JPH01190272A - Displacement magnifying mechanism for solid state actuator - Google Patents

Abstract

PURPOSE:To enhance the rigidity of mechanism and to improve its high-speed responsiveness, by adding up the displacement of a plurality of a solid state actuators for output. CONSTITUTION:A displacement magnifying mechanism C is composed of a base 10, three hollow cylindrical actuators 11-13 different in diameter and axially displaceable, cylindrical connective members 14-15 having flanges at the upper part on the outside and at the lower part on the inside, and an output member 16 to connect the parts to be positioned to the base 10. The actuator 11 is connected in turns between the base 10 and the flange on the upper part on the outside of the external connective member 14, while the actuator 12 is connected between the flange on the lower part on the inside of the connective member 14 and the flange on the upper part on the outside of the internal connective member 15, and so on sucessively connected. Thus, when the voltage is applied to each actuator 11-13, the displacement is so added up that the output member 16 expands three times as much as the single actuator of the same height and the displacement can be magnified.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a solid state actuator that can be applied to small component precision positioning mechanisms in information equipment such as magnetic disk devices and optical disk devices, semiconductor manufacturing equipment, ultra-precision measurement equipment, etc. Regarding the displacement amplification mechanism.

[Conventional technology]

Conventionally, as a solid-state actuator for precision positioning, a thin plate-shaped piezoelectric ceramic "laminated actuator A" that utilizes the piezoelectric longitudinal effect, as shown in Fig. 5, has been widely used because it has a large generated force and high-speed response. .

However, in such laminated piezoelectric ceramics, the strain generated per unit electric field strength is small, so 10 μm
Even in order to obtain a certain range of motion, it is necessary to reduce the thickness of each ceramic element and to use a high driving voltage. Furthermore, since the number of laminated sheets increases and the length of the actuator in the displacement direction inevitably increases, it is difficult to miniaturize the precision positioning mechanism.

Therefore, if a relatively large range of motion is required, the sixth
As shown in the figure, a displacement magnification mechanism B was used. 1
is a laminated piezoelectric ceramic, 2 is a lever, 3 is a base,
4 is a hinge, and the displacement d of the laminated piezoelectric ceramic 1 is
is magnified n times by the lever 2 according to the lever principle, and the displacement of the tip of the lever 2 becomes nd times. Further, although the description will be omitted, there is also an example in which a bimorph that can obtain a relatively large displacement with a low voltage is used as an actuator.

[Problem to be solved by the invention]

However, since these conventional devices include members that are easily bent, they have a problem of having a low resonance point and lacking in high-speed response.

In view of the above points, an object of the present invention is to provide a solid actuator displacement magnifying mechanism that has a large movable range compared to the dimension in the displacement direction and has excellent high-speed response.

[Means to solve the problem]

To this end, the present invention comprises a plurality of solid-state actuators that utilize mechanical strain inside a solid body caused by various electrophysical phenomena such as piezoelectric effects, electrostrictive and magnetostrictive phenomena, and phase transformation, and a connecting member that connects them. In this precision positioning mechanism, a plurality of the solid actuators are arranged in parallel in a plane perpendicular to the displacement direction by the coupling member, and the displacements of the individual solid actuators are added and output.

[Effect]

The present invention does not perform expansion based on the lever principle using levers, hinges, etc., but outputs the sum of the displacements of multiple solid actuators, so the shape of the actuators and coupling members is, for example, cylindrical. As a result, the mechanical rigidity can be increased compared to conventional displacement magnification mechanisms, and high-speed response can be achieved. Furthermore, if the required displacement is constant, the mechanical dimensions in the displacement direction can be made smaller compared to a single actuator, which means that the movable range can be larger than the dimensions in the displacement direction, and the drive voltage can also be reduced. A precision positioning mechanism for small parts can be easily realized.

〔Example〕

Examples of the present invention will be described below. FIGS. 1 and 2 are diagrams showing a displacement magnifying mechanism C according to one embodiment.

10 is a base, 11 to 13 are three axially displaceable hollow cylindrical actuators with different diameters, 14.15
1 is a cylindrical connecting member having a collar on the outer upper part and the inner lower part;
Reference numeral 6 denotes an output member that connects the parts to be positioned with respect to the base.

The actuator 11 has a base 10 and an outer coupling member 14.
The actuator 12 is located between the outer upper collar of the coupling member 14 and the outer upper collar of the inner coupling member 15, and the actuator 13 is located between the inner lower collar of the coupling member 14 and the outer upper collar of the inner coupling member 15. They are each coupled between the inner lower collar and the output member 16.

In this example, when a voltage is applied to the three actuators 11 to 13 so that they extend and displace in the axial direction, the displacements of the individual actuators 11 to 13 are added, and the output member 16 is The elongation and displacement will be approximately three times that of the case, and the displacement can be expanded.

In this way, in this embodiment, all the actuators 11
-13 are driven in the same direction. The specific wiring connection method for driving in this manner is well known, so a description thereof will be omitted. Further, by using a cylindrical member as in this embodiment, high rigidity can be obtained. Furthermore, in this embodiment, unlike the enlargement mechanism using a lever,
Since flexible members such as hinges are not required, a highly rigid design is possible.

FIG. 3 is a diagram showing a displacement magnification mechanism of another embodiment.

20 is a base, and 21 to 23 are three axially displaceable cylindrical actuators having different diameters. The actuators 21, 22 have a hollow cylindrical shape, and the actuator 23 has a solid cylindrical shape. 24 and 25 are disc-shaped coupling members, and 26 is an output member.

The upper coupling member 24 couples the upper part of the actuator 21.22, and the lower coupling member 25 couples the upper part of the actuator 22.22.
Join the lower side of 23.

In this embodiment, the actuators 21 to 23 are driven so that the actuator 21 extends, the actuator 22 contracts, and the actuator 23 extends.
The output member 26 is expanded and displaced in the extending direction with respect to the base 20. In this manner, in this embodiment, adjacent actuators are driven so that their displacement directions are opposite to each other.

FIG. 4 is a diagram showing a displacement magnification mechanism E of yet another embodiment. In this embodiment, the actuator 23 of the displacement magnification mechanism shown in FIG. A sensor 27 is provided, and the drive voltage is controlled by a detection signal from the displacement sensor 27.

For example, a piezoelectric actuator has a large displacement hysteresis with respect to a drive voltage, so it is necessary to detect displacement and compensate the drive voltage for highly accurate positioning.

This displacement sensor can be constructed compactly by using, for example, a capacitance sensor, but a sensor based on another principle may also be used. The operation is the same as that of the displacement magnifying mechanism shown in FIG.

Although a cylindrical actuator is used in each of the embodiments described above, the shape thereof does not limit the present invention. Further, although the case where the number of actuators is three has been described, if there are two or more, the configuration of the present invention can be realized and the displacement can be expanded.

〔Effect of the invention〕

As explained above, the solid actuator of the present invention! - According to the vertical displacement amplifying mechanism, the size of the mechanism in the displacement direction can be significantly reduced compared to the case where it is operated by a single actuator, and this has an effect suitable for miniaturizing the precision positioning mechanism. In addition, due to the shape design using a cylindrical actuator and coupling member, it is possible to increase the rigidity of the mechanism compared to the conventional lever-based expansion mechanism, which has the advantage of being able to construct a precision positioning mechanism with excellent high-speed response. be.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a displacement magnifying mechanism according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line nn in FIG. 1, and FIG. 3 is a cross-sectional view of a displacement magnifying mechanism according to another embodiment. 4 are sectional views of a displacement amplifying mechanism according to yet another embodiment, and FIGS. 5 and 6 are explanatory diagrams of a conventional displacement amplifying mechanism. 10...Base, 11-13...Actuator,
14.15... Connection member, 16... Output member, 20
... base, 21-23.231 ... actuator, 24.25 ... coupling member, 26 ... output member,
27...Displacement sensor. Agent Patent Attorney Tsuneaki Nagao Figure 2

Claims (1)

[Claims] (1) Precise positioning consisting of multiple solid-state actuators that utilize mechanical strain inside a solid body caused by various electrophysical phenomena such as piezoelectric effects, electrostrictive and magnetostrictive phenomena, and phase transformation, and a connecting member that connects them. In the mechanism, a plurality of the solid actuators are arranged in parallel by the coupling member in a plane perpendicular to the displacement direction, and the displacements of the individual solid actuators are added and output. Actuator displacement expansion mechanism.