CN101162877B - Circular multi-degree-of-freedom ultrasonic motor and its electric excitation method - Google Patents

Abstract

The invention discloses an annular multi-degree-of-freedom ultrasonic motor and an electric excitation method, which belong to the field of ultrasonic motors. The ultrasonic motor includes a rotor and a stator, which are characterized in that the rotor is a spherical rotor (1); the stator is a metal ring (2), and six piezoelectric ceramic sheets (3) are uniformly pasted on the side of the ring stator; There are three upper bosses (4) evenly distributed along the circumferential direction on the upper end surface, and they are at the same position as the platform (6) on which the ceramic sheet is pasted, which are used to support and drive the spherical rotor; the rotor provides the preset required between the stator and the rotor through its own weight Pressure; the lower end surface of the ring stator also has three small bosses (5) corresponding to the position of the upper boss (4), which are used to support the whole motor. When the driving signal supplies power to any two opposing piezoelectric ceramic sheets (3), the in-plane double-bend vibration mode of the stator will be excited to generate a standing wave, driving the spherical rotor around the center of the rotor sphere and connecting with the two piezoelectric ceramics Pieces rotate on parallel axes. The ultrasonic motor can realize rotation around multiple rotating shafts, and has the advantages of simple structure, easy miniaturization, high efficiency, reliable operation and the like.

Description

Circular multi-degree-of-freedom ultrasonic motor and its electric excitation method

Technical field:

The invention relates to an annular multi-degree-of-freedom ultrasonic motor and an electric excitation method, belonging to the field of ultrasonic motors.

Background technique:

Ultrasonic motor is a new concept power device that utilizes the inverse piezoelectric effect of piezoelectric material and ultrasonic vibration of elastic body. At present, the multi-degree-of-freedom ultrasonic motor is mostly a rod-type stator and a spherical rotor structure. The rod-type stator uses two bending vibrations and one longitudinal vibration to realize the rotation of the three rotation axes of the rotor. In practice, the frequency of bending vibration is difficult to match with the frequency of longitudinal vibration, but the driving frequency of the motor can only be one, so the driving efficiency of the motor will be low, and the output performance of the motor will be affected. In addition, because the rod-type multi-degree-of-freedom motor utilizes two bending vibration modes and longitudinal vibration modes, as well as the limitation of the stator assembly size, its axial size is difficult to reduce, which is not conducive to miniaturization, so the application range is limited.

Invention content:

The purpose of the present invention is to develop a multi-degree-of-freedom ultrasonic motor with simple structure, easy miniaturization, high efficiency, reliable operation, fast response speed and wider application range.

The circular multi-degree-of-freedom ultrasonic motor of the present invention is composed of a rotor and a stator. Its characteristic is that the rotor is a spherical rotor. The stator is a metal ring, and six piezoelectric ceramic sheets are uniformly pasted on the side of the ring stator, and the two opposite piezoelectric ceramic sheets are aligned in parallel. There are three upper bosses on the upper end surface of the ring stator, which are evenly distributed along the circumference, and the upper bosses are at the same position as the three platforms on which the ceramic sheets are pasted, and are used to support and drive the spherical rotor. On the lower end surface of the ring stator, at the same position corresponding to the upper boss, there are three small bosses, which are used to support the whole motor. The rotor provides the required pre-pressure between the stator and the rotor through its own weight.

The number of platforms and piezoelectric ceramic sheets pasted with ceramic sheets is twice the number n of the upper or lower bosses. n can take the value 3 or 5.

When the driving signal supplies power to any two opposing piezoelectric ceramic sheets, the in-plane two-bend vibration mode of the stator will be excited to generate standing waves. At this time, one of the upper bosses has a frictional thrust on the spherical rotor, driving the spherical rotor The rotor revolves around the center of the rotor sphere and rotates on an axis parallel to the two piezoelectric ceramic sheets.

In addition to the general characteristics of ultrasonic motors, the annular multi-degree-of-freedom ultrasonic motor has a simple structure and is easy to miniaturize due to the use of an annular stator; the working mode adopted is the in-plane two-bend vibration mode, and the single Vibration mode, there is no problem of inconsistency between the two-phase modal frequencies of the composite vibration mode multi-degree-of-freedom motor, and the work efficiency is high; the motor is excited by three sinusoidal signals, and the drive circuit is simple, which can realize the rotation of the rotor around multiple rotation axes .

Description of drawings:

Figure 1 is a structural schematic diagram of a circular multi-degree-of-freedom ultrasonic motor.

Fig. 2 is a circular multi-degree-of-freedom ultrasonic motor stator structure, a schematic diagram of piezoelectric ceramic sheet polarization and pasting methods.

Fig. 3 is a schematic diagram of the driving signal for exciting the ring stator to generate the in-plane double-bend vibration mode.

Fig. 4 is a schematic diagram of the vibration of the stator within one cycle when only the signal input terminal 7 is connected to the drive signal. Among them, Figure (I), Figure (II), Figure (III), and Figure (IV) are schematic diagrams of four states in one cycle of the stator.

Figure 1 and Figure 2 label names: 1 spherical rotor, 2 ring stator, 3 piezoelectric ceramic sheet, 4 upper boss, 5 lower boss, 6 platform pasted piezoelectric ceramic sheet.

Label names in Fig. 3: 7, 8, 9 Stator drive signal input terminals.

Label names in Fig. 4: X, Y, X1, Y1, X2, Y2 are Cartesian coordinates.

Detailed ways:

The specific embodiment and working principle of the present invention are described according to the accompanying drawings.

As shown in FIG. 1 , the circular multi-degree-of-freedom ultrasonic motor of the present invention is mainly composed of a rotor and a stator. The rotor is a spherical rotor 1; the stator is a metal ring 2, and six piezoelectric ceramic sheets 3 are uniformly pasted on its side, and the two opposite piezoelectric ceramic sheets are aligned in parallel; the upper end surface of the ring stator has three upper bosses 4. They are evenly distributed along the circumferential direction, and the upper boss is at the same position as the platform 6 on which three piezoelectric ceramic sheets are pasted, which are used to support and drive the spherical rotor; the rotor provides the preset required between the stator and the rotor through its own weight. Pressure; the lower end surface of the ring stator also has three small bosses 5, and their positions are the same as those of the upper boss 4, which are used to support the entire motor. The "+" shown in FIG. 2 indicates the polarization direction of the piezoelectric ceramic sheet 3, and all piezoelectric ceramic sheets are pasted in the same way, with the "+" pasted outward.

The invention utilizes the piezoelectric ceramic element to excite the in-plane two-bend vibration mode of the stator to generate standing waves and push the rotor to rotate. When the driving signal of ultrasonic frequency supplies power to any two opposing piezoelectric ceramic sheets, the ring stator will deform and generate standing waves. At this time, one of the upper bosses has a frictional thrust on the spherical rotor, driving the spherical rotor to bypass The center of the rotor rotates on an axis parallel to the two piezoelectric ceramic sheets. Three sets of opposite piezoelectric ceramic sheets are respectively excited to drive the rotor to rotate around the three rotation axes.

1) The spherical rotor revolves around the center of the rotor and rotates on an axis parallel to the Y axis

As shown in Figure 3, when only the drive signal E=Vsin(ωt) or E=Vcos(ωt) is provided to the signal input terminal 7, the in-plane double-bending vibration mode of the stator will be excited, and standing waves will be generated to push the spherical rotor around The axis passing through the center of the rotor and parallel to the Y axis rotates.

FIG. 4 shows four states of the ring-shaped stator in one cycle when only the drive signal E=Vsin(ωt) is provided to the signal input terminal 7 . Fig. 4 (I) is the state of the stator when the input voltage to the signal input terminal 7 is 0, and the stator is not deformed at this moment. Figure 4(II) is the state of the stator when the input voltage to the signal input terminal 7 is V, the stator deforms and shrinks along the X direction, and the upper boss 4a (see Figure 3) has a tangential force on the spherical rotor, pushing the rotor around The axis passing through the center of the rotor and parallel to the Y axis rotates. Fig. 4 (III) is the state of the stator when the input voltage to the signal input terminal 7 is 0, and the stator is not deformed at this moment. Figure 4 (IV) shows the state of the stator when the input voltage to the signal input terminal 7 is -V, and the stator deforms and elongates along the X direction at this time. After a sinusoidal excitation period, the spherical rotor has rotated around the center of the rotor sphere and an axis parallel to the Y axis by an angle, and so on, so that the rotor can continue to rotate around the rotation axis.

2) The spherical rotor goes around the center of the rotor and rotates on an axis parallel to the Y1 axis

As shown in Figure 3, when only the drive signal E=Vsin(ωt) or E=Vcos(ωt) is provided to the signal input terminal 8, the in-plane double-bend vibration mode of the stator will be excited, and standing waves will be generated to push the spherical rotor around The axis passing through the center of the rotor and parallel to the Y1 axis rotates.

3) The spherical rotor goes around the center of the rotor and rotates on an axis parallel to the Y2 axis

As shown in Figure 3, when only the drive signal E=Vsin(ωt) or E=Vcos(ωt) is provided to the signal input terminal 9, the in-plane double-bending vibration mode of the stator will be excited, and standing waves will be generated to push the spherical rotor around The axis that passes through the center of the rotor and is parallel to the Y2 axis rotates.

Claims (2)

1. an annular multiple freedom degrees ultrasound motor comprises stator and rotor, it is characterized in that: described rotor is spherical spinner (1); Described stator is an annulus (2), and six piezoelectric ceramic pieces (3) are uniform to stick on six platforms (6) of stator side, and two relative piezoelectric ceramic pieces are parallel to each other; There is circumferentially uniform convex platform (4) of three edges the stator upper surface, and convex platform (4) and three platforms (6) of pasting piezoelectric ceramic pieces wherein are at same position, is used for supporting and drives the spherical spinner rotation; In the lower surface of stator, on the corresponding identical position of convex platform (4), three small boss (5) are arranged, be used to support whole motor.

2. the electric excitation method thereof of an annular multiple freedom degrees ultrasound motor as claimed in claim 1, it is characterized in that: when the drive signal of supersonic frequency is given two relative arbitrarily piezoelectric ceramic piece power supplies, can encourage the face interior two curved mode of oscillations of stator, produce standing wave, one of them convex platform (4) has a thrust to spherical spinner (1), drives spherical spinner and walks around the rotor centre of sphere and the rotational parallel with this two piezoelectric ceramic piece.

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