CN109889089B - Twice stepping piezoelectric rotary driver - Google Patents

Abstract

The application relates to a twice stepping piezoelectric rotary driver, which comprises a base, a driving flexible hinge, a piezoelectric stack, a U-shaped plate, a parallelogram flexible hinge a, a parallelogram flexible hinge b, a rotary platform, a bearing, a triangular microprotrusion, a base and a mandrel, wherein the base is provided with a first driving flexible hinge and a second driving flexible hinge; the positive pressure between the outer surfaces of the parallelogram flexible hinges a and b and the rotating platform can be changed by the parallelogram flexible hinges a and b which are symmetrical about the center line of the mandrel, the triangular microprotrusions which are symmetrical about the center line of the mandrel enable the friction coefficients of the outer surfaces of the parallelogram flexible hinges a and b along the positive direction and the negative direction of the X axis to be different, under the combined action of the positive and negative directions, the electric signals excite the extension/shortening deformation of the piezoelectric stack to drive the U-shaped plate to reciprocate along the positive direction and the negative direction of the X axis, and in one working period, the parallelogram flexible hinges a and b alternately drive the rotating platform to realize two rotations in the anticlockwise direction.

Description

A Two-step Piezoelectric Rotary Driver

technical field

The invention relates to a two-step piezoelectric rotary driver, which belongs to the technical field of micro-nano precision driving.

Background technique

With the rapid development of precision ultra-precision machining, electronics, biotechnology, precision measurement and other fields, the requirements for micro-nano precision drive technology are getting higher and higher, and various research institutions are also actively developing large-travel, high-precision piezoelectric actuators. research. In the existing large-stroke, high-precision piezoelectric actuators, the driving process can usually be divided into the piezoelectric stack extension stage and the piezoelectric stack retraction stage, using the slow elongation and rapid retraction of the piezoelectric stack accomplish. During this process, the positive rotation of the driver can only be achieved through the extension stage of the piezoelectric stack, and the retraction stage of the piezoelectric stack cannot make the driver rotate forward, and even cause the driver to retreat, which greatly reduces the driving force of the driver. output efficiency.

Contents of the invention

In order to improve the output efficiency of the driver while realizing large stroke and high precision, the invention discloses a two-step piezoelectric rotary driver.

The present invention is realized through the following technical solutions:

A two-step piezoelectric rotary driver, including a base, a driving flexible hinge, a piezoelectric stack, a U-shaped plate, a parallelogram flexible hinge a, a parallelogram flexible hinge b, a rotating platform, a bearing, a triangular micro-protrusion, The base and the mandrel; the base, the driving flexible hinge and the U-shaped plate are rigidly connected in sequence, fixed on the base through the base, the piezoelectric stack is tightly fitted inside the driving flexible hinge, and the two U-shaped arms of the U-shaped plate The inner side is provided with parallelogram flexible hinges a, b, and the outer surface of the parallelogram flexible hinges a, b is processed with triangular micro-protrusions, the triangular micro-protrusions are in contact with the rotating platform, and the rotating platform, bearings, and mandrels are installed on the base in cooperation; The parallelogram flexible hinge a is inclined to the U-shaped bottom of the U-shaped plate, and the parallelogram flexible hinges a and b symmetrical to the center line of the mandrel can change the positive pressure between the outer surface of the parallelogram flexible hinge a and b and the rotating platform, The triangular micro-protrusions that are symmetrical about the center line of the mandrel make the friction coefficients of the outer surfaces of the parallelogram flexible hinges a and b different along the positive and negative directions of the X-axis. Under the joint action of the two, the electric signal excites the piezoelectric stack. The elongation/shortening deformation drives the U-shaped plate to reciprocate along the positive/negative direction of the X axis. In one working cycle, the parallelogram flexible hinges a and b alternately drive the rotating platform to realize two rotations in the counterclockwise direction.

The inner sides of the two U-shaped arms of the U-shaped plate are provided with parallelogram flexible hinges a and b with the same inclination angle. When the piezoelectric stack is extended, the U-shaped plate moves in the negative direction of the X-axis, and the outer surface of the parallelogram flexible hinge b is affected by the force along the X-axis. Under the action of friction in the positive direction of the axis, the parallelogram flexible hinge b has a tendency to deform in the positive direction of the X-axis, and the positive pressure between it and the surface of the rotating platform decreases, and the outer surface of the parallelogram flexible hinge a is subjected to friction along the positive direction of the X-axis force, has a tendency to deform toward the positive direction of the X-axis, and the positive pressure between the surface of the rotating platform increases, so that the friction between the parallelogram flexible hinge a and the rotating platform is greater than that between the parallelogram flexible hinge b and the rotating platform The friction force of the rotating platform rotates counterclockwise; when the piezoelectric stack shortens, the friction force between the parallelogram flexible hinge b and the rotating platform is greater than the friction force between the parallelogram flexible hinge a and the rotating platform, so that the rotating platform continues to reverse The hour hand rotates.

Non-centrosymmetric triangular micro-protrusions are processed on the outer surfaces of the parallelogram flexible hinges a and b, and the inclination direction of the triangular micro-protrusions is consistent with the inclination direction of the parallelogram flexible hinge, so that the friction coefficient on the inclined side is greater than that on the other side One side; the friction coefficient of the outer surface of the parallelogram flexible hinge a along the positive direction of the X axis is greater than that along the negative direction of the X axis; the friction coefficient of the outer surface of the parallelogram flexible hinge b along the negative direction of the X axis is greater than that along the positive direction of the X axis coefficient of friction.

The beneficial effect of the present invention is that: using one piezoelectric stack in one working cycle, the driver generates two steps, and the output efficiency of the driver is improved.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention, and constitute a part of the application. The schematic examples and descriptions of the present invention are used to explain the present invention, and do not constitute improper limitations to the present invention.

Figure 1 shows a schematic diagram of the overall structure of the present invention;

Fig. 2 shows the working principle diagram of the present invention;

Fig. 3 shows the enlarged view of the triangular micro-protrusion on the surface of the parallelogram flexible hinge a of the present invention;

Figure 4 shows an enlarged view of the triangular micro-protrusion on the surface of the parallelogram flexible hinge b of the present invention;

Detailed ways

The detailed content of the present invention and its specific implementation will be further described below in conjunction with the accompanying drawings.

Referring to FIG. 1 to FIG. 4 , this embodiment provides a specific implementation of a two-step piezoelectric rotary driver. The two-step piezoelectric rotary driver uses a piezoelectric stack (3) to make the driver produce two steps in one working cycle; the structure includes a base (1), a flexible hinge (2) , piezoelectric stack (3), U-shaped plate (4), parallelogram flexible hinge a (5), parallelogram flexible hinge b (6), rotating platform (7), bearing (8), triangular micro-protrusion ( 9), the base (10) and the mandrel (11); the base (1), the driving flexible hinge (2) and the U-shaped plate (4) are sequentially rigidly connected as one, and fixed on the base ( 10), the piezoelectric stack (3) is tightly fitted inside the driving flexible hinge (2), and the inner sides of the two U-shaped arms of the U-shaped plate (4) are provided with parallelogram flexible hinges a (5), b (6), The outer surfaces of the parallelogram flexible hinges a (5) and b (6) are processed with triangular micro-protrusions (9), and the triangular micro-protrusions (9) are in contact with the rotating platform (7). The rotating platform (7), the bearing (8) ), the mandrel (11) is mounted on the base (10); the parallelogram flexible hinge a (5) is inclined to the U-shaped bottom of the U-shaped plate (4), and the parallelogram is symmetrical about the center line of the mandrel (11) The flexible hinges a(5), b(6) can change the positive pressure between the outer surface of the parallelogram flexible hinges a(5), b(6) and the rotating platform (7), and are symmetrical about the center line of the mandrel (11) The triangular micro-protrusions (9) make the friction coefficients of the outer surfaces of the parallelogram flexible hinges a (5) and b (6) different along the positive and negative directions of the X-axis. Under the joint action of the two, the electric signal excites the piezoelectric stack The elongation/shortening deformation of the pile (3) drives the U-shaped plate (4) to reciprocate along the positive/negative direction of the X-axis. In one working cycle, the parallelogram flexible hinges a (5) and b (6) are driven alternately The rotating platform (7) realizes two rotations in the counterclockwise direction.

The inner sides of the two U-shaped arms of the U-shaped plate (4) are provided with parallelogram flexible hinges a (5) and b (6) with the same inclination angle. When the piezoelectric stack (3) is extended, the U-shaped plate (4) moves along the X The axis moves in the negative direction, and the outer surface of the parallelogram flexible hinge b(6) is subjected to friction along the positive direction of the X-axis. The parallelogram flexible hinge b(6) has a tendency to deform in the positive direction of the X-axis. The positive pressure between the surfaces decreases, the outer surface of the parallelogram flexible hinge a (5) is subjected to friction along the positive direction of the X-axis, and has a tendency to deform in the positive direction of the X-axis, and the positive force between the surface of the rotating platform (7) The pressure increases, so that the friction between the parallelogram flexible hinge a (5) and the rotating platform (7) is greater than the friction between the parallelogram flexible hinge b (6) and the rotating platform (7), and the rotating platform (7 ) rotates counterclockwise; when the piezoelectric stack (3) shortens, the friction between the parallelogram flexible hinge b (6) and the rotating platform (7) is greater than that between the parallelogram flexible hinge a (5) and the rotating platform (7) The friction between them makes the rotating platform (7) continue to rotate counterclockwise.

Non-centrosymmetric triangular micro-protrusions (9) are processed on the outer surfaces of the parallelogram flexible hinges a (5) and b (6), and the inclination direction of the triangular micro-protrusions (9) is the same as that of the parallelogram flexible hinge. The inclination direction is the same, so that the friction coefficient of the inclined side is greater than that of the other side; the friction coefficient of the outer surface of the parallelogram flexible hinge a (5) along the positive direction of the X axis is greater than the friction coefficient along the negative direction of the X axis; the parallelogram flexible hinge b (6 ) The friction coefficient of the outer surface along the negative direction of the X-axis is greater than that along the positive direction of the X-axis.

Claims (1)

1. A two-step piezoelectric rotary actuator, characterized by: using a piezoelectric stack to make the driver step twice in a working period; the structure comprises a base (1), a driving flexible hinge (2), a piezoelectric stack (3), a U-shaped plate (4), a parallelogram flexible hinge a (5), a parallelogram flexible hinge b (6), a rotating platform (7), a bearing (8), a triangular microprotrusion (9), a base (10) and a mandrel (11); the base (1), the driving flexible hinge (2) and the U-shaped plate (4) are sequentially and rigidly connected into a whole, the piezoelectric stack (3) is fixed on the base (10) through the base (1), the piezoelectric stack (3) is tightly matched and installed inside the driving flexible hinge (2), the inner sides of two U-shaped arms of the U-shaped plate (4) are provided with parallelogram flexible hinges a (5) and b (6), triangular microprotrusions (9) are processed on the outer surfaces of the parallelogram flexible hinges a (5) and b (6), the triangular microprotrusions (9) are contacted with the rotating platform (7), and the rotating platform (7), the bearing (8) and the mandrel (11) are matched and installed on the base (10); the parallelogram flexible hinge a (5) inclines towards the U-shaped bottom of the U-shaped plate (4), positive pressure between the outer surfaces of the parallelogram flexible hinges a (5) and b (6) and the rotating platform (7) can be changed by the parallelogram flexible hinges a (5) and b (6) which are symmetrical about the center line of the mandrel (11), the triangular microprotrusions (9) which are symmetrical about the center line of the mandrel (11) enable the friction coefficients of the outer surfaces of the parallelogram flexible hinges a (5) and b (6) along the positive direction and the negative direction of the X axis to be different, under the combined action of the parallelogram flexible hinges a (5) and b (6), the electric signal excites the extension/shortening deformation of the piezoelectric stack (3) to drive the U-shaped plate (4) to reciprocate along the positive direction and the negative direction of the X axis, and in one working period, the parallelogram flexible hinges a (5) and b (6) alternately drive the rotating platform (7) to realize two rotations in the anticlockwise direction; the inner sides of the two U-shaped arms of the U-shaped plate (4) are provided with parallelogram flexible hinges a (5) and b (6) with the same inclination angle, when the piezoelectric stack (3) stretches, the U-shaped plate (4) moves along the X axis in the negative direction, the outer surfaces of the parallelogram flexible hinges a (5) and b (6) are subjected to the friction force action along the positive direction of the X axis, the positive pressure between the parallelogram flexible hinge b (6) with the deformation trend towards the positive direction of the X axis and the surface of the rotating platform (7) is reduced, the positive pressure between the parallelogram flexible hinge a (5) with the deformation trend towards the positive direction of the X axis and the surface of the rotating platform (7) is increased, so that the friction force between the parallelogram flexible hinge a (5) and the rotating platform (7) is larger than the friction force between the parallelogram flexible hinge b (6) and the rotating platform (7), and the rotating platform (7) rotates anticlockwise; when the piezoelectric stack (3) is shortened, the friction force between the parallelogram flexible hinge b (6) and the rotating platform (7) is larger than the friction force between the parallelogram flexible hinge a (5) and the rotating platform (7), so that the rotating platform (7) continues to rotate anticlockwise; triangular microprotrusions (9) which are not in central symmetry are processed on the outer surfaces of the parallelogram flexible hinges a (5) and b (6), and the inclination direction of the triangular microprotrusions (9) is consistent with the inclination direction of the parallelogram flexible hinges, so that the friction coefficient of the inclined side is larger than that of the other side; the friction coefficient of the outer surface of the parallelogram flexible hinge a (5) along the positive direction of the X axis is larger than that along the negative direction of the X axis; the friction coefficient of the outer surface of the parallelogram flexible hinge b (6) along the X-axis negative direction is larger than that along the X-axis positive direction.