JPH08237971A - Micro motor - Google Patents

Abstract

PURPOSE: To obtain a high driving force by attaching a ceramic spacer to a short edge of a piezoelectric plate and providing an elastic force source for pressing the spacer to an object surface to a part of the plate. CONSTITUTION: Electrodes 14, 16, 18, 20 are placed on a piezoelectric ceramic (SK) 10 surface. The opposite surface of the SK 10 is entirely covered and grounded. The electrodes (14 and 20, 16 and 18), arranged in the diagonal direction, are connected with wires 22, 24. A ceramic spacer 26 is mounted to the center of a short side 28 of SK10. The resonance mode is used, depending on Dx, Dy sizes of SK10. SK10 is restricted in its movement by supporting bodies 32, 34 and supporting bodies with springs 36, 38. The supporting bodies 32 to 38 are placed in contact with the SK10 along the longer sides 40, 42 at the position 0. These supporting bodies are designed to be slidable in a y-direction. The supporting body 44 with spring is pressed to the center of short side 43, giving a pressure between ceramic 26 and main body 30. Thereby, the movement of the ceramic 26 is transferred to the main body 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micromotor, and more particularly to a piezoelectric motor.

[0002]

BACKGROUND OF THE INVENTION The use of resonant piezoceramics to provide linear and rotary motion is known. A great advantage of such a system is the ability to achieve very good movements without the use of moving mechanical parts. Generally, such systems are limited to motion accuracy of 1 micrometer in open loop operation and 50 nanometers in closed loop operation. When the weight of the plate to be moved is 0.5 kg, the speed is limited to 5-10 mm / sec. Under such circumstances, the force exerted on the plate in the direction of movement is limited to about 5N. Better solutions for such motors, i.e. achieving faster speeds and greater driving forces, are beneficial in many situations. This improved solution would be particularly beneficial if the ability to move at relatively high speeds is retained.

[0003]

SUMMARY OF THE INVENTION SU693493 is
Disclosed is a piezoelectric motor composed of a flat rectangular piezoelectric plate having one electrode covering the entire one large surface (back surface) of the plate and four electrodes covering the front quadrant. . The electrodes on the back surface are grounded and the electrodes on the diagonal are electrically connected. Two ceramic pads are attached to one of the two longitudinal edges of the plate, and these pads are pressed against the driven object by a spring mechanism that presses the other longitudinal edge.

Longitudinal and longitudinal movements are made so that when an AC voltage is applied to one pair of electrodes connected, the object moves to one side and when a voltage is applied to the other pair, the object moves to the other side. The latitudinal direction has adjacent resonant frequencies (for different mode commands).

It is an object of the present invention to provide a micromotor having higher speed, higher driving force and smaller minimum step size than conventional micromotors.

[0006]

The first feature of the present invention is to:
It consists of a thin rectangular piezoceramic having at least one electrode on one large surface and a plurality of electrodes on the other large surface. Preferably, a single spacer of hard material is mounted centrally on the short edge of the piezoceramic,
Pressed against an object. When at least some of the electrodes are energized, movement of either the piezoceramic or the object occurs along the length of the edge of the piezoceramic, as described below.

In a first embodiment of the features of the invention, the dimensions of the large rectangular surface are close to x and y (the dimensions of the large rectangular rectangular surface of the piezoelectric ceramic), although the piezoelectric ceramic is in different modes. It is preferably chosen to have resonances arranged in close proximity. Preferably the resonances have overlapping response curves.

Excitation of the piezoceramic is accomplished by applying an AC voltage at a frequency where both modes are excited to a selected one of a plurality of electrodes. In this embodiment, the resonant excitation is applied for at least some minimum periods when small displacements are required and for longer periods when larger displacements are required.

In a second embodiment of a feature of the invention, the excitation is a non-resonant asymmetric pulsed voltage on some of the electrodes. The inventor has found that very small movements are achieved when such a pulse is used, for example a rectangular pulse having a high time which is relatively higher than the low time. Such excitation is particularly useful when it is desired that no residual voltage remains on the electrode after exercise.

In a third embodiment of the inventive feature, there is switched between resonant AC excitation for relatively large steps and preferably rectangular pulse excitation when small steps are required.

Many electrode configurations are possible with the present invention. In one embodiment, the plurality of electrodes comprises two rectangular electrodes, each electrode covering one half of a rectangular surface of the piezoelectric ceramic and lying along the length of the large rectangular surface of the ceramic.

The second preferred electrode geometry provides four electrodes that cover the four quadrants of the large surface of the piezoceramic. One, two, or three of these electrodes are excited if different excitation modes (AC and pulse) and excitation shapes result in a larger or smaller minimum step size for the motion produced by the motor.

Another feature of the present invention involves the use of a plurality of laminated piezoceramics having the same resonant frequency, but it is preferably formed of different piezoelectric materials,
One of them is substantially softer than the other. Ceramics with different hardness are driven out of phase signal at the same frequency. In such systems, harder materials provide higher driving force during the portion of the cycle that drives the object, and softer materials provide longer contact times but less force. This combination allows a high start drive to overcome inertia and static friction forces, with smooth movement during movement.

The preferred embodiment of the present invention involves the use of a mode suppressor which increases the efficiency of the micromotor by suppressing resonant modes other than the desired mode.

According to yet another feature of the invention, one end of the arm is attached to the short edge of the piezoelectric ceramic opposite the spacer bearing edge. A spacer biased against the object is attached to the second end of the arm. In operation, the two spacers are excited in a similar manner and move away from the phase motion at the driven object, increasing the output of the micromotor and utilizing the motion and force across the piezoceramic A smooth movement of the object being biased.

Another feature of the invention involves the use of elastic elements to apply elastic forces to the longitudinal edges of the piezoelectric plate at points having a motion of approximately zero perpendicular to the longitudinal edges. Such elements are used to impart symmetrical motion to the object in both directions parallel to the short edge of the piezoelectric plate.

According to still another aspect of the present invention, the piezoelectric micromotor according to the present invention is used for moving an optical or magnetic read / write head of a disk drive.

Accordingly, in a preferred embodiment of the invention, the micromotor for moving the object comprises longitudinal and lateral edges, first and second faces, electrodes mounted on the first and second faces, a first edge. At least one rectangular piezoelectric plate preferably having ceramic spacers attached to its short edge, preferably in the center thereof, and pressed against the object, and a force, preferably at its center, on the second edge opposite the first edge. And an elastic force source that presses the ceramic spacer against the object and an electric power source that excites at least some of the electrodes.

In a preferred embodiment of the invention, the voltage source energizes at least some of the electrodes with a symmetrical, unipolar pulsed excitation voltage.

Preferably, the voltage source operates to selectively apply a number of electrodes, either with symmetrical, unipolar pulsed or AC excitation.

In a preferred embodiment of the invention, the electrodes comprise a plurality of electrodes, preferably on each quadrant of the first side of the piezoelectric plate, and at least one electrode on the second side. .

In a preferred embodiment of the invention, the electrodes in the quadrant along one longitudinal edge of the first side of the plate are applied with a unipolar symmetrical pulse voltage having a first polarity, The electrodes in the quadrant along the other longitudinal edge of face 1 are applied with a unipolar symmetrical pulse voltage of opposite polarity.

Alternatively, each quadrant electrode adjacent to the ceramic spacer may be applied with a unipolar symmetrical pulse voltage of opposite polarity, or each quadrant electrode remote from the ceramic spacer. A unipolar symmetrical pulse voltage with opposite polarity is applied.

In a preferred embodiment of the present invention, the electrodes of the first set of quadrants located on the diagonal line are applied with a unipolar symmetrical pulse voltage having a predetermined polarity, preferably on the diagonal line. A unipolar symmetrical pulse voltage having a polarity opposite to the predetermined polarity is applied to the second set of electrodes in the quadrant located.

In a preferred embodiment of the invention, the micromotor comprises a plurality of said piezoelectric plates, the ceramic spacers of each plate being elastically pressed against the object. Preferably, at least one of the plurality of plates is formed of a relatively stiffer piezoelectric material and at least one of the plurality of plates is formed of a relatively softer piezoelectric material. In a further preferred embodiment of the invention, the voltage source applies a voltage to at least one of the plurality of plates out of phase with each other.

Further, in a preferred embodiment of the present invention, there are electrodes attached to the long and short edges, the first and second faces, the first and second faces, and at least some of the electrodes. At least one rectangular piezoelectric plate which is symmetrical with respect to and applied with a unipolar pulse excitation voltage, and an elastic force source which elastically biases one edge or an extension of one or more edges against an object And a micromotor for moving an object is provided.

Further, in a preferred embodiment of the present invention, at least one rectangular piezoelectric plate having longitudinal and lateral edges, electrodes attached to the first and second sides, the first and second sides, and one A symmetric and unipolar pulsed or AC excitation voltage is selected for at least some of the electrodes and an elastic force source for elastically urging the edge, or one or more edge extensions, against the object. There is provided a micromotor for moving an object consisting of a voltage source for applying a voltage.

Furthermore, a preferred embodiment of the present invention has electrodes attached to the long and short edges, the first and second faces, the first and second faces, at least some of which are excited. And a plurality of rectangular piezoelectric plates and an elastic force source that elastically biases one edge or one or more edge extensions of the plurality of plates toward the object. A motor is provided.

Further, in a preferred embodiment of the present invention, there are electrodes attached to the long and short edges, the first and second faces, the first and second faces, at least one of the electrodes being at a voltage. At least one of the other electrodes is excited to cause a force toward only one edge of the plate and at least one of the other electrodes is excited with a voltage to cause movement of at least a portion of the edge having an element along said edge; A micromotor is provided which moves an object consisting of a rectangular piezoelectric plate.

Further, in a preferred embodiment of the present invention, at least one rectangular piezoelectric plate having longitudinal and latitudinal edges, first and second sides, electrodes attached to the first and second sides, and at least some A power supply for applying the voltage of the other electrode to establish a desired resonance mode of the piezoelectric plate,
A micromotor for moving an object is provided which includes a mode suppressing unit that suppresses a resonance mode other than a desired resonance mode.

In a preferred embodiment of the invention said mode suppressing means comprises at least one suppressing means adapted to suppress dimensional changes caused by resonance modes other than the desired resonance mode.

Further, in the preferred embodiment of the present invention, 2
At least one rectangular piezoelectric plate having one long edge and two short edges, first and second faces, and a first ceramic spacer attached to the center of the first short edge of the piezoelectric plate and pressed against an object; An arm having a second spacer attached to one end and having the other end attached to a second latitudinal edge of the piezoelectric plate, the first and second spacers being biased against the object. A micromotor for moving an object is provided having adjacent parallel surfaces adapted.

Further, in a preferred embodiment of the present invention, there are electrodes attached to the long and short edges, the first and second faces, the first and second faces, at least some of which are excited. And a plurality of rectangular piezoelectric plates having holes arranged at regular intervals along a central longitudinal axis, and at least one lever having one end rotatably mounted in the holes, and a micromotor for moving an object. It is provided.

Preferably, the other end of the lever is rotatably mounted on a fixed plate or, alternatively, a plate constrained to move only in the direction of the axis.

In all of the above embodiments, the ceramic spacer is preferably mounted on one of the short edges of the piezoelectric plate, preferably in the center of the short edges. This creates an optimum drive movement at the short edge of the ceramic plate so that the available space perpendicular to the engagement surface is such that the long edge of the seat is substantially perpendicular to the engagement surface. In systems where the available surface perpendicular to the engagement surface is limited, an alternative ceramic micromotor is provided according to a preferred embodiment of the present invention. Here, the movement of the latitudinal edge of the piezoceramic plate moves the object juxtaposed with the longitudinal edge of the plate using spacers attached to the longitudinal edge of the plate near the corners of the longitudinal edge and the short edge. Used for.

According to this feature of the invention, the spacers follow a resonant movement at their short edges, but the engagement surfaces are driven parallel to the longitudinal axis of the ceramic plate. In order to avoid left-right symmetry, it is preferable to use two juxtaposed piezoceramic plates, with adjacent corners being supported by spacers.

Further, in a preferred embodiment of the present invention, first and second rectangular piezoelectric plates having first and second longitudinal edges, first and second lateral edges, front and back surfaces, and a first plate of the first plate. The first latitudinal edge is juxtaposed substantially parallel to the first latitudinal edge of the second plate, each plate having electrodes attached to the front and back surfaces, and each plate having a first
A ceramic spacer attached to the first longitudinal edge at one end near the short edge and engaging the surface of the object,
Piezoelectric micromotors are provided that provide motion to an object consisting of an elastic force source applied to a portion of each plate to press the ceramic spacer against the surface of the object.

In a preferred embodiment of the invention, the elastic force source is applied to at least a part of the second longitudinal edge. Additionally or alternatively, the elastic force source is applied to a point on the piezoelectric plate and the motion amplitude perpendicular to the plane is substantially zero.

Further, in a preferred embodiment of the present invention, first and second generally rectangular piezoelectric plates spaced apart from each other, each plate having two longitudinal edges and two lateral edges, a front surface and a back surface. The faces of adjacent plates are parallel and face each other, the longitudinal edges of the adjacent plates are parallel, and at least one fixed support engaging the first longitudinal edge of the first plate; At least one elastic support engaging the second longitudinal edge, at least one elastic support engaging the first longitudinal edge of the second plate, and at least one fixation engaging the second longitudinal edge of the second plate A piezoelectric micro-module comprising a support, wherein the first longitudinal edge of the first plate is adjacent to the first longitudinal edge of the second plate and imparts motion to the object. Data is provided.

Preferably, each support engages a respective longitudinal edge and is slidable in a direction substantially parallel to the longitudinal edge at a point where there is substantially zero movement in a direction perpendicular to the longitudinal edge.

Further, in a preferred embodiment of the present invention, the longitudinal and latitudinal edges, the first and second surfaces, the electrodes attached to the first and second surfaces, and the motion of substantially zero in the direction perpendicular to the longitudinal edges. At least one rectangular piezoelectric plate having elastic elements for applying elastic forces to each of the longitudinal edges at two points, and at least some of the electrodes in two modes, namely the parallel first direction of the short edges. A means for moving an object, which comprises: a first mode for applying a short-circuit movement to a person and a power supply for selectively exciting in a second mode for providing a second direction opposite to the first direction; A motor is provided.

In another preferred embodiment of the invention, the micromotor further comprises a structural assembly adapted to provide symmetrical movement and force in the first and second directions. Preferably, the structural assembly comprises elastic elements.

In a preferred embodiment of the invention said voltage source applies an AC excitation voltage to at least some of said electrodes.

Furthermore, in a preferred embodiment, the electrodes consist of a plurality of electrodes on the front surface of each piezoelectric plate and at least one electrode on the back surface of each piezoelectric plate. Preferably, the plurality of electrodes comprises electrodes in each quadrant of the front surface and the voltage source applies an AC excitation voltage to at least some electrodes on the front surface.

In the preferred embodiment of the present invention, the excitation voltage of the same polarity is applied to the electrodes in the quadrants located on the diagonal of each plate.

Further, in a preferred embodiment, the electrodes of the quadrant between the first long edge and the first short edge of the first piezoelectric plate are applied with the excitation voltage of the first polarity, and the electrodes of the second piezoelectric plate are applied. A voltage of a second polarity opposite to the first polarity is applied to the electrode in the quadrant between the first long edge and the first short edge.

In one preferred embodiment of the invention, the power source comprises at least some electrodes an AC excitation voltage pulse with a DC voltage having an absolute value greater than the amplitude of the AC excitation voltage separated at regular intervals. Apply pulse excitation voltage. Preferably, the pulse rate of the pulsed excitation voltage corresponds approximately to the self-resonant frequency of the object.

In a further preferred embodiment of the invention said first and second rectangular piezoelectric plates have at least one additional electrode connected to at least one longitudinal edge and the voltage source has at least some additional electrodes. Is applied.
Preferably, the at least one additional electrode comprises an electrode having a first long edge proximate the first short edge. More preferably, the at least one additional electrode comprises an electrode at a second long edge near the second short edge.

Preferably, the voltage source applies an excitation voltage to the additional electrode, thereby increasing the movement of the ceramic spacer in a direction substantially perpendicular to the plane. Preferably, the voltage source applies to each additional electrode an excitation voltage of the same polarity as the electrode in the front quadrant adjacent to the additional electrode.

In a preferred embodiment of the invention, the first and second piezoelectric plates are elastically supported at points on the plate where the motion amplitude perpendicular to the plane is approximately zero.

In a preferred embodiment of the invention, the elastic force source is adjustable.

In a preferred embodiment of the present invention, the micromotor comprises the plurality of first piezoelectric plates and the plurality of second piezoelectric plates, and the ceramic spacers of each plate elastically press the object. .

In a preferred embodiment of the invention, the micromotor further engages the surface of the object opposite the surface engaging the spacer to provide a reaction force to the force applied by the spacer to the object. A reverse support device is further included. Preferably, the counter-support device comprises a piezoceramic bearing having electrodes mounted on at least one flat surface, and the voltage source applies a voltage to at least some piezoceramic bearings.

Further, in a preferred embodiment of the present invention, the first and second ends which are rotatable around an axis and are spaced from the axis on both sides by a constant distance, a read / write head attached to the first end, and a second end. A disk drive is provided comprising an arm having a rigid body at an end and at least one piezoelectric plate micromotor elastically biased against the rigid element.

In the preferred embodiment of the invention, the piezoelectric plate is stationary. In an alternative preferred embodiment of the invention said piezoelectric plate is movable with respect to said axis.

Further, in a preferred embodiment of the present invention, the arm comprises an arm pivotable about an axis, and the arm is attached to the first and second ends, which are spaced apart from the axis on both sides by a constant distance. A disk drive is provided having a read / write head, a piezoelectric plate attached to the second end and movable with the arm.

In a preferred embodiment of the invention, the shaft extends through the piezoelectric plate.

In a preferred embodiment of the invention, the micromotor further comprises a rigid element biased against the piezoelectric plate.

Furthermore, in a preferred embodiment of the present invention, a first rectangular piezoelectric plate pivotable about an axis and having two long edges and two short edges and two long edges and two short edges. A second rectangular piezoelectric plate having a ceramic spacer attached to the edge, the spacer being biased against the edge of the first piezoelectric plate, a micromotor for moving an object is provided.

Preferably, the spacer attached to the second piezoelectric plate is biased against the longitudinal edge of the first piezoelectric plate.

In some preferred embodiments of the present invention, the micromotor further comprises a stiffness located between the spacer of the second piezoelectric plate and the longitudinal edge of the first piezoelectric plate on which the spacer is biased. It consists of bow elements.

[0062]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is made to FIG. 1 which shows one large surface of a relatively thin rectangular piezoceramic used in a motor according to a preferred embodiment of the present invention. On the surface of this piezoelectric ceramic (hereinafter referred to as “first surface”), four electrodes 14, 1
6, 18 and 20 have been plated or otherwise glued to form a checker pattern consisting of rectangles each substantially covering one quarter of the first surface. There is. The opposite surface of the piezoceramic (hereinafter referred to as the "second surface") is preferably substantially entirely covered by one electrode (not shown). Diagonally arranged electrodes (14 and 20; 16 and 1
8) is preferably the junction of the four electrodes (juncti)
is electrically connected by wires 22 and 24 arranged in the vicinity of (on). The electrode on the second surface is preferably grounded. Alternatively, the electrodes may be connected by printed circuit technology similar to the technology used to form it.

A relatively stiff ceramic spacer 26
For example, with a bonding agent, it is attached to the short side 28 of the piezoelectric ceramic 10, preferably at the center of the side.

Piezoelectric ceramic 10 has a number of resonance modes. In particular, piezoelectric ceramic 1
The dimension of 0 is such that the resonance modes in the Dx and Dy directions are close (closely spaced), and the excitation curve (excitation curve)
s) are chosen so that they overlap. In particular, the preferred resonance according to the present invention is, as shown in FIGS. 2 and 4, 1/2 mode resonance in the Dy direction and Dx
In terms of direction, it is 11/2 mode resonance. However, other resonant modes can be used depending on the dimensions of the ceramic 10.

When the piezoceramic 10 is excited at a frequency within the band shown as ω0 in FIG.
Both x and Dy resonant modes are excited. FIG.
It shows an example (one configuration) of exciting two resonance modes by applying a voltage to a predetermined electrode.
In this example, voltage is applied to electrodes 16 and 18 and electrodes 14 and 20 remain floating (or less preferably grounded), but the amplitude of that mode is shown in FIG. . The excitation in this example makes Dx negative when Dy is positive, so that if the movement of the piezoelectric ceramic 10 is blocked, the body 30 pressed against the piezoelectric ceramic 10 will move to the left. Become.
The surface of the body 30 is depicted as curved like the surface of a cylinder to be rotated, but the surface may be flat if linear movement is desired.

A voltage is applied to the electrodes 14 and 20 and the electrode 1
For the example of excitation shown in FIG. 5, where 6 and 18 remain floating (or less preferably grounded), the Dy modes are identical, but the Dx modes are out of phase. Yes, causing a movement to the right.

In the preferred embodiment of the present invention, the piezoceramic 10 comprises a fixed pair of supports 32 and 34 and 2.
Spring loaded supports 36
And 38 prevent movement. Support 32
˜38 are the piezoelectric ceramic 10 and a pair of long sides 40 and 42 of the ceramic at the position where the movement in the x direction is 0
Touches along. These supports are designed to slide in the y direction.

The mounting of the spring in this way reduces the effect of wear and protects the piezoelectric ceramic to a certain degree.
otection).

The spring-loaded support 44 is preferably pressed against the center of the second short side 43 of the piezoelectric ceramic 10 opposite the short side 28. The support 44 is a ceramic 26
And a pressure is applied between the body 30 and the body 30, whereby the movement of the ceramic 26 is transmitted to the body 30. It should be noted that the spring loaded support 44 has a response time that is substantially longer than one period of the frequency at which the piezoceramic 10 is excited. Thus, when the ceramic 26 is moving against the direction of motion imparted to the body 30, the surface of the ceramic 26 that is being pressed against the body 30 actually leaves the body for a portion of its cycle. .

In the preferred embodiment of the invention, the spring-loaded supports 36, 38 and 44 are solid, solid rubber cylinders (springs), preferably having a Shore A hardness (a) of about 60. It has a Shore A hardness of about 60) and is preferably made of silicone rubber. In fact, such a "spring" is an O-ring (for example a hoodie).
It can be manufactured by cutting a part of Hanifin (marketed by Parker-Hannifin) into a desired size. Preferably, the resonant mode of the spring should be far away from the resonant mode of the piezoceramic used. In a preferred embodiment of the invention, a spherical or hemispherical rigid element is arranged between the spring element and the ceramic.

In the preferred embodiment of the invention, the dimensions of the piezoceramic 10 are determined by Morgan MTR.
Using the PZT piezoelectric material manufactured by atroc Inc.), it measures 30 mm x 7.7 mm with a thickness between 2 mm and 5 mm. For this example, depending on the desired speed, the weight of the body 30 (and / or the pressure of the spring 44), and the power required, an alternating current of 30-500 volts to excite the piezoceramic 10 Can be used. Such devices operate at frequencies in the range of 20-100 kHz and have a minimum step size in the range of 10 nanometers (nm).
(a minimum step size) and has a maximum velocity of about 15-350 mm / sec (or more). These are just the nominal range, the materials used as piezoelectric ceramic 10,
It will vary depending on the dimensions, the resonance mode selected, and other factors.

In practice, larger size ceramics
It can be between 20 mm and 80 mm, smaller sizes can be between 3 mm and 20 mm. For example, a very long and thin device (eg 3mm x 80mm) would result in a very high speed motor.

By using the spacer 26 attached to the short side 28 of the piezoelectric ceramic 10 which is urged against the main body 30, the force generated from the micromotor of a given size is the same size without the spacer attached. Increase compared to other micromotors. If the spacer is not attached, the short side 28 engages the body 30 directly. This increase in force is a result of the energy of the resonant modes generated in the piezoceramic during excitation being concentrated in the spacer.

Preferably, the spacer 26 should not affect the resonant modes of the system. It is also desirable to achieve the maximum possible amplitude for movement in the x direction for a given energy output. These goals may be achieved by using extremely thin spacers. However, thinned spacers in terms of resonance frequency are often too thin and therefore impractical. A more practical solution according to the preferred embodiment of the present invention is a 2/2, 3 of resonant mode in the spacer.
The use of spacers with a length almost equal to / 2 or 4/2 wavelengths. The spacer 26 is made of 99% aluminum. Due to the difference in the material of the ceramic and this spacer, the half wavelength of the resonance mode of the spacer is almost three times shorter than the half wavelength of the ceramic of the same frequency (almost 1/3 the length). . In fact, about 4 ~
Ceramic spacers with a length of 5 mm have proven suitable.

In the embodiment described above in connection with FIGS. 1-6, the piezoelectric ceramic 10 in FIG.
It is excited by an AC voltage with a frequency close to the resonance of the piezoelectric ceramic. The method depicted in FIGS. 7 and 8 is excited by a pulsed unipolar voltage. In this pulsed excitation embodiment of the present invention, electrodes 14, 16, 18 and 20 are
It is not connected in a fixed manner as in the embodiment of FIG. 1 but in different ways depending on the minimum steps required, as will be explained below.

The operating principle of the pulsed method is illustrated in FIG. In this figure, the second part of the piezoelectric ceramic 10
Electrodes 14 and 18 are excited by a positive DC voltage and electrodes 16 and 20 are excited by a negative DC voltage with respect to the electrodes on the surface. Under this excitation, the left side 10 of the piezoceramic 10 becomes longer than the right side (illustrated very exaggerated in FIG. 7) and the ceramic 26 moves to the right. Of course, when no voltage is applied,
This ceramic returns to its original position.

However, an asymmetric voltage pulse, eg, FIG.
The inventor has found that when a voltage pulse, such as that shown in Figure 5, is applied to the electrodes, the body does not return to its starting position by the ceramic 26 while returning to zero. Preferably, the fall time of this pulse should be at least four times longer than the rise time. The total pulse time (a total
The pulse time is preferably 10 to 50 milliseconds, but the exact time depends on the mass moved by the piezoceramic and the force of the spring 44. In the experiment, excellent results were obtained with a rise time of 1 microsecond and a fall time of 15 milliseconds. The minimum step in this example is pulse voltage dependent and can vary from 2 to 6 nm for a peak voltage of 30 to 100 Volts, with larger masses resulting in increased inertia and thus a larger minimum step. Become. This mode is generally not used for large movements, but is useful for final stage placement of moving objects. If the polarity of excitation is reversed, or if the rise time is made longer and the fall time is made shorter, it will move in the opposite direction. The operation of the body in this mode is not well understood, but extremely small minimum steps can be achieved.

Alternatively to the above, only one electrode pair is electrified and the other electrode pair is grounded or left floating.

In an alternative embodiment in which the motor operates in pulses, the same voltage is applied to electrodes 14 and 16 and the opposite polarity voltage is applied to electrodes 18 and 20 (or grounded or floating). Left alone). Even with such voltage application (electrification), an extremely small movement is performed.

Another example of exciting the electrodes with such a pulsed voltage provides another minimum step value. For example, the electrode 14 is excited with a positive pulse and the electrode 16
Is excited with a negative pulse (while electrodes 18 and 20 are either grounded or left floating), a minimum step of about 2-5 nm is obtained. By exciting electrodes 18 and 20 with positive and negative pulses, respectively (while preferably leaving electrodes 14 and 16 floating), a minimum step of 5-8 nm is obtained. When a pulse of one polarity is applied to electrodes 14 and 18 and a pulse of the opposite polarity is applied to electrode 20 (electrode 16 is floating),
Minimum steps of similar value are obtained. As an alternative, the electrodes that were said to be floating above could be grounded, but this would result in reduced efficiency.

In a particularly useful differential mode, two electrodes 14 and 20 are positively pulsed while 2
The two electrodes 16 and 18 are grounded and floated,
Alternatively, a negative pulse is applied. In this mode, very small minimum movements can be achieved in the 0.1 to 2 nm range. Pulses of the same or different amplitude may be applied to the diagonal electrodes.

Excitation by pulsed voltage is preferably as shown in FIG.
The above-described SU69349, which has a shape as shown in FIG. 1, and in which each electrode can be separately excited.
It is also useful when applied to prior art geometries such as the No. 4 geometry.

In the preferred embodiment of the motor according to the present invention, the piezoceramic 10 first produces a high speed motion in the vicinity of the target position, as described with reference to FIGS. It is excited by an alternating voltage and then by a pulsed voltage as described above with reference to FIGS. 7 and 8. A preferred embodiment of a motor system including an arrangement for such excitation is shown in block diagram form in FIG.

As shown in FIG. 9, the control system 50 applies energy to, for example, a pair of voltage regulated regulator power supplies 54 and 56, respectively, and four switch / modulator circuits 58, 60,62
And 64, which is a microcontroller 52 for controlling. Each of the switch / modulator circuits is connected to one of the electrodes 14, 16, 18 or 20. The electrodes on the second surface are preferably grounded via tuning inductor 66.

Microcontroller 52 is preferably
Microcontroller 52 for indicating the position of body 30
A position signal is received from a position indicator (or position detector) 68 that provides feedback to. The microcontroller 52 also preferably receives the position (or movement) and optionally also the user interface 70.
Receive speed command from.

During operation, the microcontroller 5
2 receives the position command from the user interface 70 and compares it with the actual position indicated by the position indicator 68. If the command is a move command, its position is stored (recorded) for later comparison only.

The microcontroller 52 stores the amount of movement required and, based on predetermined optimization criteria, whether AC or pulse mode is appropriate, and the direction in which most bodies move. Determines which direction it is. A plurality of suitable signals may be either an alternating voltage or a pulsed voltage (or no voltage or ground voltage) for each electrode so that the piezoceramic 10 operates with the appropriate excitation geometry as described above. ) Is generated and output to the switch / modulator circuit as applied. The remaining distance to be moved is reduced below an appropriate level and the microcontroller 52
And switch to the high resolution slow mode utilizing appropriate pulse excitation, as described above with reference to FIG. Some variations in the excitation modality may be made as appropriate when high positional accuracy is desired. When the body 30 reaches the target position, the excitation of the plurality of electrodes is terminated.

The inductor 66 is used to tune the electrical resonance of the piezoelectric ceramic 10 and the wiring connected thereto to the same frequency as the mechanical resonance of the piezoelectric ceramic 10.
Is used. The electric circuit is the first of the piezoelectric ceramic 10.
And most of the capacitance formed by the plurality of electrodes on the second surface, so as to "set this capacitance out of tuning" and improve the efficiency of the system, for example inductor 66 It is appropriate to add such an inductor.

Although the motion control of the system has been described for a closed loop system, less accurate open loop operation is possible. For closed loop operation, we believe that the system can achieve better than about 0.5 nm accuracy. For open loop operation, the amount of motion can be detected fairly accurately and the position can be controlled within about 0.1% to 1% of the total amount of motion.

According to a preferred embodiment of the present invention, at least one constraining member is used to increase the performance of the micromotor by suppressing resonant modes other than the desired resonant mode.
FIG. 32 shows a configuration in which two restraint members are used.
3 shows a form similar to FIG. 32 which shows the ceramic 10 for the desired mode with the deviation from the actual size highlighted. The constraining members 300 and 302 that are tightly attached to the contour of the piezoelectric ceramic 10 and attached can be made of a thread or a wire, and can be adhered to the piezoelectric ceramic. The members 300.302 can also include plastic or metal moldings. Member 300.
302 is preferably located at a point where there is zero dimensional change in the X direction for the desired mode of operation, that is, approximately 1/6 and 5/6 of the length of ceramic 10.
Other modes have dimensional changes at one or both of their positions and are thereby suppressed. In such a configuration, the motion amplitude of the spacer 26
Can be increased by reaching 30% compared to the range of motion obtained with the same input power in a micromotor without restraints. Also, reference numeral 300 or reference numeral 3
Only one of the restraint members 02 is used.

In the preferred embodiment of the present invention, FIG.
In order to increase the output of the micromotor and smoothen the operation of the body pressed by the spacer, the fixed arm 310 causes the piezoelectric ceramic 10 to have a short edge with respect to the spacer bearing edge. Attached to. The arm 310 is preferably mounted substantially parallel to the surface of the piezoceramic 10 and the arm 31
One end of 0 is attached to the short-circuit end 43 of the ceramic 10 via the vertical member 314. The spacer 312 that is pressed and attached to the main body 30 is attached to the other end of the arm 310 near the end of the ceramic 10 to which the spacer 26 is attached.

There are many other preferred forms of the embodiment of FIG. In one such form, the spacers 312 are preferably ceramic and the vertical members 314 are
Are preferably made of aluminum. In this configuration, special care must be taken to avoid shorting the vertical member 314 to the electrodes on the first side of the piezoelectric ceramic 10. In another form, the vertical member 314 is ceramic. In the form described above, the vertical member 314
Can be attached along the entire short-circuit end 43, or can be attached only to the central part of the short-circuit end 43 by, for example, a ceramic spacer.

In the configuration as shown in FIG. 3 or 5, the piezoelectric ceramic 10 is excited by an AC voltage.
One of the forms described above with reference to FIG.
As shown in (3), the spacer 312 is out of phase with respect to the spacer 26 (180 ° phase difference). As a result, the force exerted on the body 30 is doubled and the movement of the body 30 is smoother than a micromotor without such an arm.

Further, other excitation of the element 10 (excitati
ons) and configurations can be used in connection with the device shown in FIGS. 32 to 35, as described herein. In a preferred embodiment of the motor according to the invention, a plurality of piezoceramics can be formed to increase the output of the motor and to reduce the variability that exists between different devices. One such configuration, shown in FIG. 10, is two piezoelectric ceramics 1 in a comb configuration.
With 0, 10 '. That is, the piezoelectric ceramics 10, 1
Two piezoceramics 10, 10 'are mounted in a comb shape in the direction of motion induced by 0'. Two piezoelectric ceramics are used in the control system 50 shown in FIG.
It can be driven by a common control system or a separate control system. The control system and electrical connections are not shown in FIG. 10 for clarity.

As shown in FIG. 10, the piezoelectric ceramic 1
The spacer unit 74 located in the middle of 0, 10 'is
The piezoelectric ceramic is supported and separated. The four spring-loaded side supports 76 and the two spring-loaded end supports 78 support the piezoceramic pair in the same manner as described above in connection with the embodiment of FIG. In practice, the piezoceramic 10,10 'is preferably a spacer unit 74 and a spring biased support 76,7.
The extension of 8 constrains movement perpendicular to the surface of the piezoceramic. Such a form is shown in FIG.

FIG. 11 shows six piezoelectric ceramics formed in a two unit and three unit comb / parallel configuration. Due to the constraints shown, the spring biasing support and the pressure spacer unit 7 for the piezoelectric ceramics
No. 4 mechanism is not shown, but its preferred support mechanism is that shown in FIG. There is also another form, 2x
A 4 comb / parallel configuration is also useful.

In the preferred embodiment of the motor according to the invention, the piezoceramics used in the embodiments shown in FIGS. 10 and 11 are not all the same. In this embodiment of the invention, one or more piezoelectric ceramics are P
Made of a relatively hard material such as ZT-8 (manufactured by Morgan Matroc Inc.), one or more piezoelectric ceramics such as PZT-5H (manufactured by Morgan Matroc Inc.). Created with a soft material. The above two types of materials have the same x, y dimensions and the same resonance, and can be physically shaped so that the resonance frequency is obtained by adjusting the thickness of the individual piezoceramics. it can. It is also possible to use both materials with the same thickness. In such a configuration, the soft material broader Q above would assume that both hard and soft materials would be sufficiently excited at the same frequency.

When the soft piezoelectric ceramic is charged, the resonance width becomes large in both Dx and Dy, and the portion (time) during which the ceramic 26 contacts the main body becomes larger than that of the hard piezoelectric ceramic. However, due to this property, the amount of motive force exerted by the soft piezoelectric ceramic is low, and the unevenness of operation is also low.

In the preferred embodiment of the invention, where both types of piezoceramics are used as described in the preceding paragraph, the hard piezoceramics are capable of suppressing stiction and other inertial forces, and soft piezoceramics. Ceramics have the ability to provide smoother, more accurate motions on smooth start and stop than if only rigid piezoelectric ceramics were used.

In the preferred embodiment of the present invention, the two types of ceramics are out of phase with each other (180 ° out of phase). In this case, the two types of ceramic are essentially independent of each other (excitation cycle).
in different parts of the cycle) resulting in minimal friction due to the different behavior of the two types of piezoceramic.
In the preferred embodiment of the invention, phase reversal is achieved by using two ceramics with opposite polarization directions. It is also possible to apply voltages that are out of phase. The anti-phase operation of the ceramic also
It is also beneficial when two piezoelectric ceramics with the same properties are used.

XY Having All the Advantages of the Invention
Exercise is also possible. One form of producing an XY movement is shown in FIG. The integral X-shaped section 90 is formed of a piezoceramic material and has front and back electrodes formed on the large flat inner surface of the section. The inner surface, which is not shown (and for the surface shown completely or partially), is provided with a single electrode which is arranged over the entire surface. The single electrodes are grounded (or connected to the system power common return) and, according to a preferred embodiment of the invention, the electrodes shown are activated according to the mechanism described above. Constructing an XY table with such a device need only add a flat table that holds the ceramic and contacts the ceramic 26 as described above with reference to FIGS. Multiple X-shaped sections 9 of the same or different ceramics
0 is parallel-as described above with respect to FIGS.
It can be used in comb form.

FIG. 13 shows a second, reminiscently simple, but not compact form, in which the two piezoelectric ceramics as shown in FIGS.
It is affixed together so as to achieve an X movement at one end and a Y movement at the other end.

An XY table 100 using the configuration of FIG. 13 and constructed as a preferred embodiment of the present invention.
Are shown in simplified form in FIG. The table 100 includes a fixed base 102 and a top 10.
It is composed of two piezoelectric ceramics 10 in the configuration of FIG.
10, 112, 114 and 116, 118 and 12
0 is the support 32, 34, 36 and 38 of FIGS.
They are identical in shape and function. Support 106 ~
All 120 are fixed (not clearly marked)
However, it is not attached to the base 102. However, it is preferable to provide a slider that is allowed to slide between the fixed material and the base 102 in the X direction (indicated by an arrow 122), and the slider is attached to the fixed material.

A set of sliders 124, 126 and 1
28 is provided so as to allow the operation of the top 104 with respect to the fixed material in the Y direction indicated by the arrow 130. The sliders 124-128 are preferably attached to the fixed material.

In short, the fixed product has the upper and lower piezoelectric ceramics 10 and the support for the slider, and the slider is fixed in the X direction with respect to the base 102 and in the Y direction with respect to this fixed product. The top 104 is allowed to slide.

During use, the excitation of the lower piezoceramic causes it to move in the X direction. Since the top 104 is restricted by the fixed material to move in the X direction with respect to the fixed material, the top 104 moves in the X direction by the same amount as the fixed material. Therefore, excitation of the lower piezoceramic causes an X motion of the top 104. When the upper piezoelectric ceramic is excited, the top 104 moves in the Y direction with respect to the fixed material. Since the fixed matter is restricted so as to move in the Y direction with respect to the base, the top 104 moves with respect to the base 102. .

Selective excitation of the upper and lower piezoceramics causes an XY motion of the top 104 relative to the base 102, and the linear motion implementation shown above for the embodiment of FIGS. 1-11. It has all the advantages of the example. Excitation of only one of the piezoceramics results in motion in only one direction.

It is possible to use the principles outlined for X, Y, Z motions, X, Y, Θ motions, or directions of motion along multiple axes that are not at right angles, to move along each axis. Different ceramics may be provided.

Further, the two columns and the series arrangement of the piezoelectric ceramics made of different or identical parts are the same as those described above by referring to FIGS. 10 and 11, like the two columns arrangement for the linear motion device. Cause utilization.

The use of the piezoceramic according to the invention for achieving a rotary movement is illustrated in FIG.
A two-tandem configuration of piezoceramic 150, similar to that shown at 0, has been applied along cylinder 152 and to rotate cylinder 152. With such a configuration, the surface of the ceramic spacer 26 preferably has a concave shape along the surface of the cylinder 152. A single piezoceramic similar to that shown in FIGS.

When circular movement and three-dimensional positioning of a sphere are required, the configuration as shown in FIG. 15 is similar to the configuration 150 for rotating and positioning the sphere, three orthogonally arranged ceramics. It is used by modifying it by providing the composition. If only rotation (and 3
If no dimensional positioning is required), two orthogonal drives are sufficient. In this embodiment, the outer surface of the ceramic 26 is formed along the surface of the sphere.

When using the present invention, speed, accuracy,
It is possible to improve the combination of driving forces. By using only a single ceramic pad 26, more force can be used to push the ceramic against the body 30 over the prior art for cracking where excessive force is required. The use of two tandem ceramics results in an unexpected increase in driving force and speed. In general, both higher speeds and higher driving forces can be achieved simultaneously with the same volume of piezoelectric ceramic in the present invention.

In addition, according to the present invention, when the rectangular electrodes shown in the above-mentioned embodiments are used, the movement is not a perfect straight line, that is, because of the rotational characteristic of the movement of the ceramic 26, It can be seen that only a portion contacts the moving body 30. 14 ', 16',
If 18 'and 20' are the non-stiff electrodes of the linearized version shown in the previous figure, this can be improved, for example, by cutting the electrodes as shown in FIG. Although a sinusoidal variation is shown in FIG. 16, other electrode geometries can also be modified to linearize the device.

As a preferred embodiment of the present invention, an example is shown in FIG. 36. An arrangement including a plurality of piezoelectric ceramics is as follows.
Used to make the movement of the body 30 symmetrical in the opposite direction along the X axis. If this arrangement is used substantially, the same forces and amplitudes can be applied in the X and -X directions. The arrangement shown in FIG. 36 corresponds to X,
Two parallel piezoelectric ceramics 10,1 oriented in the same direction in the XY plane formed by the Y direction
Has 0 '

As shown in FIG. 36, the piezoelectric ceramic 1
0 and 10 'are a pair of fixed supports 32 and 34, respectively.
The movement is restricted by the pair of elastic supports 36 and 38. The supports 32-38 attract the ceramics 10, 10 'along the longitudinal corners 40, 42 and 40', 42 'of each ceramic in an attempt to provide substantially zero displacement along the X-axis. There is. Supports 32 to 38
Is preferably slidable along the Y axis.

The fixed supports 32 and 34 attract the piezoceramic 10 along the longitudinal corners 40,
On the other hand, since the piezoelectric ceramic 10 'is fixed, the supports 32, 34 attract the corners 42' in the longitudinal direction. The elastic supports 36, 38 attract the piezoceramic 10 along the longitudinal corners 42, while the piezoceramic 10 'causes the elastic supports 36.38 to move along the longitudinal corners 40'. I'm looking for a 10 '. With this arrangement, some differences between the X and -X motions caused by one piezoceramic are compensated for by the other piezoceramic of the same and opposite.

An alternative arrangement for providing symmetrical movement along the X axis is illustrated in FIG. 37 as a preferred embodiment of the present invention.

FIG. 37 shows a device having two identically constructed assemblies 320 and 340. Assembly 320 consists of two rigid bodies 322 and 324, which are connected by a hinge 326 and attached to a base (not shown) by hinges 328 and 329, respectively. Similarly, the assembly 340 is attached to the base by hinges 327, 341, 342, respectively.

The hinges 326 and 327 extend into the holes of the piezoelectric ceramic 10, in particular the ceramic surface. Hinge 3
Holes for 26 and 327 are provided along the short edge between the two electrodes, for example between electrodes 14 and 16 and between electrodes 18 and 20, respectively, at positions that do not move along the X axis. Preferably. In the preferred embodiment of the invention, the hinges 326 and 327 are 1/6 and 5 / of the ceramic 10.
They are separated by a length of 6 from each short edge 28.

Each element 322 preferably has two arms 330 and 331 on opposite sides of the ceramic 10 and each element 324 preferably has arms 334 and 335 on opposite sides of the ceramic 10. As a result, the ceramic 10 has the arm 33
0 and 331 and between the arm portions 334 and 335. The elastic elements 337 and 338 are the arms 330 and 3 of the element 322.
31, preferably disposed between arms 334 and 335 of element 324. Elastic element 33 of assembly 320
7 and 338 apply elastic force to the piezoelectric ceramic 10 at about 1/6 of the ceramic length.
Similar elements provide elastic forces at about 5/6 the length of the ceramic 10.

In one typical device, the piezoceramic 10 is composed of PZT-4 and has a length of 300 mm, a width of 7 mm and a thickness of 3 mm. The elastic elements 337 and 338 in this device are silicon cylinders with a length of 5 mm, a diameter of 2.5-3 mm and a Shore hardness of 60-70. The elastic element 44 has a length of 5 mm and a diameter of 2.5.
In mm, it is possible to exert a force of about 5 N (Newton) on the short edge 43 of the piezoceramic 10. 3 or 5
As shown in, when the piezoelectric ceramic is excited by AC 200-300V and this device is used, 0.1-0.3μ
A resolution of m and a speed of up to about 400 mm / sec are obtained.

In the preferred embodiment of the present invention, an electrode having the shape shown in FIG. 17 is used. For this embodiment, in addition to the electrodes 14, 16, 18, 20 an additional electrode 150 has been applied to the piezoceramic. Electrode 150
Is preferably extended to the same width as the ceramic 10 and is excited by a DC voltage or a harmonic voltage used on other electrodes. As a result of such excitation, the ceramic 10 is stretched, preloading the motor with respect to the moving object. By using harmonic excitation, this preload is synchronized to the other electrodes, increasing the contact time between the ceramic 26 and the moving object. In theory it is possible to omit the spring 44 from such a system, but in practice some elastic biasing force (which reacts more slowly than a piezoceramic) is used and is even needed. Similar effects can be obtained from the embodiment of FIGS.

Another mounting means applicable to both a single motor and a plurality of ceramic motors is shown in FIG.
In this mounting means, the hole is located at the center of the piezoelectric ceramic 10,
It is formed at positions 1/6 and 5/6 on the center line. These holes are 20 and 30 of the thickness of the ceramic 10.
It preferably has a diameter of%. Pin 152 is about ± 10
It is disposed in the hole with a gap of 0 μm, and at least one end is attached to one end of the levers 154, 156, 158. The pin is made of a material that has the same acoustic velocity as it propagates in the ceramic 10. The pins may be constructed of metal, ceramic or other suitable material.

Due to the resonant mode of the ceramic 10 used in the preferred embodiment of the present invention, the ceramic moves only in the longitudinal direction of the hole. In fact, the central hole hardly moves. When the other end of the lever is rotatably attached to the fixed body 160, the ceramic 10 is moved only along its major axis. This allows the springs 36 and 38 to be removed. In addition, the spring 44
Pushes one of the levers in the direction the object is moved,
It is replaced by a spring 44 'which biases the motor. Many such springs are used to bias other levers.

The same principle applies only to mounting two juxtaposed piezoelectric ceramic elements 10 and 10 ', as shown in FIG. In this arrangement, the piezoceramics 10 and 10 'are mounted on the five levers 162, 164, 166, 168, 170 used in the above described means. It should be noted that the lever 170 is preferably a single piece lever mounted in the center of both ceramics and affixed to the center of the plate 172. The other lever has one end rotatably mounted in one hole of the ceramic and the other end rotatably mounted in the plate 172. Each ceramic 10 and 10 'is separately biased at its lower end by a spring 44.

In another form, the ceramics 10 and 10 '.
Is not spring biased. However, the plate 172 can only move vertically.
It is biased by a spring (not shown) at its lower end to bias the ceramics 10 and 10 'against the moving object. Various width dimensions of the mounting means can be obtained by using this principle in these preferred embodiments.
Of course, technical improvements are possible.

The main advantage of mounting the piezoceramic on the pins described above is to significantly reduce the temperature of the ceramic, which is achieved by removing heat from the mounting location. The mounting position is also the hot part in the preferred mode of operation. In particular, the temperature at these locations can be reduced from 50-80 ° C to about 30 ° C by using this means.

When the heat transfer from the ceramic to the pin is good, the cooling effect of the pin is enhanced. To ensure such heat transfer, the pins should be fixed in a relatively heat-conductive, relatively soft material, for example an elastomer coating the inner wall of the hole. One suitable material is epoxy, which is used in insufficient amounts to cure. Such an elastic material is sufficient to cause the pin to rotate in small portions at the holes. In the preferred embodiment of the invention, the epoxy is approximately 40% filled with PZT powder (of a material similar to the piezoceramic itself). Such filling allows the acoustic velocity with the epoxy to be matched to the piezoceramic.

The movement of the device can be measured based on the amount of time that the ceramic 26 is in contact with the moving object. To facilitate such measurements, the surface of the ceramic facing the moving object is coated with metal,
The electrode is in contact with this coating. For this purpose, the coating extends on the sides of the ceramic 26. The moving object is made of metal (or has a metal coating), and the contact time can be measured as a short circuit time between the metal coating of the ceramic 26 and the moving object.

22, 23, and 24 show the case where a ceramic motor is applied to the movement of the stage, and it is used as an optical disk reader such as a CD reader. In such an apparatus, a hole 164 is formed in the stage 160, and the hole 164 is detected (and read) by an optical reader (not shown alone) mounted on the stage 160.

In FIG. 22, the stage 160 is mounted on two rails 162 and a ceramic motor 166.
This ceramic motor, preferably of one of the types described herein, is movably mounted at one edge of stage 160 to move the stage along a rail.

In FIGS. 23 and 24, one edge of the stage 160 is mounted on the rail, and the other edge is meshed with the worm 168 by the rack 170. The ceramic motor 172 is preferably one of the types described herein and drives a wheel 174 mounted at one end of the worm. 23 and 24 differ in the way the motor drives the wheels.

In all the embodiments described above, the spacer between the ceramic plate and the surface on which the micromotor is mounted is mounted on one of the short edges of the ceramic plate, preferably at the center of the short edge. The longitudinal direction of the plate is perpendicular to the mounting surface. This arrangement is preferred because the optical drive action is obtained with the short edges of the ceramic plate. However, in some applications, for example, when the motor is placed between the slide and its housing,
There is a limit to the usable space, which is orthogonal to the mounting surface, and is shorter than the longitudinal direction of the ceramic plate. To solve this problem, the present invention provides another ceramic micromotor. It is that the longitudinal direction of the ceramic plate is parallel to the mounting surface, but the optical movement produced by the short edges of the ceramic plate is available.

With respect to this aspect of the invention, the ceramic spacers are attached to one end of the long edge of the piezoelectric plate and in a plane parallel to the long edge. The spacers so mounted are arranged near the short edges of the ceramic plate, so that the spacers move at the short edges in relation to the resonant movement. As a result of the movement of the spacers,
The movement of the surface or the micromotor engaging the spacer is obtained. The movement depends on the two being constrained parallel to the longitudinal direction of the ceramic plate. However, disposing spacers at or near the ends of the long edges of the plate, rather than at the center, creates asymmetric movement of the spacers. The movement of the mounting surface or the micromotor in one direction is then different, eg less forceful or slower than a coordinated movement in the other direction.
In order to eliminate this asymmetry, it is preferable to use a pair of piezoelectric ceramic plates as will be described later.

FIG. 15 diagrammatically illustrates a pair of piezoelectric micromotors 200 mounted on surface 210.
Now refer to. In the unpaired embodiments described above, movement of either surface 210 or micromotor 200 is constrained, allowing other movements depending on the force applied. The micromotor 200 is preferably
Two piezoelectric ceramic plates 212 and 214 mounted in a housing 220 made of aluminum are provided. The housing 220 is preferably pressed against the surface 210. The outer short edges of plates 212 and 214, ie plate 2 illustrated in FIG.
The right edge of 12 and the left edge of the plate 214 are
It is preferably supported by a horizontal support member 222 formed of a relatively stiff material, such as a ceramic material. The inner short edges of the plates 212 and 214, ie the left edge of the plate 212 and the right edge of the plate 214, are preferably provided by a resilient connecting member 226, preferably formed of a rigid rubber or plastic material. Supported. Plates 212 and 214 are supported from the bottom by a bottom support member 224, which can be formed of the same material as member 226, or preferably a stiffer material.

According to a preferred embodiment of the present invention, a spacer 216, preferably made of ceramic, is attached to the upper surface of plate 212 at its left end and a similar spacer 28 is attached to the upper surface of plate 214 at its right end. Attached to. Spacers 212 and 214 are functionally mated and attached to surface 210 when micromotor 200 is pressed against surface 210. In the preferred embodiment of the present invention, the housing 220 comprises a protective frame 215, preferably formed or coated with a low friction material such as Teflon, which frame 215 comprises spacers 21.
Surface 2 fitted and attached by 6 and 218
It is at least partially separated from the area of 10 and prevents unwanted material such as debris from accumulating on the surface 210.

The four electrodes are plated to form a checkerboard pattern electrode having a plurality of rectangular shapes, or otherwise attached to the front surface of each of the piezoelectric ceramic plates 212 and 214. , Where each of the plurality of rectangles of the patterned electrode is shown in FIG.
Cover substantially 1/4 of the front surface, as described above with reference to electrodes 14, 16, 18 and 20 in. The back surface of each piezoceramic plate is substantially entirely covered with one electrode (not shown), as described above with reference to FIG. As in the embodiment of FIG. 1, two diagonally located electrodes are electrically connected by a plurality of wires 230 preferably located near the junction of the four electrodes. The plurality of electrodes on the back surface of each ceramic plate are preferably grounded. Alternatively, the plurality of electrodes can be connected by techniques similar to the printed printed wiring technology used to form the plurality of electrodes.

The plurality of electrodes on plates 212 and 214 are preferably driven by the excitation circuit illustrated in block diagram form in FIG. The excitation circuit comprises a controller, which is, for example, a microcontroller 244 that controls the application of energy to a regulated regulator power supply 242 and the switch / modulator circuit 240. The plurality of switches in the switch / modulator circuit 240 are coupled to the plate 2 via wires 234 and 236 or equivalents thereof such as an electrode pattern of the printed wiring.
Connected to each preselected group of electrodes on the front of 12 and 214. Ceramic plates 212 and 2
The plurality of electrodes on the back surface of 14 are preferably amplifiers 24
6 and ground via a tuning circuit comprising coil 248.

Apart from the special excitation modes described below, the plurality of electrodes on each ceramic plate 212 and 214 of the present invention provides a micromotor 200 having the desired characteristics according to a given application. They may be interconnected and excited according to any of the modes described above with reference to the unpaired embodiment. Similarly, the ceramic spacers 214 and 216 may be formed of a relatively soft or relatively stiff ceramic, as in the embodiments described above. However, plate 2
Excitation of the plurality of electrodes on 12 causes the surface 2 to
Spacers 216 and 21 in the same horizontal direction with respect to 10.
In order to obtain 8 movements, it needs to be reversed compared to the excitation of the electrodes on the plate 214.

Piezoelectric ceramic plates 212 and 214
Referring again to FIG. 26, which illustrates a plurality of preferred xy resonant modes in FIG. As illustrated in FIG. 26, the plurality of electrodes on plates 212 and 214 are preferably two groups of electrodes, electrode 25.
4 and electrode 256. The excitation voltage applied to electrode 254 generally has a polarity opposite to that applied to electrode 256, that is, a positive voltage is applied to electrode 254 when a negative voltage is applied to electrode 256. ,
Also, a voltage is applied opposite to them.

The spacer 216 is attached to the left end of the plate 212, while the spacer 218 is attached to the plate 2
26, the excitation method in FIG. 26 is such that the two spacers are in the same direction along the Y-axis,
That is, when moving in the vertical direction, the spacers 216 and 218 in the same direction along the X axis, that is, in the horizontal direction.
It should be recognized that it will bring about the movement of. Therefore, spacers 216 and 218 always move in the same direction relative to surface 210 as desired. According to this excitation method, a schematic graph of the X and Y resonant modes of the piezoceramics 212 and 214 is obtained by
It is shown diagrammatically on the underside of 14. As further illustrated in FIG. 26, the bottom support member 224 is preferably provided underneath a plurality of points on the plates 212 and 214, where movement along the Y-axis, or Δy, is substantially. Becomes zero. This improves the stability of the micromotor 200 and maximizes the amplitude obtained by the micromotor 200 along the y-axis.

Electrode 25 according to a preferred embodiment of the present invention
Microcontroller 24 provided in 4 and 256
Reference is now made to FIG. 27, which schematically illustrates a pulse-shaped excitation signal controlled by 4 (FIG. 25). The excitation signal of FIG. 27 consists of a plurality of pulses of drive excitation voltage separated by a predetermined DC voltage interval that actuates the spacers without contacting the surface 210. In FIG. 27, the voltage difference between the upper peak of the excitation voltage and the lower peak of the excitation voltage is indicated by “A” and the DC voltage between the pulses is indicated by “B”. There is. According to this embodiment of the invention, which is suitable for the unpaired micromotors described above, the pulse rate of the excitation signal is set substantially according to the self-resonant frequency of the body mounted by the micromotor. .

Typical resonance frequencies of the bodies driven by the micromotor, ie 300H
Frequencies in the order of z are generally much lower than the drive AC frequency used, and each pulse contains the actual number of periods of the AC drive. The DC voltage B applied to the electrodes 254 and 256 (see FIG. 25) between the pulses is typically a spacer 216 and 2
Depending on whether electrode 254 or 256 is driven such that 18 moves away from surface 210 between pulses, either below the peak on the low drive frequency side or on the high drive frequency side. Higher than peak. Therefore, the driven body autonomously moves between pulses. This interrelationship between the pulse rate of the excitation signal and the self-resonance of the matingly mounted body is destructive between the drive pulse and the response of the body driven in response. Prevent unnecessary interference.

Reference is now made to FIG. 28 which schematically illustrates an alternative electrode geometry on the ceramic plates 212 and 214. According to this embodiment of the invention, additional electrodes 260 are provided on the upper and lower edges of plates 212 and 214. Multiple electrodes 260
Are preferably excited by the same plurality of excitation voltages used to drive the plurality of electrodes 256 (FIG. 26). In this shape, the spacer 2 along the Y-axis
The amplitude of the movement of 16 and 218 depends on the spacers 216 and 2
It should be appreciated that the amplitude of movement of the plurality of spacers along the X-axis is greater, as illustrated schematically above 18; In contrast to the substantially circular movement of the spacers in FIG. 26, which is shown diagrammatically above the spacers, this movement of the slightly tilted, elliptical shapes of spacers 216 and 218 is such that Since the movement increases the time of contact between the spacers 216 and 218 and the surface 210, the micromotor 200 having a greater driving force and a better traction force (traction friction force) between the plurality of spacers and the surface 210 is provided. provide.

Piezoelectric ceramic plates 212 and 214
Reference is now made to FIG. 29, which illustrates an alternative mounting structure of FIG.
In addition to the horizontal support member 222 and the connecting member 226, the plates 212 and 214 are below and between the plates 212 and 214 and the housing 2
20 (FIG. 25) supported by a mounted base 266. The plurality of plates 212 and 214 are also supported by a plurality of holders 262, which are preferably resilient. One end of each holder 262 is preferably rotatably mounted on a mount 265 fixedly mounted to the housing 220, while the other end of each holder 262 is plate 212 or 2
14 is rotatably mounted on each pin 264 extending through each hole in 14. Four pins 264 are preferably mounted on plates 212 and 214, with two pins on each plate mounted at multiple points where the amplitude along the Y axis is substantially zero as described above. To be done. In the preferred embodiment, two holders 262 are mounted on each pin 264, one holder for the plate 21.
2 or 214 on each side. A resilient bottom support member 263 is preferably mounted between the lower end of each holder 262 and the bottom edge of plate 212 or plate 214. Providing the holders 262 to support the plates 212 and 214 in optimal positions as described above improves the stability of the micromotor 200. The plurality of spacers 262 are preferably tilted as shown in FIG. 29, thereby allowing drive movement of the piezoelectric plates 212 and 214 along the Y axis.

Another for Plates 212 and 214
Reference is now made to FIG. 30, which illustrates one alternative mounting structure. With this construction, pins 268, similar to pins 264 of FIG. 29, are mounted on plates 212 and 214 at positions where the amplitude of motion is substantially zero, as described above. It Therefore, three pins 268 may be mounted on each plate according to the multiple resonance modes described above. At least one spring 270, preferably a steel spring, is mounted on the plurality of pins 268 in the manner illustrated in FIG. The end of the spring 270 is preferably connected to an adjusting screw in the housing 220 so that the spring 70 extends between two bobbins 272 mounted on a support member 222, which is preferably horizontal. This stretching also biases the horizontal support 222 against the outer lateral edges of the plates 212 and 214, providing better support for the piezoelectric plate. The tension of spring 70, which can be adjusted using screw 274, controls the elasticity of plates 212 and 214 for movement along the y-axis. Thereby, the contraction, speed, and force of the micromotor 200 can be controlled.

Referring to FIG. 31, the micromotor 20
A preferred arrangement for engaging the 0 with a relatively thin object 278 is shown. In general, when a micromotor engages a thin object, the pulsed force applied by the motor to the object can cause slight damage or bending of the object in the engagement area. For this reason, the present inventor has proposed a counter bearing device 2 which minimizes this problem.
The 80 was devised. In accordance therewith, the preferred embodiment counter-bearing device 280 of the present invention includes a housing 282, which is the micromotor 200.
Preferably, the housing 220 is fixedly connected via a connector 290. At least one bearing 284 in the housing 282 includes spacers 216 and 21.
For the force applied to the front surface of object 278 by
It provides rigid support for the backside of object 278 (ie, the side that does not engage micromotor 200). Bearing 284 may be any known bearing, such as a metal cylinder.

In a particularly preferred embodiment of counter-bearing device 280, bearing 284 includes plate 212.
And piezoceramics similar to 214. In this embodiment, the ground electrode (not shown) substantially covers one flat surface of the bearing 284, while the other surface of the bearing 284 includes two separate electrodes 286 and 288, which are the surfaces thereof. Cover half of the. When the electrodes 286 and 288 are arranged as shown in FIG. 31, that is, above and below, and when the AC voltage is applied as described above, the bearing 284 becomes y−.
It vibrates at the resonant frequency along the axis. When the bearing 284 is driven in the appropriate direction, eg, upwards, at the y-axis frequency of the plates 212 and 214, the spacers 216 and 218 are gradually lowered, and the spacers are raised, the micromotor 200.
Provides a highly effective counter-bearing for the force exerted by. This embodiment of the invention has the advantage that, with suitable structural adjustments, it can likewise be applied to micromotors other than those mentioned above.

The micromotor 200 has one plate 2
Although described as including only 12 and one plate 214, it should be understood that variations of the embodiment of FIGS. 25-31 using multiple sets of piezoelectric plates 212 and 214 are also within the scope of the present invention. I have to. In such cases, the sets of plates are preferably mounted parallel to each other.

In some preferred embodiments of the invention,
Piezoelectric ceramic 10 is utilized in a disk drive to move and position the read / write head. Such a configuration is shown in Figures 38-41. 38 is read /
FIG. 6 is a block diagram of a disk drive including a piezoelectric micromotor that moves a writing head. Disk drive 3
50 houses a disc 352 rotatable about an axis 354 and a read / write assembly 360. The read / write assembly 360 includes an arm 3 that is pivotable about an axis 372.
70 and the piezoceramic 10 utilized to pivot the arm 370 about the axis 372. Disk 3
Scanning of 52 is accomplished by rotating disk 352 about axis 354 while rotating arm 370 about axis 372. Disk 352
Reading and writing is accomplished via a read / write head 374, which may be any known head attached to the end of arm 370.

FIG. 39 is a detailed view of the read / write assembly 360. As shown in FIG. 39, the piezoelectric ceramic 1
0 can use any of the above-mentioned types, but a through mount (throug) is attached to a fixed base (not shown).
h mounts) 385 and 386 are preferably fixedly mounted on slidably mounted elements. The piezoelectric ceramic 10 is elastically biased by the elastic element 44 against the rigid element 380 of the arm 370. The elastic element 44 is preferably pressed against a fixing element in a fixing base (not shown). When excited according to one of the above-described excitation shapes, the piezoelectric ceramic 10 causes the spacer 26, which is biased against the rigid element 380, to move in either the x or -x direction depending on the applied voltage. Moving. Relative movement between spacer 26 and arm 370 via rigid element 380 causes arm 370 to pivot 372.
Turn around. As a result, the read / write head 374
Moves in the direction of either θ or −θ which is almost in contact with the radius of the disk 352.

The mounts 385 and 386 extend through the holes of the piezoelectric ceramic 10. The holes are preferably located between the electrodes along the longitudinal axis of the ceramic 10 at about 1/6 and 5/6 of the length of the ceramic 10. At these points, the displacement and dimensional change of the ceramic 10 along the x-axis is substantially zero.

40 and 41 show the piezoelectric ceramic 10
Is different from FIG. 39 in that it is mounted on the fixed base. As shown in FIG. 40, the piezoelectric ceramic 10 can be attached to the fixed base by a pair of fixing elements 390 and 391. The anchoring elements 390 and 391 preferably engage the piezoceramic 10 at points of about 1/6 and 5/6 of the length of the ceramic. The piezoceramic 10 is located in the guide holes formed in the elements 390 and 391 to allow movement along the longitudinal axis of the ceramic 10 while constraining the movement of the ceramic 10 perpendicular to its longitudinal axis. May be.

Alternatively, as shown in FIG. 41, the piezoceramic 10 can be mounted on a fixed base by means of elastic support elements 392. The supporting elasticity is the supporting element 392.
It is determined by the rigidity of the material constituting the. Support element 3
92 is attached to a fixed base (not shown) and extends along the longitudinal axis of the ceramic 10 about 1/6 of the length of the ceramic.
And preferably engages the ceramic 10 at points 5/6.

The ends 395 and 396 of the support element 392 are
It is preferable to engage the element 380 of the arm 370 to remove dust accumulated on the element 380. Protrusions 397 and 3 preferably located on the spacer facing side of element 380 between spacer 26 and ends 395 and 396.
Reference numerals 98 limit the range of angular displacement of the arm 370, respectively, and prevent dust from accumulating in the vicinity of the spacer 26.

In a practical example, element 3 for axis 372
The radius of gyration R1 of the point on 80 and the reading about axis 372 /
The ratio between the radius of gyration R2 of the point on the writing head 374 is
The order is 1 to 3, or 1 to 5. Therefore,
Linear displacement for a given angular displacement _D theta read / write head 374 on the disk 352, 5-fold to about 3 than linear displacement for a given angular displacement _D theta spacer 26 larger.

In the preferred embodiment of the present invention, in order to increase the read and write capacity of the disk drive,
Many piezoelectric ceramics are used. The example arrangement shown in FIG. 42, which represents two parallel piezoelectric ceramics 10, 10 ′, is mounted on a shaft 400. This arrangement can be used to simultaneously or alternatively read or write on the opposite side of a single disk for simultaneous reading or writing of the above on a single disk. However, only one of the piezoceramics 10 or 10 'is used for reading or writing to a single sided disk.

In the arrangement shown in FIG. 42, both arms 37 are
The 0, 370 'are pivotable with respect to a shaft 400 extending through the holes in the piezoceramic 10, 10'.

For each piezoceramic, the holes are preferably located between adjacent electrodes along their respective short ends 28, approximately 1/6 of the length of the ceramic.
Only away from each of the short ends 28 described above. The piezoceramic 10, 10 'is a rotatable shaft 400
Is fixed to and can move according to a rotating shaft 400. On the other hand, the piezoelectric ceramics 10 and 10 '
It can also be rotatably mounted on a shaft 400 fixedly held between holding elements 404 and 405 so that each can be moved independently. The holding element 4
04, 405 are preferably attached to a fixed base (not shown).

The piezoceramics 10, 10 'are attached to the read / write heads 374, 374' by connecting elements 408, 408 ', respectively. The element 408 is preferably attached to or grips the piezoceramic 10 along the long ends 40, 42. Element 408 has an end 2 that is about 1/2 the length of the ceramic and about 5/6 shorter.
It is preferable to engage the piezoceramic at a point remote from 8. Corresponding elements 408 'have long ends 40', 42 '.
Are preferably engaged with the piezoceramic 10 'at points 1/2 and 5/6 along. At points 1/2 and 5/6 above, the ceramics 10, 10 'in the x direction
There is almost no movement or dimensional change. The rigid element 410 preferably uses elastic elements 411 to provide spacers 26, 26 'for the ceramic 10, 10'.
It is preferable that they are respectively biased.

In an actual arrangement as shown in FIG. 42,
Radius of gyration of a point on element 410 with respect to shaft 400 and read / write head 3 with respect to shaft 400
The ratio of the point on 74 to the radius of gyration is 1 to 5 to 1:10
It can range between. As a result, the linear movement of the read / write head 374 on the disk 352 can be made 5 to 10 times larger than the linear movement of the spacer 26 by the given angular movement _D θ. it can.

This system, including piezoceramics 10, 10 ', is operated in a closed loop mode and includes a disk drive track controller (not shown) to determine the position of the write head.

In the preferred embodiment of the present invention, a large number of piezoelectric ceramics are used to enhance rotational performance and increase read / write head travel. FIG. 43 shows an example of such an arrangement, in which three piezoelectric ceramics are used. A pair of piezoceramics 10 ′, 10 ″ are utilized to rotate the piezoceramic 10 with respect to a shaft 420 which is preferably mounted on a fixed base (not shown). The spacer 26 is biased to the end 440 of the arm 370. The force exerted by the spacer 26 on the end 440 of the arm 370 follows the movement of the spacer 26.
70 and rotation of the read / write head 374 attached thereto on shaft 372.

In the preferred embodiment of the present invention, as described above with reference to FIG. 39, piezoelectric ceramics 10 ', 1
0 ″ is fixed with respect to the shaft 420 and
It can be attached to the fixed base by means of a shaft attached to an element which is slidably mounted on a fixed base (not shown). Alternatively, the piezoceramics 10 ', 10 "may be attached to the fixed base by a fixing element, as shown in FIG. 40, or by other methods described herein.
A shaft 420 extends through a hole located in the center of the piezoceramic 10, preferably at the intersection of the four electrodes of the ceramic. Piezoelectric ceramic 1
Spacer 26 'attached to 0'is biased to the concave side of rigid arcuate element 426. The convex surface of the element 426 is preferably mounted approximately in the center of the long end 40 of the piezoceramic 10. Piezoelectric ceramic 10 '
Excitation causes the spacer 26 'to move in the y-direction or the -y-direction, depending on the applied voltage. The force exerted by spacer 26 'on element 426 causes movement of element 426 in accordance with the movement of spacer 26'.

The force exerted by element 426 on piezoceramic 10 causes rotation of piezoceramic 10 in the θ or −θ direction. Arc-shaped element 42 similar to element 426
7 is biased against the long end 42 of the piezoceramic 10 to couple movement of the spacer 26 "of the piezoceramic 10" with rotation of the piezoceramic 10, as described above for element 426. preferable. The movement of the spacer 26 ″ in the y direction or the −y direction causes the piezoelectric ceramic 10 to rotate in the −θ direction or the θ direction, respectively, and the rotation direction thereof is approximately the same movement as the spacer 26 ′.
Opposite the direction induced by the piezoelectric ceramic 10 'with _D y. Besides, x direction or -x
The movement of the spacer 26 which induces a linear movement of the body in a direction can be achieved by direct excitation of the piezoceramic 10.

Piezoelectric ceramics 10, 10 'and 10 "
Are spacers 26, 26 'and 26 "attached to each piezoelectric ceramic 10, 10' and 10" respectively.
Are electrically connected in order to correlate the movements of the. The overall movement of the spacers 26 and the resulting movement of the read / write head 374 is a superposition of the movements individually produced by each of the piezoceramics 10, 10 'and 10 ". It will be appreciated by those skilled in the art that the present invention is not limited to what has been particularly shown and described herein, but, rather, the scope of the present invention should be determined solely by the appended claims. is there.

Utilizing the apparatus described above in connection with the mode of electrification shown in FIG. 43 and previously described, the read-out is compared to a disk drive that does not use such an arrangement. And / or write head 374 can be provided with an expanded range of angles and linear movements while improving the ability to finely adjust the read / write head movements throughout its range of movement. be able to. Excitation of piezoceramics 10, 10 'and 10 "
A wide variety of motion contours for the writing head 374 can be achieved.

[0168]

As is apparent from the above description, according to the present invention, it is possible to provide a micromotor having a higher speed, a higher driving force and a smaller minimum step size than those of the conventional micromotors.

[Brief description of drawings]

FIG. 1 shows a schematic diagram of a piezoceramic element useful in a motor according to a preferred embodiment of the present invention.

FIG. 2 shows a first excited form of the element of (A) according to a preferred embodiment of the present invention.

FIG. 3 shows a mode diagram of FIG.

FIG. 4 shows a first excited form of the element of (A) according to a preferred embodiment of the present invention.

5 shows a mode diagram of FIG.

6 shows resonance curves for two closely arranged resonance modes of the element of FIG. 1 according to a preferred embodiment of the invention.

FIG. 7 illustrates a bimorph movement of a piezoelectric element useful in a motor according to a preferred embodiment of the present invention.

FIG. 8: When applied to the electrodes of the element shown in FIG.
Figure 5 shows a voltage pulse causing a controlled movement of an object in contact with an element.

FIG. 9 is a block diagram of a micromotor that achieves controlled movement according to a preferred embodiment of the present invention.

FIG. 10 is a perspective view of a tandem piezoceramic element useful in a motor according to a preferred embodiment of the present invention.

FIG. 11 is a perspective view of a tandem / parallel piezoelectric ceramic element useful in a motor according to a preferred embodiment of the present invention.

FIG. 12 shows a perspective view of a piezoceramic element adapted for xy motion according to a preferred embodiment of the present invention.

FIG. 13 shows a perspective view of two piezoceramic elements adapted for xy motion according to a preferred embodiment of the present invention.

FIG. 14 is a perspective view of an xy table utilizing the embodiment of FIG.

FIG. 15 illustrates the use of a piezoceramic element for rotating a cylinder or sphere according to a preferred embodiment of the present invention.

FIG. 16 shows another electrode shape for a piezoelectric ceramic according to a preferred embodiment of the present invention.

FIG. 17 shows an electrode shape suitable for applying a preloading force of a piezoelectric ceramic to a driven object according to a preferred embodiment of the present invention.

FIG. 18 shows an electrode shape suitable for applying a preloading force of a piezoelectric ceramic to a driven object according to a preferred embodiment of the present invention.

FIG. 19 illustrates an electrode shape suitable for applying a preloading force of a piezoelectric ceramic to a driven object according to a preferred embodiment of the present invention.

FIG. 20 shows another method of mounting the piezoelectric ceramic according to the preferred embodiment of the present invention.

21 shows an application of the mounting principle of FIG. 20 for mounting two piezoelectric ceramics according to a preferred embodiment of the present invention.

FIG. 22 shows another form of using a ceramic motor in the stage of the CD reader according to the preferred embodiment of the present invention.

FIG. 23 shows another form of using a ceramic motor in the stage of the CD reader according to the preferred embodiment of the present invention.

FIG. 24 shows another form of using a ceramic motor in the stage of the CD reader according to the preferred embodiment of the present invention.

FIG. 25 is a block diagram of a piezoelectric micromotor manufactured and operated according to a further preferred embodiment of the present invention.

26 is a schematic diagram of the micromotor of FIG. 25 showing the preferred xy resonance modes of the piezoelectric ceramic of the micromotor.

FIG. 27 FIG. 25 according to one preferred embodiment of the present invention.
FIG. 3 is a schematic diagram of a pulse excitation signal for driving the piezoelectric ceramic of the micromotor of FIG.

FIG. 28 is a schematic diagram of a piezoelectric micromotor driven with different x and y excitation amplitudes.

FIG. 29 is a schematic view of another mounting state of the ceramic plate of the piezoelectric micromotor of FIG. 25.

FIG. 30 is a schematic view of still another mounted state of the ceramic plate of the piezoelectric micromotor of FIG. 25.

FIG. 31 is a schematic diagram showing a preferred state of operatively coupling the micromotor of FIGS. 25, 26, 28-30 to an object.

FIG. 32 shows a schematic view of a piezoelectric micromotor utilizing a suppression member for suppressing an unwanted resonance mode according to a preferred embodiment of the present invention.

FIG. 33 shows an exaggerated oscillatory motion of the micromotor of FIG.

FIG. 34 shows a schematic view of a piezoelectric micromotor utilizing a rigid arm to provide increased power and smoother movement according to a preferred embodiment of the present invention.

35 quantitatively illustrates the relative movement of two spacers preferably utilized by the micromotor of FIG. 34 for selected excited states.

FIG. 36 is a schematic view of another micromotor adapted to provide a symmetric motion parallel to the short edge of a piezoceramic according to a preferred embodiment of the present invention.

FIG. 37 is a schematic view of yet another micromotor adapted to provide a symmetric motion parallel to the short edge of a piezoceramic according to a preferred embodiment of the present invention.

FIG. 38 shows a schematic block diagram of a disk drive according to a preferred embodiment of the present invention using a piezoelectric micromotor to move the read / write head.

39 is a schematic view showing another form of the read / write arm of the disk drive of FIG. 38 according to a preferred embodiment of the present invention.

40 is a schematic view showing another form of the read / write arm of the disk drive of FIG. 38 according to a preferred embodiment of the present invention.

41 is a schematic view showing another form of the read / write arm of the disk drive of FIG. 38 according to a preferred embodiment of the present invention.

FIG. 42 is a schematic diagram of a dual disk drive according to a preferred embodiment of the present invention.

FIG. 43 is a schematic of a three piezoelectric plate arrangement adapted to provide good tuning of read / write head motion while providing increased rotational and linear displacement range, according to a preferred embodiment of the present invention. It is a figure.

[Explanation of symbols]

10 ... Piezoelectric plate, 14, 16, 18, 20 ... Electrode,
26 ... Spacer.

Claims (37)

[Claims] 1. First and second longitudinal edges, first and second
First and second piezoelectric plates having short edges, front and back surfaces, and electrodes connected to the front and back surfaces, and attached to the first long edge at one end near the first short edges, and on the surface of the object. The first piezoelectric element includes an engaging ceramic spacer, an elastic force source that is applied to a part of each plate and presses the ceramic spacer against the surface of an object, and a voltage source that applies an excitation voltage to at least some electrodes. A piezoelectric micromotor for imparting movement to an object, characterized in that the first short edge of the plate is substantially parallel and close to the first short edge of the second piezoelectric plate. 2. The micromotor of claim 1, wherein the elastic force source is applied to at least a portion of the second longitudinal edge. 3. The micromotor according to claim 1, wherein the elastic force source is applied to a point on the piezoelectric plate, and a motion amplitude perpendicular to the surface is substantially zero. 4. The micromotor of claim 1, wherein the voltage source applies an AC excitation voltage to at least some of the electrodes. 5. The electrodes include a plurality of electrodes on a front surface of each piezoelectric plate and at least one electrode on a back surface of each piezoelectric plate.
The micromotor according to claim 1, comprising one electrode. 6. The method of claim 5, wherein the plurality of electrodes comprises electrodes in each quadrant of the front surface and the voltage source applies an AC excitation voltage to at least some electrodes on the front surface. Micro motor. 7. The micromotor according to claim 5, wherein an excitation voltage of the same polarity is applied to the electrodes in the quadrants located on the diagonal of each plate. 8. An electrode of the quadrant between the first long edge and the first short edge of the first piezoelectric plate is applied with an excitation voltage of a first polarity, and the electrodes of the first long edge of the second piezoelectric plate are The micromotor according to claim 5, wherein a voltage having a second polarity opposite to the first polarity is applied to the electrodes in the quadrant between the first short edges. 9. A rectangular piezoelectric plate having first and second surfaces, electrodes attached to the first and second surfaces, and at least some of the electrodes having an absolute value greater than the amplitude of the AC excitation voltage. A having a DC voltage separated at regular intervals
A micromotor comprising a power source for applying a pulse excitation voltage composed of a C excitation voltage pulse. 10. The micromotor according to claim 9, wherein a pulse rate of the pulse excitation voltage substantially corresponds to a self-resonant frequency of an object. 11. The first and second rectangular piezoelectric plates are at least one connected to at least one longitudinal edge.
The micromotor according to claim 1, comprising one additional electrode, the voltage source applying at least some additional electrodes. 12. The at least one additional electrode is a first electrode.
The micromotor of claim 11, comprising an electrode having a first long edge near the short edge. 13. The at least one additional electrode is a second electrode.
13. The micromotor of claim 12, comprising an electrode on a second long edge near the short edge. 14. The micromotor of claim 11, wherein the voltage source applies an excitation voltage to the additional electrode, thereby increasing the movement of the ceramic spacer in a direction substantially perpendicular to the plane. 15. The first and second rectangular piezoelectric plates have an additional electrode attached to a first longitudinal edge near a first lateral edge, and the voltage source has an additional electrode on the first electrode. The micromotor according to claim 8, wherein the first excitation voltage is applied and the second excitation voltage is applied to the additional electrode of the second plate. 16. The micromotor of claim 1, wherein the first and second piezoelectric plates are elastically supported at points on the plate having a motion amplitude perpendicular to the plane of substantially zero. 17. The micromotor of claim 1, wherein the elastic force source is adjustable. 18. The first piezoelectric plate and the second piezoelectric plates, wherein the ceramic spacers of each plate elastically press an object.
Micro motor. 19. The back support device of claim 1, further comprising a counter support device that engages a surface of the object opposite a surface that engages the spacer to provide a reaction force to a force applied to the object by the spacer. Micro motor. 20. The counter-support device comprises a piezoceramic bearing having electrodes mounted on at least one flat surface, and the voltage source applies a voltage to at least some piezoceramic bearings. Micro motor. 21. A rectangular piezoelectric plate having first and second surfaces, two longitudinal edges and two latitudinal edges, a ceramic spacer attached to the first latitudinal edge and pressed against an object, and a spacer support edge. An elastic force source for applying a force to the opposite second short edge, and an electric power source for exciting at least some of the electrodes, the length of the spacer is equal to an integral multiple of a half wavelength, and the wavelength is piezoelectric. A micromotor that moves an object corresponding to the wavelength of the spacer with respect to the frequency of the desired resonant mode of the plate. 22. Long and short edges, first and second edges
At least one rectangular piezoelectric plate having electrodes attached to the first surface, the first surface and the second surface; a power supply for applying a voltage to at least some electrodes to establish a desired resonant mode of the piezoelectric plate; A means for moving an object, comprising a mode suppressing means for suppressing a resonance mode other than the resonance mode. 23. The micromotor of claim 22, wherein the mode suppressing means comprises at least one suppressing means adapted to suppress dimensional changes caused by resonance modes other than the desired resonance mode. 24. At least one rectangular piezoelectric plate having two longitudinal edges and two latitudinal edges, first and second faces, and mounted on the center of the first latitudinal edge of the piezoelectric plate and pressed against an object. A first ceramic spacer and an arm having a second spacer attached to one end and having the other end attached to a second short edge of the piezoelectric plate, the first and second spacers being relative to an object A micromotor for moving an object having adjacent parallel surfaces adapted to be biased. 25. Two long edges and two short edges, first and second faces, said faces being parallel to and facing each other, and being spaced apart from each other, consisting of adjacent plates whose longitudinal edges are parallel. At least first and second rectangular piezoelectric plates, at least one fixed support engaging a first longitudinal edge of the first plate, and at least one elastic support engaging a second longitudinal edge of the first plate. A first longitudinal edge of the first plate, at least one elastic support engaging the first longitudinal edge of the second plate, and at least one fixed support engaging the second longitudinal edge of the second plate, Is a micromotor adjacent to the first longitudinal edge of the second plate. 26. Each said support engages each said piezoelectric plate along its respective longitudinal edge at a movement point of substantially zero in a direction parallel to the latitudinal edge, each said support being parallel to said longitudinal edge. The micromotor according to claim 25, which is slidable in any direction. 27. A rectangular piezoelectric plate having longitudinal and latitudinal edges, first and second surfaces, and a piezoelectric plate having a dimensional change of substantially zero along the longitudinal edge in a direction parallel to the latitudinal edge. A micromotor including a plurality of elastic elements for applying elastic force. 28. A piezoelectric plate having two longitudinal edges and two lateral edges and a spacer attached to one of the longitudinal edges; a piezoelectric plate pivotable about an axis and spaced on both sides by a constant distance from the axis. 1 and a second end, a read / write head attached to the first end, and a rigid arm at the second end, the spacer of the piezoelectric plate being elastically biased against the rigid element. Disk drive. 29. The disk drive of claim 28, wherein the piezoelectric plate is stationary. 30. The disk drive according to claim 28, wherein the piezoelectric plate is movable with respect to the axis. 31. An arm pivotable about an axis,
The arm has first and second ends that are spaced apart from the axis on both sides, a read / write head attached to the first end, and a piezoelectric plate that is attached to the second end and is movable with the arm. Have a disk drive. 32. An arm pivotable about an axis,
The arm has first and second ends, a read / write head attached to the first end, and a piezoelectric plate attached to the second end, the shaft extending through the piezoelectric plate. drive. 33. An arm rotatable about an axis, the arm having first and second ends, a read / write head attached to the first end, and a piezoelectric plate attached to the second end. A disk drive, wherein the shaft extends through the piezoelectric plate and comprises a rigid element biased against the piezoelectric plate. 34. A first rectangular piezoelectric plate pivotable about an axis and having two longitudinal edges and two latitudinal edges, two longitudinal edges and two latitudinal edges, and a ceramic attached to the edges. A second rectangular piezoelectric plate having a spacer, the spacer being biased against an edge of the first piezoelectric plate to move an object. 35. The micromotor of claim 34, wherein the spacer is biased against a longitudinal edge of the first piezoelectric plate. 36. A rigid arcuate element located between the spacer and a longitudinal edge of the first piezoelectric plate, the arcuate element coupling a movement of the spacer and a movement of the first piezoelectric plate. Micromotor according to. 37. Further comprising a third piezoelectric plate pivotable about an axis, the third piezoelectric plate having a spacer attached to an edge thereof, wherein the spacer of the third piezoelectric plate is the first piezoelectric plate. 35. The micromotor of claim 34, wherein the spacers of the two piezoelectric plates are biased against the edge of the first piezoelectric plate opposite the biased edge.