Showing papers on "Piezoelectric motor published in 1986"

Piezoelectric ultrasonic transducer with acoustic matching plate

Abstract: A monolithic array ultrasonic transducer has a plurality of transducer elements formed thereon by isolating metallized areas on a piezoelectric plate without cutting the piezoelectric plate apart for each transducer element, and an acoustic matching layer having a longitudinal wave velocity within ±25% of a longitudinal wave velocity of the piezoelectric plate and a thickness equal to one half of that of the piezoelectric plate. The acoustic matching layer suppresses the radiation to an object of a partial wave in a direction of 60° to a normal line to the plane of the piezoelectric plate.

Linear motor driving device

Abstract: A linear motor driving device includes a pair of actuators each having a first piezoelectric element, a pair of levers connected to the first piezoelectric element, and an apparatus for magnifying the displacement caused by the first piezoelectric element. A second piezoelectric element is connected to the pair of actuators. The second piezoelectric element translates the levers in a direction perpendicular to the direction of actuation of the levers.

Coarse and fine motion positioning mechanism

Abstract: The positioning system, particularly useful for moving a stage mounting a semiconductor wafer for the manufacture of semiconductor devices, provides a lead screw and zero backlash nut for coarse motion of the stage. A thrust member fixedly mounts the nut and the member is flexurally mounted to a housing supporting the stage acting through a piezoelectric motor connection. This action brings the stage in a coarse adjustment mode into the capture range of the piezoelectric motor for fine adjustment by in and out movement of a pusher rod extending from the motor. Flexures allow motion of the thrust member parallel to the lead screw and protects the piezoelectric motor from undesirable side loads. A separate duplicate mechanism is used for each of x-axis and y-axis movements of the housing and stage to bring the stage to a precise position by the respective coarse and fine translationary movements of the lead screw, thrust members and piezoelectric motors.

Input frequency control device for surface acoustic wave motor

Abstract: A surface acoustic wave motor utilizing ultrasonic vibration has an elastic member and piezoelectric elements for vibrating the elastic member. The motor is provided with a monitor voltage detecting circuit for detecting a monitor voltage generated by the vibration, from a portion of the piezoelectric elements not receiving the input voltage, and a frequency control circuit for controlling the input power supply frequency in such a manner that the monitor voltage assumes a predetermined value lower than a maximum monitor voltage obtained at the resonance frequency of the stator consisting of the elastic member and piezoelectric elements, in a frequency range higher than the resonance frequency.

Method and apparatus for generating low frequency acoustic energy waves

Abstract: An acoustic transmitter is employed in a borehole logging tool for generating low frequency acoustic energy waves. A tube of piezoelectric material is sealed at both ends and filled with liquid. A pliable boot surrounds such piezoelectric tube. At least one passageway communicates the inside of the piezoelectric tube with the inner surface of the boot. Differing electrical polarities are applied to the inner and outer surfaces of the piezoelectric tube. These electrical polarities are modulated to excite the piezoelectric tube to resonate at a frequency controlled by the inertia of the liquid in the passageway and the mass of the liquid inside the piezoelectric tube.

Displacement sensor including a magnetically responsive member and a pair of piezoelectric elements

Abstract: A displacement sensor is provided with first and second piezoelectric elements, a pair of electrodes at one and the other ends of each of the first and the second piezoelectric elements; a permanent magnet mechanically fixed to one end of the first piezoelectric element; a small piece mechanically fixed to one end of the second piezoelectric element and having almost the same weight as that of the permanent magnet; and a base plate to which the other ends of the first and the second piezoelectric elements are mechanically fixed; wherein the electrodes provided at the other end of each of the first and the second piezoelectric elements are electrically connected, and the electrodes provided at one end of each of the first and the second piezoelectric elements are used as output terminals. Also, a pair of small pieces made of a magnetic material and a non-magnetic material can be used instead of the above permanent magnet and small piece.

Pulse Driving Method of Piezoelectric Actuators

Abstract: Dynamical ana lys i s o f p i e z o e l e c t r i c ac tua to rs has been s tud ied f o r a s tep o r a pu l se vo l tage applied. The s t r a i n induced i s , i n general, associated w i t h an overshoot and r i n g i n g . When the r i s e t ime f o r t he vo l tage i s a p p r o p r i a t e l y ad justed ( i .e. e q u a l l y t o t h e resonance per iod) , t h i s r i n g i n g i s r a d i c a l l y reduced. To suppor t t he analys is , t h e experiment has been made by us ing a bimorph-type actuator .

Piezoelectric current generating device

Abstract: In an electric pulses generating apparatus for therapeutic applications, a piezoelectric generator is connected to electrodes. Some of the electrodes at least are placed in contact or in vicinity of a skin of a patient to be treated. A current of piezoelectric origin in caused to flow through a distribution head formed with notches.

Acoustic piezoelectric power transducer

Abstract: An acoustic piezoelectric power transducer of sandwich shape with supply conductors pressed into grooves in the electrically conductive metal inserts and/or the piezoelectric plates.

Piezoelectric type motor

Abstract: PURPOSE:To control revolution easily and stably by forming the function of in eccentric can for a harmonic gear mechanism by radially arranged laminating type piezoelectric bodies. CONSTITUTION:A piezoelectric type motor is constituted of a plurality of laminating type piezoelectric bodies 1-8, a rigid body ring 9, a stator ring 10 as an elastic body, and a rotor ring 11 as a rigid body organized as a moving piece. The piezoelectric bodies 1-8 are each mounted to respective side of an octagonal fixed base 22 unified onto a support shaft 21, and the rigid body ring 9 is disposed in a parallel displaceable manner with the support shaft 21. The combination of the piezoelectric bodies 1-8 and the rigid body ring 9 is incorporated to the stator ring 10 as a pressure mechanism, and the rotor ring 11 is installed rotatably, using the support shaft 21 as a coaxial center every time the stator ring 10 is deformed elastically. Accordingly, each piezoelectric body 1-8 is driven in succession by employing voltage patterns of four kinds, thus turning the rotor ring 11.

Drive circuit for a piezoelectric actuator

Abstract: A drive circuit for a piezoelectric actuator includes a pair of power input terminals for supplying either AC or DC power, with the piezoelectric actuator being connected between these power input terminals. A device for supplying current for driving the piezoelectric actuator in one direction is interposed between one of the power input terminals and an end of the piezoelectric actuator. Further, there is provided connected in parallel to the piezoelectric actuator a switching circuit which turns into a high resistance state when the device is on and serves as an active discharge path for the electric charges of the piezoelectric actuator.

Piezoelectric valve and its driving method

Abstract: PURPOSE: To obtain a sufficient pressing force by making both a mechanical deflection force and a force produced by an electric field of the same direction with that of residual polarization of a piezoelectric deflection element work on a valve piece. CONSTITUTION: When a valve piece 22 is closing an input port 24, piezoelectric deflection element 6 is forcibly made to deflect mechanically upward. Between leads 19 and 20 is applied a voltage with the side of the lead 19 positive to produce an electric field of the same direction with that of residual polarization in a piezoelectric plate 11. This produces a contraction force only in the piezoelectric plate to produce a downward force at a free end of the piezoelectric deflection element 6 due to the contraction force of the piezoelectric plate 11. Thus, the valve piece 22 closes the input port 24 by means of the piezoelectric element 6. COPYRIGHT: (C)1987,JPO&Japio

Piezoelectric motor using roll

Abstract: PURPOSE:To remove a cause of a friction or a creak caused by the irregular moving speed by using a roll between opposed surfaces of the end of a stator and a movable element as means for generating and transmitting moving torque. CONSTITUTION:Ball bearings 8, 8' are disposed between a cantilever 1 and a rotor 6 of a piezoelectric motor. The bearings 8, 8' are supported to a shaft 9 to contact with the end of the cantilever along the radial line, and the shaft 9 is secured to a shaft 7 so as not to separate rotatably from the radial line. The shaft 7 passes the inner hollow portion of the shaft 6' of a rotor 6, which is supported by the bearings 8, 8' press-fitted to the bottom center of the disc of the rotor.

Piezoelectric motor using cantilever beam twist supersonic vibrator

Abstract: PURPOSE:To reduce the size and the weight and to increase the torque of a piezoelectric motor by press-bonding a rotor on the end of a supersonic vibrator which twists and bendably vibrates CONSTITUTION:Piezoelectric thickness vibrators 31, 32 are formed of doughnut- shaped ceramics, and polarized through silver electrode films formed on the front and back surfaces A terminal board 42 of the same shape as the vibrators is interposed between the positive electrode sides of two vibrators 31, 32, a terminal board 41 is superposed at the negative load side, aluminum washers 2, 5 are superposed on the outside, and a cap bolt 6 is passed through a bolt hole at the bottom side of the washer 6 A hollow shaft is erected at the center of a rotor 8, a bolt 10 is inserted through a coil spring 11 sandwiched by bearings 91, 92 at the shaft, and press-bonded to the end of the beam 11 by the spring 11 in the shape for supporting the rotation of the rotor 8 by the bearings 91, 92 Leads 71, 72 are passed through the vibrators 31, 32 and a sinusoidal wave voltage is applied to rotate the rotor 8

Piezoelectric weighing device

Abstract: A piezoelectric device is used to determine the absolute weight of an unknown sample by comparison to a control sample whose weight is known. A piezoelectric driver is resiliently attached to a base that is isolated from vibrations. A piezoelectric receiver and a reed are resiliently attached to the piezoelectric driver so that (1) the reed is moved in response to motion of the piezoelectric driver, and (2) the piezoelectric receiver gives an electric signal out proportional to motion of the system. The entire system is set to operate on the leading edge of the resonant frequency for the system. By applying an oscillating sine wave voltage, such as 140 hertz, to the piezoelectric driver, and by applying a known mass to the tip of the reed, a first output is obtained from the piezoelectric receiver which represents the calibrated weight. Next by exchanging an unknown sample for the known mass, a second output is obtained that represents the second weight. By a ratio of the second output/first output (or a signal equivalent to the weights being measured), the absolute weight of the unknown sample is determined.

Both-end cross support beam drive piezoelectric motor

Abstract: PURPOSE:To simultaneously generate resonant state of deflection and twist modes of beam by vibrating the center of a beam supporting surface in the normal direction of the surface in the state that both ends of the radial beam are supported to cross th central axis. CONSTITUTION:Both end cross support beams 1, washers 2, piezoelectric vibrator 3 and a cap bolt washer 4 are clamped by a cap bolt 5 to form a stator. A shaft 9 attached to the center of the rotor 8 is held at the core 15 of a motr case 10 using a ball bearing 12. A stator washer 4 is set to four pins 101 for anti-rotating around a stator at the bottom of the case 10, leads 6, 7 are led out of the case 10, the case cover 15 is bonded fixedly to the case 10 to form a piezoelectric motor. Thus, elliptical vibrations rotating reversely in the plane vertical to the central axis are generated at both opposed supporting ends of the beam 1 to rotate the opposed rotors 8.

Piezoelectric motor using twist vibrator periphery drive

Abstract: PURPOSE:To enhance the efficiency and to readily drive by using a supersonic vibrator of twist mode coupled integrally with a piezoelectric thickness vibrator, a twist coupler and a twist mode resonator with a supersonic vibration source. CONSTITUTION:Two piezoelectric thickness vibrators 1, 2 made of doughnut- shaped ceramic are superposed each other in an inverted direction, matched with a twist coupler 3 and a twist resonator 4, and integrally coupled by a bolt 6 passed through a washer 5. When a sinusoidal voltage is applied across the vibrator 1, a strong output torque is obtained at a main rotational shaft.

Both-end face rotary type piezoelectric motor

Abstract: PURPOSE:To simultaneously rotate two rotors in the same direction by the same torque by press-holding the rotors on both end faces of a supersonic elliptical vibrator CONSTITUTION:Piezoelectric vibrators 13, washers 12, cantilevers 11 are symmetrically disposed at both sides of a terminal board 14 attached with leads 171, and clamped to threaded holes of bottom back surfaces of the cantilevers 11 at both ends through bolts 16 The rotors 18 are press-bonded to the ends 1 of the cantilevers 11 projected at both ends Thus, the shafts of the rotors 18 are simultaneously rotated with respect to the stator 15 in the same direction 19 to form a both-end face rotary piezoelectric motor Thus, the two rotors 8 can be vibrated in the same frequency, to simultaneously rotate in the same direction 19 by the same torque

Mode contraction type piezoelectric motor

Abstract: PURPOSE:To obtain a large torque by press-bonding a rotor to the free end of a cantilever vibrated by twist by a piezoelectric vibrator, and switching the frequency of a high frequency electric signal applied to the vibrator. CONSTITUTION:Piezoelectric thickness vibrators 31, 32 are formed of doughnut- shaped ceramics, and polarized through silver electrode films formed on the front and back surfaces. A terminal board 42 of the same shape as the vibrators is interposed between the positive electrode sides of two vibrators 31, 32, a terminal board 41 is superposed at the negative load side, aluminum washers 2, 5 are superposed on the outside, and a cap bolt 6 is passed through a bolt hole at the bottom side of the washer 6, and clamped. A cantilever 1 is of an aluminum part erected in an inverted T shape on a disk-shaped base 12, and the supporting bolt 10 of a rotor 8 is screwed to the upper end of the beam 11. Leads 71, 72 are passed through the vibrators 31, 32 and a sinusoidal wave voltage is applied to switch the frequency.

Piezoelectric motor using bent supersonic vibrator

Abstract: PURPOSE:To reduce the size and weight of a motor rotated by transmitting the supersonic vibration of a supersonic vibrator through a vibration piece to a rotor by using a piezoelectric drive bent supersonic vibrator as the supersonic vibrator. CONSTITUTION:In a motor in which a supersonic vibrator and a rotor 11 are opposed and a vibration piece (toothed plate) 111 secured to either one is interposed therebetween to rotate the rotor 11, a piezoelectric drive bent supersonic vibrator 8 is used as the vibrator. The vibrator 8 is formed by matching a crown-shaped ring 2 to a bent vibration plate 1 and further superposing piezoelectric ceramic vibrators 3, 4 to generate a supersonic vibration by applying a high frequency voltage to leads 6, 7. Thus, the length of the vibrator can be largely shortened to reduce the entire size.

Principle op piezoelectric damping of vibration: an experimental investigation

Abstract: Since the vibration behaviours of a piezoelectric vibration system change with an electrical load, the Vibration of such a system will be damped, when the electrical load includes a resistance component Based on this effect, a principle of piezoelectric damping of vibration is developed In this paper, piezoelectric damping configurations for both thickness and longitudinal vibrations are experimentally studied The results show that the piezoelectric material may become a new type of material for damping and the piezoelectric vibrator can be used as a new type of damper The piezoelectric damping adjustment is convenient and can be carried out continuously and instantaneously

Piezoelectric motor using cantilever beam supersonic elliptical vibrator

Abstract: PURPOSE:To obtain a large moving torque with light weight and compactness by press-bonding a moving element to the free end of a cantilever and applying a moving torque of the direction along the bending direction of the cantilever beam in the press-bonding surface of the moving element. CONSTITUTION:A cantilever beam 1 is of part of aluminum in the shape erected from the beam 12 in an inverted T shape on a circular base 12. Piezoelectric thickness vibrators 31, 32 for exciting the beam is formed of thickness vibrators made of doughnut-shaped Pb(Zr-Ti)O2 ceramic, and when a sinusoidal voltage is applied to the vibrators 31, 32 through leads 71, 72 connected with terminal boards 42, 43, the thickness vibrations of the vibrators 31, 32 produce deflecting vibration of the base 12, thereby causing the vibration of the end of the beam 12 to draw an elliptical motion.

Piezoelectric linear motor

Abstract: PURPOSE:To enhance energy efficiency with a simple structure by driving a piezoelectric actuator with polyphase AC, and transmitting the displacements of the actuators magnetically to a movable element. CONSTITUTION:A piezoelectric motor has a movable elements 1, 6 bimorph type actuators 2 disposed oppositely to the element 1, and a stator frame 3. The actuators 2 vibrate when 3-phase power sources V1-V3 are applied, and the poles 6 at the end vibrate in response to the phase of the applied power by the application of 3-phase power source V1-V3. The vibration is transmitted magnetically to the element 1, and the element 1 linearly moves. The element 1 has a plurality of poles 5 disposed at the prescribed interval along the moving direction, and the actuators 2 have poles 6 opposed to the element 1.

Rotary type piezoelectric motor

Abstract: PURPOSE:To enhance the durability of a piezoelectric motor by providing members having grooves at the prescribed interval and a plurality of piezoelectric vibrators having different phase relation in pressure contact with the members. CONSTITUTION:A rotary type piezoelectric motor has a rotor 7 and a stator 10, and a plurality of grooves 8 are formed on the rotor 7 substantially at the constant interval. The grooves 8 are disposed in the rows 7A, 7B of perpendicular direction to the moving direction of the rotor 7 and displaced at the period by 1/2. Piezoelectric vibrators 3A (3B) of the stator 10 is disposed to contact on the groove rows 7A, 7B. Thus, even if the end of the vibrator 3A (3B) is worn to vary the pressures of both owing to the continuous contact of the vibrator 3A (3B) with the rotor 7, the drive amount becomes constant because of the constant interval of the rows 7A, 7B, thereby reducing the influence due to the aging change.

Driving gear in vacuum vessel

Abstract: PURPOSE:To eliminate the generation of a gas, etc., damaging the vacuum atmosphere by using as a driving source a piezoelectric motor utilizing the rotation moment generated in a rotor pressed on the end surface of an ultrasonic vibrator generating ultrasonic vibration. CONSTITUTION:A rewinding roll 3 and a winding roll 4 both using a piezoelectric motor 2 as a power source are placed on both sides of a vaporization source 5 in a vacuum vessel 1 of a vacuum vapor deposition device. A base film 6 can be continuously vapor-deposited while being moved along a guide roller 7. The film can be vapor-deposited, when needed, while being heated by a heater 8. The driving gear in the vacuum vessel never generates a gas causing the damage of the vacuum atmosphere that must be controlled to the utmost. Consequently, the gear can be operated safely for a long time in the vacuum vessel.

Power supply system using supersonic piezoelectric motor

Abstract: PURPOSE:To accurately control the displacement of a piezoelectric motor by switching element pair operated in reverse phase to each other by the characteristic frequency of the motor to drive the motor. CONSTITUTION:The sinusoidal voltage of the characteristic frequency of a piezoelectric motor 5 is applied between lead 6 and 7 connected with a piezoelectric vibrator of the motor 5, the motor 5 operates. Switching elements 1, 2, 3 are added as two pairs to the leads 6, 7 to connect the elements 1, 3 with a DC power source, and to connect the elements 2, 4 through a resistor 8 with the ground side of a power source. The elements 1-4 are switched by the characteristic frequency of the motor 5 to drive the motor 5.