JPH0255582A - piezoelectric drive - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a linear drive device, a scanner drive source, a paper conveyance drive source, and a seek drive source for optical pickup of an optical disk device, using a piezoelectric ceramic element as a solid element. The present invention relates to a piezoelectric drive device used as such.

Conventional technology In general, this type of linear drive/precision positioning uses a motor such as a pulse motor or DC servo motor, and converts the movement into linear motion using belts, wire cables, gears, etc. .

However, in such a method, the positioning accuracy is limited to about 10 to 20 μm due to mechanical play and backlash. Furthermore, in a linear drive system that combines a voice coil and a spring, there are limits to the generated stress and response speed.

For this reason, minute displacement, which is a characteristic of piezoelectric members,
A piezoelectric linear drive source that can perform minute positioning using high response horn generation has been proposed.

For example, as shown in US Pat. No. 3,902,084 and US Pat. No. 3,902,085, there is a device that uses a cylindrical piezoelectric member to finely move a shaft body using an inchworm method.

For example, as shown in FIG. 14, this device consists of clamping piezoelectric elements 2 and 3 and a moving piezoelectric element 4 (all cylindrical) positioned between the elements 2 and 3 relative to the round bar shaft 1. , a drive signal is applied to each element 2, 3.4 to move it step by step. That is, the two clamping piezoelectric elements 2 and 3 on both sides exhibit a clamping action in which the inner diameter of the cylinder becomes smaller due to the electrostrictive effect accompanying voltage application, thereby tightening the round bar shaft 1. Further, the moving piezoelectric element 4 is configured to exhibit displacement extending in the axial direction by applying a voltage.

Further, as shown in U.S. Pat. No. 3,684,904, a drive device includes two piezoelectric elements for movement provided on both sides of a solid part and two piezoelectric elements for clamping provided vertically. There is also.

Furthermore, as shown in Japanese Patent Publication No. 12497/1997, there is a drive device that clamps using electrostatic force and uses a piezoelectric member for movement.

Problems to be Solved by the Invention All of these piezoelectric devices use a single piezoelectric element as a drive source, so the amount of displacement is minute and the movement speed is slow at several mm/see, and high speed I have a sexual problem. Further, the clamping mechanism requires high dimensional accuracy of several μm or less, which is not practical.

For example, considering the case of FIG. 14, piezoelectric elements 2.3.
4, the amount of displacement when voltage is applied is about 2 to 3 μm at most, and the gap between the inner diameter of the piezoelectric elements 2 and 3 for clamping and the round bar shaft 1 naturally requires ultra-precision machining of 2 μm or less. That will happen.

Furthermore, it is necessary to use a filler material having the same expansion coefficient with respect to temperature changes, which limits the materials that can be used.

Means for Solving the Problems The invention according to claim 1 provides a piezoelectric member that is disposed between a pair of opposing sliding rails and is displaced in a clamping direction by voltage application, and a displacement that magnifies the displacement of this piezoelectric member. Two or more clamping units including an enlarging mechanism, and one or more moving units including a piezoelectric member that is displaced in a moving direction by voltage application and a displacement enlarging mechanism that amplifies the displacement of the piezoelectric member.

In this case, in the invention according to claim 2, the clamping unit and the moving unit are assembled in the same plane, and the displacement direction of the displacement amount of the displacement magnifying mechanism of each unit is set in the same plane.

Further, in the invention as claimed in claim 3, the displacement amplifying mechanism of the moving unit has a folded structure having two or two or more fulcrums for expanding the displacement, and the clamping units are arranged on both sides of the moving unit. .

Furthermore, in the invention set forth in claim 4, the displacement magnifying mechanisms of the clamping unit and the moving unit are integrally formed by a cutout structure of a plate-like member.

In this case, in the fifth aspect of the invention, the fixed side in the displacement amplifying mechanism of the clamping unit and the displacement amount in the displacement amplifying mechanism of the moving unit are formed by the same side.

According to the invention described in claim 1, the clamping unit can be alternately moved linearly by the clamp sacell inch worm method while the moving unit is being expanded and contracted. On this occasion,
Both clamping and movement depend on the displacement due to voltage application to the piezoelectric member of each unit, but in both cases, the displacement is expanded by each displacement magnification mechanism, so there is no requirement for CC precision on the clamping mechanism. The lamp state can be reliably secured, and high-speed movement can be achieved by +-iJ.

In step 1), high-speed movement and high-speed response are achieved.

In this case, according to the invention as claimed in claim 2, each unit is assembled in the same plane, and the displacement direction is also in the same plane, so that the device becomes very thin.

Furthermore, according to the third aspect of the invention, since the displacement magnification mechanism of the moving unit has a folded structure, a large magnification displacement can be obtained even though the dimension in the width direction is small.

Further, according to the invention as claimed in claim 4, since the displacement magnification mechanism of the clamping unit and the moving unit has an integral structure, it is possible to improve the responsiveness determined by the material rigidity and shape. It is possible to increase the speed, and because it is directly connected in one piece, there is little displacement loss and high efficiency.

In this case, according to the invention set forth in claim 5, in the integral fixing structure, the fixed side for the clamp in the displacement amplifying mechanism of the clamping unit and the displacement amount in the displacement amplifying mechanism of the moving unit are the same side. Since it is formed as , it has a simpler structure.

Embodiment An embodiment of the invention according to Claims] to 3 will be described based on FIGS. 1 to 5. FIG. This embodiment is configured as an inch worm type drive device, and includes one set of moving units 12 between a pair of sliding rails 10 and 11 facing each other, and two sets of moving units arranged on both sides in the moving direction. Clamp units 13 and 14 are provided.

The clamping units 13 and 14 have the same structure, for example, as shown in FIG. 2. Roughly speaking, it is made up of a combination of a piezoelectric member 15 made of a laminated piezoelectric element that is displaced by voltage application, and a displacement amplifying mechanism 16 that magnifies the displacement of the piezoelectric member 15. This displacement magnifying mechanism 16 is constructed by appropriately moving a rectangular plate-shaped part 17 made of SK steel material (for example, one with a thickness of 1.5 to 3 mm) one unit in front of the fixed side 18 in one direction from both ends of the fixed side 18. A displacement amount of 19.20 is formed between the piezoelectric member 15 and the piezoelectric member 15 is adhesively fixed at the adhesive portion 21 between the displacement amount of 19.20.

Here, the displacement of the piezoelectric member 15 alone is about 4 to 5 μm based on the application of a voltage of 80 to 100 V, but the amount of displacement 19
．． A structure in which a mechanically expanded displacement amount can be obtained at the tip of the tip 20 is shown in FIG. That is, plate-shaped member]
By forming an arc-shaped notch 22 at a predetermined position of 7 by wire-cut electric discharge machining, a displacement fulcrum 23 is provided near the base of 9.20, and when the piezoelectric part vJ'15 is displaced, this displacement fulcrum 23 is The tip is expanded and displaced at the center with a displacement amount of 19.20. With the example of the displacement magnifying mechanism 16 shown in FIG. 2, it is easy to magnify the displacement by 3 to 5 times the displacement of the piezoelectric member 15.

Further, the moving unit] 2 is configured as shown in FIG. 3, for example. Roughly speaking, it is made up of a combination of a piezoelectric member 24 made of a laminated piezoelectric element that is displaced by voltage application, and a displacement amplifying mechanism 25 that magnifies the displacement of the piezoelectric member 24. This displacement magnification mechanism 25 is the displacement magnification mechanism 16 described above.
Similarly to the above case, a rectangular plate member 26 (same thickness as the plate member 17) made of, for example, SK steel is suitably processed, but it is configured as a folded and enlarged structure. First, the first displacement side 28.29 is moved in one direction from both ends of the first fixed side 27.
An arcuate notch 30. The piezoelectric member 24 is formed with a first displacement fulcrum 31 between these first displacement sides 28 and 29.
is adhesively fixed at the adhesive part 32. In this case as well, the piezoelectric member 24 alone has 4 to 4
Although the displacement is about 511 m, this displacement is expanded at the tip of the first displacement side 29.30 using the first displacement fulcrum 31 as a fulcrum. Such a structure is similar to that of the displacement magnifying mechanism 16. However, the displacement magnifying mechanism 25 has a folded structure, and a second fixed side 33 is set on the axillary side of the first fixed side 27, and the first displacement side 29 is extended from both ends of the second fixed side 33.
．． The second displacement side 34.35, which is separated and connected to 30 by a slit or the like, is connected to the arcuate notch 36.35. It is formed with a second displacement fulcrum 37. As a result, the enlarged displacement on the first displacement side 28.29 is turned back to the second displacement side 34.35 using the second displacement fulcrum 37 as a fulcrum, and the displacement is further expanded at the tip of the second displacement side 34.35. The displacement of the piezoelectric element 24 with respect to one displacement side 28.29 corresponds to the displacement of the first displacement side 28.29 with respect to the second displacement side 34., 35)
. In the case of an example of the displacement magnifying mechanism 25 as shown in FIG.
The displacement of the piezoelectric member 24 can easily be expanded by 5 to 10 times at the tip of the second displacement side 34.35.

In any case, the displacement responsiveness of the displacement magnifying mechanism 1.6.25 is determined by the natural frequency. Here, if the mass of the displacement part is M and the rigidity is K, the natural frequency ω is. Basically, ω. =JK/M.

This natural frequency ω. In order to increase the height of the plate member 1.
As a material having a large longitudinal elastic modulus E of 7.26 and a large proportional limit σ, SK steel as in this embodiment, carbon steel, high tensile strength steel, etc. may be used.

Also, the radius of the arcuate notch 2, 30.36, the displacement fulcrum 2
Since the rigidity K is determined by the thickness of 3, 31.37 and the overall plate thickness, it is necessary to set it to an appropriate value. Figure 2,
In the example shown in Fig. 3, the radius of the arc-shaped notch 2, 30.36 is set to 0.5 to 2 mm, and the thickness of the displacement fulcrum 23, 31.37 and the overall plate thickness are set to about 1 to 3 mm. Therefore, the number k
Responses below Hz are possible.

In such a set of moving units 12, as shown in FIG. It is arranged so as to be located on the moving rail 11 surface. In addition, two sets of clamping units 13° 14 located on both sides of the moving unit 12 are connected to the second displacement side 3 of the displacement magnifying mechanism 26.
Fixed side 18 of each displacement magnification mechanism 16 for 4.35
are coupled and arranged to be step-driven.

Here, the connection between the second displacement side 34, 35 and the fixed side 18 is, for example, the fixed side 1 of the clamping units 13, 14.
8 may be coupled by a plate spring or the like, or a method may be employed in which the tips of the second displacement sides 34 and 35 and the fixed sides 18 are mechanically coupled. In any case, Figure 1 (
a) As in (b), these units 12, 13, 1
．． 4 are incorporated in the same plane.

In such a configuration, the clamping unit 13.1
．． When a voltage is applied to the piezoelectric member 15 of 4, its displacement is magnified by the displacement magnifying mechanism 16, and a ramp displacement acts on the sliding rail 10.11 as shown by arrow A in FIG.
It is in a clamped state with respect to the slide rail 10.11 (it is in a free state when no voltage is applied). Further, when a voltage is applied to the piezoelectric member 24 of the moving unit 12, the displacement is magnified by the displacement magnifying mechanism 25, and the drive displacement due to expansion/contraction as shown by arrow B in FIG. .35 to both side clamping units 13,1
．． It acts on the fixed side 18 of 4. In other words, all units)
The displacement directions A and B of the displacement magnifying mechanisms 16.25 of 12, 13, and 1.4 are also in the same plane as in the arrangement. Therefore, the entire unit 12, 13, 14 has a very thin thickness of about 1 to 3 mm. In particular, since the displacement magnifying mechanism 25 of the moving unit 12 has a folded structure having two or more pairs of displacement fulcrums, it is small in width direction and one dimension, although it has a large displacement.

By the way, the signal waveform applied in the structure of FIG. 1 is shown in FIG. 4. First, the signal S1 has a peak value of, for example, 8.
The voltage signal is a sine wave or a square wave of 0 V, and is applied to the piezoelectric member 15 of the moving unit 12. Also,
Signal S2 is a pulse voltage signal applied to the piezoelectric member 24 of one clamp unit 13, and signal S2 is a clamp pulse voltage signal applied to the piezoelectric member 24 of the other clamp unit 14. Therefore, for example, when the signal S2 is outputted at 80V, the displacement magnifying mechanism 2 of the clamping unit 13
5 is in a clamped state with respect to the slide rail 10.11, the voltage of the signal S1 is in a rising period and the displacement magnification mechanism 16 performs a widening operation. At this time, the displacement magnifying mechanism 25 of the clamping unit 14 is in a free state with respect to the sliding rail 1.0.11.

Then, when the signal S1 reaches its rising peak, the signal S2. S is reversed, and the displacement magnifying mechanism 25 of the clamping unit 14 becomes the clamping state with the 80V output of the signal S3, while the displacement magnifying mechanism 2 of the clamping unit 13
5 changes from a clamped state to a free state. During this period, the voltage of the signal S is in a falling period, and the displacement magnifying mechanism 16
is compressed and is displaced to the right together with the clamping unit 13), and when it reaches the downward peak point, the clamp signal S2. S is inverted again and the above operation is repeated. By repeating such an operation, a linear movement operation from the left side to the right side is performed.

Signal S2. By reversing the inversion timing of S, it is possible to move from the right side to the left side.

Such signals 81-S can be generated by a signal generating circuit as shown in FIG. First, the pulse signal is compensated by the phase adjustment circuit 40 so that the signal S1 is synchronized with the pulse signal, and then a sine wave (or triangular wave) is generated by the sine wave (or triangular wave) conversion circuit 41. ,
This is passed through the amplification drive circuit 42 to 80 vp-1'
) will be output to the moving piezoelectric member 15 as an output impedance signal. In addition, the clamp signal S
2. S2 is also generated by processing this pulse signal manually in order to invert it in synchronization with the pulse signal. A gate circuit 43 is provided for inverting characteristics with S3,
In addition, a movement direction switching terminal 44 for manually applying a switching signal H/L to reverse the operation depending on the movement direction.
is connected to the gate circuit 43.

Then, the output divided into two by the gate circuit 43 is divided into three parts.
A drive circuit 45 consisting of three power MO3FETs outputs a low output impedance signal of 80V to the piezoelectric member 24 of the clamping unit 13 as a signal S2.

On the other hand, the piezoelectric member 2 of the clamping unit 14 is output as an 80V low output impedance signal S3 by the drive circuit 46, which also consists of three power MO3FETs.
4 is output. In addition, when the terminal 44 is at H level, the left →
The movement is to the right, and when the level is ■, the movement is from right to left.

With such a configuration and control, for example, the displacement amount of the moving piezoelectric member 15 can be 4 μm, the displacement magnification amount by the displacement magnification mechanism 16 can be increased five times, the driving frequency can be 1.0 kHl, and the efficiency can be 80.
When expressed as %, units 12, 13゜14 are 160mm/
Moves at a speed of sec. In addition, by lowering the voltage applied to the piezoelectric member 15 for movement, the value of the amount of movement per step can be varied to an extremely small degree, and high resolution can be achieved, similar to the conventional piezoelectric type. It is.

FIG. 6 shows a modification of the displacement magnification mechanism in the moving unit 12, in which the fixed side 50 is set in the middle part, and displacement sides 51° 52, 53, 54 are formed on both sides from both ends of this fixed side 5o. It is. 55 is an arcuate notch, and 56 is a displacement fulcrum.

Further, FIG. 7 shows a modification of the displacement magnifying mechanism 16 of the clamping unit 1.3.14 in which only the displacement side 20 is made effective. That is, the arc-shaped notch 22 and the displacement fulcrum 23 corresponding to the displacement side 19 in FIG. 2 are eliminated. Then, a moving unit 13.14 is placed on the side that no longer functions as the displacement side 19.
The tip sides of the second displacement sides 34 and 35 are made to correspond to each other, thereby stabilizing the operation. Such a one-sided displacement side structure may be similarly applied to the displacement magnification mechanism 25 of the moving unit 12. FIG. 8 shows this modification. In this case, it is only on one side, and the number of displacement fulcrums 31.degree. 37 is also two instead of two pairs (=four).

Next, an embodiment of the invention according to claim 4 will be described with reference to FIGS. 9 to 13. In this embodiment, each displacement magnifying mechanism 16.25 of the clamping unit 13.14 and the moving unit 12 is mounted on a single plate member 60 with a thickness of about 1 to 3 pieces.
It is integrally formed with an appropriate notch structure by wire cut electrical discharge machining or the like.

First, FIG. 9 shows a structure for an inchworm system in which a moving displacement amplifying mechanism 16 and clamping displacement amplifying mechanisms 25 located on both sides thereof are connected by an arcuate notch 61. This is an example of a structure where there is only the displacement side 28.29 and no displacement side 3/1.35.

In FIG. 10, the displacement magnifying mechanism 16 for movement has a first displacement side 28.29 and a second displacement side 34.35, as in the case of FIG.
An example of a folded structure is shown in which a larger amount of displacement expansion than the structure shown in FIG. 9 can be obtained.

FIG. 11 shows an embodiment corresponding to the invention set forth in claim 5,
The displacement sides 28 and 29 for movement and the fixed side 18 for clamping are used as both. That is, the clamping unit 1
3. Fixed side 18 in the displacement magnification mechanism 16 of I/I and displacement side 28, 29 in the displacement magnification mechanism 25 of the moving unit 12
(A structure in which the displacement sides 34 and 35 are not present) are formed by the same sides. Therefore, the structure becomes simpler.

FIG. 12 also shows an embodiment corresponding to the invention set forth in claim 5, which is based on the configuration of FIG.
This also serves as the fixed side 18 for clamping.

These are mounted on sliding rails 10 and 111 to form a linear motor. For example, FIG. 13 shows an example in which the structure shown in FIG. 12 is mounted. The drive control may be similar to that shown in FIGS. 4 and 5.

According to this embodiment, the displacement magnification mechanism for clamping and moving is not connected by a leaf spring or the like, but has an integral structure by the plate-shaped part 'vJ60, so that it depends on the material rigidity and shape of the plate-shaped member 60. will have a responsiveness determined by −
It is possible to speed up the layer.

Moreover, it is highly efficient with no displacement loss.

Effects of the Invention As described above, in the invention according to claim 1, the present invention has the following features:
Two or more clamping units disposed between a pair of opposing sliding rails and including a piezoelectric member that is displaced in the clamping direction when a voltage is applied and a displacement magnifying mechanism that magnifies the displacement of the piezoelectric member; Since one or more moving units including a piezoelectric member that is displaced in the moving direction and a displacement magnifying mechanism that magnifies the displacement of the piezoelectric member are provided, both movement and clamping are faster than when the piezoelectric member is displaced alone. Due to the enlarged displacement, the clamping mechanism does not require high precision, ensuring a reliable ramp condition, and high-speed movement is possible, thus achieving high-speed movement and high-speed response as a linear motor. In this case, in the invention according to claim 2, the clamping unit and the moving unit are assembled in the same plane, and the displacement direction of the displacement side of the displacement magnifying mechanism of each unit is set in the same plane. Therefore, it can be made very thin, and in the invention according to claim 3, the displacement amplifying mechanism of the moving unit has a folded structure having two or more pairs of fulcrums for expanding the displacement,
Since the clamping units are arranged on both sides of this moving unit, it is possible to obtain a large expansion and contraction of movement, but the widthwise (''-modulus for this purpose can be small), and the invention according to claim 4 In this case, since the displacement magnification mechanisms of the clamping unit and the moving unit are integrally formed by the notch structure of the plate-shaped part, it is possible to provide responsiveness determined by the material rigidity and shape. It is possible to achieve higher speeds, and because it is directly connected in one piece, there is less displacement loss, resulting in high efficiency. Since the same side is used as the displacement side in the displacement magnification mechanism, a simpler and more compact structure can be achieved.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the invention according to claims 1 to 3, and FIG. 1(a) is an overall front view;
b) is its side view, Fig. 2(a) is a front view of the clamping unit, (1)) is its bottom view, Fig. 3(a,) is a front view of the moving unit, and (b) is its A bottom view, FIG. 4 is a timing waveform diagram, FIG. 5 is a circuit diagram of the signal generation circuit, FIG. 6 is a front view showing a modification of the mobile unit, and FIG.
a) is a front view showing a modification of the whole, (+) is a side view thereof, FIG. 8 is a front view showing a modification of the displacement magnification mechanism for movement, and FIGS. 9 to 13 are claims 4 9 to 12 are front views showing various integrated structure examples, FIG. 13 is an overall front view, and FIG. 14 is a longitudinal sectional front view showing a conventional example. be. 10.1] Sliding rail, 12 ・Movement unit,
13.14... Clamping unit, 15 - Piezoelectric member, 16... Displacement magnifying mechanism, 18... Fixed side, 19.
20. Displacement side, 23. Displacement fulcrum, 24. Piezoelectric member, 25. Displacement magnification mechanism, 28. 29. Displacement side, 31.
... Displacement fulcrum, 34.35... Displacement side, 37... Displacement fulcrum, 51, 52, 53.54... Displacement side, 56... Displacement fulcrum, 60... Plate-shaped part benefit

Claims (5)

[Claims] 1. Two or more clamping units disposed between a pair of opposing sliding rails and including a piezoelectric member that is displaced in the clamping direction by applying a voltage, and a displacement magnifying mechanism that magnifies the displacement of the piezoelectric member; 1. A piezoelectric drive device comprising one or more moving units including a piezoelectric member that is displaced in a moving direction by a piezoelectric member and a displacement amplifying mechanism that amplifies the displacement of the piezoelectric member. 2. 2. The piezoelectric drive device according to claim 1, wherein the clamping unit and the moving unit are assembled in the same plane, and the displacement direction of the displacement side of the displacement magnifying mechanism of each unit is set in the same plane. . 3. Claim 1 or 2, characterized in that the displacement amplifying mechanism of the moving unit has a folded structure having two or more pairs of fulcrums for expanding the displacement, and clamping units are arranged on both sides of the moving unit in the moving direction. 2. The piezoelectric drive device according to 2. 4. 2. The piezoelectric drive device according to claim 1, wherein the displacement amplifying mechanisms of the clamping unit and the moving unit are integrally formed by a cutout structure in a plate-like member. 5. 5. The piezoelectric drive device according to claim 4, wherein the fixed side of the displacement amplifying mechanism of the clamping unit and the displacement side of the displacement amplifying mechanism of the moving unit are formed by the same side.