JP2013038982A - Ultrasonic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact ultrasonic linear actuator that eliminates the need for adjustments between a plurality of vibrators and provides a large generative force.SOLUTION: A ultrasonic actuator includes a drive section, a plurality of movable bodies, a plurality of transfer sections, 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 sandwich the first and second piezoelectric bodies therebetween. The drive section expands and contracts in a sandwiching direction of the first and second elastic bodies. The movable bodies are arranged so as to be movable with respect to the drive section. The transfer sections are joined to the driving section, and are configured so as to allow adjustment of gripping force on the respective movable bodies. The control section synchronizes the expansion and contraction of the drive section with the gripping force adjustment of the transfer sections. The transfer sections are arranged on a side of a first end of the drive section in the sandwiching direction, and at respective positions where a plurality of antinodes of vibration of the drive section are located.

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 an object of the present invention is to provide a linear ultrasonic actuator that does not require adjustment between a plurality of transducers and that has a small generation force but a strong generation force.

  In order to solve the above-described problems and achieve the object, the ultrasonic actuator according to the present invention is arranged so as to face the first piezoelectric body that is polarized in the thickness direction, and is polarized in the thickness direction. The second piezoelectric body, and the first elastic body and the second elastic body sandwiching the first piezoelectric body and the second piezoelectric body, and driving to expand and contract in the sandwiching direction between the first elastic body and the second elastic body A plurality of movable bodies arranged to be movable with respect to the drive section, a plurality of transmission sections coupled to the drive section and configured to be able to adjust gripping forces on the plurality of movable bodies, respectively, A control unit that interlocks expansion and contraction and grip force adjustment of the transmission unit, and the plurality of transmission units are arranged on one end side of the drive unit in the clamping direction, and a plurality of antinode positions of vibration of the drive unit It is characterized by being arranged respectively.

  In the ultrasonic actuator according to the present invention, the two transmission units adjust the gripping force for each of the two moving bodies in synchronization with each other, and the gripping states of the two moving units by the two transmission units are the same as each other or The reverse is preferred.

  The ultrasonic actuator according to the present invention is advantageous in that it is small in size and has a strong generating force.

It is a perspective view which shows the structure of the ultrasonic actuator which concerns on embodiment of this invention. It is a disassembled perspective view which shows the structure of the ultrasonic actuator which concerns on embodiment of this invention. It is a side view showing composition of an ultrasonic actuator concerning an embodiment of the present invention. It is a front view which shows the structure of the ultrasonic actuator which concerns on embodiment of this invention. It is a rear view which shows the structure of the ultrasonic actuator which concerns on embodiment of this invention. It is sectional drawing in the VI-VI line of FIG. It is a block diagram which shows the structure of the control part in embodiment of this invention. It is a perspective view which shows the state which fixed the support part in 1st Embodiment of this invention with two support plates. It is a perspective view which shows the relationship between the support part in 1st Embodiment of this invention, and two support plates. It is a figure which shows the change of the grasping force of two moving bodies by time by expansion / contraction of the drive part and bending of the main-body part of two transmission parts in embodiment of this invention.

Embodiments of an ultrasonic actuator according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by the following embodiment.
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 piezoelectric element for adjusting the gripping force of 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 a plurality of transmission parts are arranged on one end side of the driving part, two action parts are provided, so that the number of operation parts can be increased.

  1 to 5 are diagrams showing a configuration of an ultrasonic actuator 100 according to an embodiment of the present invention. FIG. 1 is a perspective view, FIG. 2 is an exploded perspective view, FIG. 3 is a side view, and FIG. FIG. 5 and FIG. 5 are rear views. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 is a block diagram illustrating a configuration of the control unit 150 in the present embodiment.

  The ultrasonic actuator 100 includes a driving unit 110, two moving bodies 121 and 122 arranged to be movable with respect to the driving unit 110, two transmission units 130 and 140, a control unit 150 (FIG. 7), Is provided.

  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 an embedding as a second elastic body. A nut portion 114. The elastic connecting portion 113 includes a support portion 113e.

  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 passes through the first piezoelectric element 111 and the second piezoelectric element 112 through the bolt part 113c extending from the elastic coupling part 113, and further fits into the screw on the inner surface of the nut part 114, thereby the first piezoelectric element. The element 111 and the second piezoelectric element 112 are fastened 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). ).

  The elastic coupling unit 113 mechanically and acoustically couples the driving unit 110 and the two transmission units 130 and 140, that is, vibrations generated in the first piezoelectric element 111 and the second piezoelectric element 112 are coupled to the first transmission unit. 130 and the 2nd transmission part 140 are comprised so that it can transmit efficiently. The elastic connecting portion 113 includes a tip portion 113b, a horn portion 113a, a support portion 113e, and a bolt portion that are arranged concentrically in order along the direction A in which the first piezoelectric element 111 and the second piezoelectric element 112 are sandwiched. 113c. The tip portion 113b has a screw formed on a cylindrical inner surface, and the bolt portion 113c has a screw formed on the outer surface.

  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 portion 113a has a smaller cross-sectional diameter along the direction A in which the first piezoelectric element 111 and the second piezoelectric element 112 are sandwiched from the first piezoelectric element 111 side toward the first transmission portion 130 side. With a horn shape. The horn shape of this cross section preferably varies exponentially, but may be other shapes as long as it decreases from the first piezoelectric element 111 side toward the first transmission unit 130 side.

The first transmission unit 130 includes a main body 131 and a third piezoelectric element 132, and is coupled to the driving unit 110 by the first connecting plate 101. The second transmission unit 140 includes a main body unit 141 and a fourth piezoelectric element 142 and is coupled to the driving unit 110 by the second connecting plate 106.
The 1st transmission part 130 and the 2nd transmission part 140 are arrange | positioned at the one edge part side of the drive part 110 regarding the support part 113e.

  The main body 131 of the first transmission unit 130 is coupled to the tip 113b of the drive unit 110 by 101 at a substantially antinode position of the vibration W (FIG. 3) of the drive unit 110. The main body part 141 of the second transmission part 140 is coupled to the distal end part 113b of the drive part 110 by 106 at a substantially abdominal position different from the abdominal position where the first transmission part 130 is disposed.

The first transmission unit 130 and the second transmission unit 140 are arranged at positions shifted from each other in a direction perpendicular to the direction A in which the first piezoelectric element 111 and the second piezoelectric element 112 are sandwiched.
Specifically, for the second transmission portion 140, the tip end portion 113 b of the elastic coupling portion 113 is penetrated through the second coupling plate 106, and the screw 108 penetrating the 106 is fitted into the main body portion 141. 106 is fixed to a predetermined position of the tip 113b. As for the first transmission part 130, the screw 102 penetrating the first connection plate 101 is fitted into the tip part 113 b of the elastic connection part 113, and the screw 104 penetrating the first connection plate 101 is attached to the main body part 131. Fit.

  A through hole 133 is provided in the main body 131 of the first transmission unit 130 along a direction A in which the elastic coupling portion 113 and the nut portion 114 sandwich the first piezoelectric element 111 and the second piezoelectric element 112. A rod-shaped first moving body 121 is movably inserted into the through hole 133. A third piezoelectric element 132 as a third piezoelectric body is attached to the lower surface of the main body 131.

  A through hole 143 is provided in the main body 141 of the second transmission unit 140 along the direction A in which the first piezoelectric element 111 and the second piezoelectric element 112 are sandwiched. A rod-shaped second moving body 122 is movably inserted into the through hole 143. A fourth piezoelectric element 142 as a fourth piezoelectric body is attached to the upper surface of the main body 141.

  The main body 131 of the first transmission unit 130 is bent by energizing the third piezoelectric element 132, thereby generating a force with which the main body 131 grips the first moving body 121. Further, the main body 131 recovers from bending by stopping energization to the third piezoelectric element 132, and the gripping force to the first moving body 121 is reduced. That is, the 1st transmission part 130 is comprised so that adjustment of the holding | grip force with respect to the 1st mobile body 121 is possible.

  The main body part 141 of the second transmission part 140 is bent by energizing the fourth piezoelectric element 142, thereby generating a force with which the main body part 141 grips the second moving body 122. Further, the main body 141 recovers from bending by stopping energization of the fourth piezoelectric element 142, and the gripping force to the second moving body 122 is reduced. That is, the 2nd transmission part 140 is comprised so that adjustment of the holding | grip force with respect to the 2nd mobile body 122 is possible.

  As illustrated in FIG. 7, 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 amplifier 155 and output to the first transmission unit 130 (third piezoelectric element 132) and the second transmission unit 140 (fourth piezoelectric element 142). .

  The signals output to the driving unit 110, the first transmission unit 130, and the second transmission unit 140 are synchronized with each other with a predetermined delay time through the delay circuit 153. In addition, the control which does not synchronize the phase of the signal output to the drive part 110 and the two transmission parts 130 and 140 is also possible.

  The signals output from the control unit 150 to the driving unit 110 and the two transmission units 130 and 140 are the first piezoelectric element 111 and the second piezoelectric element 112 of the driving unit 110, the third piezoelectric element 132, and the fourth piezoelectric element 142, respectively. And applied respectively. Thereby, the expansion and contraction of the drive unit 110 and the operation of adjusting the gripping force by the first transmission unit 130 and the second transmission unit 140 are interlocked, and by repeating this, the first moving body 121 and the second moving body 122 are moved. It can be driven linearly in a predetermined direction.

  Here, the second signal generator 154 outputs a signal to the first transmission unit 130 and the second transmission unit 140 through the second power amplification unit 155 at the same timing. Thereby, the 1st transmission part 130 and the 2nd transmission part 140 can respectively adjust the holding force with respect to the 1st moving body 121 and the 2nd moving body 122 synchronizing with each other.

  When the second signal generator 154 outputs the same signal to both the first transmission unit 130 and the second transmission unit 140, the first moving body 121 by the first transmission unit 130 and the second transmission unit 140 The gripping states of the second moving bodies 122 are the same as each other.

  On the other hand, when the second signal generator 154 outputs a signal to one of the first transmission unit 130 and the second transmission unit 140 but not to the other, the first transmission unit 130 and the second transmission unit The gripping states of the first moving body 121 and the second moving body 122 by 140 are opposite to each other. That is, the first mobile body 121 is gripped by the first transmission unit 130 to which a signal is applied, and the second mobile body 122 is gripped by the second transmission unit 140 because no signal is applied to the second transmission unit 140. The power to do is reduced.

  As shown in FIGS. 8 and 9, the support portion 113 e is a plate-like member that is sandwiched between the horn portion 113 a and the bolt portion 113 c and is integrally formed therewith. The support portion 113e is disposed at a substantially node position of vibration of the drive unit 110 and is sandwiched between the two support plates 161 and 162. As a result, the ultrasonic actuator 100 is supported at the approximate node position of the vibration of the drive unit 110 and can be attached to an external member. Here, FIG. 8 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. 9 is a perspective view showing the relationship between the support portion 113e and the two support plates 161 and 162. FIG.

  Next, a process of moving the two moving bodies 121 and 122 by interlocking the expansion and contraction of the drive unit 110 and the gripping force adjustment of the two transmission units 130 and 140 will be described with reference to FIG. FIG. 10 illustrates the gripping force of the first moving body 121 and the second moving body 122 due to the expansion and contraction of the driving unit 110 and the bending of the main body part 131 of the first transmission unit 130 and the main body part 141 of the second transmission unit 140. It is a figure which shows a change over time. FIG. 10 shows a case where the gripping states of the first moving body 121 and the second moving body 122 by the first transmission unit 130 and the second transmission unit 140 are the same.

  FIG. 10A shows the basic state. In this basic state, since no voltage is applied to the first piezoelectric element 111, the second piezoelectric element 112, the third piezoelectric element 132, and the fourth piezoelectric element 142, the drive unit 110 does not expand and contract, The main body portions 131 and 141 are not bent.

  FIG. 10B shows a state in which no voltage is applied to the first piezoelectric element 111 and the second piezoelectric element 112, and a predetermined power is supplied from the second power amplifier 155 to the third piezoelectric element 132 and the fourth piezoelectric element 142. A state in which voltages are applied in synchronization is shown. In this state, with respect to the first moving body 121, the main body portion 131 is bent, so that a gripping force of the first moving body 121 due to the bending of the inner surface of the through hole 133 is generated. 1 is held by the transmission unit 130. With respect to the second moving body 122, the main body portion 141 is bent to generate a gripping force of the second moving body 122 due to the bending of the inner surface of the through-hole 143. To be gripped.

  FIG. 10C shows the first piezoelectric element 111 and the first piezoelectric element 111 from the first power amplification unit 152 while continuing to apply the voltage to the third piezoelectric element 132 and the fourth piezoelectric element 142 from the state of FIG. 2 shows a state in which a predetermined voltage is applied to the piezoelectric element 112. The difference between the timing shown in FIG. 10B and the timing shown in FIG. 10C corresponds to the delay time determined by the delay circuit 153. In the state of FIG. 10C, the driving unit 110 extends while the first moving body 121 and the second moving body 122 are held by the transmission units 130 and 140, respectively. And the 1st moving body 121 and the 2nd moving body 122 which the 2nd transmission part 140 holds respectively move to the left.

  FIG. 10D shows a state in which the voltage application to the third piezoelectric element 132 and the fourth piezoelectric element 142 is stopped while the voltage is applied to the first piezoelectric element 111 and the second piezoelectric element 112. Show. In the state of FIG. 10 (d), the first piezoelectric element 111, the second piezoelectric element 112, and the horn part 113a are fully extended, while the first transmission part 130 and the second transmission part 140 are recovered from the bending and become the first. The force for gripping each of the first moving body 121 and the second moving body 122 is reduced.

  FIG. 10E shows a state in which application of voltage to the first piezoelectric element 111 and the second piezoelectric element 112 is stopped while application of voltage to the third piezoelectric element 132 and the fourth piezoelectric element 142 is stopped. . In the process from FIG. 10D to FIG. 10E, the first piezoelectric element 111, the second piezoelectric element 112, and the horn portion 113a are degenerated to the basic state (FIG. 10A) by stopping the voltage application. However, since the gripping force of each of the moving bodies 121 and 122 by the transmission units 130 and 140 is reduced, the first moving body 121 and the second moving body 122 are moved by the first transmission unit 130 and the second transmission unit 140. Regardless, it remains in the position shown in FIG.

  By the above operation, the first moving body 121 and the second moving body 122 move to the left side from the state shown in FIG. 10A, and by repeating this, the first moving body 121 and the second moving body 122 are moved. It can be moved to a desired position.

On the other hand, the 1st moving body 121 and the 2nd moving body 122 can also be moved to the right side by performing operation | movement contrary to the operation | movement shown in FIG.
More specifically, the holding force of the first moving body 121 and the second moving body 122 by the first transmitting portion 130 and the second transmitting portion 140 is reduced, and the first moving body 121 and the second moving body 122 are moved. The operation of extending the drive unit 110 while maintaining the position, and the drive unit 110 is retracted in a state where the gripping force of the first moving body 121 and the second moving body 122 by the first transmission unit 130 and the second transmission unit 140 is increased. Thus, the first moving body 121 and the second moving body 122 are moved to the right side by sequentially performing the operation of moving the first moving body 121 and the second moving body 122 to the right side.

FIG. 10 shows a case in which the gripping states of the first moving body 121 and the second moving body 122 by the first transmission unit 130 and the second transmission unit 140 are the same. The gripping state of the two moving bodies 122 may be reversed.
For example, the first transmission unit 130 is the same as that shown in FIG. 10, while the second transmission unit 140 is the fourth piezoelectric in FIGS. 10B and 10C, contrary to the voltage application state shown in FIG. A voltage is not applied to the element 142 but a voltage is applied to the fourth piezoelectric element 142 in FIGS. If it does in this way, with respect to the state shown to Fig.10 (a), the 1st moving body 121 will move to the left side, and the 2nd moving body 122 will move to the right side, respectively.

  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 101 1st connection board 102,104 Screw 106 2nd connection board 108 Screw 110 Drive part 111 1st piezoelectric element 112 2nd piezoelectric element 113 Elastic connection part 113a Horn part 113b Tip part 113c Bolt part 113e Support part 114 Nut part 121 1st moving body 122 2nd moving body 130 1st transmission part 131 Main body part 132 3rd piezoelectric element 133 Through-hole 140 2nd transmission part 141 Main body part 142 4th piezoelectric element 143 Through-hole 150 Control part 151 1st Signal generator 152 First power amplification section 153 Delay circuit 154 Second signal generator 155 Second power amplification section 161, 162 Support plate

Claims (2)

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 plurality of movable bodies arranged to be movable with respect to the drive unit;
A plurality of transmission units coupled to the drive unit and configured to be capable of adjusting a gripping force with respect to the plurality of moving bodies; and
A control unit that interlocks expansion and contraction of the drive unit and grip force adjustment of the transmission unit;
With
The ultrasonic actuator, wherein the plurality of transmission units are arranged on one end side of the drive unit in the clamping direction, and are arranged at a plurality of antinode positions of vibration of the drive unit, respectively. .   The two transmission parts adjust the gripping force for each of the two mobile bodies in synchronization with each other, and the gripping states of the two mobile bodies by the two transmission parts are the same or opposite to each other The ultrasonic actuator according to claim 1.

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