide was used as the material for the contact portion provided separately from the substrate  21 A, but the material is not limited to these options alone and may be silicon nitride, zirconia, silicon carbide, or another type of ceramic; or nitrided steel, cemented steel, or another type of treated steel. In other words, the material for the contact portion should be selected such that at least the surface in contact with the rotating body has a higher degree of hardness than the substrate material in cases in which the contact portion can be configured from the substrate  21 A alone.  
         [0136]     In the above description, the substrate and piezoelectric elements were substantially rectangular and plate-shaped, but other shapes may be arbitrarily selected according to the application conditions and intended use. For example, in the above description, the piezoelectric elements were formed into substantially flat surfaces, but it is also possible to use a block configuration or the like. In these cases, the contact portion should be formed so as to protrude in a specific direction from the end of the piezoelectric elements on the side of the rotating body. The specific direction is within ±30° of the surface perpendicular to the plane that contains the end surface of the piezoelectric elements on the side of the rotating body, and is more preferably within ±15°, and even more preferably within ±10°.

Technology Classification (CPC): 7