JPH0267772A - Piezoelectric driving gear - Google Patents

Abstract

PURPOSE:To execute a fine motion of a small-sized and high-accuracy rotation by a method wherein a rectlinear motion by an expansion and a contraction of a piezoelectric element for drive use is converted into a rotary motion and only the rotary motion in a desired direction is transmitted to a rotary body by an expansion and a contraction of a piezoelectric element for clutch use. CONSTITUTION:When electricity is supplied to a piezoelectric element 6 for drive use and this element is elongated, a driving pulley 5 is turned to the right direction via a steel wire 9b; however, when a clutch plate 3 is pressure- bonded to a fixed disk 4, its motion is not transmitted, Then, when electricity is stopped, the driving pulley 5 is turned to the left direction by a preliminary pressure of a spring 7. During this process, when electricity is supplied to a piezoelectric element 2 for clutch use, the clutch plate 3 is pressure-bonded to the driving pulley 5; the driving pulley 5 and a rotary body 1 are turned collectively to the left direction.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a piezoelectric drive device, and is particularly used for driving semiconductor manufacturing equipment and industrial robots. The present invention relates to a rotary piezoelectric drive device that moves and continuously operates by repeating minute movements.

[Prior Art] FIG. 3(a) is a plan view showing the configuration of a rotating machine # mechanism as an example of a piezoelectric drive device driven by a conventional piezoelectric element described in Japanese Patent Application Laid-Open No. 60-118072. FIG. 3(b) is a sectional view taken along the line mb-mb.

In the figure, (Ila), (llbl) are movable parts, and (12al).

(+2bl is fixing pressure 7r, x element, f13a), (
13bl, (13cl.

(13dl is a drive piezoelectric element, (14) is a rotating plate, (1
5) are vivo throat bearings, (16a), (16bl
is the fixed part.

Drive piezoelectric elements (13a), (13b), (13
One end of c:), (13d) is the fixed part (+6
al, (16bl), and the other end is fixed to either the movable part (Ilal, (llb), and the movable part (Ilb), +l1b) rotates around the hinge part. The pivot bearing (15) is provided on the hinge part, and the rotating plate (15) can be slightly deformed.
4) can rotate around the pivot bearing (15). The fixing piezoelectric elements (+2a) and (+2b) are the movable part (l
Ia), (I It has a structure in which it is fixed on Ibl and restrains and releases the rotary plate (14) by expansion and contraction.The piezoelectric element (+21) (13) is made of, for example, ceramics.

Next, the operation will be explained. For example, the operation on the right side as viewed in FIG. 3 will be explained. First, the identification piezoelectric element (12
a) is extended to restrain the rotating plate (14) to the movable part (11al).Next, by extending the drive piezoelectric element (13a) and contracting the drive piezoelectric element (13b), the movable part (I Ia
J and the rotating plate (14) restrained by it rotate iJI in the direction of arrow A. After that, the fixing piezoelectric element (12al) is contracted to open the rotating plate (14), and the driving piezoelectric element [1
If 3a) is contracted and the piezoelectric element (13b) is extended, the 5-rotation plate (14) will remain in the rotating state and the movable part (eye a) can be returned to its original position. By repeating the above operation, it becomes possible to give a large angle of rotation to the rotating part. Also, the drive piezoelectric elements (+3c) and (+3d) provided on the opposite side of the rotating plate (14) and the fixing piezoelectric elements (+3c) and (+3d) Since the piezoelectric element (+2bJ) and the movable part (llb) also operate in the same way as above, by alternately operating the - group of devices, it is possible to perform rotational operation without losing the rotation i (+41) constraint. Become.

[Problem to be solved by the invention] The idle piezoelectric side 17 device is configured as shown below, and the number of piezoelectric elements used for driving and fixing increases, and the piezoelectric elements themselves and their The mechanisms associated with support and displacement transmission made the device complicated and large. For this reason, there is a problem in that it is difficult to use it as a drive motor in fields that require a compact drive device, such as small optical devices and micromanipulators.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a piezoelectric drive device that is small in size and has a highly accurate rotational fine movement ability.

[Means for Solving the Problems] A piezoelectric drive device according to the present invention includes a drive pulley rotatably attached to a rotating body, a drive piezoelectric element whose one end is coupled to a fixed part and rotationally drives the drive pulley; a reverse drive means for rotationally driving the drive pulley in a direction opposite to the rotation by the drive piezoelectric element; a first wire having one end fixed to the drive pulley and the other end coupled to the fixed part via the reverse direction drive means;
A second wire has one end fixed to the driving pulley and the other end fixed to the driving piezoelectric element, a part of which is fixed to the rotating body, and the other part has a clutch plate, which controls the rotation of the driving pulley to the rotating body. A clutch piezoelectric element that can switch between transmission and non-transmission is provided, and the expansion and contraction of the drive piezoelectric element is transmitted to the drive pulley via the second wire, and the movement by the reverse drive means is transmitted via the first wire. When the rotation of the drive pulley is transmitted to the drive pulley and the drive pulley rotates around the rotating body, the clutch plate presses against the drive pulley and rotates when the rotation of the drive pulley is transmitted to the rotating body by the expansion and contraction of the piezoelectric element for the clutch. The clutch plate connects the body and the drive pulley, and when the rotation of the drive pulley is not transmitted to the rotating body, the clutch plate presses against the fixed part to connect the rotating body and the fixed part and drive the rotating body to rotate. It is.

[Function] The piezoelectric drive device of the present invention converts the linear motion caused by the expansion and contraction of the drive piezoelectric element into rotational movement by the second wire and the drive pulley, and by the expansion and contraction of the clutch piezoelectric element,
The rotating body is rotationally driven by transmitting only rotational motion in a direction that coincides with a desired rotational driving direction to the rotating body.

[Embodiment] Hereinafter, a piezoelectric drive device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partially sectional perspective view of a piezoelectric drive device according to an embodiment of the present invention. In FIG. 6, (1) is a rotating body, and (2) is a part, for example, one end is a rotating body (1). (3) is a cylindrical clutch piezoelectric element fixed to the clutch piezoelectric element (2), (3) is the other part of the clutch piezoelectric element (2), such as a clutch plate fixed to the other end, (4) is a fixed part of the case (not shown) ), and drive yI pulley 5 (6), which is rotatably mounted around the rotating body (1), is a cylindrical drive piezoelectric element, and The end face is fixed to the case, and the opposite end face has a bottom plate. (7) is a spring whose one end is connected to the fixed part, and serves as a reverse drive means for rotating the drive pulley (5) in the opposite direction to the direction of rotation by the drive piezoelectric element (6). .

(8) controls the clutch piezoelectric element (2) and the drive piezoelectric element (6)? (9a) is a first wire, (9b) is a second wire, and in this embodiment, the first wire (9a) and the second wire (9b) are one steel wire. It is wound around the drive pulley (5) in a U-shape. Furthermore, one end of the steel wire (9a), which is fixed to the drive pulley (5) at one point in the center of the U-shape and extended in the direction of contact, is always under the pressure of the spring (7).
) is fixed to the case via. In addition, one end of the steel wire (9b) is fixed to the bottom plate through the center of the drive piezoelectric if'-(6), so that a compressive force is always applied to the drive piezoelectric element (6), and the drive piezoelectric element is weak against tensile force. (6)
is constructed in such a way that it cannot be destroyed.

Next, the operation will be explained. Figure 2 (a), (bl
is related to this one embodiment! ! l) This is an explanatory diagram for explaining the operation, and for example, a case where the rotating body (1) is driven to rotate to the left will be described. As shown in FIG. 2(a), when the driving piezoelectric element (6) is energized and expanded, the steel wire (9b) fixed to the bottom plate receives this tension, and the driving pulley (5) Rotate to the right as in . At this time, the clutch piezoelectric element (2) is not energized, and the clutch plate (4) is not energized.
) is crimped onto the fixed disk (4) to connect the rotating body (1) and the fixed disk (4). Therefore, the drive pulley (5) idles, and the operation of the drive pulley (5) is not transmitted to the rotating body (1). In addition, at this time, the clutch plate (3) is connected to the fixed disc (
4), this prevents the rotating body ill from rotating due to the load torque applied to the rotating body (1).

Next, as shown in Fig. 2 fb), a drive piezoelectric element (5
) is no longer energized and the drive piezoelectric element (6) also contracts to its original state, the drive pulley (5) rotates to the left as shown by the arrow due to the preload force of the spring (7). . At this time,
The clutch piezoelectric element (2) is energized and the clutch Fi (
3) is crimped onto the drive pulley (5) to connect the rotary body and the drive pulley (5).Therefore, the drive pulley (5) and the rotary body rotate to the left as one.

As described above, in synchronization with the expansion and contraction of the driving piezoelectric element (6), the clutch piezoelectric element (2) is controlled by the control device (8), and the rotating body (1) of the driving pulley (5) is controlled. ), it is necessary to switch between transmission and non-transmission to the rotating body (
+1, and by repeating this operation, continuous operation can be realized. In this embodiment, one clutch pressure '+! With the element and one drive piezoelectric element, highly accurate rotational positioning can be performed, the device can be miniaturized, and furthermore, the structure is simple and the number of parts is small, so it can be inexpensive.

In addition, in the above embodiment, an example was shown in which the clutch piezoelectric element (2) and the control device (8) were directly connected, but the rotating body (+
The same effect can be obtained even if the wires are connected via a slip ring (not shown) provided between the case and the case.

Further, in the above embodiment, the steel wire (9al).

Although (9b) is shown as an example constructed with one steel wire, they may be constructed separately.Furthermore, steel wire (
Although an example is shown in which a spring (7) is connected to one end of 9a as a reverse direction driving means, a driving piezoelectric element is connected instead of this spring (7), and a driving piezoelectric element is connected to the steel wire (9b). The drive pulley (with the phase opposite to the piezoelectric element (6)
5) may be driven.

In addition, in the embodiment described in 1., the clutch piezoelectric element (2) connects the drive pulley (5) and the rotating body +1), and the fixed disc (
4) and the case in which clutch switching is performed exclusively for the connection of rotating body +11, but even if two piezoelectric elements are used for the clutch and both clutches are operated independently good.

[Effect of the Invention J As described above, according to the present invention, there is provided a drive pulley which is rotatably attached to a rotating body, a drive piezoelectric element whose one end is connected to a fixed part and which rotationally drives the drive pulley, and a drive pulley which is rotatably attached to a rotating body. Reverse drive to rotate the pulley (drive in the opposite direction to the rotation by the piezoelectric element): T-stage, one end fixed to the drive pulley,
a first whose other end is coupled to the fixed part via a reverse drive means;
Wire 5 A second wire having one end fixed to the driving pulley and the other end fixed to the driving piezoelectric element, a part of which is fixed to the rotating body and the other part has a clutch plate, and is used to rotate the driving pulley to the rotating body. Equipped with a clutch piezoelectric element that can switch between transmission and non-transmission of motion, the expansion and contraction of the drive piezoelectric element is transmitted to the drive pulley via the second wire, and the movement by the reverse drive means is transferred to the first wire. The clutch circular pressure is transmitted to the drive pulley through the
When the rotation of the drive pulley is transmitted to the rotating body by expansion and contraction of the core element, the clutch plate presses against the drive pulley to connect the rotating body and the drive pulley, and when the rotation of the drive pulley is not transmitted to the rotating body, The clutch plate is crimped onto the fixed part to connect the rotary body and the fixed part and drive the rotary body in rotation, which provides high-precision rotational fine movement capability and greatly reduces the number of parts including piezoelectric elements. The structure can be reduced to 11, and the structure is simple.
This has the effect of making it possible to obtain a small and inexpensive piezoelectric drive device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view, partially in section, of a piezoelectric drive device according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are explanatory views for explaining the operation of the embodiment. Figure 3 (a
t is a plan view showing the conventional piezoelectric part #I device, FIG. 3(b)
is a sectional view taken along the [IIb-uIb line in FIG. 3 (11). 5) Drive pulley, (6) Drive piezoelectric element, (7) Elastic body, (9a) First wire, (9b) Second wire. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A driving pulley rotatably attached to a rotating body, a driving piezoelectric element whose one end is connected to a fixed part and rotationally drives the driving pulley, and a driving piezoelectric element that rotates the driving pulley in the opposite direction to the rotation by the driving piezoelectric element. a first wire having one end fixed to the drive pulley and the other end coupled to the fixing part via the reverse drive means, one end fixed to the drive pulley and the other end driving the drive pulley; A second wire fixed to the piezoelectric element has a part fixed to the rotating body and a clutch plate in the other part, so that transmission/non-transmission of rotation of the drive pulley to the rotating body can be switched. A clutch piezoelectric element is provided, and the expansion and contraction of the drive piezoelectric element is transmitted to the drive pulley via a second wire, and the movement by the reverse direction drive means is transmitted to the drive pulley via the first wire. When the driving pulley rotates around the rotating body and the rotation of the driving pulley is transmitted to the rotating body by expansion and contraction of the clutch piezoelectric element, the clutch plate is pressed against the driving pulley. to connect the rotating body and the drive pulley, and when the rotation of the drive pulley is not transmitted to the rotating body, the clutch plate presses against the fixed part to couple the rotating body and the fixed part, A piezoelectric drive device, characterized in that the rotating body is rotationally driven.