JPH04150780A - Piezoelectric motor - Google Patents

Abstract

PURPOSE:To prevent the pulsating rotation of an output shaft by fixing many piezoelectric elements in the centripetal direction at the cylindrical inside periphery of a fixed housing, and opening and bearing a flexible deformed ring, which does not have teeth, on the inside driving faces of the piezoelectric elements. CONSTITUTION:When voltage is applied to the piezoelectric elements 6a and 6b positioned in the vicinity on one side of a contact P, the piezoelectric elements 6a and 6b elongate in the centripetal direction, that is, toward the axis of the output shaft 2, and pushes up a flexible deformed ring 7 as shown by a two-dot chain line, and makes the pressure act on the inside periphery of a rolling ring 5, but the crank shaft 4 is in the eccentric position to the output shaft 2, so the centripetal pressure produces the component for rotating the crank shaft 4 in the direction A around the output shaft 2, and the rolling ring 5 rolls in the direction B while being inscribed in the inside periphery of the flexible deformed ring 7, and shifts in the direction opposite to the port, and rotates the output shaft 2 in the direction A.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a prime mover that can be used in various ways as a drive motor for robots and the like.

2. Description of the Related Art A conventional piezoelectric motor has teeth TI on its outer periphery, as shown in FIG.
A fixed shaft S having a plurality of, for example, eight piezoelectric elements E fixed radially is arranged in a flexible deformable ring R having ugly teeth T2
Two piezoelectric elements E1 and E2 extend in the vertical direction, and two piezoelectric elements E extend in the horizontal direction.

A voltage is applied to each piezoelectric element so that E4 and E4 contract. Note that (number of teeth T, x number of teeth T2).

Then, as shown in FIG. 3, the flexible deformable ring R is distorted into an elliptical shape and the long axis direction is elongated, and the teeth T of the flexible deformable ring are
1 and the meshing tooth T2 of the rolling wheel mesh with each other.

In this way, the meshing position of the two teeth T1 and T2 is controlled by the voltage applied to each piezoelectric element, so by switching the voltage of each piezoelectric element in an orderly manner, the meshing position of the two teeth T, T2 can be adjusted. The rolling wheel F can rotate the flexible deformable ring R by one rotation, and the rolling wheel F has a tooth number difference (TI
T2).

Therefore, by continuing to switch the voltages mentioned above,
This is to drive the rolling wheels F to rotate.

Problems to be Solved by the Invention In the conventional piezoelectric motor described above, since the elliptical gear on the outer periphery of the flexible transformation ring R meshes with the annular gear formed on the inner periphery of the rolling wheel F, the expansion and contraction stroke of the piezoelectric element If it is not large, there is a risk that the teeth will not fully engage and disengage.
Since the piezoelectric elements are arranged at a distance, the elliptical deformation of the flexible deformable ring is displaced into a polygonal shape, causing pulsation in the rotation of the rolling wheel F, and furthermore, the flexible deformable ring has many teeth cut into it. Therefore, it has the disadvantage of lacking durability against repeated bending deformation.

Problems and Means for Solving the Problems The present invention solves the above-mentioned drawbacks of the prior art, in which a large number of piezoelectric elements are fixed in the centripetal direction of the cylindrical inner peripheral surface of a fixed housing, and the piezoelectric elements are driven inside. A crankshaft formed on the output shaft, which supports a flexible deformable ring having no teeth on its surface in an expanded manner, and has a rotatable output shaft disposed on the central axis of the cylindrical inner circumferential surface of the fixed housing. A rolling ring that is inscribed in the flexible deformable ring and rolls thereon is rotatably supported.

Operation When a voltage is applied to the piezoelectric element located near one side of the contact point of the rolling wheel inscribed in the flexible deformable ring, the piezoelectric element extends in the centripetal direction and presses against the outer peripheral surface of the rolling wheel.

The pushing force acts in the centripetal direction of the output shaft, but since the output shaft and the rolling wheels are in eccentric positions, a force that pushes the rolling wheels is generated, so the rolling wheels flexibly deform around the output shaft. Rolls internally against the inner peripheral surface of the ring.

Therefore, by sequentially switching the voltage applied to the piezoelectric element in the circumferential direction, the rolling wheel rolls on the inner circumferential surface of the flexible deformable ring and moves internally, so the crankshaft rotates around the output axis. This will give rotational motion to the output shaft.

Embodiment FIG. 1 is a front cross-sectional view of the present invention, and FIG. A crankshaft 4 is formed by the crank plate 3, and a rolling wheel 5 is rotatably supported on the crankshaft 4.

Further, on the cylindrical inner peripheral surface 1' of the housing 1, a large number of piezoelectric elements 6 are fixedly arranged at equal intervals in the centripetal direction, and on the inner driving surface of the piezoelectric elements 6 there are provided flexible A deformable ring 7 is supported in an expanded manner, and the outer periphery of the rolling wheel 5 is inscribed in the inner peripheral surface of the flexible deformable ring 7. In FIG. 2, the rolling wheel 5 has a flexible deformable ring 7 at the contact point P.
is inscribed in

Therefore, the piezoelectric elements 6a, 6 located near one side of the contact P
When a voltage is applied to the piezoelectric element 6a.

6b extends in the centripetal direction, that is, toward the center of the output shaft 2 as shown in FIG. However, since the crankshaft 4 is at an eccentric position with respect to the output shaft 2, the pressing force in the centripetal direction generates a component force that rotates the crankshaft 4 in the direction of arrow A around the output shaft 2, and the rolling wheels 5 rolls in the direction of the arrow while being inscribed in the inner periphery of the flexible deformable ring 7, moves in the opposite direction, and rotates the output shaft 2 in the direction A.

Therefore, by sequentially switching the voltage applied to the piezoelectric element 6, the rolling wheel 5 undergoes internal rotation in the direction of the arrow and continues to move in the opposite direction, so that the output shaft 2 is given continuous rotation in the direction A. , rotation is produced on the output shaft.

Moreover, when braking the rotation of the output shaft 2, it is sufficient to apply a voltage to the piezoelectric elements 6c and 6d on the other side of the contact P to cause them to expand, thereby preventing the rolling wheels 5 from inwardly moving.

Furthermore, since the phase of the rolling wheels when they are stationary can be detected by an encoder attached to the output shaft or other known means, the output shaft can be driven by applying a voltage to the piezoelectric element in accordance with the position of the rolling wheels. , the stop can be controlled.

Effects of the Invention In the present invention, the inner driving surface of the continuously disposed piezoelectric element pushes the rolling wheel via the continuous surface of the flexible deformable ring, so that the pushing action is continuously applied. This prevents pulsating rotation of the output shaft, and the rotation is imparted to the output shaft by the rotational movement of the internal rolling wheels, not by the meshing of teeth as in the conventional example, but by the rotation and revolution of the internal rolling wheels. Without providing meshing teeth on the flexible deformable ring, the durability of the deformable ring, which is repeatedly bent, is significantly improved, and the speed can be controlled freely, including forward and reverse directions, resulting in significant effects. be.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of the present invention, FIG. 2 is a side sectional view of the same, and FIG. 3 is a side sectional view of the conventional example. 1... Fixed housing 2... Output shaft 4... Crankshaft 5... Rolling wheel 6... Piezoelectric element 7... Flexible deformable ring Fig. 2b Fig. 3

Claims (1)

[Claims] A large number of piezoelectric elements are fixed on the cylindrical inner peripheral surface of the fixed housing at equal intervals in a centripetal direction, and a flexible deformable ring having no teeth is supported in an expanded manner on the inner drive surface of the large number of piezoelectric elements, A rotatable output shaft is disposed on the central axis of the cylindrical inner peripheral surface of the housing, and a rolling ring that is inscribed in the flexible deformable ring and rolls on a crankshaft formed on the output shaft is rotatable. A piezoelectric motor supported on.