JPS6348168A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To simplify and miniaturize a structure by using a rectangular spindle and connecting said spindle with a central expansion and contraction part so that clamped faces by two shaft clamping parts differ from each other. CONSTITUTION:A piezoelectric actuator is composed of a spindle 10 with rectangular cross section, a central expansion and contraction part 12 provided in the manner of surrounding said spindle, and first-second shaft clamping parts 14-16 connected with both ends of said part 12 to hold and separate the rectangular spindle 10. Said central expansion and contraction part 12 is composed of a laminated piezoelectric body and clamping parts 14-16 are composed of clamp bars 20 and expansion piezoelectric elements 22. Further, both clamping parts 14-16 are titted to the rectangular spindle 10 in directions differing from each other at an angle of 90 deg. and connected with the central expansion and contraction part 12 by a linking material 24. Thus, in respective shaft clamping parts 14-16, the clamp bars 20 are displaced by eypansion and contraction of the piezoelectric elements 22 to hold and separate the spindle 10 and a driving force is given to the shaft clamping parts 14-16 (spindle 10) as the central expansion and contraction part 12 is expanded and contracted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an actuator using a piezoelectric element,
In more detail, we use a square spindle and use two different types.
The present invention relates to a piezoelectric actuator in which a rectangular spindle is gripped and released by first and second shaft clamps on a pair of parallel surfaces.

[Prior Art] Precise positioning is extremely important in the manufacturing process of various electronic components and electronic devices including LSIs. It is no exaggeration to say that the performance of a product is determined by how precisely it can perform positioning.

Various actuators using piezoelectric elements are considered to be promising as such precision positioning drive devices, and various types of actuators have been developed.

In the conventional technology related to piezoelectric actuators, a shaft clamping section consisting of a ring-shaped piezoelectric element that can expand and contract in the radial direction and can clamp a spindle with a circular cross section is provided at both ends of a cylindrical laminated piezoelectric material that expands and contracts in the axial direction. The structure is such that the spindle passes through the interior, and the laminated piezoelectric material is expanded and contracted in the axial direction by alternately driving both shaft clamps to grip and release the spindle, and by the combination of these, the spindle moves like an inchworm. Mechanisms in which the spindle is moved intermittently along the spindle, or conversely, mechanisms in which the spindle is intermittently driven are known.

[Problems to be Solved by the Invention] However, in the piezoelectric actuator of the conventional structure as described above, two shaft clamp parts each consisting of a ring-shaped piezoelectric element are disposed on the same axis. They must have the same inner diameter and the same center. usually,
Since the amount of radial displacement of the piezoelectric element is extremely small, the gap between the spindle and the inner surface of the piezoelectric element requires highly accurate grinding. In that case, if one circular spindle is inserted into two ring-shaped piezoelectric elements as described above, it is not possible to deal with the problem by only grinding the outside diameter of the spindle side, so the piezoelectric element side must be ground inside the cylinder. However, it has the disadvantage that it is not only very expensive, but also extremely difficult to mass produce.

SUMMARY OF THE INVENTION An object of the present invention is to provide a piezoelectric actuator having a structure that eliminates the drawbacks of the prior art as described above and allows easy adjustment of the clearance between the spindle and the shaft clamp.

[Means for Solving the Problems] The present invention has a central extensible section having a piezoelectric material that is expandable and deformable in the axial direction, and first and second sections that are connected to both ends of the central extensible section and grip and release a spindle inserted therein. It is assumed that the piezoelectric actuator is equipped with a shaft clamp section.

In order to achieve the above object, in the present invention, the spindle has a rectangular cross section, and the shaft clamp part has clamp bars arranged parallel to each other so as to sandwich the square spindle, and the clamp bar is connected between both ends of the clamp bars. It has a structure in which the first and second shaft clamp parts are connected to the central telescopic part in directions 90 degrees different from each other.

[Function] In each shaft clamp section, the piezoelectric element expands and contracts, and the clamp bar is displaced to independently grip or release the square spindle. Further, the piezoelectric body of the central expandable portion expands and contracts in the axial direction by applying an external voltage to it or removing the voltage application thereto, thereby applying a driving force in the axial direction to the shaft clamp portion. By adjusting the timing of expansion/contraction deformation of the shaft clamp part and the timing of expansion/contraction deformation of the central piezoelectric body in a predetermined sequence, the device can be moved intermittently in the axial direction, or the device can be fixed and the spindle can be freed. If this is done, the spindle can be driven.

In the present invention, since the clamping surfaces of the first and second shaft clamp parts are different from each other by 90 degrees, the clearance between the square spindle and the shaft clamp part can be adjusted independently,
It can be handled by out-of-plane grinding of a square spindle, making it extremely easy to manufacture. Further, as described above, since the clamping surfaces of the first and second shaft clamping parts are different, movements such as rotation are naturally regulated, and there is no need for a guide rail or the like to define the operating plane as in the prior art.

[Embodiment] FIG. 1 is a perspective view showing an embodiment of a piezoelectric actuator according to the present invention. The piezoelectric actuator includes a spindle 10 having a rectangular cross section, a central telescopic portion 12 provided to surround the rectangular spindle 10, and first shaft clamps connected to both ends of the central telescopic portion 12 for gripping and releasing the rectangular spindle 10. section 14 and a second shaft clamp section 16.

In this embodiment, the central expandable portion 12 is made of a rectangular tube-shaped laminated piezoelectric material, and has a structure that can be expanded and contracted in the axial direction by removing and applying a voltage. On the other hand, the first and second shaft clamp parts 14.16 each have a clamp bar 20 disposed in parallel to sandwich the square spindle 10, and an expandable and retractable part that connects the ends of both clamp bars 20 with the same earthen floor. Piezoelectric element 22
It consists of

And the first and second shaft clamp parts 14°16 are 90°
It fits into the square spindle lO in different directions, and is connected to the central telescopic portion 12 by a link member 24. In other words, the second
As is clear from the figure, the first shaft clamp part 14 clamps the square spindle 10 between both sides, while the second shaft clamp part 16 clamps the square spindle 10 as shown in FIG. 10 is sandwiched between the upper and lower surfaces.

By applying a voltage to the extensible piezoelectric element 22, it contracts and narrows the gap between the clamp bars 20, thereby firmly holding the rectangular spindle 10, and by removing the voltage application, the rectangular spindle 10 can be placed in a free state. can be returned to.

As described above, the features of the present invention are that a rectangular spindle is used and that the first and second shaft clamp parts clamp the rectangular spindle in different parallel planes.

The operation of the piezoelectric actuator constructed in this way is as follows. If you want to fix the square spindle 1o and move the entire device, for example, to the right in the drawing (direction of arrow A),
Alternatively, if it is desired to fix the entire apparatus and drive the rectangular spindle 10 to the left in the drawing (in the direction of arrow B), do as follows. A voltage is applied to the extensible piezoelectric element of the left first shaft clamp part 14 to contract it, and the clamp bar 20
The square spindle 10 is clamped and fixed between both sides thereof.

The voltage to the center telescopic part 12 is released to cause it to expand, and in this state, a voltage is applied to the telescopic piezoelectric element of the second shaft clamp part 16 on the right side to contract it, and the clamp bar 20 is used to clamp the top of the rectangular spindle 10. Secure by sandwiching between the bottom surfaces.

Then, the voltage application to the telescopic piezoelectric element of the first shaft clamp part 14 is released to make it expand and become free with respect to the square spindle 10, and the voltage is applied to the laminated piezoelectric element of the central telescopic part 12 to contract it. .

Thereafter, by repeating such operations, it is possible to move in the above-mentioned direction.

If it is desired to drive in the opposite direction, the timing of the telescoping movements of the first and second shaft clamping parts 14,16 and the central telescoping part 12 may be changed.

In the present invention, since the first or second shaft clamp section always clamps the parallel surfaces of the rectangular spindle, rotation does not occur, and the operating plane can be defined only by the above configuration.

Although a preferred embodiment of the present invention has been described above in detail, it is understood that the present invention is not limited to only such a configuration. The clamp bar may be a simple flat plate structure, but in order to make it stronger and exert more ramp force, it is recommended to use a second clamp bar.
A protrusion may be provided on the inner surface side as shown in FIG. 3 and FIG. Alternatively, an adjustment screw may be provided passing through the clamp bar, and the amount of tightening thereof may be adjusted to adjust the clearance with the square spindle.

[Effects of the Invention] As described above, the present invention uses a square spindle and is connected to the central telescopic part so that the clamping surfaces of the two shaft clamp parts are different, so that the connection between the square spindle and the shaft clamp part is Since the clearance can be adjusted independently and can be handled by machining a square spindle outside the flat surface, it has the effect of making manufacturing extremely easy.

Furthermore, in the present invention, since the two shaft clamps are configured to clamp different opposing surfaces of the rectangular spindle, movements such as rotation are naturally regulated, and unlike conventional piezoelectric actuators, guide rails etc. that define the operating plane are not required. There is also the advantage that there is no need to provide a separate structure, and the structure can be simplified and downsized.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a piezoelectric actuator according to the present invention, FIG. 2 is an explanatory view of a first shaft clamping portion thereof, and FIG. 3 is an explanatory view of a second shaft clamping portion thereof. 10... Square spindle, 12... Central telescopic part, 1
4... First axis clamp part, 16... Second axis clamp part, 20... Clamp bar, 22... Expandable piezoelectric element, 24... Link material.

Claims (1)

[Claims] 1. A piezoelectric actuator comprising a central extensible section having a piezoelectric body that is expandable and deformable in the axial direction, and first and second shaft clamp sections that are connected to both ends of the central extensible section and grip and release the spindle inserted therein. has a rectangular cross-section, and the shaft clamp part is composed of clamp bars arranged in parallel to sandwich the square spindle and a telescopic piezoelectric element that connects both ends of both clamp bars, respectively.
A piezoelectric actuator in which first and second shaft clamp parts are connected to the central telescoping part in 90 degree different orientations.