JPH0526433B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an actuating device for moving parts of various types of equipment, such as cutting tools and microscope specimens, with high precision.

"Prior art" A rectilinear electric body that extends in the direction of a driven object when a voltage is applied, which is composed of laminated piezoelectric elements that extend in the axial direction when a voltage is applied, and both ends of the rectilinear piezoelectric body. A linear type whose side surface has an H-shape due to a pair of piezoelectric bodies at the rear and front, which are fixed to the surface in a direction perpendicular to this, expand in the same direction when a voltage is applied, and come into pressure contact with the bottom surface of the outer case. A piezoelectric motor (hereinafter referred to as a piezoelectric motor) has been proposed as a linear step motor in Japanese Patent Application Laid-open No. 100059/1983 (Japanese Patent Application No. 1983-1989).
8322).

"Problems to be Solved by the Invention" The piezoelectric motor disclosed in the above-mentioned Japanese Patent Application Laid-open No. 55-100059 has three groups of piezoelectric motors connected in an H shape, as will be described in detail in the embodiments that follow. Although signal voltages are sequentially applied to the body to move the entire body toward the driven body, there are intermittent stoppages, so
For example, when used as a driving body for a cutting tool, a problem arises in that a step corresponding to the stopping time is formed on the cutting surface.

"Means for solving the problem" Two sets of piezoelectric motors each consisting of three groups of piezoelectric bodies connected in an H shape are connected in the same driving direction, and the first
When the (first stage) piezoelectric motor stops, the second (next stage)
When the piezoelectric motor in the previous stage advances, the piezoelectric motor in the subsequent stage advances when the piezoelectric motor in the previous stage advances, thereby successfully making the driven object move continuously without stopping.

"Example" In Fig. 1, M ₁ and M ₂ both have a pair of rear and front piezoelectric bodies 1b and 1c for clamping at the rear and front ends of the piezoelectric body 1a for straight movement, and have a rectangular front face and an H-shape side face. The piezoelectric body 1a for straight movement is made of a thin plate of lead titanate-based compound, etc., and both main surfaces have metalized electrode surfaces (not shown) by baking silver or the like. ),
Polarized annular piezoelectric elements 11 are connected mechanically in series and electrically in parallel via an electrode plate 12 made of a thin plate of phosphor bronze, etc. Here, the outer ends of the piezoelectric elements at both ends are set as negative polarity sides. A tightening bolt 1 that is laminated and connected by a conductive wire (not shown) extending from an electrode plate 12 and inserted through the center hole of the laminated body in an insulated state.
3 is fastened to the seat surfaces 141a, 151a at the center of a pair of end plates 14a, 15a, and the end plates 14a, 15a have an outer diameter that is approximately equal to or less than the outer diameter of the stacked piezoelectric elements 11. The seat surfaces 141a, 151a are rectangular with sides slightly larger than
A pair of elongated pedestals 1 each extending in the longitudinal direction of the
42a, 142a and 152a, 152a, preferably the bearing surface opposite to the screwing side, 1 in the drawing.
The laminate of the piezoelectric element 11 and the electrode plate 12 is elongated due to the applied voltage between the head 131 of the tightening bolt housed in the recess 151a' bored on the 51a side and the bottom of the recess 151a'. The tightening bolt 13
Insert the spring 16 so that it is not obstructed by the

Next, the rear piezoelectric body 1b for clamping is arranged at the rear end of the piezoelectric body 1a for straight movement so that the side surface exhibits an H shape, and the front piezoelectric body 1c is arranged at the front end.
Similar to the linear piezoelectric element 1a, a polarized annular piezoelectric element 1 is formed with metalized electrode surfaces on both main surfaces.
1 and 11 are stacked and connected mechanically in series and electrically in parallel via electrode plates 12 and 12, and tightening bolts 13 and 13 are inserted insulatively through the center holes of these stacked bodies. A pair of end plates 1 each having a rectangular shape with sides equal to or slightly larger than the outer diameter of the laminate.
4b, 15b and 14c, 15c, and preferably have a thin layer of insulating paint (not shown) formed on the outer peripheral surface according to a conventional method. 14c and 15c are pedestals 142a and 142 extending vertically from the end plates 14a and 15a of the straight piezoelectric body 1a, respectively.
a, 152a, and 152a by bolts 17 and 17, etc., so as to form an H-shaped side surface. These bolts 17, 17 are connected to the end plates 14b, 17 so as not to hinder the elongation of the piezoelectric elements 11 of the rear and front clamping piezoelectric bodies 1b and 1c, respectively, when they expand in response to voltage. 15b, 14c, 15c, here only the lower 14b and 14c side, and the other end plate 15b, 15c is simply brought into close contact with the pedestal 142a, 152a on the end face of the straight-travel piezoelectric body 1a so that it can freely slide. , the end plate 1 as before
Springs 16 and 16 are inserted between the bottoms of recesses 15b' and 15c' bored in holes 5b and 15c and the heads 131 and 131 of the tightening bolts 13 and 13, and these side surfaces are H-shaped. The assembly of the piezoelectric body 1a and the pair of clamping piezoelectric bodies 1b, 1c corresponds to the elongated front shape of the assembly, and the clamping piezoelectric bodies 1b, 1c normally slide freely and maintain voltage. A rectangular through hole 21 in which the end surfaces of the end plates 14b, 15b and 14c, 15c are pressed and fixed to the opposing bottom surfaces 211, 211, respectively, and cannot slide when the end plates 14b, 15b and 14c, 15c extend in the axial direction The rear end plate 1 of the rectilinear piezoelectric body 1a is housed in a cylinder 2 having
Similarly to 4a, the board 3 is attached with the tightening bolt 17, and the operating rod 4 is provided to protrude.

The first linear piezoelectric motor assembled in this way
M ₁ and the second linear piezoelectric motor M ₂ are connected to a driven body such as a coupled tool stand T as shown in FIG.
In the figure, the second linear piezoelectric motor M ₂ is placed on the slider S, but this slider S is omitted and the first and second piezoelectric motors M ₁ and M ₂ are directly connected to each other.
may be concatenated.

"Function" Now, the piezoelectric body ₁ for straight movement of the first piezoelectric motor M1
From the state before operation of the three groups of a and the pair of clamping piezoelectric bodies 1b and 1c, (a) applying a direct current voltage (hereinafter referred to as voltage) to the rear clamping piezoelectric body 1b to make it expand in the vertical direction; The end plates 14b and 15b at both ends are pressed and fixed to the bottom surfaces 211 and 211 of the through hole of the cylinder 2.

(b) While maintaining this state, a voltage is applied to the straight movement piezoelectric body 1a, and the end plate 14 is brought into contact with and fixed to the end plates 14b and 15b of the rear piezoelectric body 1b for clamping.
End plates 14c and 15 extend horizontally using a as a base and abut and fix with the opposite end plate 15a.
The front piezoelectric body 1c for clamping having the piezoelectric body 1c and the actuating rod 4 extending from the piezoelectric body through the substrate 3 are extended forward.

(C) In this state, a voltage is applied to the front clamping piezoelectric body 1c to make it expand in the vertical direction, and the end plates 14c and 15c at both ends are attached to the bottom surface of the through hole 21 of the cylinder in the same way as in (A) above. 211, 211
Press and fix.

In this state, the rectilinear piezoelectric pair 1a is extended in the through hole 21 of the cylinder, and the rear and front piezoelectric members 1b for clamping are also extended and fixed to the bottom surfaces 211, 211 of the cylinder through hole 21. It is fixed at 1c.

(d) In this way, three groups of piezoelectric bodies 1a, 1b and 1c
When the entire length of the clamping piezoelectric body 1b is fully extended, the voltage applied to the rear clamping piezoelectric body 1b is released, its full length is restored and shortened, and the piezoelectric body 1b is released from the through hole 21 of the cylinder.

(e) Next, the voltage applied to the straight-travel piezoelectric body 1a is released, its full length is restored and shortened, and together with the rear clamping piezoelectric body 1b released from the through hole 21 of the cylinder, the front fixed clamping It is pulled toward the piezoelectric body 1c.

(f) Finally, the voltage applied to the front clamping piezoelectric body 1a is released, and the piezoelectric body 1c is released from the through hole 21 of the cylinder to return to the state before the initial operation.

The process consisting of (a) to (f) is regarded as one cycle, and from the initial state, the piezoelectric bodies 1a, 1b and 1c are assembled in an H shape, and the linear piezoelectric body 1a is elongated by d. Move forward. This state is shown in FIGS. 3A to 3F.

In addition, the steps (a) to (f) above are, for example, (a) and (b),
(d)
and (e) can be performed in one step, and the order of voltage application is not limited to the above embodiments and can be changed.

By repeating the above steps (a) to (f), the amount of displacement (movement dimension) increases over time as shown in Figure 4A, but during the above steps, during time period (d), the displacement However, in the present invention, a second piezoelectric motor M2 exhibiting the same time-displacement as _M1 is used instead of the second piezoelectric motor _M2 , which exhibits the same time-displacement amount as M1. 1
mechanically connected in series with the piezoelectric motor M ₁ of the fourth
The first and second The time-displacement amounts of the piezoelectric motors _M1 and _M2 are linearized as in No. 4C.

[Effects of the Invention] The piezoelectric motor actuating device of the present invention having the above-mentioned configuration moves linearly and continuously without intermittent movement, and is therefore highly effective as a fine movement feed device for various precision instruments. In addition, in order to simplify the explanation, the moving speed is the same as the displacement time in steps (a) to (c) and (a)' to (c)' in FIGS. 4A and B.
C)～(F)
and (c)′ to (f)′, making the intermittent time without displacement equal,
Although the displacement speed is doubled as shown in C in the same figure, the displacement speed can be further increased by setting the voltage application time to each piezoelectric body so that the displacement time is increased and the time during which no displacement is shortened. be able to.

[Brief explanation of the drawing]

FIG. 1A is a side sectional view showing the basic aspect of the linear piezoelectric motor used in the present invention, and FIG. 1B
1A is a cross-sectional view taken along line A--A in FIG. An explanatory diagram of each process showing the operating state of the motor actuating device, and Fig. 4 is a diagram showing the relationship between time and displacement of the linear piezoelectric motor, and Fig. 4A is a diagram showing the relationship between the time and the displacement amount of the linear piezoelectric motor. Figure B shows the case of the second piezoelectric motor alone, and Figure 4C shows the case of the actuating device of the present invention in which the first and second piezoelectric motors are connected. 11...Piezoelectric element, 1a...Piezoelectric body for straight movement, 1
b...Rear piezoelectric body for clamping, 1c... Piezoelectric body for front clamp, _M1 ...first linear piezoelectric motor, _M2 ...second linear piezoelectric motor.

Claims (1)

[Claims] 1 A linear piezoelectric body 1a housed in a cylinder 2 and made up of a plurality of laminated piezoelectric elements 11 that expand in the axial direction when a voltage is applied, and actuated in the direction of a driven object; Rear and front clamping piezoelectric bodies 1b are fixed to both end faces of the body with H-shaped side surfaces perpendicular thereto and operate in the same direction.
and 1c, and two sets M ₁ and M ₂ of first and second linear piezoelectric motors move forward and stop repeatedly by voltages applied alternately to these three groups of piezoelectric bodies. an actuating device for a linear piezoelectric motor, characterized in that the following are connected so that when one stops, the other moves.