JPS6095271A - Fine adjustment device - Google Patents

Abstract

PURPOSE:To make it possible to perform low voltage drive, by disposing a lamination type piezo element between shafts, and by providing cylindrical piezo elements on the outer peripheral surfaces of the shafts. CONSTITUTION:A lamination type piezo element 9 is held between shafts 12, 13 by means of holding members 10, 11, and cylindrical piezo elements 14, 15 are provided on the outer peripheral surfaces of the shafts 12, 13. With this arrangement, the longitudinal effect distortion of the elements may be effectively utilized, and therefore the high degree of distortion may be efficiently generated. Accordingly, freedom is appreciated in the range of distortion utilized for a micro adjustment device so that low voltage drive may be conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fine movement device, and particularly to a fine movement device used for fine positioning of a target object.

Previously, this Yuzu micro-tremor device was published in U.S. Patent No. 390.
The inchworm-type micro-tremor devices disclosed in US Pat. No. 2,084, and No. 3,902,085 are well known. As shown in Figure 1, this fine movement device has electrodes coated with silver on the inner and outer surfaces of a cylindrical element made of pressure*@ material, which expands and contracts in the axial direction when an electric field is applied inside the element through these electrodes. When an electric field is applied to the center element 1, which causes an action, the clamp elements 3 and 4, which expand and contract in the radial direction and restrain the position of the shaft 2, and the center element 1 The holding member 6 is housed and fixed in the housing, and the holding member 6 has a shape as shown in FIG. and a connecting member 8.

In such a configuration, paying particular attention to the means for applying a cage to the center cable 1, electrodes are provided on the inner and outer circumferential surfaces of the cylindrical cable and a voltage is applied in the thickness direction, and the voltage is applied perpendicularly to the direction of application. As is well known, this is to make use of the transverse effect type of the element.

. In general, given the properties of the strong d'tun ceramic that is the material of the device, a relationship holds that under the same electric field strength, the amount of strain due to the transverse effect is 1/3 to 1/2 of the amount of strain due to the longitudinal effect. However, this is also mentioned in the specification of JP-A No. 1649-86816. Therefore, when trying to obtain the same strain, using the transverse effect type requires an electric field strength two to three times as much as when using the longitudinal effect strain, which is extremely inefficient.

In order to solve this shortcoming, please follow the steps shown in Figure 3.
It is conceivable to configure both end faces of the center element 10 with vc" tam 29.30 Y to actively utilize the longitudinal effect strain, but since the distance between both end faces is extremely long compared to the distance between the thick parts, 'In order to obtain the electric field strength (v/rn), an even higher voltage is required.

As mentioned above, in the conventional example, the use of the longitudinal effect of elements that require high voltage is avoided, and the electric field is reduced by configuring the element in a cylindrical shape and applying an electric field between the inner and outer surfaces with a short distance. In order to increase the J degree, the transverse effect type is deliberately used, but there are functional limits of the constituent elements and limits in the application technology, making it inefficient and requiring high voltage. The shortcomings are also unavoidable.

The present invention eliminates the above-mentioned drawbacks by employing a laminated piezoelectric element as the element that exhibits the expansion and contraction action, and is configured to fully utilize the longitudinal effect strain generated by the piezoelectric element. The present invention provides a fine movement device as described above.

According to the present invention, a laminated piezoelectric element exhibiting an inverse piezoelectric effect;
means for applying an electric field within the laminated piezoelectric element in order to cause an expansion and contraction action in the multilayer piezoelectric element; and means for applying an electric field to change the intensity of the applied electric field; 111. A shaft made of a non-magnetic and low thermal expansion material that clamps and fixes the laminated piezoelectric element via a holding member between the end face in the polarization direction of the laminated piezoelectric element and the opposite end face thereof. and a cylindrical element made of a piezoelectric material that is slidably layered on the outer circumferential surface of each of the shafts, and a cylindrical element made of a piezoelectric material that is slidably layered on the outer peripheral surface of each shaft, and a cylindrical element that causes expansion and contraction in the radial direction of the inner cylindrical element to restrain the position of the shaft. means for applying an electric field within the cylindrical element in order to apply the electric field; means for applying an electric field to the cylindrical element; The multilayer piezoelectric element is generated by changing the electric field applied to the multilayer piezoelectric element. The shaft is made into a step shape by the alternating expansion and contraction action and the alternating position restraint of the N-Y foot, which is caused by alternating the electric field applied to the cylindrical folding element.
! li; The following motion device is intended to be operated.

- One of the ultimate goals for the function of a piezoelectric lambda is to generate a deformable amount of strain due to low pressure applied drive, and in order to achieve this goal, the thickness direction of the thin plate-like longitudinal effect element is It is well known and has even been put into practical use that electrodes are set on the front and back surfaces of a , and a voltage is applied in parallel to an integrated element by stacking many of these layers! The ultra-compact piezoceramic element, which was recently developed by NEC Corporation and introduced in a paper by the Institute of Electronics and Communication Engineers (US83-8), uses adhesives by applying the manufacturing technology of multilayer ceramic capacitors. This is an innovative multilayer piezoelectric element that integrates piezoelectric ceramic plates into one layer.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 is a plan sectional view of one embodiment of the fine movement device according to the present invention, FIG. 5 is a vertical sectional view, FIG. 6 is a side sectional view, and FIG. It is a cross-sectional schematic diagram of an example.

In FIGS. 4, 5, and 6, reference numeral 9 denotes the laminated piezoelectric element developed in the above-mentioned manner, and 12.13 is adhesively and press-fitted onto both end surfaces of the element through holding members 10 and 11, respectively. shaft, 14.15 is each shirt) 12
．． 13 (a circular piezoelectric element IL3 having a pole thickness, which is movably mounted and independently applied on the inner and outer circumferential surfaces of the piezoelectric element), 7.18 is a closed piezoelectric element of these cylinders. shaped element 1
4.15 is integrated with the laminated piezoelectric element 9 and assembled into a shaft 12.13 in a state of sliding contact, and is housed and held in the housing 16. 19 is a T-housing at one end. 16, an L-shaped bar member provided at the end of the holder of the retaining part 10 in i41 to guide the fitting and fitting; 20 denotes the three piezoelectric elements 9, 14;
．． 15, a group of lead wires for supplying voltage; 21, a cable; 22, 23, a case to be connected to the housing 16; 24, one end of the shirt (12, 13); It is a rod-shaped member that has a connecting means for holding an object at the other end.

As shown in FIG. 7, the laminated pressure element 9 has a large number of internal electrode layers 25 embedded in a layered manner inside the semicircle.
Exposed at the element end face. This exposed internal electrode layer 25 is covered every other layer with an insulator 26, and the external polarization layers 27, 28' are covered with layers, so that the elements between each polarization layer are mutually connected to each other at once. They will be connected in parallel.

In addition, since these elements are polarized in the thickness direction, when a voltage is applied between the external electrodes, the magnitude of the voltage changes in the thickness direction, that is, in Figures 4 and 5. It expands and contracts in the axial direction of the shaft in proportion to.

In the fine movement device according to the present invention, since it is necessary to accurately produce an extremely small amount of displacement on the submicron level, at least members directly involved in movement, such as the holding member 10.
．． 112.13 and the coupling member 17.18 are preferably stacked piezoelectric elements 9 and cylindrical pressure plate elements 14.
It is preferable to use a ceramic material with a low coefficient of thermal expansion equal to or close to 15. It goes without saying that the shaft 12.13 and the connecting member 17.18 must be made of a non-conductive material since they are in direct contact with the outer pole. In addition, since the shirt 12.13 is a member that receives the contractile force of the cylindrical element 14.15 and slides, it is preferable that it is made of the above-mentioned ceramic material from the viewpoint of wear resistance.

Since the cylindrical elements 14, 1.5 are polarized in the radial direction, when a voltage is applied between the electrodes, the cylindrical elements 14, 1.5 polarize in the radial direction.
Sculpting or shrinkage occurs. In order to restrict the position of the shaft 12, 13, it is sufficient to consider the direction of voltage application to cause contraction, and when the voltage application state is removed, the shaft returns to its original shape and dimensions.

When no voltage is applied, the distance between the outer peripheral surface of the shaft and the inner peripheral surface of the element is adjusted so that each dimension is approximately zero fitting, taking into account the prevention of radial wobbling and the grip force associated with the contraction of the element. All you have to do is set .

The coupling members 17 and 18 have a pentagonal cross section as shown in FIG. It is positioned and fixed with adhesive at the shoulder of the stepped step.

The rod-shaped member 24 has means for coupling with the object, and is preferably made of a metal material having a low coefficient of thermal expansion in order to transmit force to the object and function when positioned.

The L-shaped rod member 19 has the function of suppressing the rotation of a moving object including the shirts 12, 13, the laminated temperature and pressure element 9, the rod member 24, and the like.

Next, the operation sequence of the fine movement device according to the present invention will be explained with reference to FIG. In the drawing, only three piezoelectric elements 9, 14, 15, shirt 12, 13, and voltage applying means are shown, and other components are omitted for easy understanding.

According to the figure, the cylindrical elements 14 and 15 are electrically connected to a switch 81181 and a power source El + L, respectively, and when the switch is closed, a sleeping pressure is applied between the electrodes, causing a contraction action on the element and the shaft 13. restrain in that position. The laminated piezoelectric element 9 is connected to a switch S and a power source E, and expands in proportion to the applied voltage when the switch is closed.

As shown in Figure 8 (a), the switch S1. After releasing the restraint of the clamp 12 (shirt on the left after disengaging switch SI) with closed switch S, the switch S is closed as shown in FIG. At this time, it is also possible to gradually increase the voltage and apply it in a superimposed manner until the desired dimensions are obtained. After that, close the switch S and the same figure (
After establishing a stable state as shown in d), and then disengaging switch S as shown in figure (e), switch S! When released, the elongated laminated piezoelectric element 9 contracts, and the right shaft 13 moves to the left, returning to the original length of the shaft system. After this, when the regeneration switch Ss is closed, the state is the same as that shown in FIG. 2A, except that the shaft has moved to the left, and if this sequence is repeated, the shaft will move to the left in a stepwise manner. Moreover, if it is desired to move the shaft to the right, the opening and closing states between the switch position and 83 may be reversed.

Although FIG. 8 shows a case in which the laminated pressure L element expands when a voltage is applied, it goes without saying that another operation sequence is possible by contracting when a voltage is applied. In Figure 8, the switches are shown mechanically for ease of understanding, but it is also possible to configure a switching circuit to perform automatic opening and closing operations using pure electrical control. be.

Also, instead of operating a switch, you can use the power supply KID + E2 r.
It is also possible to use mutually synchronized pulse power supplies as ha. By changing the repetition period of this pulse, it is also possible to arbitrarily change the moving speed.

The laminated piezoelectric element expands and contracts in proportion to the applied voltage, and regardless of whether it is a switch operation method or a pulse-1tlt method, it can be moved by combining changes in the magnitude of the applied voltage and changes in the repetition period. change in speed,
It goes without saying that the amount of movement can be changed freely, and if this is combined with a programmable logic control circuit of a personal computer, it will be suitable for a variety of uses.

In this way, by employing the above-mentioned newly developed laminated piezoelectric element as the element that acts to expand and contract, 1) the longitudinal effect strain of the element can be fully utilized, so a high amount of strain can be generated with high efficiency;

2) Therefore, since there is a free range of strain that can be adopted as a device, low voltage driving is possible.

3) Mass production and reliability are high due to the integrally fired multilayer element.

4) With the above, it is possible to make the device and drive circuit smaller and more compact.

As explained above, according to the present invention, a micro8 device that can be efficiently driven at a low voltage is integrated.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of an example of a conventional fine movement device, Fig. 2 is a perspective view of its connecting member, and Fig. 3 is an extensible element in the case of trying to utilize the vertical effect in the device shown in Fig. 1. FIG. 4 is a plan sectional view showing one embodiment of the present invention, FIG. 5 is a vertical sectional view thereof, FIG. 6 is a side sectional view, and FIG. FIG. 8, which is a schematic cross-sectional view of an example, is a sequence diagram showing the operation mode of the device of the present invention. 9...Laminated piezoelectric element, 10.11...
- Holding member, 12.13...Shaft, 14.
15... Cylindrical pressure forming element, 16...
Housing, 17.18101. -9 coupling member, 25.
...Internal electrode layer, 26 ...Insulator, 27
゜28...External electrode. z 7 Figure cod Z Figure z 3 Figure Y4- Figure K 5 Figure Y 6 Figure Mei 7 Eup

Claims (1)

[Claims] A laminated piezoelectric element exhibiting an inverse piezoelectric effect, a means for applying an electric field within the laminated piezoelectric element to cause the laminated piezoelectric element to expand and contract, and an applied electric field for changing the intensity of the applied electric field. a control means; a shaft made of a non-conductive and low thermal expansion material, which clamps and fixes the laminated piezoelectric element between the end face in the polarization direction of the laminated piezoelectric element and the opposite end face thereof via a holding member; , a cylindrical element made of a piezoelectric material that is slidably fitted onto the outer peripheral surface of each of the shafts, and the cylindrical elements expand and contract in the radial direction to restrain the position of the shaft. means for applying an electric field within the cylindrical element; applied electric field control means for intermittent application of the applied voltage; The housing includes a coupling member for holding together and a housing for storing and fixing the coupling member, and the alternating expansion and contraction of the laminated piezoelectric element caused by changing the electric field applied to the laminated piezoelectric element and the cylindrical element. A fine movement device, characterized in that the shaft is driven in a stepwise manner by alternately restraining the position of the shaft, which is caused by alternately interrupting and discontinuing an applied electric field.