CN104467521A - Double-oscillator standing wave ultrasonic motor and excitation method thereof - Google Patents

Abstract

The invention discloses a two-vibrator standing wave ultrasonic motor and an excitation method thereof, belonging to the technical field of ultrasonic motors, comprising first and second T-shaped frames, an arched beam structure and two rod-shaped sandwich structure piezoelectric transducers; The counterweights of the two rod-shaped sandwich structure piezoelectric transducers are fixedly connected through the first and second T-shaped frames, and the arched beam structure is arranged on the excitation source of the rod-shaped sandwich structure piezoelectric transducer At the same time, a first protrusion is provided in the middle of the top of the arched beam structure to form a driving foot, and the A and B two-phase voltage excitation signals are respectively applied to the two rod-shaped sandwich structure piezoelectric transducers, and one of the screws penetrates Phase A is applied to two sets of excitation sources, and phase B is applied to two sets of excitation sources penetrated by another screw. The piezoelectric ceramic sandwich structure arrangement of the present invention can obtain a higher mechanical quality factor, and both transducers work at the same The first-order bending vibration mode has good symmetry, the fundamental mode is easy to excite, and the efficiency is high.

Description

A two-vibrator standing wave ultrasonic motor and its excitation method

technical field

The invention relates to an ultrasonic motor and an electric excitation method thereof, belonging to the technical field of ultrasonic motors.

Background technique

Langevin piezoelectric transducers are widely used in ultrasonic devices, such as positioning devices, micro-manipulation systems, robots, etc. Langevin piezo transducers consist of piezoelectric ceramics, metal weights and preload screws, featuring high mechanical quality factor, low impedance and easy clamping.

When an alternating electric field with a frequency equal to the resonance frequency of the transducer is applied to the piezoelectric ceramic, the Langevin piezoelectric transducer excites longitudinal vibration by the d ₃₃ effect of the piezoelectric ceramic. Since the piezoelectric constant d ₃₃ of the barium titanate piezoelectric ceramic is greater than d ₃₁ , the piezoelectric actuator using the d ₃₃ effect has higher efficiency than the piezoelectric actuator using the d ₃₁ effect. Under the prestressing effect of the pre-tightening screw, the piezoelectric ceramic is always under the compressive stress during operation, so the sound transmission of the transducer assembly is more efficient, and the mechanical quality factor is improved at the same time. This makes Langevin transducers suitable for the demands of high-power ultrasonic devices.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a dual vibrator standing wave ultrasonic motor with simple structure, large thrust-to-weight ratio, high precision and fast response and its excitation method.

In order to achieve the above object, the technical solution adopted by the present invention is: a double vibrator standing wave ultrasonic motor, comprising first and second T-shaped frames, an arched beam structure and two rod-shaped sandwich structure piezoelectric transducers; The counterweights on the same side of the two rod-shaped sandwich structure piezoelectric transducers are fixedly connected through the first T-shaped frame, while the counterweights on the other side are fixedly connected through the second T-shaped frame. One end of the bottom of the beam structure is set between the excitation sources of one of the rod-shaped sandwich structure piezoelectric transducers, and the other end is set between the excitation sources of the other rod-shaped sandwich structure piezoelectric transducers, while the The middle part of the top of the arched beam structure is provided with a first protrusion to form a driving foot.

Preferably: the piezoelectric transducer with a rod-shaped sandwich structure includes first and second counterweights, screws, and two sets of excitation sources, and the two sets of excitation sources are respectively the first and second excitation sources ; The first and second counterweights are a square cuboid with opposite faces, the first counterweight is provided with a light hole in the center of one side of the square, and the first counterweight is provided with one of the light holes The surface is provided with a first groove perpendicular to the diameter of the light hole and parallel to the upper end of the T-shaped frame, and the second counterweight is provided with a threaded hole in the center of one side of the square, and the second counterweight is provided with a threaded hole. One surface is provided with a second groove perpendicular to the diameter of the threaded hole and parallel to the upper end of the T-shaped frame; the piezoelectric ceramic is ring-shaped, and its inner diameter is the same as the diameter of the light hole; the electrode sheet is soft conductive metal, and The piezoelectric ceramics have the same annular shape, and a second protrusion is provided on the outer ring for connecting the current lead; one end of the first T-shaped frame is arranged on the first rod-shaped sandwich structure piezoelectric transducer. In one groove, the other end is set in the first groove of another rod-shaped sandwich structure piezoelectric transducer; one end of the second T-shaped frame is set in one of the rod-shaped sandwich structure piezoelectric transducers In the second groove of the device, the other end is set in the second groove of another rod-shaped sandwich structure piezoelectric transducer; the bottom end of the arched beam structure is set in one of the rod-shaped sandwich structure piezoelectric transducers between the first and second excitation sources of the transducer, and the other end is arranged between the first and second excitation sources of another rod-shaped sandwich structure piezoelectric transducer; the same rod-shaped sandwich structure presses The central axis of the first and second excitation sources on the electric transducer coincides with the axis of the light hole on the transducer; the first and second excitation sources on the same rod-shaped sandwich structure piezoelectric transducer The central axis of the excitation source coincides with the axis of the threaded hole on the transducer; the screw on one of the piezoelectric transducers with a rod-shaped sandwich structure passes through the first counterweight, the first T-shaped One end of the frame, the first excitation source, one end of the bottom of the arched beam structure, the second excitation source, one end of the second T-shaped frame, and screwed into the threaded hole on the second counterweight; and the other rod The screws on the piezoelectric transducer with a sandwich structure pass through the first counterweight on the transducer, the other end of the first T-shaped frame, the first excitation source, the other end of the bottom of the arched beam structure, and the second The excitation source, the other end of the second T-shaped frame, and are screwed into the threaded holes on the second counterweight.

Preferably: each group of excitation sources is composed of 5 electrode sheets and 4 piezoelectric ceramics, and the polarization directions of the piezoelectric ceramics are opposite to each other.

Preferably: the vibration of the first protrusion in the middle of the arched beam structure causes the rotor in contact with it to rotate or the mover to move in translation.

An excitation method for a standing wave ultrasonic motor with two vibrators. The electrode sheets on four sets of excitation sources are respectively connected to wires, the electrode sheets on both sides and the middle of each group of excitation sources are grounded through wires, and the same voltage is applied to the other two electrode sheets. Excitation signal, the voltage excitation signal is divided into two phases A and B, wherein the two groups of excitation sources penetrated by one screw apply phase A, and the two groups of excitation sources penetrated by the other screw apply phase B; the A, The B two-phase voltage excitation signals are all sinusoidal voltage signals of equal amplitude and same frequency, and the two-phase voltage signals have a phase difference of π/2.

Preferably: when the two rod-shaped sandwich structure piezoelectric transducers are excited by the A and B two-phase voltage excitation signals, the first protrusion in the middle of the arched beam structure vibrates on an elliptical track.

Compared with the prior art, the dual vibrator standing wave ultrasonic motor and its excitation method provided by the present invention have the following beneficial effects: the piezoelectric ceramic sandwich structure arrangement can obtain a higher mechanical quality factor, and both transducers work in the same The first-order bending vibration mode has good symmetry, the basic-order mode is easy to excite, and the efficiency is high. Therefore, the invention has the advantages of simple structure, large thrust-to-weight ratio, high precision and fast response.

Description of drawings

Figure 1 The structure of the dual vibrator standing wave ultrasonic motor;

Fig. 2 Excitation mode of dual vibrator standing wave ultrasonic motor;

Figure 3 Schematic diagram of vibration in working state;

Figure 4 is a schematic diagram of driving the rotor to rotate;

Fig. 5 is a schematic diagram of driving the mover to output linear motion;

Among them, 1-piezoelectric transducer; 2-arched beam structure; 3-T-shaped frame; 4-rotor; 5-stator.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

A kind of dual vibrator standing wave ultrasonic motor, as shown in Figure 1, comprises first and second T-shaped frames, an arched beam structure and two rod-shaped sandwich structure piezoelectric transducers; the two rod-shaped sandwich structures The counterweights on the same side of the piezoelectric transducer are fixedly connected through the first T-shaped frame, while the counterweights on the other side are fixedly connected through the second T-shaped frame. The bottom end of the arched beam structure is set on Between the excitation sources of one rod-shaped sandwich structure piezoelectric transducer, the other end is arranged between the excitation sources of the other rod-shaped sandwich structure piezoelectric transducer, while the top middle of the arched beam structure A first protrusion is provided to form a driving foot.

The piezoelectric transducer with a rod-shaped sandwich structure includes first and second counterweights, screws, and two groups of excitation sources, the two groups of excitation sources are respectively the first and second excitation sources; the first 1. The second counterweight is a cuboid whose opposite surface is a square, and the first counterweight is provided with a light hole in the center of one side of the square, and a surface of the first counterweight is provided with a light hole. There is a first groove perpendicular to the diameter of the light hole and parallel to the upper end of the T-shaped frame, and the second counterweight is provided with a threaded hole in the center of one side of the square, and one surface of the second counterweight is provided with the threaded hole There is a second groove perpendicular to the diameter of the threaded hole and parallel to the upper end of the T-shaped frame; the piezoelectric ceramic is ring-shaped, and its inner diameter is the same as the diameter of the light hole; the electrode sheet is soft conductive metal, and the piezoelectric ceramic It has the same ring shape, and there is a second protrusion on the outer ring, which is used to connect the current lead; one end of the first T-shaped frame is set in the first groove of one of the rod-shaped sandwich structure piezoelectric transducers The other end is set in the first groove of another rod-shaped sandwich structure piezoelectric transducer; one end of the second T-shaped frame is set in the first groove of one of the rod-shaped sandwich structure piezoelectric transducers In two grooves, the other end is set in the second groove of another rod-shaped sandwich structure piezoelectric transducer; the bottom end of the arched beam structure is set in one of the rod-shaped sandwich structure piezoelectric transducers Between the first and second excitation sources, the other end is arranged between the first and second excitation sources of another rod-shaped sandwich structure piezoelectric transducer; the same rod-shaped sandwich structure piezoelectric transducer The central axis of the first and second excitation sources on the transducer coincides with the axis of the optical hole on the transducer; the first and second excitation sources on the same rod-shaped sandwich structure piezoelectric transducer The central axis of the transducer coincides with the axis of the threaded hole on the transducer; the screw on one of the piezoelectric transducers with a rod-shaped sandwich structure passes through the first counterweight on the transducer and one end of the first T-shaped frame in turn. , the first excitation source, one end of the bottom of the arched beam structure, the second excitation source, one end of the second T-shaped frame, and screwed into the threaded hole on the second counterweight; and the other rod-shaped sandwich structure The screws on the piezoelectric transducer pass through the first counterweight on the transducer, the other end of the first T-shaped frame, the first excitation source, the other end of the bottom of the arched beam structure, and the second excitation source , the other end of the second T-shaped frame, and screw into the threaded hole on the second counterweight.

Each group of excitation sources is composed of 5 pieces of electrode pieces and 4 pieces of piezoelectric ceramics, and the polarization directions of the piezoelectric ceramics are opposite to each other.

The vibration of the first protrusion in the middle of the arched beam structure causes the rotor in contact with it to rotate or the mover to move in translation.

An excitation method for a standing wave ultrasonic motor with two vibrators. The electrode sheets on four sets of excitation sources are respectively connected to wires, the electrode sheets on both sides and the middle of each group of excitation sources are grounded through wires, and the same voltage is applied to the other two electrode sheets. Excitation signal, the voltage excitation signal is divided into two phases A and B, wherein the two groups of excitation sources penetrated by one screw apply phase A, and the two groups of excitation sources penetrated by the other screw apply phase B; the A, The B two-phase voltage excitation signals are all sinusoidal voltage signals of equal amplitude and same frequency, and the two-phase voltage signals have a phase difference of π/2.

Two piezoelectric transducers with a rod-shaped sandwich structure are excited by the A and B two-phase voltage excitation signals, and the first protrusion in the middle of the arched beam structure vibrates on an elliptical track.

In order to better illustrate the present invention, an example is given for illustration.

The dual vibrator standing wave ultrasonic motor, as shown in Figure 1, consists of two rod-shaped sandwich structure piezoelectric transducers (1), a T-shaped frame (2) and an arched beam structure (3); the two rod-shaped sandwich structures press The electric transducers (1) are arranged side by side, and the middle is connected by the arched beam structure (2) and the T-shaped frame (3). There is a protrusion in the middle of the arched structure, and the T-shaped frame is symmetrically arranged on both sides of the arched beam structure. .

The excitation mode of the dual vibrator standing wave ultrasonic motor is shown in Figure 2: A and B two-phase voltage excitation signals are respectively applied to the two rod-shaped sandwich structure piezoelectric transducers. The A and B two-phase voltage excitation signals are sinusoidal voltage signals of equal amplitude and same frequency, and the two-phase voltage signals have a phase difference of π/2. Two piezoelectric transducers with a rod-shaped sandwich structure are excited by the A and B two-phase voltage excitation signals, and the protrusions in the middle of the arched beam structure vibrate on an elliptical track.

The piezoelectric transducer consists of a counterweight, an arched beam structure, screws, piezoelectric ceramics and electrode sheets. There are two sets of counterweights, which are two cubes with through holes connected into one body through a T-shaped frame. The surface of the cube with two through holes is a square, and the through hole is located in the middle. Parallel; one group of through holes set on the two groups of counterweights is threaded holes, and the other group is light holes; both sides of the T-shaped frame are connected with the cube, and two mounting holes are opened at the bottom; the cube is designed One of the surfaces with the through hole is provided with a groove along the diameter of the through hole and parallel to the upper end of the T-shaped frame. The driving foot is composed of two cubes connected by an arched structure. The top of the arched structure is provided with a protrusion. The two cubes are the same as the cube on the counterweight. The piezoelectric ceramic is ring-shaped, its diameter is the same as the side length of the square of the cube on the counterweight, and its inner diameter is the same as the through hole on the surface of the square. The electrode piece is soft conductive metal, has the same ring shape as the piezoelectric ceramic, and has a protrusion on the outer ring for connecting the electric lead. 16 pieces of piezoelectric ceramics and 20 pieces of electrode sheets form 4 groups of identical excitation sources, each group of excitation sources consists of 5 pieces of electrode sheets and 4 pieces of piezoelectric ceramics, the polarization directions of the ceramic sheets are opposite to each other, and the electrode sheets are respectively It is located on the two ring surfaces of the ceramic sheet and the centers of the circles coincide. The four sets of excitation sources are located on both sides of the two cubes of the driving feet, and the central axis of the excitation source composed of piezoelectric ceramics and electrode sheets coincides with the axis of the light hole on the cube, and the two counterweights are respectively located on the four sets of excitation On the outside of the vibration source, and the through hole on the counterweight coincides with the central axis of the four groups of excitation sources. In the threaded holes on the weight, the two sets of T-shaped brackets are aligned and the side with the mounting holes is opposite to the side where the protrusion on the drive foot arch is located.

As shown in Figure 2, the electrode sheets on the four groups of excitation sources are respectively connected to the wires, the electrode sheets on both sides and the middle of each group of excitation sources are grounded through the wires, and the remaining two electrode sheets apply the same voltage excitation signal, the voltage The excitation signal is divided into two phases, A and B. The two sets of excitation sources penetrated by one screw apply the A phase, and the two sets of excitation sources penetrated by the other screw apply the B phase. The A and B two-phase voltage excitation signals are sinusoidal voltage signals of equal amplitude and same frequency, and the two-phase voltage signals have a phase difference of π/2.

Apply voltage excitation to the four groups of piezoelectric units as shown in Figure 2, and the protrusion in the middle of the arch structure will vibrate in an elliptical trajectory, as shown in Figure 3, pressing the protrusion on the surface of another object with a certain force will generate one-way friction .

A working mode of a double vibrator standing wave ultrasonic motor, two rod-shaped sandwich structure piezoelectric transducers are excited by A and B two-phase voltage excitation signals, and the protrusion in the middle of the arch structure vibrates on an elliptical track.

As shown in Fig. 4, the vibration of the protrusion in the middle part of the arched structure causes the rotor (4) in contact with it to rotate.

As shown in Fig. 5, the vibration of the protrusion in the middle part of the arched structure causes translation of the mover (5) in contact with it.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (6)

1. a two vibrator standing wave ultrasound electric machine, is characterized in that: comprise first, second T-shaped frame, arched girder structure and two shaft-like sandwich structure PZT (piezoelectric transducer)s; The balancing weight of described two shaft-like sandwich structure PZT (piezoelectric transducer) phase the same sides is fixedly connected with by the first T-shaped frame, and the balancing weight of opposite side is by being fixedly connected with by the second T-shaped frame, the bottom end of described arched girder structure is arranged between the exciting source of one of them shaft-like sandwich structure PZT (piezoelectric transducer), the other end is arranged between the exciting source of another shaft-like sandwich structure PZT (piezoelectric transducer), and the top middle portion of described arched girder structure is provided with the first projection and forms driving foot simultaneously.

2. according to claim 1 pair of vibrator standing wave ultrasound electric machine, is characterized in that: described shaft-like sandwich structure PZT (piezoelectric transducer) comprises first, second balancing weight, screw and two groups of exciting sources, and described two groups of exciting sources are respectively first, second exciting source; It is foursquare cuboid that first, second balancing weight is a relative face, described first balancing weight offers unthreaded hole at the center of foursquare one side, and the surface that the first balancing weight is provided with unthreaded hole is provided with and first groove of parallel T-shaped frame upper end vertical along unthreaded hole diameter, and the second balancing weight offers screwed hole at the center of foursquare one side, the surface that described second balancing weight is provided with screwed hole is provided with vertical and the second groove of parallel T-shaped frame upper end of threadingly bore dia; Described piezoelectric ceramic is ring-type, and its internal diameter is identical with unthreaded hole diameter; Described electrode slice is soft conducting metal, has identical circular profile with piezoelectric ceramic, and is equipped with the second projection outside, for connecting energising lead-in wire; In first groove of one end shaft-like sandwich structure PZT (piezoelectric transducer) disposed therein of described first T-shaped frame, the other end is arranged in the first groove of another shaft-like sandwich structure PZT (piezoelectric transducer); In second groove of one end shaft-like sandwich structure PZT (piezoelectric transducer) disposed therein of described second T-shaped frame, the other end is arranged in the second groove of another shaft-like sandwich structure PZT (piezoelectric transducer); The bottom end of described arched girder structure is arranged between first, second exciting source of one of them shaft-like sandwich structure PZT (piezoelectric transducer), and the other end is arranged between first, second exciting source of another shaft-like sandwich structure PZT (piezoelectric transducer); The dead in line of the unthreaded hole on the central axis of first, second exciting source on described same shaft-like sandwich structure PZT (piezoelectric transducer) and this transducer; The dead in line of the screwed hole on the central axis of first, second exciting source on described same shaft-like sandwich structure PZT (piezoelectric transducer) and this transducer; Screw on one of them shaft-like sandwich structure PZT (piezoelectric transducer) runs through one end of the first balancing weight on this transducer, one end of the first T-shaped frame, the first exciting source, arched girder structural base successively, and one end of the second exciting source, the second T-shaped frame also screws in the screwed hole on the second balancing weight; And the screw on another shaft-like sandwich structure PZT (piezoelectric transducer) runs through the other end of the first balancing weight on this transducer, the other end of the first T-shaped frame, the first exciting source, arched girder structural base successively, the other end of the second exciting source, the second T-shaped frame also screws in the screwed hole on the second balancing weight.

3. according to claim 2 pair of vibrator standing wave ultrasound electric machine, is characterized in that: often organize exciting source and be made up of 5 plate electrode sheets and 4 piezoelectric ceramic, the polarised direction of piezoelectric ceramic is relative between two.

4. according to claim 3 pair of vibrator standing wave ultrasound electric machine, is characterized in that: in the middle part of arched girder structure, the vibration of the first projection causes the rotor turns or mover translation that contact with it.

5. the motivational techniques of a two vibrator standing wave ultrasound electric machine as claimed in claim 1, it is characterized in that: the electrode slice on four groups of exciting sources connects wire respectively, often organize the electrode slice of both sides and centre in exciting source through wired earth, all the other two panels electrode slices apply identical voltage excitation signals, described voltage excitation signals is divided into A, B two-phase, two groups of exciting sources that wherein screw runs through apply A phases, and two groups of exciting sources that another root screw runs through apply B phases; Described A, B two-phase voltage excitation signals is all the same sine voltage signal frequently of constant amplitude, and two phase voltage signals have the phase difference of pi/2.

6. the motivational techniques of according to claim 5 pair of vibrator standing wave ultrasound electric machine, it is characterized in that: two shaft-like sandwich structure PZT (piezoelectric transducer)s under the excitation of A, B two-phase voltage excitation signals, the first projection generation elliptic vibrations in the middle part of arched girder structure.