JP5582839B2 - Piezoelectric drive device and vibration drive device for tactile presentation device provided with the same - Google Patents

Description

  The present invention relates to a piezoelectric drive device using a piezoelectric element, and more particularly to a piezoelectric drive device capable of suppressing abnormal vibration based on a resonance phenomenon of a mechanism that expands displacement, and a vibration drive device for a tactile presentation device including the piezoelectric drive device.

  2. Description of the Related Art Conventionally, a piezoelectric drive device that generates vibration using a piezoelectric actuator (piezoelectric element) is known, and a device that generates a displacement or vibration by adding a displacement expansion mechanism to the piezoelectric actuator is also known. For example, in Patent Document 1, a piezoelectric actuator capable of enlarging the displacement of a piezoelectric actuator several times to several tens of times by using a so-called pantograph-shaped displacement enlarging mechanism in which a hinge and a link are combined based on a lever principle. An actuator displacement enlarging device has been proposed.

JP-A-1-290272 Japanese Unexamined Patent Publication No. 2007-034991

  However, since the displacement magnifying device proposed in Patent Document 1 has low rigidity of the members constituting the lever, when the mass of the driven body driven by the displacement magnifying device is large, the piezoelectric actuator, the displacement magnifying mechanism And the resonance frequency of the vibration system constituted by the driven body tends to be low.

  Here, when the piezoelectric actuator is driven at a frequency close to the resonance frequency with respect to this vibration system, the amplitude becomes abnormally large, and there is a concern that fatigue failure may occur in the component member for a long-term continuous drive. .

  On the other hand, if the piezoelectric actuator is driven at a frequency exceeding the resonance frequency for this vibration system, a phase shift occurs between the vibration of the piezoelectric actuator and the vibration of the driven body, making it difficult to accurately control the vibration. Become. In addition, when the piezoelectric actuator is driven so that the frequency continuously changes across the resonance frequency, there is a problem that abnormal vibration such as a beat occurs in the vicinity of the resonance frequency.

  Therefore, if the above displacement magnifying device is used for a touch panel display as shown in Patent Document 2, for example, when the above problem occurs, the amount of displacement proportional to the input voltage to the piezoelectric actuator cannot be obtained. However, there is a problem that a linear response cannot be obtained and the sense of reality of the tactile sensation is significantly reduced.

  The present invention has been made in view of the above circumstances, and provides a piezoelectric drive device capable of suppressing the occurrence of resonance and abnormal vibration in a driving frequency band, and a vibration drive device for a tactile presentation device including the piezoelectric drive device. For the purpose.

According to the piezoelectric driving device of the present invention, a pair of external electrodes in which the internal electrode layers are electrically connected to every other layer are provided on the side surface of a columnar stacked body in which a plurality of piezoelectric layers and internal electrode layers are alternately stacked. The laminated piezoelectric element that is deposited and the both ends of the laminated piezoelectric element that are arranged on both sides of the laminated piezoelectric element are connected to both ends in the laminating direction of the laminated piezoelectric element. A pair of bending members whose shapes change according to expansion and contraction in the stacking direction, and the stacked piezoelectric elements are disposed between the stacked piezoelectric elements, and attached to the center portions of the pair of bending members, respectively. A pair of driven bodies whose distances change in the orthogonal direction according to the movement in the direction orthogonal to the stacking direction of the stacked piezoelectric element in the central portion due to expansion and contraction in the stacking direction, and the pair of driven bodies The distance between each other increases And an elastic member which applies a force to the can has to have a tension to the pair of bending members are characterized by being Nde free.

  Here, in the piezoelectric driving device of the present invention, one driven body of the pair of driven bodies is fixed, and the other driven body is arranged to be movable in accordance with the movement of the central portion. It is preferable.

  In the piezoelectric driving device of the present invention, it is preferable that the elastic member is a helical spring or a leaf spring.

  In the piezoelectric driving measure of the present invention, the elastic member may be disposed between the pair of driven bodies, and the elastic member may be disposed outside the pair of driven bodies.

  In the piezoelectric driving device of the present invention, the elastic member is formed so as to surround the multilayer piezoelectric element and the pair of bending members, and is joined to the pair of central portions, and each of the pair of bending members It is preferable that the pair of driven bodies is attached to the central portion of the pair via the elastic member.

  Furthermore, the present invention includes the above-described piezoelectric driving device, wherein the other driven body includes a touch panel, and the stacked piezoelectric element expands and contracts in the stacking direction in response to a touch sensed by the touch panel. This is a vibration drive device for a tactile sense presentation device.

According to the piezoelectric driving device of the present invention, a pair of external electrodes in which the internal electrode layers are electrically connected to every other layer on the side surfaces of the columnar laminate in which a plurality of piezoelectric layers and internal electrode layers are alternately laminated. A laminated piezoelectric element having electrodes attached thereto, and disposed on both sides of the laminated piezoelectric element, with both ends connected to both ends in the laminating direction of the laminated piezoelectric element, and the laminated piezoelectric element A pair of bending members whose shapes change according to expansion and contraction in the stacking direction of the elements, and the stacked piezoelectric elements arranged between the stacked piezoelectric elements and attached to the center portions of the pair of bending members, respectively. A pair of driven bodies whose distances change in the orthogonal direction in accordance with the movement of the central portion in the direction orthogonal to the stacking direction of the stacked piezoelectric element due to expansion and contraction in the stacking direction of the elements; The distance between each other It wants and a resilient member that applies a force in a direction to have a tension to the pair of bending members. According to this configuration, tension is applied to the pair of bending members by the elastic member, and the apparent spring constant is increased. Therefore, the stacked piezoelectric element (driving source), the bending member (spring), the driven body (mass), The resonance frequency of the vibration system constituted by can be shifted to the high frequency side so that resonance does not occur in the driving frequency band.

  Further, according to the piezoelectric driving device of the present invention, one driven body of the pair of driven bodies is fixed, and the other driven body is disposed so as to be movable according to the movement of the central portion. In this case, the amount of change (displacement) in the distance between the center portions of the pair of bending members is not easily attenuated, and the driven body can be displaced more efficiently.

Furthermore, according to the piezoelectric driving device of the present invention, when the elastic member is a helical spring, the spring constant is relatively low, so that the change in tension applied to the bending member is small even when the displacement of the driven body is large. Thus, the displacement of the driven body that is nearly proportional to the expansion / contraction amount of the multilayer piezoelectric element can be obtained.

  Furthermore, according to the piezoelectric drive device of the present invention, when the elastic member is a leaf spring, a large force can be generated with a smaller volume compared to the helical spring, and the device can be miniaturized.

  Furthermore, according to the piezoelectric driving device of the present invention, when the elastic member is disposed between the pair of driven bodies, the elastic member can be disposed in the vicinity of the laminated piezoelectric element and the bending member, The apparatus can be simplified and configured at a low cost.

  Furthermore, according to the piezoelectric driving device of the present invention, when the elastic member is disposed outside the pair of driven bodies, the driven body can be supported from two directions, and disturbance such as touching with a hand. The vibration can be continued stably.

  Further, according to the piezoelectric driving device of the present invention, the elastic member is formed so as to surround the laminated piezoelectric element and the pair of bending members, and is joined to the central portion, and the elastic member is attached to each central portion of the bending member. When the pair of driven bodies are attached via the laminated piezoelectric element, the bending member, and the elastic member are integrally configured, the apparatus can be downsized.

  According to the vibration drive device for a tactile presentation device of the present invention, the piezoelectric drive device described above is provided, and the other driven body includes a touch panel, and the stacked piezoelectric element is stacked in accordance with the contact sensed by the touch panel. By expanding and contracting in the direction, displacement follows even at a high frequency and there is little loss, so that it is possible to show good responsiveness (displacement amount, generated force, frequency responsiveness) as a tactile sense presentation device.

It is the schematic which shows an example of embodiment of the piezoelectric drive device of this invention. FIG. 2 is an enlarged view showing the multilayer piezoelectric element and a pair of bending members shown in FIG. 1, wherein (a) shows an example in which the pair of bending members are bent and (b) shows that the pair of bending members are curved. The example which deform | transforms is shown. It is the schematic which shows the example by which one to-be-driven body in the piezoelectric drive device shown in FIG. 1 was fixed. It is the schematic which shows the example which used the helical spring as an elastic member in the piezoelectric drive device shown in FIG. It is the schematic which shows the example which used the leaf | plate spring as an elastic member in the piezoelectric drive device shown in FIG. It is the schematic which shows the other example of embodiment of the piezoelectric drive device of this invention. It is the schematic which shows the further another example of embodiment of the piezoelectric drive device of this invention. It is a schematic perspective view which shows an example of embodiment of the vibration drive device for tactile presentation devices of this invention.

  An example of an embodiment of a piezoelectric driving device of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view showing an example of an embodiment of a piezoelectric drive device of the present invention, FIG. 2 is an enlarged view showing a laminated piezoelectric element and a pair of bending members shown in FIG. 1, and FIG. The example which deform | transforms so that a pair of bending member may be bent is shown, (b) has shown the example which deform | transforms so that a pair of bending member may curve.

The piezoelectric drive device shown in FIG. 1 has a pair of external electrodes each having an internal electrode layer electrically connected to each side surface of a columnar laminate in which a plurality of piezoelectric layers and internal electrode layers are alternately laminated. The laminated piezoelectric element 1 and the laminated piezoelectric element 1 disposed on both sides of the laminated piezoelectric element 1 are connected to both ends of the laminated piezoelectric element 1 in the laminating direction. Between the pair of bending members 2a and 2b whose shape changes according to the expansion and contraction in the stacking direction and the laminated piezoelectric element 1, and are attached to the center portions 21a and 21b of the pair of bending members 2a and 2b, respectively. In accordance with the movement of the central portions 21a and 21b in the direction orthogonal to the stacking direction of the stacked piezoelectric element 1 due to the expansion and contraction of the stacked piezoelectric element 1 in the stacking direction, the pair of intervals changes in this orthogonal direction. Driven bodies 3a, 3b and a pair of driven 3a, it is characterized in that comprises an elastic member 4a which applies a force in a direction extending the interval between each other, and 4b with respect 3b.

  The multilayer body constituting the multilayer piezoelectric element 1 is formed by alternately laminating piezoelectric layers and internal electrode layers, and the internal electrode layers are formed by alternately forming positive and negative electrodes every other layer. The laminated body is formed in a rectangular parallelepiped shape having, for example, a length of 1 to 8 mm, a width of 1 to 8 mm, and a height of about 10 to 100 mm.

The plurality of piezoelectric layers constituting the laminate are made of piezoelectric ceramics (piezoelectric ceramics) having piezoelectric characteristics, and the piezoelectric ceramics forming the piezoelectric layers are formed with an average particle size of, for example, 0.1 to 10 μm. As the piezoelectric ceramic, for example, a perovskite oxide made of PbZrO ₃ —PbTiO ₃ (PZT: lead zirconate titanate) or the like, lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), or the like can be used.

  The internal electrode layers are made of, for example, silver, silver-palladium alloy, silver-platinum, copper, and the like. The internal electrode layers are alternately formed between the layers of the piezoelectric layers, and are alternately arranged in the stacking order. A drive voltage is applied to the sandwiched piezoelectric layer. Specifically, one of the internal electrode layers is a positive electrode and the other is a negative electrode (or a ground electrode), and the internal electrode layers are alternately led to opposite side surfaces of the stacked body, and a part of the end surface is exposed.

  And the external electrode electrically connected to the internal electrode layer is joined to the side surface of the laminate. The external electrode is formed, for example, by applying and baking a conductive paste made of silver and glass. A conductive member (not shown) is soldered to each external electrode (an external electrode electrically connected to the internal electrode layer serving as the positive electrode and an external electrode electrically connected to the internal electrode layer serving as the negative electrode). A drive voltage is applied to the laminated piezoelectric element 1 so that the laminated piezoelectric element 1 expands and contracts in the stacking direction.

  As shown in FIGS. 1 and 2, the pair of bending members 2 a and 2 b are arranged on both sides (sides) of the multilayer piezoelectric element 1 with the multilayer piezoelectric element 1 as the center, and both ends of each of the bending members 2 a and 2 b are laminated piezoelectric elements 1 are connected to both ends in the stacking direction. The pair of bending members 2a and 2b are made of, for example, a plate-like body made of metal or resin, and the shape changes according to the expansion and contraction of the stacked piezoelectric element 1 in the stacking direction. Here, when the pair of bending members 2a and 2b is made of a metal plate-like body, the thickness of the bending members 2a and 2b (the thickness in the plane of the paper in FIGS. 1 and 2) is 0.02 to 2 mm. A range is desirable. This is because the bending members 2a and 2b follow the expansion and contraction of the multilayer piezoelectric element 1 and are displaced in the direction perpendicular to the stacking direction without causing fatigue fracture when the driven bodies 3a and 3b are driven to vibrate. In the work generated by the multilayer piezoelectric element 1, the rate at which the work exerted on the driven bodies 3a and 3b is reduced by the elastic strain energy stored inside the elastic members of the bending members 2a and 2b is reduced as much as possible. This is to alleviate. For the same reason, the width of the bending members 2 a and 2 b (the width in the direction perpendicular to the paper surface of FIG. 1) is desirably in the range of 10 to 500% with respect to the width of the multilayer piezoelectric element 1.

As shown in FIG. 2, each of the pair of bending members 2 a and 2 b is formed so as to be inclined by an angle α from the stacking direction of the multilayer piezoelectric element 1 and extend in the stacking direction. Are connected to both ends in the stacking direction. Specifically, an epoxy resin, an acrylic resin, a silicone resin, a ceramic adhesive, and so on are attached to both end portions in the stacking direction of the multilayer piezoelectric element 1 to both end surfaces in the stacking direction of the multilayer piezoelectric element 1. A pair of piezoelectric element connection plates 7 fixed by solder or the like are provided, and both ends of the pair of bending members 2a and 2b are connected to the piezoelectric element connection plate 7, and the piezoelectric element connection plates 7 are interposed through the piezoelectric element connection plates 7. A pair of bending members 2 a and 2 b are connected to both ends of the multilayer piezoelectric element 1 in the stacking direction.

  For example, when the pair of bending members 2a and 2b and the pair of piezoelectric element connection plates 7 are made of metal, these are, for example, wire electric discharge machining, bending the metal plate, resistance welding, laser welding, soldering, etc. It is formed by the method. When the pair of bending members 2a and 2b and the pair of piezoelectric element connection plates 7 are made of resin, it is preferably formed by injection molding.

  The pair of bending members 2a, 2b and the pair of piezoelectric element connection plates 7 are preferably formed in advance and then attached to the multilayer piezoelectric element 1, and the pair of piezoelectrics before being attached to the multilayer piezoelectric element 1 is preferable. The distance between the element connection plates 7 is preferably formed to be slightly smaller than the distance between the end faces of both end portions in the stacking direction of the multilayer piezoelectric element 1. This is because when the bending members 2a and 2b are connected to both ends of the multilayer piezoelectric element 1, that is, when the pair of piezoelectric element connection plates 7 are bonded to both end surfaces of the multilayer piezoelectric element 1 in the stacking direction. By inserting the laminated piezoelectric element 1 while expanding the distance between the plates 7, the bonding strength is increased, and the bending members 2a and 2b are tensioned to increase the rigidity of the bending members 2a and 2b. This is because it is possible to reduce play when displacement and force when the piezoelectric element 1 is driven are transmitted to the driven bodies 3a and 3b. The distance between the end faces of both ends of the laminated piezoelectric element 1 in the stacking direction is set to be slightly smaller than the distance between the end faces of both ends of the stacked piezoelectric element 1 in the stacking direction. It is desirable that the ratio is 1/1000 to 1/10. If the amount to be made smaller than the distance between the end faces is smaller than this range, the tension generated in the bending members 2a and 2b cannot be sufficiently increased, and conversely if larger than this range, the bending members 2a and 2b The deformation becomes large, and distortion may occur after attachment to the driven bodies 3a and 3b, and when the multilayer piezoelectric element 1 is driven, asymmetric abnormal vibration may occur in the driven bodies 3a and 3b.

  2 (a) and 2 (b), the pair of bending members 2a, 2b and the laminated piezoelectric element 1 at the connection portion between the pair of bending members 2a, 2b and the piezoelectric element connection plate 7 are provided. The angle α formed by the stacking direction (stretching direction) is preferably in the range of 2 to 30 degrees. If the angle α is smaller than this, there is a problem that the force for moving the driven bodies 3a and 3b becomes small and the movement is not smooth. On the other hand, when the angle α is larger than this, there is a problem that the amount of displacement for moving the driven body becomes small and the amplitude of vibration becomes small.

The central portions 21a and 21b of the pair of bending members 2a and 2b are portions serving as connection portions with driven bodies 3a and 3b described later. The central portions 21a and 21b are formed integrally with the other portions constituting the pair of bending members 2a and 2b by the above-described method such as wire electric discharge machining, and other portions constituting the pair of bending members 2a and 2b. It is preferably formed thicker than the part. When the central portions 21a and 21b are formed thick, the thickness of the central portions 21a and 21b provides rigidity necessary for the central portions 21a and 21b to drive the driven bodies 3a and 3b. At the same time, the range of 0.1 to 5 mm is desirable so that the mass does not become excessive and the resonance frequency is not lowered. The central portions 21a and 21b may be formed by, for example, joining separately formed plate-like bodies, or may be formed to have the same thickness as other portions.

As shown in FIG. 2A, the bending members 2a and 2b are connected to the central portions 21a and 21b and the piezoelectric element connecting plate 7 by the deformation of the bending members 2a and 2b (the central portions 21a and 2b). 2b) may maintain its shape, bend near both ends of the central portions 21a and 21b, and change only the angle of the bent portions, as shown in FIG. 2 (b). In addition, the bending members 2a and 2b may be deformed so that the entire portions are bent without bending near both ends of the central portions 21a and 21b.

  The pair of driven bodies 3a and 3b are disposed with the laminated piezoelectric element 1 therebetween, and are attached to the center portions 21a and 21b of the pair of bending members 2a and 2b, respectively. Then, according to the movement of the central portions 21a, 21b in the direction orthogonal to the stacking direction of the stacked piezoelectric element 1 due to expansion and contraction in the stacking direction of the stacked piezoelectric element 1, the distance between them changes in this orthogonal direction. It has become.

  Here, the pair of driven bodies 3a and 3b may be arranged so as to be movable in accordance with the movement in the direction orthogonal to the stacking direction of the stacked piezoelectric element 1, for example, as shown in FIG. One driven body 3b may be fixed to a pedestal or the like (not shown) by fixing screws 5a and 5b, and the other driven body 3a may be movably disposed. At this time, it is arbitrary which of the driven bodies 3a and 3b is movably disposed. According to this configuration, the amount of change (displacement) in the distance between the central portions of the pair of bending members 2a and 2b is not easily attenuated, and the driven body can be displaced more efficiently.

  And it is important to provide the elastic member 4 (4a, 4b) which is applying force to the pair of driven bodies 3a, 3b in a direction in which the distance between the driven bodies 3a, 3b increases.

  As this elastic member 4 (4a, 4b), as shown in FIG. 4, a pair of helical springs 41a, 41b can be used. In this case, since the spring constant is relatively low, even when the displacement of the driven bodies 3a and 3b is large, the change in tension applied to the bending members 2a and 2b is small and is almost proportional to the amount of expansion and contraction of the multilayer piezoelectric element 1. The displacement of the driven bodies 3a and 3b is obtained. Here, as the helical springs 41a and 41b, it is preferable to use spring steel, but other non-ferrous metal materials, resin materials, and ceramic materials may be used. The length of the helical springs 41a and 41b is such that the free height, which is the length prior to assembly to the piezoelectric drive device, is greater than the distance (interval) formed by the pair of driven bodies 3a and 3b. When this occurs, a force is generated in a direction in which the distance between the pair of driven bodies 3a and 3b is increased. The spring wire diameter, coil average diameter, pitch, and the like must be appropriately selected so as to obtain a spring constant necessary for increasing the resonance frequency to a target value. The force exerted on the pair of driven bodies 3a and 3b in the direction of expanding the distance between the pair of driven bodies 3a and 3b when combined with the piezoelectric driving device is 0.01 to 1000 N (Newton) in total of the pair of helical springs 41a and 41b. It is preferable to be in the range.

  As the elastic members 4a and 4b, a pair of leaf springs 42a and 42b can be used as shown in FIG. The leaf springs 42a and 42b shown in FIG. 5 are shaped such that a contact portion that contacts the driven body 3a and a contact portion that contacts the driven body 3b are connected via a connecting portion having a V-shaped cross section. It is formed. In this case, a large force can be generated with a small volume compared with the helical springs 41a and 41b, and the apparatus can be miniaturized. Here, it is preferable to use spring steel as the leaf springs 42a and 42b, but other non-ferrous metal materials, resin materials, and ceramic materials may be used. The length of the leaf springs 42a and 42b in the expansion / contraction direction is such that the length before assembling to the piezoelectric driving device is greater than the distance formed by the pair of driven bodies 3a and 3b, A force is generated in a direction in which the distance between the driving bodies 3a and 3b is increased. The plate thickness and width of the spring, the maximum stress point distance that is the length of the arm, and the like need to be appropriately selected so as to obtain a spring constant necessary for increasing the resonance frequency to a target value. Further, the force exerted on the pair of driven bodies in the direction of expanding the distance when assembled to the drive device is in the range of 0.01 to 1000 N (Newton) in total of the pair of leaf springs 42a and 42b. Is preferred. As the leaf springs 42a and 42b, a so-called cross section U in which a contact portion that contacts the driven body 3a and a contact portion that contacts the driven body 3b are connected via a connecting portion having a curved cross section. It may be formed in a letter shape.

  When the elastic members 4a and 4b are helical springs 41a and 41b as shown in FIG. 4 or leaf springs 42a and 42b as shown in FIG. 5, at least two (elastic member 4a and elastic member 4b) are provided. When the elastic members 4a and 4b are disposed between the pair of driven bodies 3a and 3b, the elastic members 4a and 4b are disposed near the laminated piezoelectric element 1 and the bending members 2a and 2b. The apparatus can be simplified and configured at a low cost.

  1 and 3 to 5 show a mode in which the elastic member 4 is disposed between the pair of driven bodies 3a and 3b. However, the present invention is not limited to this mode, and as shown in FIG. The elastic members 4a and 4b may be disposed outside the pair of driven bodies 3a and 3b. At this time, the elastic members 4a and 4b are preferably fixed to a pedestal or the like (not shown) by, for example, elastic member mounting supports 6a and 6b and fixing screws 5a and 5b. In this case, the driven bodies 3a and 3b can be supported from two directions, and can continue to vibrate stably against disturbances such as touching with a hand.

  Furthermore, in the piezoelectric driving device of the present invention, as shown in FIG. 7, the elastic member 4 is formed so as to surround the laminated piezoelectric element 1 and the pair of bending members 2a and 2b, and is formed at the pair of central portions 21a and 21b. It is also possible to employ a structure in which a pair of driven bodies 3a and 3b are attached to the central portions 21a and 21b of the pair of bending members 2a and 2b via the elastic member 4 respectively.

  In this case, the elastic member 4 is formed in an annular shape so that the shape seen from the side of the multilayer piezoelectric element 1 is an ellipse, the shape seen from the side of the multilayer piezoelectric element 1 is a hexagon, etc. And those formed in a polygonal shape. As the material of the elastic member 4, resin material, ceramics, etc. can be adopted in addition to spring steel. However, since the elastic member 4 is joined to the central portions 21a and 21b of the bending members 2a and 2b, the bending members 2a and 2b are used. It is good to form with the same material. When the elastic member 4 and the bending members 2a and 2b are both made of metal, a method such as resistance welding, laser welding, or soldering is adopted as the joining method, and both the elastic member 4 and the bending members 2a and 2b are made of resin. In this case, methods such as ultrasonic welding, epoxy resin bonding, and acrylic resin bonding are employed. When the elastic member 4 and the bending members 2a and 2b are both made of ceramic, a method such as ceramic adhesive or silver brazing is employed. Is done. Here, the space | interval (short diameter) of the part joined to a pair of center part 21a, 21b in the elastic member 4 is the distance (outer surface of the center part 21b in the bending member 2a, and the outer surface of the center part 21b in the bending member 2b). The distance between the two surfaces is set to be larger than the distance between the two surfaces so that a force is generated in the direction of expanding the distance between the pair of driven bodies 3a and 3b when assembled to the piezoelectric driving device.

  In the case shown in FIG. 7 as well, the plate thickness, width, and cross-sectional shape of the elastic member 4 need to be appropriately selected so as to obtain a spring constant necessary for increasing the resonance frequency to a target value. In addition, when the elastic member 4 is assembled between the driven bodies 3a and 3b together with the laminated piezoelectric element 1 and the bending members 2a and 2b, the elastic member 4 expands the distance with respect to the driven bodies 3a and 3b. The force exerted on the direction is preferably in the range of 0.01 to 1000 N (Newton).

  Then, as shown in FIG. 8, the piezoelectric driving device can function as a part of the vibration driving device for a tactile presentation device. That is, FIG. 8 is a schematic perspective view showing an example of an embodiment of the vibration drive device for a tactile presentation device of the present invention.

Specifically, the vibration drive device for a tactile presentation device shown in FIG. 8 includes a laminated piezoelectric element 1, a pair of bent portions 2 a and 2 b, and an elastic member 4. The driven members 3a and 3b are provided with driven bodies 3a and 3b whose distances change in the orthogonal direction in accordance with the movement of the bending members 2a and 2b in the direction orthogonal to the stacking direction of the stacked piezoelectric element 1. And at least one of the driven bodies 3b (driven body 3b in FIG. 8) includes a touch panel, and the stacked piezoelectric element 1 expands and contracts in the stacking direction in accordance with the contact sensed by the touch panel. Yes. In the example shown in FIG. 8, the laminated piezoelectric element 1, the pair of bent portions 2a and 2b, the elastic member 4, the driven body 3a, and the driven body 3b are mounted on the base 8, and the driven body 3b is fixed to the pedestal 8, and rollers 9a, 9b, 9c, and 9d made of, for example, a metal cylinder are inserted between the driven body 3a and the pedestal 8. In addition, the rollers 9a, 9b, 9c, and 9d represent portions that are seen through the driven body 3a by broken lines.

  Then, due to the expansion and contraction of the stacked piezoelectric element 1 in the stacking direction, the driven body 3a moves in a direction perpendicular to the stacking direction of the stacked piezoelectric element, and the distance between the driven body 3a and the driven body 3b increases. It becomes wider and narrower.

  Here, the touch panel is provided with a touch sensor that detects that the fingertip is touched, and a signal for applying a driving voltage to the stacked piezoelectric element 1 is transmitted by the detection of the touch sensor, and the driven body An input frequency such that 3a is driven at a vibration frequency of 150 to 350 Hz is applied to the laminated piezoelectric element 1 with a driving voltage of, for example, a voltage ± 15 V, and a driven body (3a including a touch panel is provided as the laminated piezoelectric element 1 is driven. Alternatively, 3b) moves (vibrates), whereby the vibration of the driven body (3a or 3b) is transmitted to the fingertip touching the touch panel. That is, the vibration driving device for a tactile presentation device of the present invention is a vibration driving device for a tactile presentation device in which vibration is transmitted to a fingertip by an arbitrary vibration signal.

  The piezoelectric drive device and the vibration drive device for a tactile presentation device of the present invention were produced by the following method.

  First, the multilayer piezoelectric element 1 has an outer dimension of 2 mm × 2 mm × 18 mm, the number of stacked internal electrodes is 360 layers, and a displacement amount when applying 30 V is 8 μm.

  Next, a pair of bending members 2a and 2b was prepared. Specifically, the pair of bending members 2a and 2b and the pair of piezoelectric element connection plates 7 were integrally formed by wire electric discharge machining using spring steel. The bending members 2a and 2b have a plate thickness of 0.1 mm, a plate width of 2.0 mm, and an angle α shown in FIG. 2 of about 7 degrees. At this time, the distance between the pair of piezoelectric element connection plates 7 was formed to be about 0.1 mm smaller than the distance between the end faces of both ends of the multilayer piezoelectric element 1 in the stacking direction.

Next, the elastic member 4 was formed so as to surround the multilayer piezoelectric element 1 and the bending members 2a and 2b. Specifically, the elastic member 4 is made of spring steel, and a ribbon having a plate thickness of 0.2 mm and a width of 2 mm is wound into an ellipse having a major axis of about 30 mm and a minor axis of about 15 mm, and both ends of the ribbon are wound. Then, resistance welding was performed so as to join the central portion 21a of the bending member 2a and the central portion 21b of the bending member 2b.

  Next, driven bodies 3a and 3b were produced. The plate thickness was 2 mm, and the size of the driven bodies 3a and 3b was 10 mm × 10 mm in one plan view and the other was 10 mm × 5 mm in plan view.

  Next, the piezoelectric drive device was assembled. The piezoelectric element connection plates 7 were positioned at both ends of the multilayer piezoelectric element 1 in the stacking direction, and both were fixed with an epoxy adhesive.

  Next, the central portions 21a and 21b of the bending members 2a and 2b were connected to the driven bodies 3a and 3b via the elastic member 4. At this time, the minor axis of the elastic member 4 was 15 mm, and was larger than the distance (distance between the two surfaces) between the outer surface of the central portion 21a of the bending member 2a and the outer surface of the central portion 21b of the bending member 2b. For this reason, the elastic member 4 was attached with a shorter diameter. The force required at this time was about 20N.

Next, the driven body 3b was fixed to the base 8 with an epoxy adhesive. Rollers 9a, 9b, 9c, and 9d made of metal cylinders having a diameter of 1 mm were inserted between the driven body 3a and the base 8.

  In this way, a vibration drive device for a tactile presentation device provided with a piezoelectric drive device as shown in FIG. 8 was obtained.

  Using the obtained vibration drive device for a tactile sensation device (piezoelectric drive device), an input signal for driving the driven body 3a at a vibration frequency of 150 to 350 Hz is applied to the multilayer piezoelectric element 1 at a drive voltage of ± 15V. When applied, it was confirmed that a displacement of about ± 30 μm was obtained in the driven body 3a. It was also confirmed that there was no resonance point below this vibration frequency. In this state, when the main surface of the driven body 3a was pressed with a finger from a direction perpendicular to the main surface, clear vibration was transmitted to the finger, and this feeling did not disappear even if the pressing force with the finger was increased. .

  On the other hand, the elastic member 4 is removed from the vibration drive device (piezoelectric drive device) for the tactile sense presentation device, and an input signal for driving the driven body 3a at a vibration frequency of 150 to 350 Hz is applied to the multilayer piezoelectric element 1 as described above. When a voltage of ± 15 V was applied, it was confirmed that the displacement of the driven body 3a did not follow and the displacement amount was about ± 2 μm. After that, when the frequency of the input signal was lowered, the phenomenon that the vibrations of the multilayer piezoelectric element 1 and the bending members 2a and 2b increased near 20 Hz was observed, but the displacement of the driven body 3a at that time was almost measured. There wasn't.

  From these results, in the piezoelectric driving device without the elastic member 4, resonance or abnormal vibration occurs in the driving frequency band, but in the piezoelectric driving device of the present invention having the elastic member 4, resonance or abnormal vibration occurs in the driving frequency band. In the vibration drive device for a tactile presentation device provided with this piezoelectric drive device, a clear vibration is transmitted to the finger and good response (displacement, generated force, frequency response) can be realized. It was confirmed that it was possible.

1 Laminated piezoelectric element 2a, 2b Bending member
21a, 21b Central part 3a, 3b Driven body 4, 4a, 4b Elastic member
41a, 41b helical spring
42a, 42b Leaf springs 5a, 5b Fixing screws 6a, 6b Elastic member mounting support 7 Piezoelectric element connection plate 8 Bases 9a, 9b, 9c, 9d Roll

Claims (8)

A laminated piezoelectric material in which a pair of external electrodes, each of which is electrically connected to every other internal electrode layer, are attached to the side surface of a columnar laminate in which a plurality of piezoelectric layers and internal electrode layers are alternately laminated. Elements,
Arranged on both sides of the multilayer piezoelectric element, both ends are connected to both ends of the multilayer piezoelectric element in the stacking direction, and the shape changes according to the expansion and contraction of the multilayer piezoelectric element in the stacking direction. The laminated portion of the central part by expansion and contraction in the laminating direction of the laminated piezoelectric element, which is disposed with a pair of bending members interposed between the laminated piezoelectric elements and attached to the central part of the pair of bending members. A pair of driven bodies whose distances change in the direction perpendicular to the direction perpendicular to the stacking direction of the piezoelectric elements,
Piezoelectric drive device, characterized in that has Nde contains an elastic member that to have a tension to the pair of bending members apply a force in a direction in which spread distance therebetween with respect to the pair of the driven member.   The one driven body of said pair of driven bodies is fixed, and the other driven body is arrange | positioned so that a movement according to the movement of the said center part is possible. Piezoelectric drive device.   The piezoelectric driving device according to claim 1, wherein the elastic member is a helical spring.   The piezoelectric drive device according to claim 1, wherein the elastic member is a leaf spring. The piezoelectric driving device according to claim 1, wherein the elastic member is disposed between the pair of driven bodies.   The piezoelectric driving device according to claim 1, wherein the elastic member is disposed outside the pair of driven bodies.   The elastic member is formed so as to surround the laminated piezoelectric element and the pair of bending members, and is joined to a pair of the central portions, and the elastic members are interposed in the central portions of the pair of bending members, respectively. The piezoelectric drive device according to claim 1, wherein the pair of driven bodies are attached. The piezoelectric driving device according to claim 2, wherein the other driven body includes a touch panel, and the stacked piezoelectric element expands and contracts in the stacking direction in response to a touch sensed by the touch panel. Vibration drive device for tactile presentation device.

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