JPS60213274A - Finely moving device - Google Patents

Abstract

PURPOSE:To suppress a vibration with a simple and inexpensive construction by forming a device body housing for storing and holding piezoelectric element group of a ferrite composite material. CONSTITUTION:A movable unit 3 is composed of a piezoelectric stretchable element 4 which axially stretches and contracts of a shaft 1 and a pair of front and rear piezoelectric clamping elements 5, 6 which stretches and contracts in a direction perpendicular to the stretching and contracting directions of the element 4. The shaft 1 is press-fitted fixedly to the hole 7a of a coupling member 7. A pair of coupling members 8, 9 couple and hold the both ends of the element 4, and are bonded fixedly to the elements 5, 6 integrally as the unit 3. A voltage is alternately applied to the elements 4-6 to telescope the shaft 1 integral with the unit 3 in the axial direction. In this case, a housing 2 for storing and holding the unit 3 and the like is formed of a ferrite composite material. Thus, since the damping characteristic is high and the impact vibration attenuating characteristic is excellent, the vibration absorbing effect can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fine movement device suitable for use in precisely micro-positioning and fixing a moving object.

[Prior art]

Conventionally, in this type of micro-movement device, a group of piezoelectric elements that perform a so-called inchworm movement are constructed by skillfully combining piezoelectric ceramics for active motion and clamping.
Piezoelectric micro-movement devices have attracted attention in recent years because they can easily and reliably perform micro-positioning of moving objects with high precision. are collecting. .

By the way, in conventional fine movement devices, metals such as iron and aluminum or plastics are used as the material for the main body housing for storing and holding the piezoelectric element group as the main part and its related coupling members. In the case of a housing made of a book-like material, when vibrations of a group of piezoelectric elements driven at a high frequency are propagated through the coupling member and the guide member, the vibration absorption performance is reduced. Because it is small, it has the disadvantage of causing resonance. Further, such resonant vibrations conversely transmit to the piezoelectric element group via the guide member and the coupling member, posing the problem of inducing complex high-order vibrations. Problems caused by such vibrations not only cause serious functional problems, especially in fine movement devices whose purpose is to extract high-precision displacements at the submicron level, but also cause noise problems due to resonance, which cannot be ignored. in,
It is hoped that some kind of countermeasure will be taken.

[Summary of the invention]

The present invention was made in view of these circumstances, and
The simple construction of the installation body housing, which stores and holds the piezoelectric element group and its related components, made of ferrite composite material suppresses the propagation of vibrations generated in the piezoelectric element group housed and held inside. This provides a fine movement device that improves the stability of high-precision displacement, which is desired from an operational point of view, and also achieves low noise.

〔Example〕

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

The drawing shows an embodiment of the fine movement device according to the present invention, and in the drawing, the reference numeral 1 indicates a shaft having a coupling means (screw hole 1a in this embodiment) with an object to be moved (not shown) at one end thereof. The other end of the shaft l is inserted into the housing 2, which has a rectangular cylindrical shape, through an opening 2a at one end thereof, and is bonded and fixed to the movable body 3 made of piezoelectric ceramics. That is, this movable body 3 includes a piezoelectric elastic element 4 configured to be expandable and retractable in the axial direction of the shaft 1 (its forward and backward direction), and a piezoelectric elastic element 4 arranged at both ends of the piezoelectric elastic element 4 and perpendicular to the expansion and contraction direction of the piezoelectric elastic element 4. It is constituted by a pair of piezoelectric clamp elements 5.6 at the front and rear which perform an expansion/contraction operation in the direction of movement. The shaft 1 is inserted into a hole 7a provided at the opening side end (left end in the figure) of a connecting member 7 whose right end in the figure is adhesively fixed to the center in the axial direction of the piezoelectric elastic element 4 described above. It is press-fitted and fixed. Note that 8 and 9 in the figure engage and hold both ends of the piezoelectric elastic element 4, and are adhesively fixed to the center portions of the above-mentioned front and rear pair of piezoelectric clamp elements 5 and 6 in the expansion and contraction direction, thereby making them movable. A pair of coupling members 10.11 integrated as the body 3 have U-shaped grooves for slidingly guiding both ends of the piezoelectric clamping elements 5 and 6 in the axial direction of the housing 2. A pair of guide members 12 provided in parallel to the inner wall of the housing 2 for guiding the movement of the movable body 3 in the axial direction hold the shirt 1 movably within the opening 2a of the housing 2. It is a ring member. Also,
In the figure, 7b is an opening provided in the connecting member 7 that holds the front end in the moving direction of the piezoelectric elastic element 4 and the front piezoelectric clamp element 5 in an M-fitting state.

According to the present invention, in the fine movement device having the above-mentioned configuration, the movable body 3 includes the piezoelectric expansion and contraction element 4 and a pair of front and rear piezoelectric clamp elements 5.6, and its related coupling members (1; 7. 8, 9, 10, and 11) is made of a ferrite composite material that is particularly excellent in terms of vibration absorption performance.

Here, as the double-stranded ferrite composite material, it is preferable to use Ferriston (trade name; manufactured by NEC Environmental Engineering Co., Ltd.) or the like. This is a composite material made of ferrite material and organic resin material, and its density is 3.
0~3.5 Xl01Kg/m', Young's modulus 18~2
? X 109N/m', logarithmic attenuation rate 0.04-0.06
It has extremely high damping properties, excellent external vibration isolation properties and shock vibration damping properties, and its vibration absorption effect is about 100% higher than that of conventionally used iron, aluminum, etc.
That's twice as much.

In the fine movement device having the above-described configuration, when a voltage is applied to the piezoelectric elastic element 4, this element 4
On the other hand, when voltage is applied to the front and rear piezoelectric clamp elements 5゜6,
These extend and contract in a direction perpendicular to the axial direction of the shaft 1, and when they extend, they press the guide members io and tt, thereby restraining their positions. Therefore, by not repeating the cycle of alternately applying a voltage to each piezoelectric element 4.5.6, the movable body 3 performs an inchworm movement, and as a result, the shirt (l) integrated with it moves in the direction of its axis. It moves forward and backward. However, the problem here is that the amount of displacement of the piezoelectric element mentioned above is minute, and in order to realize a large displacement or high speed as the movable body 3, a high frequency switching operation is required. . In such a fine movement device, when the above-mentioned high frequency switching operation is performed,
Vibration occurs in the piezoelectric element group, and this vibration is propagated to the housing 2 side through the guide member 10.11, but as described above, this housing 2 is made of a ferrite composite material with high vibration absorption performance. This vibration is absorbed and resonance is suppressed. Therefore, with such a configuration, even if the above-mentioned vibration occurs, it will not have any effect on the piezoelectric element group 4.5.6 and the shaft l.

Note that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each part may be modified and changed as appropriate.

For example, the material of the housing 2 mentioned above may be any ferrite composite material, and various materials other than the above-mentioned ferristone can be considered. Further, the shape and structure of each part of this fine movement device may be modified as necessary.

〔Effect of the invention〕

Claims (1)

[Claims] A piezoelectric micro-movement device that moves the driven shaft step by step by applying an electric field alternately to a piezoelectric element group consisting of a piezoelectric elastic element that expands and contracts in the axial direction and a pair of piezoelectric clamp elements installed at both ends of the element before and after performing a clamping action. A fine movement device, characterized in that a housing for storing and holding the piezoelectric element group and its related coupling members is formed of a ferrite composite material.