JPH0520632B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an actuator, and more particularly to an actuator that drives a moving object by effectively utilizing the displacement force of a piezoelectric element.

2. Description of the Related Art Actuators that utilize fluid pressure, such as hydraulic pressure or air pressure, have been widely used for transporting moving objects in various machines. Actuators of this type are essential to drive systems in order to generate relatively large forces and strokes. On the other hand, this type of actuator has hitherto encountered a problem in that it is difficult to control it with high precision because it uses fluid.

By the way, piezoelectric elements (piezo) have been attracting attention in recent years. In other words, the displacement force of a piezoelectric element is obtained by the distortion that occurs when an electric field is applied to a certain type of crystal or sintered body. Therefore, if this displacement force is used to drive a moving body, Since the drive is based on an electric field, it is easy to control and has high accuracy.

Therefore, the present invention was made by focusing on the remarkable performance improvement of piezoelectric elements in recent years such as the invention of composite piezoelectric ceramics, and the present invention is designed to effectively utilize the displacement force of piezoelectric elements to drive a moving object. The purpose is to provide a new actuator.

To achieve the above object, the present invention comprises a main body part 14 and a displacement member 16, the displacement member 16 having a horizontal part 22 and a second part extending in opposite directions from both ends of the horizontal part 22. The first vertical portion 18 has a first vertical portion 18 and a second vertical portion 24, the tip of the first vertical portion 18 is fixed to the main body portion 14, and the horizontal portion 22 has a first vertical portion 18 that expands and contracts in the axial direction. The second vertical part 24 has a second piezoelectric element unit 26b which expands and contracts in the axial direction thereof, and the first
Piezoelectric element unit 26a and second vertical portion 24
It is characterized by displacing a desired moving body in a predetermined direction via the .

Hereinafter, preferred embodiments of the actuator according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of an actuator according to the present invention.

In the figure, reference numeral 10 indicates a moving body, and this moving body 10 is configured to reciprocate in the direction of arrow A in the figure by an actuator 12, which will be described later. The actuator 12 includes a main body 14 and a substantially square rod-shaped displacement member 16 implanted on the surface of the main body 14. That is, the displacement member 16 includes a horizontal portion 22 that once extends in the horizontal direction from the end of the first vertical portion 18 in FIG.
It has a second vertical portion 24 extending vertically downward from the end portion of the horizontal portion 22, and has a bent shape as a whole. Note that the displacement member 16
is formed in the shape of a round bar with a circular cross section, and the tip of the first vertical portion 18 is press-fitted into a mounting hole 20 formed on the surface of the main body 14 and fixed to the main body 14. Piezoelectric element units 26a and 26b constituted by stacking piezoelectric elements are disposed in a portion of the horizontal portion 22 and vertical portion 24.

That is, the first and second piezoelectric element units 26a and 26b are formed by laminating a large number of disk-shaped piezoelectric ceramics into round rod shapes with a predetermined length extending in the axial direction, and the power wires 28a and 28b They are each independently connected to a DC (not shown) via. Therefore, in this embodiment, when a voltage of a predetermined polarity is applied to the first and second piezoelectric element units 26a and 26b via the power supply lines 28a and 28b, the horizontal portion 22 and the second vertical portion Each of the sections 24 can be extended and displaced in the longitudinal direction (axial direction).

The actuator according to the present invention is basically constructed as described above, and its operation and effects will now be explained with reference to FIGS. 2a to 2d.

Now, when it is desired to move the movable body 10 in the right direction from the state shown in FIG.
A predetermined voltage is applied to the terminal via the power supply line 28b. As a result, the second vertical part 24
The piezoelectric element unit 26b is elongated and displaced in its axial direction, and its tip end surface 24a is displaced as shown in FIG.
comes into contact with the surface of the moving body 10 and is strongly pressed against it.

Next, while maintaining the above state, this time the horizontal part 22
Similarly, the power line 2 is connected to the first piezoelectric element unit 26a.
A predetermined voltage is applied via 8a. As a result, the first piezoelectric element unit 2 in the horizontal portion 22
6a is extended and displaced in its axial direction, that is, in the horizontal direction in the figure, as in the state shown in FIG. 2b. At this time, the distal end surface 24a of the second vertical portion 24 remains pressed against the movable body 10, so the movable body 10 is moved in the horizontal direction shown by the arrow due to the frictional resistance between the distal end surface 24a and the movable body 10. Move to. Of course, the opposite surface (not shown) of the movable body 10 is held by appropriate means so as to be horizontally slidable.

Thereafter, the application of voltage to the second piezoelectric element unit 26b of the second vertical portion 24 is stopped.
As a result, the piezoelectric element unit 26b is contracted and displaced, and its tip end surface 24a is separated from the surface of the moving body 10 (see the state shown in FIG. 2c).

Finally, the application of voltage to the first piezoelectric element unit 26a of the horizontal portion 22 is stopped.
As a result, the piezoelectric element unit 26a is contracted and displaced in the horizontal direction (see the state shown in FIG. 2d), and the displacement member 16 eventually returns to the state shown in FIG. 1.

In this way, the displacement member 16 is moved from the vertical displacement (extension displacement) in the second piezoelectric element unit 26b to the horizontal direction displacement (extension displacement) in the first piezoelectric element unit 26a to the second piezoelectric element unit 2.
If the vertical displacement (contraction displacement) at 6b→horizontal displacement (contraction displacement) at the first piezoelectric element unit 26a is repeated as one cycle, the movable body 10 is sequentially moved to the right in the figure. . In other words, the displacement member 16 moves like a so-called inchworm to linearly move the movable body 10 by a predetermined stroke.

On the other hand, when it is desired to move the movable body 10 to the left from the state shown in FIG. (Extension displacement)→Horizontal displacement (contraction displacement) in the first piezoelectric element unit 26a→Second
It will be easily understood from the above explanation that the vertical displacement (contraction displacement) in the piezoelectric element unit 26b can be repeated as one cycle.

Next, FIGS. 3 to 5 show the embodiments of the actuator shown in FIGS. 2 to 4 according to the present invention.

That is, in the embodiment shown in FIG. 3, the tip surface 24 of the second vertical portion 24 is different from the embodiment shown in FIG.
Further, an elastic body 30 made of rubber or the like is disposed at a. With this configuration, it is possible to increase the frictional resistance during pressure bonding with the movable body 10, and the movable body 10
displacement can be further ensured.

Furthermore, FIG. 4a shows the displacement member 1 in FIG.
6 are arranged in a plurality of directions outward in the circumferential direction with respect to the shaft-shaped moving body 10, and are arranged in multiple stages in the axial direction, and the period of the displacement operation is also directed in the circumferential direction and is arranged in a plurality of stages. An embodiment is shown in which the displaceable members 16 arranged have the same period, and the displaceable members 16 disposed in multiple stages in the axial direction are sequentially and continuously displaced, as shown in FIG. 4b.

For example, in FIG. 4c, the moving body 10 moves intermittently because the displacement member is in one stage. However, if the movable body 10 has multiple stages as in this embodiment, the moving speed of the movable body 10 in the axial direction will be uniform, and the movable body 10 will move smoothly, as shown in FIG. 4d. In other words, the moving body 10 achieves more continuous axial movement than intermittent axial movement.

FIG. 5 shows an embodiment in which the actuator in FIG. 4a is applied as an actuator for an on-off valve. That is, the displacement members 16 arranged in multiple stages
A poppet-shaped valve body 32 is fixed to the distal end of the movable body 10, which moves in the axial direction, and is provided adjacent to a valve chamber 36 in a valve housing 34 formed integrally with the main body 14.

Therefore, by applying a voltage with a predetermined polarity to the displacement member 16, the movable body 10 moves forward and backward in the left and right directions in the figure with respect to the valve port 38 communicating with the valve chamber 36, thereby controlling the opening and closing of the valve. becomes possible.

As explained above, according to the present invention, the displacement member is installed in the main body in a bent state, and at least a portion of the horizontal portion and the vertical portion of the displacement member is A piezoelectric element unit is provided which is displaced in the axial direction. Therefore, by effectively utilizing the displacement force of the piezoelectric element unit to drive the movable body in an arbitrary direction, it is possible to easily realize an actuator that is easy to control and has reliable positioning.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various improvements and changes in design are possible without departing from the gist of the present invention. Of course.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a first embodiment of the actuator according to the present invention, FIGS. 2a to 2d are schematic cross-sectional explanatory views showing the operating sequence of the actuator in FIG. 1, and FIG. 4 is a schematic cross-sectional explanatory diagram showing a second embodiment of the actuator according to the present invention;
Figure a is a schematic cross-sectional explanatory diagram showing the third embodiment of the actuator according to the present invention, Figure 4b is a time chart of each displacement member arranged in multiple stages in Figure 4a, and Figure 4c is a FIG. 4d is a velocity characteristic diagram of a moving body in the actuator of FIG. 1, FIG. 4d is a velocity characteristic diagram of a moving body in the actuator of FIG. 4a, and FIG. 5 is a fourth embodiment of the actuator according to the present invention. FIG. 4 is a schematic cross-sectional explanatory diagram showing an example of application of the actuator of FIG. 4a; 10... moving object, 12... actuator, 1
4...Main body part, 16...Displacement member, 18...Vertical part, 20...Mounting hole, 22...Horizontal part, 24
... Vertical portion, 26a, 26b ... Piezoelectric element unit, 28a, 28b ... Power supply line, 30 ... Elastic body, 32 ... Valve body, 34 ... Valve housing, 36
... Valve room, 38... Valve mouth.

Claims (1)

[Scope of Claims] 1. Consists of a main body portion 14 and a displacement member 16, wherein the displacement member 16 includes a horizontal portion 22 and a horizontal portion 22.
A first vertical section 18 and a second vertical section 24 extend in opposite directions from both ends of the main body 14, and the tip of the first vertical section 18 is fixed to the main body 14, and the horizontal The section 22 has a first piezoelectric element unit 26a that expands and contracts in its axial direction, and the second vertical section 24 has a second piezoelectric element unit 26b that expands and contracts in its axial direction,
An actuator that displaces a desired moving body in a predetermined direction via the first piezoelectric element unit 26a and the second vertical portion 24. 2. The actuator according to claim 1, in which an elastic body 30 with a high coefficient of friction is disposed on the end face of the distal end of the second vertical portion 24 constituting the displacement member 16.