JP2012222884A - Ultrasonic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact ultrasonic linear actuator that has a strong generative force, high operating efficiency, and high design flexibility, and allows stable drive.SOLUTION: An ultrasonic linear actuator includes a drive section, a movable body, a transmission section, and a control section. The drive section has: a first piezoelectric body that is polarized in a thickness direction thereof; a second piezoelectric body that is arranged so as to face the first piezoelectric body and is polarized in a thickness direction thereof; and a first elastic body and a second elastic body that hold the first piezoelectric body and the second piezoelectric body therebetween. The drive section expands and contracts in a holding direction of the first elastic body and the second elastic body. The movable body is arranged movably relative to the drive section. The transmission section is coupled to the driving section, and is configured so as to have an adjustable gripping force on the movable body. The control section synchronizes the expansion and contraction of the drive section with the gripping force adjustment of the transmission section. The transmission section has a through hole through which the movable body is inserted. The transmission section is configured in such a manner that an axis of the drive section in a direction of a drive center approximately coincides with a central axis of the movable body in a moving direction thereof.

Description

  The present invention relates to an ultrasonic actuator.

  As a conventional ultrasonic actuator, there is an ultrasonic motor described in Patent Document 1. In this ultrasonic motor, a driving element in which two Langevin vibrators are arranged so as to be orthogonal to each other is pressed against the outer peripheral surface of the rotor, and a rotational force is generated in the rotor by driving the vibrator.

JP 2000-152671 A

  However, in the above-described ultrasonic motor, adjustment to align the angles, positions, amplitudes, frequencies, etc. of the two Langevin transducers is necessary to obtain the desired vibration. Further, since the two Langevin vibrators are arranged so as to be orthogonal to each other, there is a drawback that the volume of the entire driver is increased.

  The present invention has been made in view of the above, and is a linear ultrasonic actuator that is small in size, has a strong generation force, has high operation efficiency, can be driven stably, and has a high degree of design freedom. The purpose is to provide.

In order to solve the above-described problems and achieve the object, an ultrasonic actuator according to the present invention is arranged so as to face a first piezoelectric body polarized in the thickness direction, the first piezoelectric body, and in the thickness direction. A polarized second piezoelectric body, and a first elastic body and a second elastic body that sandwich the first piezoelectric body and the second piezoelectric body, and sandwiched between the first elastic body and the second elastic body A drive that expands and contracts in the direction;
A movable body arranged to be movable with respect to the drive unit;
A transmission unit coupled to the drive unit and configured to be capable of adjusting a gripping force on the movable body;
A control unit that interlocks expansion and contraction of the drive unit and grip force adjustment of the transmission unit;
With
The transmission unit has a through hole for inserting the moving body,
The drive center direction axis of the drive unit and the movement direction center axis of the movable body are configured to substantially coincide with each other.

  The present invention is advantageous in that it is possible to provide a linear ultrasonic actuator that is compact but has a strong generating force, has high operating efficiency, can be driven stably, and has a high degree of design freedom.

It is a perspective view which shows the structure of the ultrasonic actuator which concerns on 1st Embodiment. It is a disassembled perspective view which shows the structure of the ultrasonic actuator which concerns on 1st Embodiment. (A) is a side view showing the configuration of the ultrasonic actuator according to the first embodiment. (B) is the cross-sectional block diagram. It is a front view which shows the structure of the ultrasonic actuator which concerns on 1st Embodiment. It is a block diagram which shows the structure of the control part in 1st Embodiment. It is a perspective view which shows the state which fixed the support part in 1st Embodiment with two support plates. It is a perspective view which shows the relationship between the support part in 1st Embodiment, and two support plates. It is a figure which shows the change of the holding force of the moving body by the expansion-contraction of a drive part and a transmission part in 1st Embodiment from a side surface. It is a figure which shows the change of the holding force of the moving body by the expansion-contraction of a drive part and a transmission part in 1st Embodiment with time. It is a perspective view which shows the structure of the ultrasonic actuator which concerns on the 1st modification of 1st Embodiment. It is a disassembled perspective view which shows the structure of the ultrasonic actuator which concerns on the 1st modification of 1st Embodiment. It is a perspective view which shows the structure of the ultrasonic actuator which concerns on the 2nd modification of 1st Embodiment. It is a disassembled perspective view which shows the structure of the ultrasonic actuator which concerns on the 2nd modification of 1st Embodiment.

  The effect by the structure of the ultrasonic actuator of this embodiment is demonstrated. In addition, this invention is not limited by this embodiment. That is, in describing the embodiment, a lot of specific details are included for the purpose of illustration, but various variations and modifications may be added to these details without exceeding the scope of the present invention. Accordingly, the exemplary embodiments of the present invention described below are set forth without loss of generality or limitation to the claimed invention.

  The ultrasonic actuator of the present invention uses the generated force of a bolt-tightened Langevin vibrator in order to increase the thrust for moving the moving body as an ultrasonic motor. In addition, a piezoelectric element is used to adjust the gripping force of the moving body in the transmission unit. The moving body is moved by interlocking the generation of force in the Langevin vibrator and the adjustment of the force for gripping the moving body by the transmission unit. In such a configuration, since the driving Langevin vibrator and the Langevin vibrator that holds the moving body are controlled independently, there is a degree of freedom in design such that it is not necessary to align these driving frequencies.

  Furthermore, by making the tip of the driving Langevin vibrator into a horn shape, the moving amount of the moving body can be increased, and the tip of the horn shape becomes thin, so it can be easily placed even in a space where space is limited. Become.

  In addition, since the Langevin vibrator is used for gripping the moving body, the moving body can be gripped by a large pressure, and an ultrasonic actuator having a strong moving force can be obtained.

  Furthermore, it is possible to obtain a linear ultrasonic actuator that has a small generation force but has a high generation force, a high operation efficiency, a stable drive, and a high degree of design freedom.

(First embodiment)
1 to 5 are views showing the configuration of the ultrasonic actuator 100 according to the first embodiment. FIG. 1 is a perspective view, FIG. 2 is an exploded perspective view, FIG. 3 is a side view, and FIG. FIG. 5 is a block diagram showing a configuration of the control unit 150 in the first embodiment.

The ultrasonic actuator 100 includes a drive unit 110, an elastic coupling unit 113, a moving body 120, a transmission unit 130, a support unit 113e, and a control unit 150 (see FIG. 5).
The drive unit 110 includes a first piezoelectric element 111 as a first piezoelectric body, a second piezoelectric element 112 as a second piezoelectric body, an elastic coupling portion 113 as a first elastic body and a coupling section, and a second elastic body. And an embedded nut portion 114.

  The first piezoelectric element 111 and the second piezoelectric element 112 each have a substantially disk shape polarized in the thickness direction, and are arranged so that the polarization directions oppose each other in the thickness direction. The drive unit 110 allows the bolt portion 113 c extending from the elastic coupling portion 113 to pass through the first piezoelectric element 111 and the second piezoelectric element 112, and is further fitted to a screw on the inner surface of the nut portion 114.

  As a result, the first piezoelectric element 111 and the second piezoelectric element 112 are clamped together. With this configuration, the drive unit 110 forms a Langevin vibrator. The drive unit 110 energizes the first piezoelectric element 111 and the second piezoelectric element 112, whereby the elastic coupling portion 113 and the nut portion 114 sandwich the first piezoelectric element 111 and the second piezoelectric element 112 in a direction A (FIG. 2). ) To expand and contract.

The elastic connecting part 113 mechanically and acoustically connects the first piezoelectric element 111, the second piezoelectric element 112, the nut part 114, and the transmission part 130 to each other.
Here, the elastic coupling portion 113, the first piezoelectric element 111, the second piezoelectric element 112, and the nut portion 114 constitute a drive unit 110.

  Thereby, the vibration generated in the drive unit 110 can be efficiently transmitted to the transmission unit 130. The elastic connecting portion 113 includes a tip portion 113b, a horn portion 113a, and a bolt portion 113c, which are arranged concentrically in order along the direction A in which the first piezoelectric element 111 and the second piezoelectric element 112 are sandwiched. A screw portion 113d extending from the tip along the clamping direction A is formed on the tip portion 113b, and a screw is formed on the outer surface of the bolt portion 113c.

  The horn part 113a has a shape in which the outer diameter decreases from the bolt part 113c side toward the tip part 113b side. In other words, the horn part 113a has a horn shape in which the cross-sectional diameter along the direction A in which the first piezoelectric element 111 and the second piezoelectric element 112 are sandwiched decreases from the drive part 110 side toward the transmission part 130 side. Prepare. The horn shape of this cross section preferably changes exponentially. However, the shape is not limited to this, and the shape may be other than this as long as it decreases from the drive unit 110 side toward the transmission unit 130 side.

  The transmission unit 130 includes a pressing bolt 135, a main body 133, a third piezoelectric element 131 (third piezoelectric body), and a fourth piezoelectric element 132 (first piezoelectric element) in order along a direction B (FIG. 2) perpendicular to the clamping direction A. 4 piezoelectric bodies) and embedded bolts 134. The transmission unit 130 is separate from the driving unit 110, and is coupled to the driving unit 110 by screwing the screw part 113 d of the elastic coupling part 113 into the main body part 133.

  The third piezoelectric element 131 and the fourth piezoelectric element 132 each have a substantially disk shape that is polarized in the thickness direction, and are arranged so that the polarization directions face each other in the thickness direction. The transmission part 130 penetrates the bolt part 134a of the embedded bolt 134 through the third piezoelectric element 131 and the fourth piezoelectric element 132, and further fits the screw on the inner surface of the main body part 133, whereby the third piezoelectric element 131 and the second piezoelectric element 132 are fitted. The four piezoelectric elements 132 are fastened together. Accordingly, the third piezoelectric element 131 and the fourth piezoelectric element 132 are sandwiched by the main body 133 and the embedded bolt 134 along the sandwiching direction B perpendicular to the sandwiching direction A.

  The transmission unit 130 has a through hole 136 through which the moving body 120 is inserted.

FIG. 3A shows a side configuration of the present embodiment. FIG. 3B shows a cross-sectional configuration of the present embodiment.
As shown in FIG. 3A, a cylindrical space 137 different from the through hole 136 is formed at the end of the transmission unit 130 as shown in FIG.
A pressing block 138 is disposed in the cylindrical space 137. The pressing bolt 135 can be screwed into the cylindrical space 137 by screwing the pressing bolt 135 from the lower surface of the transmission unit 130.

As shown in the perspective configuration diagram of FIG. 2, an opening 113 f is formed in the screw portion 113 d of the tip portion 113 b of the drive portion 113.
And as shown in the cross-sectional block diagram of FIG.3 (b), the drive part 110 has the hollow part 113g. The rod-shaped moving body 120 can be inserted from the opening 113 f into the hollow portion 113 g in the driving unit 110.
And it is comprised so that the drive center direction axis | shaft AX1 of the drive part 110 and the movement direction center axis | shaft AX2 of the mobile body 120 may correspond substantially. FIG. 4 is a front view showing the configuration of the ultrasonic actuator.
Here, “substantially coincidence” is not limited to a configuration in which the drive center direction axis AX1 of the drive unit 110 and the movement direction center axis AX2 of the moving body 120 are completely coincident with each other, but a range allowed by required specifications. In this, the configuration in which both axes AX1 and AX2 are mutually shifted is also included.

Here, a pressing block 138 is disposed at the end of the pressing bolt 135. For this reason, the moving body 120 inserted through the through hole 136 can be pressed via the pressing block 138 by screwing the pressing bolt 135 into the transmission unit 130.
Note that the surface of the pressing block 138 with which the moving body 120 abuts is preferably V-shaped. Thereby, the improvement of the positioning accuracy of the moving body 120 which has a cylindrical shape (bar shape) and the application accuracy can be achieved.

  The transmission unit 130 expands and contracts by energizing the third piezoelectric element 131 and the fourth piezoelectric element 132. When the transmission unit 130 is energized so as to cause resonance vibration, a vibration node and an antinode are generated in the transmission unit 130. At the vibration node position, the vibration direction of the vibration is opposite to the node position. Therefore, during vibration due to energization, the direction in which the force leaves and the direction in which the force separates are repeated based on the node position. For this reason, the moving body 120 sandwiched between the node positions is repeatedly gripped and released by high-speed vibration in the ultrasonic region. As a result, the force to grip the moving body 120 is weakened during energization.

In the initial state where the third piezoelectric element 131 and the fourth piezoelectric element 132 are not energized, the transmission unit 130 strongly holds the moving body 120 by the pressing bolt 135 via the main body 133 and the pressing block 138. Yes. Accordingly, the moving body 120 is fixed to the transmission unit 130.
Thus, by controlling energization and non-energization, the force with which the transmission unit 130 grips the moving body 120 can be increased or decreased.

  As shown in FIG. 5, the control unit 150 includes a first signal generator 151, a first power amplification unit 152, a delay circuit 153, a second signal generator 154, and a second power amplification unit 155. The signal generated by the first signal generator 151 is amplified by the first power amplification unit 152 and output to the driving unit 110 (the first piezoelectric element 111 and the second piezoelectric element 112). The signal generated by the second signal generator 154 is amplified by the second power amplification unit 155 and output to the transmission unit 130 (the third piezoelectric element 131 and the fourth piezoelectric element 132).

  The signals output to the drive unit 110 and the transmission unit 130 are synchronized with each other with a predetermined delay time through the delay circuit 153. Note that the phases of the signals output to the drive unit 110 and the transmission unit 130 need not be synchronized.

  Two signals output from the control unit 150 to the driving unit 110 and the transmission unit 130 are the first piezoelectric element 111 and the second piezoelectric element 112 of the driving unit 110, and the third piezoelectric element 131 and the fourth piezoelectric element of the transmission unit 130, respectively. Applied to each of the piezoelectric elements 132. Thereby, the expansion / contraction of the drive unit 110 and the adjustment of the gripping force of the moving body 120 due to the expansion / contraction of the transmission unit 130 are interlocked. By repeating this, the moving body 120 can be linearly driven in a predetermined direction.

  As shown in FIGS. 6 and 7, the support portion 113 e is disposed in the vicinity of the node of the drive unit 110 using the first piezoelectric element 111 and the second piezoelectric element 112 as drive sources, and is integrated with the elastic coupling portion 113. It is the member made into the plate shape comprised in this. The support portion 113e is disposed in the vicinity of a node of the drive unit 110 that uses the first piezoelectric element 111 and the second piezoelectric element 112 as drive sources, and the first piezoelectric element 111 and the second piezoelectric element of the drive unit 110 are disposed. 112 is arranged at a substantially node position of vibration by 112 and is sandwiched between two support plates 161 and 162. As a result, the ultrasonic actuator 100 is supported at an approximate node position of vibration by the first piezoelectric element 111 and the second piezoelectric element 112 in the drive unit 110 and can be attached to an external member. Here, FIG. 6 is a perspective view showing a state in which the support portion 113e is fixed by the two support plates 161 and 162. FIG. FIG. 7 is a perspective view showing the relationship between the support portion 113e and the two support plates 161 and 162. FIG.

  Next, the steps of moving the moving body 120 by interlocking the expansion and contraction of the drive unit 110 and the gripping force adjustment of the transmission unit 130 are illustrated in FIGS. 8A to 8D and FIGS. 9A to 9D. Will be described as an example. FIGS. 8A to 8D are views showing changes in the gripping force of the moving body 120 by the expansion and contraction of the driving unit 110 and the transmission unit 130 over time. FIGS. 9A to 9D are views showing changes in the gripping force of the moving body 120 by the expansion and contraction of the driving unit 110 and the transmission unit 130 over time. FIGS. 9A to 9D correspond to FIGS. 8A to 8D, respectively.

  FIG. 8A and FIG. 9A show an initial state. In the initial state, no voltage is applied to the first piezoelectric element 111 and the second piezoelectric element 112, so the drive unit 110 does not expand or contract. In the initial state, no voltage is applied to the third piezoelectric element 131 and the fourth piezoelectric element 132, and the moving body 120 is supported by the main body 133 and the pressing block 138 in contact with the pressing bolt 135. As a result, the movable body 120 is fixed to the transmission unit 130.

  8B and 9B maintain a state in which no voltage is applied to the third piezoelectric element 131 and the fourth piezoelectric element 132, and the first piezoelectric element 111 and the second piezoelectric element from the first power amplification unit 152 are maintained. A state in which a predetermined voltage is applied to the piezoelectric element 112 is shown. When a predetermined voltage is applied to the first piezoelectric element 111 and the second piezoelectric element 112 of the driving unit 110, the driving unit 110 expands. For this reason, the transmission part 130 and the moving body 120 move to the left together.

  FIG. 8C and FIG. 9C show the second while continuing to apply the voltage to the first piezoelectric element 111 and the second piezoelectric element 112 from the state of FIG. 8B and FIG. 9B. A state in which a predetermined voltage is applied from the power amplifier 155 to the third piezoelectric element 131 and the fourth piezoelectric element 132 is shown. The difference between the timings shown in FIGS. 8B and 9B and the timings shown in FIGS. 8C and 9C corresponds to the delay time determined by the delay circuit 153. 8C and 9C, the third piezoelectric element 131 and the fourth piezoelectric element 132 expand and contract between the main body 133 and the pressing block 138 in contact with the pressing bolt 135. The force for gripping the moving body 120 arranged in the vicinity of the node is reduced, and the moving body 120 is movable with respect to the transmission unit 130.

  8D and 9D show the voltage applied to the first piezoelectric element 111 and the second piezoelectric element 112 while maintaining the state in which the voltage is applied to the third piezoelectric element 131 and the fourth piezoelectric element 132. The state where the application is stopped is shown. In the state of FIGS. 8D and 9D, the drive unit 110 is degenerated to the initial state shown in FIGS. 8A and 9A. On the other hand, since the force of gripping the moving body 120 by the transmission unit 130 is reduced, the moving body 120 remains at the position shown in FIGS. 8C and 9C regardless of the degeneration of the transmission unit 130. .

  By the above operation, the moving body 120 moves to the left side from the state shown in FIGS. 8A and 9A, and the moving body 120 can be moved to a desired position by repeating this.

On the other hand, the moving body 120 can also be moved to the right side by performing an operation opposite to the operations shown in FIGS. 8A to 8D and FIGS. 9A to 9D.
More specifically, the operation of extending the drive unit 110 while maintaining the position of the moving body 120 in a state where the gripping force of the moving body 120 by the transmission unit 130 is reduced, and the gripping force of the moving body 120 by the transmission unit 130 In this state, the moving unit 120 is moved to the right side by sequentially performing the operation of moving the moving unit 120 to the right side by retracting the drive unit 110.

As described above, in this embodiment, the drive center direction axis AX1 of the drive unit 110 and the movement direction center axis of the moving body are configured to substantially coincide with each other.
Thus, by bringing the moving body 120 to the center of the drive unit 110, the operating point and the action point can be made the same. As a result, no rotational moment is applied during driving, so that stable driving can be performed.

Next, a modified example will be described.
FIG. 10 is a perspective view showing a configuration of an ultrasonic actuator according to a first modification of the first embodiment. FIG. 11 is an exploded perspective view showing the configuration of the ultrasonic actuator according to the first modification of the first embodiment. 10 and 11, the drive unit 110 is the same member as in the first embodiment, and therefore the same reference numerals are used and detailed description thereof is omitted.

  As shown in FIGS. 10 and 11, in the ultrasonic actuator according to the first modification, a long plate-like moving body 170 is used instead of the moving body 120 of the first embodiment. Two holes 171 and 172 are provided at the tip of the moving body 170 so that it can be joined to an external member.

  Similarly to the transmission unit 130 of the first embodiment, the transmission unit 180 has a direction B perpendicular to the direction A in which the elastic coupling unit 113 and the nut unit 114 sandwich the first piezoelectric element 111 and the second piezoelectric element 112 (FIG. 11). ), A pressing bolt 185, a main body 183, a third piezoelectric element 181 (third piezoelectric body), a fourth piezoelectric element 182 (fourth piezoelectric body), and an embedded bolt 184. Further, the transmission unit 180 is coupled to the driving unit 110 by screwing the screw part 113 d of the elastic coupling part 113 into the main body part 183.

  The third piezoelectric element 181 and the fourth piezoelectric element 182 have the same configuration as the third piezoelectric element 131 and the fourth piezoelectric element 132 of the first embodiment, and along the clamping direction B perpendicular to the clamping direction A, It is sandwiched between the main body 183 and the embedded bolt 184.

The plate-like moving body 170 is arranged so that the moving body 170 extends along the clamping direction A in the through hole 186.
The pressing bolt 185 is screwed into the cylindrical space 137 shown in FIG. 3 of the first embodiment from the lower surface of the main body 183 along the clamping direction B. A pressing block 188 is disposed on the moving body 170 side of the pressing bolt 185. Furthermore, a movable body 170 is disposed between the main body 183 and the pressing bolt 185 so as to extend along the clamping direction A with a pressing block 188 interposed therebetween. The movable body 170 is sandwiched between the lower surface of the main body 183 and the upper surface of the pressing block 188 disposed at the end of the pressing bolt 185. Here, the lower surface of the main body 183 and the upper surface of the pressing block 188 arranged at the end of the pressing bolt 185 are planes facing each other. The moving body 170 is held between the main body 183 and the upper surface of the pressing block 188 disposed at the end of the pressing bolt 185.

The transmission unit 180 expands and contracts by energizing the third piezoelectric element 181 and the fourth piezoelectric element 182, whereby the upper surface of the pressing block 188 disposed at the end of the main body 183 and the pressing bolt 185 moves the moving body 170. The gripping force increases or decreases.
Specifically, in the initial state in which the third piezoelectric element 181 and the fourth piezoelectric element 182 are not energized, the transmission unit 180 is an upper surface of the pressing block 188 disposed at the ends of the main body 183 and the pressing bolt 185. Thus, the moving body 170 is firmly held. Accordingly, the moving body 170 is fixed to the transmission unit 180. Therefore, the movable body 170 is mechanically sandwiched between the upper surfaces of the main body 183 and the pressing block 188 disposed at the end of the pressing bolt 185. On the other hand, when the third piezoelectric element 181 and the fourth piezoelectric element 182 are energized, the force for gripping the moving body 170 decreases, and the moving body 170 can move along the gripping direction A.

  FIG. 12 is a perspective view illustrating a configuration of an ultrasonic actuator according to a second modification of the first embodiment. FIG. 13 is an exploded perspective view showing the configuration of the ultrasonic actuator according to the second modification of the first embodiment. In FIGS. 12 and 13, the drive unit 110 is the same member as in the first embodiment, so the same reference numerals are used and detailed description thereof is omitted.

As shown in FIGS. 12 and 13, in the ultrasonic actuator according to the second modification, a long plate-like moving body 190 is used instead of the cylindrical (rod-like) moving body 120 of the first embodiment. Yes. Two holes 191 and 192 are provided at the distal end of the movable body 190 so that it can be joined to an external member. The moving body 190 includes a long hole portion 193 penetrating in the thickness direction. The long hole portion 193 is provided so as to extend along the longitudinal direction of the moving body 190.
This modified example is different from the first modified example in that a long hole portion 193 is formed at the center of the movable body 190 and the movable body 190 is not detached from the main body portion 203 when the movable body 190 moves. .

  Similar to the transmission unit 130 of the first embodiment, the transmission unit 200 has a direction B perpendicular to the direction A in which the elastic coupling unit 113 and the nut unit 114 sandwich the first piezoelectric element 111 and the second piezoelectric element 112 (FIG. 13). ), A pressing bolt 195, a main body 203, a third piezoelectric element 201 (third piezoelectric body), a fourth piezoelectric element 202 (fourth piezoelectric body), and an embedded bolt 204 are provided in this order.

  The third piezoelectric element 201 and the fourth piezoelectric element 202 have the same configuration as the third piezoelectric element 131 and the fourth piezoelectric element 132 of the first embodiment, and along the clamping direction B perpendicular to the clamping direction A, It is clamped by the main body 203 and the embedded bolt 204.

The pressing bolt 195 is screwed into the cylindrical space 137 as shown in FIG. 3 of the first embodiment from the lower surface of the main body 203 along the clamping direction B. A pressing block 198 is disposed on the movable body 190 side of the pressing bolt 195. A pin 198a and a pressing surface 198b are formed on the upper surface of the pressing block 198. The pin 198a engages with the long hole portion 193 of the moving body 190. The pressing surface 198b presses the moving body 190. Thereby, the moving body 190 is fixed to the main body 203.
The plate-like moving body 190 is disposed so as to extend along the clamping direction A in the through hole 196. The movable body 190 is sandwiched between the lower surface of the main body 203 and the upper surface of the pressing surface 198b of the pressing block 198 disposed at the end of the pressing bolt 195. Here, the lower surface of the main body 203 and the upper surface of the pressing surface 198b of the pressing block 198 disposed at the end of the pressing bolt 195 are planes facing each other. Further, the movable body 190 has a pin 198 a inserted through the long hole portion 193. Thereby, the moving body 190 is held between the main body 203 and the pressing block 198 disposed at the end of the pressing bolt 195. Here, the pin 198 a engages with the long hole portion 193 of the moving body 190.

  The transmission unit 200 expands and contracts when the third piezoelectric element 201 and the fourth piezoelectric element 202 are energized, whereby the pressing surface 198b of the pressing block 198 disposed at the end of the main body 203 and the pressing bolt 195 moves. The force for gripping 190 increases or decreases.

  Specifically, in the initial state in which the third piezoelectric element 201 and the fourth piezoelectric element 202 are not energized, the transmission unit 200 is pressed by the pressing block 198 disposed at the end of the main body 203 and the pressing bolt 195. The moving body 190 is firmly held by the surface 198b, and thus the moving body 190 is fixed to the transmission unit 200. Therefore, the moving body 190 is mechanically held between the main body 203 and the pressing surface 198b of the pressing block 198 disposed at the end of the pressing bolt 195.

On the other hand, when the third piezoelectric element 201 and the fourth piezoelectric element 202 are energized, the gripping force with respect to the moving body 190 existing in the vicinity of the vibration node of the transmission unit 200 decreases, and the moving body 190 moves along the gripping direction A. It becomes possible.
Further, the long hole portion 193 of the moving body 190 and the pin 198a of the pressing block 198 can be engaged to prevent the moving body 190 from dropping from the main body portion 203.

  As described above, the ultrasonic actuator according to the present invention is useful for a small actuator using a plurality of transducers including a Langevin transducer.

DESCRIPTION OF SYMBOLS 100 Ultrasonic actuator 110 Drive part 111 1st piezoelectric element (1st piezoelectric material)
112 Second piezoelectric element (second piezoelectric body)
113 Elastic connection part (1st elastic body, connection part)
113a Horn part 113b Tip part 113c Bolt part 113d Screw part 113e Support part 113f Opening part 114 Nut part (2nd elastic body)
120 moving body 130 transmitting portion 131 third piezoelectric element (third piezoelectric body)
132 Fourth piezoelectric element (fourth piezoelectric body)
133 Main body part 133a Groove part 134 Embedded bolt 134a Bolt part 135, 185, 195 Press bolt 136, 186, 196 Through hole 137 Cylindrical space 138, 188, 198 Press block 150 Control part 151 First signal generator 152 First power amplification part 153 Delay Circuit 154 Second Signal Generator 155 Second Power Amplifier 161, 162 Support Plate 170 Moving Body 171, 172 Hole 180 Transmitter 181 Third Piezoelectric Element (Third Piezoelectric)
182 Fourth piezoelectric element (fourth piezoelectric body)
183 Body 184 Embedded bolt 190 Moving body 191, 192 Hole 193 Long hole 198a Pin 198b Pressing surface 200 Transmitting part 201 Third piezoelectric element (third piezoelectric body)
202 4th piezoelectric element (4th piezoelectric body)
203 Body 204 Embedded bolt AX1 Drive center direction axis AX2 Movement direction center axis

Claims (4)

A first piezoelectric body polarized in the thickness direction, a second piezoelectric body arranged to face the first piezoelectric body and polarized in the thickness direction, and sandwiching the first piezoelectric body and the second piezoelectric body A drive unit that includes a first elastic body and a second elastic body that extend and contract in a clamping direction by the first elastic body and the second elastic body;
A movable body arranged to be movable with respect to the drive unit;
A transmission unit coupled to the drive unit and configured to be capable of adjusting a gripping force on the movable body;
A control unit that interlocks expansion and contraction of the drive unit and grip force adjustment of the transmission unit;
With
The transmission unit has a through hole for inserting the moving body,
An ultrasonic actuator characterized in that a drive center direction axis of the drive unit and a movement direction center axis of the movable body are substantially coincident. The drive part has a hollow part,
The ultrasonic actuator according to claim 1, wherein the moving body is inserted through the hollow portion.   The ultrasonic actuator according to claim 1, wherein the transmission unit is a Langevin vibrator. The ultrasonic actuator according to claim 1, wherein the moving body has a rod shape or a plate shape.

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