CN103414372B - Bi-directional drive rotary ultrasonic motor - Google Patents

Abstract

The invention discloses a two-way drive rotating ultrasonic motor. The rotor includes a turntable and a friction layer arranged on the surface of the turntable; the stator includes a bracket, two identical ultrasonic vibration transducers fixed by the bracket, and two identical elliptical vibration modes. The converter and two identical friction drive blocks arranged at the front end of the elliptical vibration mode converter; The longitudinal ultrasonic vibration generated by the ultrasonic vibration transducer is converted into the longitudinal bending composite ultrasonic elliptical vibration of the end of the elliptical vibration mode converter and the friction drive block. When the two ultrasonic vibration transducers work separately, the corresponding two friction drive blocks The rotors are respectively driven for continuous rotary motion.

Description

Bi-directional drive rotary ultrasonic motor

technical field

The invention relates to the field of ultrasonic motors utilizing the inverse piezoelectric effect of piezoelectric ceramics, in particular to a bidirectionally driven rotary ultrasonic motor.

Background technique

The rotary ultrasonic motor is a new type of micro-motor developed and applied rapidly in the 1980s. It is an electromechanical coupling device that uses the inverse piezoelectric effect of piezoelectric materials to convert electrical energy to mechanical energy. Through the friction between the stator and the rotor, the The micro-vibration of the elastomer is converted into the macro-rotational motion of the rotor, which directly drives the load. Because of its small size, light weight, low speed and high torque, low noise, fast response, high positioning accuracy, no electromagnetic interference and strong environmental adaptability, it has been increasingly widely used in medical, aerospace, robotics, MEMS and other technical fields. Applications.

In the existing rotary ultrasonic motors, the out-of-plane bending vibration mode is mainly combined into end-face traveling waves, and the rotor is driven to rotate. The common problems are small driving torque, large axial volume, and wear difference between the inner and outer diameter contact areas of the stator and rotor. In addition, even if the in-plane vibration mode is adopted, in order to apply the in-plane radial preload, the disc or ring of the vibrator or rotor is made into two semi-discs or semi-circles, and the middle passes through The springs are connected into discs or rings to apply in-plane radial preload. At present, it is also difficult to achieve high torque, and the work reliability is low. In the patent document with the publication number CN101030740A and the invention name "Single-phase Driven Bending Rotary Ultrasonic Motor", a single-phase drive standing wave rotating ultrasonic motor with a tapered body structure is disclosed. The axially stacked piezoelectric ceramic sheets excite the vibration of the stator, and the six piezoelectric ceramic sheets are fixed on the central shaft by means of compression nuts and pressure shaft sleeves. Although the motor has the advantages of large output torque, the six piezoelectric ceramic sheets of the motor must be staggered and installed by 60 degrees according to the polarization partition, and its structure is complicated. Spiral motion (rotational force) can easily cause misalignment between piezoelectric ceramic sheets, and it is difficult to ensure the technical requirement of 60 degrees of misalignment between adjacent piezoelectric ceramic sheets; in addition, there is no positioning device between the stator and rotor of the motor, which The accuracy of the contact position between the stator and the rotor is affected, which in turn affects the stability of the torque and speed of the motor; therefore, this type of rotating ultrasonic motor has a complex structure and requires high contact position accuracy between the stator and the rotor. It is difficult to manufacture and install, and the stability of motor torque and speed is poor.

Contents of the invention

The present invention provides a novel bidirectional drive rotary ultrasonic motor, aiming at overcoming the shortcomings in the above rotary ultrasonic motor.

Two-way drive rotating ultrasonic motor, including rotor and stator, the rotor includes a turntable and a friction layer arranged on the surface of the turntable; the stator includes a bracket, two sets of identical and symmetrical energy conversion devices fixed by the bracket, each set of energy devices includes an ultrasonic Vibration transducer, an elliptical vibration mode converter and a friction drive block; the outer contour of the ultrasonic vibration transducer is cylindrical, which includes bolts, rear cover plates and piezoelectric ceramics that are sequentially sleeved on the bolts sheet, electrode sheet and front cover, the front cover is provided with a flange that can be connected with the bracket, and the rear cover and front cover are connected by bolts to the rear cover, piezoelectric ceramic sheet, electrode sheet and front cover The connection and compression constitute the energy conversion part of the two-way driving rotary ultrasonic motor, which converts the ultrasonic electric energy output by the A ultrasonic power supply and the B ultrasonic power supply into the ultrasonic vibration energy of the two ultrasonic vibration transducers.

The elliptical vibration mode converter and the front cover are made as a whole and arranged on the front end of the front cover, or an additional connecting stud is used to connect the elliptical vibration mode converter to the front end of the front cover, and the elliptical vibration The mode converter is an oblique wedge structure. The oblique wedge structure elliptical vibration mode converter is originally a cuboid as a whole, and a part of one side is cut off along the axial direction of the ultrasonic vibration transducer to form an oblique wedge structure, forming two oblique wedges. Among the sides, the uncut side is parallel to the axis of the ultrasonic vibration transducer, and the other side that has been cut is at an angle of 3-30 degrees to the axis of the ultrasonic vibration transducer.

The purpose of making the elliptical vibration mode converter form an oblique wedge structure is to change the vibration mode of the ultrasonic vibration transducer so that the frequency of the longitudinal vibration mode and the frequency of the bending vibration mode are close to or equal, because the elliptical vibration mode of the oblique wedge structure Due to the existence of the mode converter, the longitudinal ultrasonic vibration generated by the ultrasonic vibration transducer is decomposed into a part of the longitudinal vibration component and a part of the The bending vibration component, and the two vibration components have a certain phase difference, and then compound at the end of the oblique wedge structure elliptical vibration mode converter to form an elliptical trajectory vibration.

The friction driving block is arranged on the front end of the elliptical vibration mode converter through welding, bonding or screw connection, and the friction driving block is in contact with the friction layer on the turntable. The two ultrasonic vibration transducers are connected together through the bracket and the flange of the ultrasonic vibration transducer, and the bracket is used to fix the stator and install the pre-pressure device. The stator and the rotor are connected as a whole to form a two-way drive rotary ultrasonic motor. The angle between the axes of the two ultrasonic vibration transducers after the flange is fixed is 20 degrees to 160 degrees.

Before being driven by an ultrasonic voltage signal, the friction driving blocks at the front end of the two elliptical vibration mode converters are in contact with the rotor at the same time.

When working, one of the ultrasonic vibration transducers is suspended, and the other ultrasonic vibration transducer is working. That is: send a DC negative voltage signal to the electrode piece of the ultrasonic vibration transducer that needs to be suspended, and use the piezoelectric effect to shrink the ultrasonic vibration transducer axially, thereby suspending the friction drive block at the front end of the elliptical vibration mode converter on the rotor. Send an ultrasonic sinusoidal electrical signal to another ultrasonic vibration transducer that needs to be driven, and the ultrasonic vibration transducer will generate ultrasonic vibration, and the ultrasonic vibration energy will be transmitted from the ultrasonic vibration transducer to the end of the elliptical vibration mode converter , which is converted into longitudinal-bending composite ultrasonic elliptical vibration with a certain phase difference combined with longitudinal vibration and bending vibration, that is, converted into longitudinal-bending composite ultrasonic elliptical vibration at the end of the elliptical vibration mode converter; and drives the friction drive block and elliptical vibration mode The ends of the converter make ultrasonic elliptical vibration together, and then drive the rotor for continuous rotation.

When the rotor needs to rotate in another direction, it is sufficient to exchange the ultrasonic electric signal driving modes of the two ultrasonic vibration transducers. Compared with the two-way drive rotary ultrasonic motor introduced in the existing literature, the rotary ultrasonic motor has the advantages of large power capacity, high energy conversion efficiency, simple structure, easy manufacture, low cost, high structural rigidity, simple control drive system and stable vibration performance. .

Furthermore, the two ultrasonic vibration transducers of the two-way drive rotary ultrasonic motor each have a set of longitudinal vibration piezoelectric ceramic sheets.

Furthermore, the two ultrasonic vibration transducers of the two-way driving rotating ultrasonic motor need to be excited by one ultrasonic electric signal respectively.

The invention adopts the mechanical vibration mode conversion mechanism to convert the longitudinal vibration of the ultrasonic vibration transducer into the longitudinal bending composite ultrasonic elliptical vibration of the elliptical vibration mode converter, simplifies the overall structure of the bidirectional drive rotary ultrasonic motor, and greatly reduces the vibration The complexity of the system reduces the difficulty of manufacturing and assembly and the production cost. The whole two-way driving rotary ultrasonic motor has a simple structure, is easy to manufacture, and has low cost; in addition, the two ultrasonic vibration transducers of the invention only need one ultrasonic electric signal for excitation. , the control difficulty is low, avoiding the complex ultrasonic power supply development cost of multi-phase ultrasonic vibration compound to form an elliptical vibration transducer, simplifying the control circuit and ultrasonic power supply structure, reducing the cost of control circuit and ultrasonic power supply, and reducing the control circuit and ultrasonic power supply. The size of the power supply makes it easy to realize the miniaturization and integration of the control circuit and the ultrasonic power supply, which improves the reliability, the working performance is more stable, and the application prospect is broad.

Description of drawings

Fig. 1 is a schematic structural view of the present invention.

Fig. 2 is a schematic diagram of an application example of the present invention.

Explanation of symbols in the figure: 1. Bolt, 2. Rear cover, 3. Piezoelectric ceramic sheet, 4. Electrode sheet, 5. Front cover, 6. Flange, 7. Elliptical vibration mode converter, 8. Turntable, 9. Friction layer, 10. Friction drive block, 11. Bracket, 12. A ultrasonic power supply, 13. B ultrasonic power supply

Detailed ways

As shown in Figures 1 and 2, the two-way drive rotating ultrasonic motor includes a rotor and a stator. The rotor includes a turntable 8 and a friction layer 9 arranged on the surface of the turntable 8; And left and right symmetrical energy conversion devices, each set of energy devices includes an ultrasonic vibration transducer, an elliptical vibration mode converter 7 and a friction drive block 10; the outer contour of the ultrasonic vibration transducer is cylindrical, It includes a bolt 1 and a rear cover 2, a piezoelectric ceramic sheet 3, an electrode sheet 4 and a front cover 5 which are sequentially set on the bolt 1, and the front cover 5 is provided with a flange which can be connected with the bracket 11 6. The rear cover 2 and the front cover 5 connect and compress the rear cover 2, the piezoelectric ceramic sheet 3, the electrode sheet 4 and the front cover 5 through bolts 1, forming the energy conversion part of the bidirectional drive rotary ultrasonic motor, The ultrasonic electric energy output by the A ultrasonic power supply 12 and the B ultrasonic power supply 13 is converted into the ultrasonic vibration energy of the two ultrasonic vibration transducers. The two ultrasonic vibration transducers of the bidirectional drive rotary ultrasonic motor each have a set of longitudinal vibration piezoelectric ceramic sheets 3, the diameter of the piezoelectric ceramic transducer section is 30mm, the material of the piezoelectric ceramic sheet 3 is PZT-8, and the size is: Ф30×Ф15×5 , the number of piezoelectric ceramic sheets 3 is 2.

The elliptical vibration mode converter 7 and the front cover 5 are made into an integral part and arranged on the front end of the front cover 5. The elliptical vibration mode converter 7 is a wedge-shaped structure as a whole, and the elliptical vibration mode conversion of the wedge-shaped structure is The device is a rectangular parallelepiped as a whole, with a cross-sectional side length of 15 × 15mm and a length of 40mm. One side is cut off along the axial direction of the ultrasonic vibration transducer to form a wedge-shaped structure, and the two sides of the wedge-shaped shape are not cut. One side is parallel to the axis of the ultrasonic vibration transducer, and the other side that has been cut is at an angle of 10 degrees to the axis of the ultrasonic vibration transducer.

The friction driving block 10 is arranged on the front end of the elliptical vibration mode converter 7 by bonding, and the friction driving block 10 is in contact with the friction layer 9 on the turntable 8 . The two ultrasonic vibration transducers are connected together through the bracket 11 and the flange 6 of the ultrasonic vibration transducer, and the bracket 11 is used to fix the stator and install the pre-pressure device, and connect the stator and the rotor as a whole to form a two-way driving rotating ultrasonic The motor, the angle between the axes of the two ultrasonic vibration transducers fixed by the flange plate 6 and the support 11 is 90 degrees.

The natural frequency of the two ultrasonic vibration transducers driving the two-way rotating ultrasonic motor is the same as 25.32KHz, the impedances are 75 and 78 ohms respectively, and the dynamic resistances are 18 and 16 ohms. Both ultrasonic vibration transducers require one ultrasonic electrical signal Excitation, A ultrasonic power supply 12 and B ultrasonic power supply 13, the output voltage range is 0-400V, the current range is 0-4A, the output frequency is 25.44±0.01KHz, and the A ultrasonic power supply 12 and B ultrasonic power supply 13 are in It has automatic frequency tracking function within the specified frequency range.

Before being driven by an ultrasonic voltage signal, the friction drive blocks 10 at the front ends of the two elliptical vibration mode converters 7 are in contact with the rotor at the same time.

When driving, a direct current negative voltage signal of -300V is sent to the electrode plate 4 of the ultrasonic vibration transducer that needs to be suspended, and the piezoelectric effect is used to make the ultrasonic vibration transducer shrink axially, thereby making the front end of the elliptical vibration mode converter 7 The friction drive block 10 is suspended on the rotor; an ultrasonic sinusoidal electrical signal is sent to another ultrasonic vibration transducer that needs to be driven, and when the ultrasonic electrical signal output by the B ultrasonic power supply 13 is connected to the electrode of the ultrasonic vibration transducer After the plate 4, the ultrasonic vibration transducer generates ultrasonic vibration, and the ultrasonic vibration energy is transferred from the ultrasonic vibration transducer to the end of the elliptical vibration mode converter 7, and then converted into longitudinal vibration and bending vibration with a certain phase difference. Longitudinal-bending composite ultrasonic elliptical vibration, that is, converted into longitudinal-bending composite ultrasonic elliptical vibration at the end of the elliptical vibration mode converter 7; and driving the friction drive block 10 and the end of the elliptical vibration mode converter 7 to perform ultrasonic elliptical vibration together, and then drive the rotor Perform a continuous rotary motion. After running for 10 minutes, the system reached a stable vibration state. The output voltage of the B ultrasonic power supply 13 was 240V, the current was 1.46A, and the peak peripheral velocity of the turntable 8 with a diameter of 40mm was 55.3mm/s.

Exchange the ultrasonic electric signal driving mode of the two ultrasonic vibration transducers. After running for 10 minutes, the output voltage of the ultrasonic power supply 12 of A is 240V, and the current is 1.48A. The peak circumferential velocity of the edge is 55.9mm/s.

Claims (4)

1. bi-directional drive rotary ultrasonic motor, comprises rotor and stator, it is characterized in that: rotor comprises rotating disk and is arranged on the frictional layer of disc surfaces; Stator comprises support, the identical and symmetrical energy conversion device by two covers that support is fixing, often overlaps energy device and comprises a single-excitation ultrasonic oval vibration energy converter, an elliptical vibration modal transducer and a friction-driven block respectively; Described single-excitation ultrasonic oval vibration energy converter outline is cylindrical, it comprises bolt and is set in back shroud, piezoelectric ceramic piece, electrode slice and the front shroud on bolt successively, front shroud is provided with the ring flange that can connect with support, back shroud, piezoelectric ceramic piece, electrode slice and front shroud are connected compression by bolt by back shroud and front shroud; Described elliptical vibration modal transducer and front shroud are made into the front end that is integrally provided in front shroud, or also comprise a connection stud, for elliptical vibration modal transducer being connected in the front end of front shroud; Described elliptical vibration modal transducer is inclined wedge-shaped structure, the former entirety of inclined wedge-shaped structure elliptical vibration modal transducer is cuboid, inclined wedge-shaped structure is formed be cut a part along its side of single-excitation ultrasonic oval vibration energy converter axis direction after, formed in two sides of inclined wedge-shaped, not cut side is parallel to single-excitation ultrasonic oval vibration energy converter axis, and the another side be cut becomes 3-30 degree angle with the axis of single-excitation ultrasonic oval vibration energy converter; Described friction-driven block is arranged on the front end of elliptical vibration modal transducer; Angle between two single-excitation ultrasonic oval vibration energy converter axis after ring flange and support are fixed is 20 degree ~ 160 degree; Two single-excitation ultrasonic oval vibration energy converter of described bi-directional drive rotary ultrasonic motor have one group of extensional vibration piezoelectric ceramic piece respectively, and two single-excitation ultrasonic oval vibration energy converter of described bi-directional drive rotary ultrasonic motor need a road ultrasonic electric signal excitation respectively.

2. bi-directional drive rotary ultrasonic motor according to claim 1, is characterized in that: described friction-driven block is arranged on the front end of elliptical vibration modal transducer by welding.

3. bi-directional drive rotary ultrasonic motor according to claim 1, is characterized in that: described friction-driven block is by the bonding front end being arranged on elliptical vibration modal transducer.

4. bi-directional drive rotary ultrasonic motor according to claim 1, is characterized in that: also comprise a joint bolt, for friction-driven block being connected in the front end of elliptical vibration modal transducer.