Composite vibration patch type ultrasonic motor vibrator, method and ultrasonic motor

Abstract

The application discloses a patch type ultrasonic motor vibrator, a method and an ultrasonic motor of composite vibration, which comprises a vibrating body and a PZT plate group; the PZT plate group comprises a torsional PZT plate and a bending PZT plate; the top of the vibrating body is provided with a driving leg; the top surface and the bottom surface of the vibrating body are provided with the torsional PZT plates, the torsional PZT plates are polarized along the thickness direction of the vibrating body, and the polarization directions of two adjacent torsional PZT plates are opposite; the bending PZT plates are arranged at the nodes corresponding to the bending vibration on the two sides of the vibrating body, and the polarization directions of the bending PZT plates are the same. The four-foot vibrating body of the torsional / bending composite vibration type is designed, and the torsional excitation mode of the'reverse polarization and synchronous excitation' is designed, so that the electromechanical coupling degree of the linear ultrasonic motor is improved, and the problems of small driving force and low mechanical output caused by the vibration mode of the traditional vibrator are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic motor, in particular to a patch type ultrasonic motor vibrator with composite vibration, a method and an ultrasonic motor. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] An ultrasonic motor is a new type of motor that converts electrical energy into mechanical energy by using the inverse piezoelectric effect, and has the advantages of simple structure, fast response speed, low noise, high positioning accuracy, self-locking after power failure, and immunity to electromagnetic interference, and can be applied to precision instruments, aerospace, micro-positioning platforms, linear motors and many other fields. Linear ultrasonic motor is a very important type and branch of ultrasonic motor, mainly composed of a vibrator and a linear guide (or a slider), which outputs linear motion and thrust through the friction coupling between the two. Generally speaking, a single vibrator linear motor is light in weight but low in mechanical output. Taking the commonly used orthogonal bending type and bending / longitudinal composite vibration mode as an example, the type of motor is driven by the bending vibration of the vibrator. However, the bending vibration has poor electromechanical coupling performance, resulting in small driving force of the motor, which seriously hinders the practical application of linear ultrasonic motor.

[0004] Research has found that by changing the material properties, vibration mode and driving structure of the vibrator in the linear ultrasonic motor, the weight of the ultrasonic motor can be reduced, the power density of the motor can be improved, and the driving force and mechanical output can be increased.

[0005] Chinese patent document CN102437782B provides a sandwich type I-shaped four-foot linear ultrasonic motor vibrator, which includes two horizontal composite beams and a vertical composite beam. The two horizontal composite beams and the vertical composite beam are arranged in an I-shaped manner, and the piezoelectric ceramic sheets on the horizontal composite beams and the vertical composite beam are respectively excited by two-phase voltage. The stretching and contraction vibration of the piezoelectric ceramic sheets excites two vibration modes in the vibrator, and the two vibration modes are superimposed on the four driving feet, i.e. the ends of the four horizontal amplitude rods. The surface particles of the driving feet produce an elliptical motion trajectory. When the four driving feet and the movers on both sides are in contact under a certain pre-pressure, the macroscopic motion output of the mover is realized through the friction coupling between the driving feet and the mover.

[0006] Chinese patent document CN101626203B provides a kind of "bend vibration mode beam linear ultrasonic motor vibrator", the motor is composed of two driving feet, two end covers, two insulation sleeves, two pairs of polarization direction is thickness direction piezoelectric ceramic sheet, flange, two thin-walled beams and mounting base, the end face of flange is stretched along its axis each screw post, each screw post is sleeved with a pair of piezoelectric ceramic sheet, the end of each screw post is screwed with end cover, the end of each end cover is provided with a driving foot, each piezoelectric ceramic sheet is composed of two symmetrical half piezoelectric ceramic sheets combined after cutting, the polarization direction of two half piezoelectric ceramic sheets is opposite, the cutting lines of two pairs of piezoelectric ceramic sheets on the two sides of flange are perpendicular to each other, and the polarization direction of piezoelectric ceramic sheet in each pair of piezoelectric ceramic sheet is opposite.

[0007] Chinese patent document CN101630924B provides a kind of "T type linear ultrasonic motor vibrator", the T type front end cover of the motor is combined by three amplitude rods small end face and arranged in T type, the driving foot is connected to the connection position of amplitude rod, and three amplitude rods and driving foot are integrated; Piezoelectric ceramic sheet is polarized along the thickness direction, the polarization direction of every adjacent two pieces on the same amplitude rod is opposite, and the polarization mode of piezoelectric ceramic sheet on two amplitude rods on the same axis is opposite, each fastening screw passes through rear end cover, piezoelectric ceramic sheet and flange and is connected on blind hole, piezoelectric ceramic sheet and flange are located between rear end cover and amplitude rod, and piezoelectric ceramic sheet is located on the two sides of flange respectively; There is an electrode sheet between each pair of piezoelectric ceramic sheet, between amplitude rod and piezoelectric ceramic sheet, and between piezoelectric ceramic sheet and flange; Insulation sleeve is fixed outside fastening screw.

[0008] The deficiencies of the prior art of linear ultrasonic motor include:

[0009] On the one hand, the existing ultrasonic motor adopts bending vibration mode, and the electromechanical coupling degree is low, which limits the reduction of the size of the ultrasonic motor and the improvement of the power density.

[0010] On the other hand, the existing ultrasonic motor mostly adopts "single foot" driving mode, that is, the time for the stator to drive the rotor is one-fourth of the working cycle, which leads to insufficient driving force of the stator and low overall power density of the motor. SUMMARY

[0011] To solve the above problems, the present application provides a patch type ultrasonic motor vibrator with composite vibration, a method and an ultrasonic motor, a four-foot vibration body with torsional / bending composite vibration mode is designed, a torsional excitation mode with "reverse polarization and synchronous excitation" is designed, the electromechanical coupling degree of the linear ultrasonic motor is improved, and the problems of small driving force and low mechanical output caused by the vibration mode of the traditional vibrator are solved.

[0012] To achieve the above purpose, the present application adopts the following technical solutions:

[0013] In a first aspect, the present application provides a patch type ultrasonic motor vibrator, comprising: a vibrating body and a PZT plate group; the PZT plate group comprises a torsional PZT plate and a bending PZT plate;

[0014] The top of the vibrating body is provided with a driving leg;

[0015] The top surface and the bottom surface of the vibrating body are provided with the torsional PZT plates, the torsional PZT plates are polarized along the thickness direction of the vibrating body, and the polarization directions of the adjacent two torsional PZT plates are opposite;

[0016] The bending PZT plates are arranged at the nodes corresponding to the bending vibration on both sides of the vibrating body, and the polarization directions of the bending PZT plates are the same.

[0017] As an optional implementation, the driving legs are arranged on the four corners of the top of the vibrating body.

[0018] As an optional implementation, the driving leg is triangular.

[0019] As an optional implementation, the torsional PZT plates are eight in total, and four are arranged on the top surface and the bottom surface respectively.

[0020] As an optional implementation, the bending PZT plates are four in total, and two are arranged on each side.

[0021] As an optional implementation, the PZT plate group is pasted on the vibrating body.

[0022] As an optional implementation, a circular hole is arranged on the top surface of the vibrating body, and a cylindrical rod is inserted through the circular hole on the bottom surface of the vibrating body.

[0023] As an optional implementation, protruding parts are arranged on both sides of the vibrating body, the protruding parts have the same width as the vibrating body, and the length and the thickness are different.

[0024] In a second aspect, the present application provides a working method of a patch type ultrasonic motor vibrator, which adopts the patch type ultrasonic motor vibrator of the first aspect, and comprises:

[0025] In the torsional mode and the bending mode, the bending PZT plates and the torsional PZT plates are excited by an alternating voltage signal with equal amplitude, the frequency being the resonant frequency of the transducer itself, and the phase difference being +90°;

[0026] The adjacent driving legs are made to oscillate at 180° out of phase by the torsional PZT plates, the longitudinal vibration of the bending PZT plates excites the orthogonal bending vibration mode in the vibrator, the bending vibration mode is superimposed on the driving leg to generate an elliptical motion track, so as to realize the macroscopic motion output of the ultrasonic motor.

[0027] In a third aspect, the present application provides an ultrasonic motor, comprising the patch-type ultrasonic motor vibrator of the first aspect.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] In view of the problems of small driving force, low mechanical output and the like caused by the vibration mode of the traditional vibrator, the present application provides a patch-type ultrasonic motor vibrator of torsional / bending composite vibration, and a torsional excitation mode based on the reverse polarization and synchronous excitation of adjacent PZT plates is designed, thereby improving the electromechanical coupling degree of the linear ultrasonic motor and significantly improving the electric-mechanical energy conversion efficiency, laying a hardware foundation for improving the overall power density of the motor.

[0030] The present application designs a four-legged vibrator of torsional / bending composite vibration, realizes the synchronous driving of the diagonal vibration legs, and increases the effective driving time, the driving force and the output power by improving the stator driving rotor time from one fourth of the overall driving cycle to one half.

[0031] The advantages of the additional aspects of the present application will be partially given in the following description, partially become obvious from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application, and do not constitute improper limitations on the present application.

[0033] Figure 1 A structure schematic diagram of the patch-type ultrasonic motor vibrator of torsional / bending composite vibration is provided for the embodiment 1 of the present application;

[0034] Figure 2 A polarization direction schematic diagram of the PZT plate group is provided for the embodiment 1 of the present application;

[0035] Figures 3(a)-3(b) A driving signal schematic diagram applied to the PZT plate group is provided for the embodiment 2 of the present application;

[0036] 1, patch-type ultrasonic motor vibrator; 11, vibrator; 12, driving leg; 13, round hole; 2, PZT plate group; 21, torsional PZT plate; 22, bending PZT plate; 3, cylindrical rod. DETAILED DESCRIPTION

[0037] The present application will be further described below in combination with the drawings and embodiments.

[0038] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0039] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, as the scope of the application will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Unless otherwise required by context, singular terms shall include pluralities and vice versa. Also, the singular forms "a", "an", and "the" include plural referents unless the context clearly indicates otherwise.

[0040] The embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0041] Embodiment 1

[0042] As shown in the figure, the embodiment provides a patch type ultrasonic motor vibrator of torsional / bending compound vibration, which comprises a vibrating body 11 and a PZT plate group 2; the PZT plate group 2 comprises torsional PZT plates 21 and bending PZT plates 22; Figure 1 The top of the vibrating body 11 is provided with driving feet;

[0043] The torsional PZT plates 21 are arranged on the top surface and the bottom surface of the vibrating body 11, the torsional PZT plates 21 are polarized along the thickness direction of the vibrating body 11, and the polarization directions of the adjacent two torsional PZT plates 21 are opposite;

[0044] The bending PZT plates 22 are arranged at the nodes corresponding to the bending vibration on both sides of the vibrating body 11, and the polarization directions of the bending PZT plates 22 are the same.

[0045] In the embodiment, the driving feet 12 are arranged on the four corners of the top of the vibrating body 11;

[0046] As an alternative embodiment, the driving feet 12 are triangular, and there are four driving feet 12 arranged on the four corners of the top of the vibrating body 11 respectively.

[0047] In the embodiment, the PZT plate group 2 is pasted on the vibrating body 11, as shown in the figure, the PZT plate group 2 comprises the torsional PZT plates 21 and the bending PZT plates 22;

[0048] Figure 2

[0049] ​​The torsional PZT plates 21 are arranged on the top and bottom surfaces of the vibrator 11, are polarized along the thickness direction of the vibrator 11, and the polarization directions of two adjacent torsional PZT plates 21 are opposite, i.e. are reverse polarized;

[0050] The bending PZT plates 22 are bonded at the nodes corresponding to the bending vibration on both sides, and have the same polarization direction.

[0051] In the torsional mode and the bending mode, the bending PZT plates and the torsional PZT plates are excited by the AC voltage signals with the same amplitude, the frequency of the transducer itself resonance frequency, and the phase difference of +90°; then, the adjacent driving legs are oscillated with 180° out of phase by the torsional PZT plates, the orthogonal bending vibration mode is excited in the vibrator by the longitudinal vibration of the bending PZT plates, the bending vibration mode is superimposed on the driving legs to generate the elliptical motion trajectory, thereby realizing the macroscopic motion output of the ultrasonic motor.

[0052] As an alternative embodiment, the torsional PZT plates 21 are provided in total eight, and four on the top surface and four on the bottom surface.

[0053] As an alternative embodiment, the bending PZT plates 22 are provided in total four, two on each side.

[0054] In the embodiment, two circular holes 13 are arranged on the top surface of the vibrator 11, and two cylindrical rods 3 are inserted into the bottom surface of the vibrator 11, the two cylindrical rods 3 are inserted into the circular holes 13 of the vibrator 11 and bonded on the vibrator 11.

[0055] As an alternative embodiment, the cylindrical rods 3 are made of stainless steel.

[0056] As an alternative embodiment, the two sides of the vibrator 11 are provided with protruding parts, the protruding parts on both sides have the same width as the vibrator 11, and different length and thickness.

[0057] As an alternative embodiment, the material of the vibrator 11 can be fine ceramic such as alumina, which has high Young's modulus and helps to improve the vibration performance of the vibrator.

[0058] Embodiment 2

[0059] The embodiment provides a working method of the patch type ultrasonic motor vibrator, which comprises the following steps:

[0060] As shown in Figures 3(a)-3(b) eight torsional PZT plates 21 are connected with the driving signal U1 (synchronous excitation), four bending PZT plates 22 are connected with the driving signal U2, and the vibrator 11 is connected with the common end GND of the driving power supply;

[0061] When the vibrator works in the torsional mode and the bending mode, the bending PZT plate 22 and the torsional PZT plate 21 are excited by AC voltage signals with equal amplitude, frequency of the resonant frequency of the transducer itself and phase difference of +90°;

[0062] The adjacent driving legs oscillate with 180° out of phase by the torsional PZT plate 21, the orthogonal bending vibration mode is excited in the vibrator by the longitudinal vibration of the bending PZT plate 22, the bending vibration mode superimposes on the four driving legs to generate an elliptical motion trajectory, and then the macro motion output of the ultrasonic motor is realized through the friction coupling between the driving legs and the slider.

[0063] Embodiment 3

[0064] The embodiment provides an ultrasonic motor, which comprises the patch type ultrasonic motor vibrator in embodiment 1.

[0065] The above describes the specific embodiments of the present application in combination with the drawings, but is not a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications or changes made on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A patch-type ultrasonic motor vibrator with composite vibration, characterized in that, It comprises: a vibrating body and a PZT plate group; the PZT plate group comprises torsional PZT plates and bending PZT plates; the top of the vibrating body is provided with driving feet; torsional PZT plates are arranged on the top surface and the bottom surface of the vibrating body, the torsional PZT plates are polarized along the thickness direction of the vibrating body, and the polarization directions of two adjacent torsional PZT plates are opposite; bending PZT plates are arranged at the nodes corresponding to bending vibration on both sides of the vibrating body, and the polarization directions of the bending PZT plates are the same; driving feet are arranged on the four corners of the top of the vibrating body; adjacent driving feet are made to oscillate out of phase by 180° by the torsional PZT plates, the bending vibration mode is excited in the vibrator by the longitudinal vibration of the bending PZT plates, the bending vibration mode is superimposed on the driving feet to generate an elliptical motion trajectory, thereby realizing the macroscopic motion output of the ultrasonic motor.

2. A compound resonant patch-type ultrasonic motor vibrator as claimed in claim 1, characterized in that, The driving feet are triangular.

3. A compound resonant patch-type ultrasonic motor vibrator as claimed in claim 1, characterized in that, The torsional PZT plates are eight in total, four on the top surface and four on the bottom surface.

4. A compound resonant patch-type ultrasonic motor vibrator as claimed in claim 1, wherein The bending PZT plates are four in total, two on each side.

5. A compound resonant patch-type ultrasonic motor vibrator as claimed in claim 1, wherein The PZT plate group is pasted on the vibrating body.

6. A compound resonant patch-type ultrasonic motor vibrator as claimed in claim 1, wherein A circular hole is arranged on the top surface of the vibrating body, and a cylindrical rod is inserted through the circular hole on the bottom surface of the vibrating body.

7. A compound resonant patch-type ultrasonic motor vibrator as claimed in claim 1, wherein Protruding parts are arranged on both sides of the vibrating body, the protruding parts have the same width as the vibrating body, and different lengths and thicknesses.

8. A method of operating a patch-type ultrasonic motor vibrator, characterized by, The patch type ultrasonic motor vibrator of any one of claims 1-7 comprises: In the torsional mode and the bending mode, the bending PZT plates and the torsional PZT plates are excited by alternating voltage signals with equal amplitudes, a frequency being the resonant frequency of the transducer itself, and a phase difference of +90°; Adjacent driving feet are made to oscillate out of phase by 180° by the torsional PZT plates, the bending vibration mode is excited in the vibrator by the longitudinal vibration of the bending PZT plates, the bending vibration mode is superimposed on the driving feet to generate an elliptical motion trajectory, thereby realizing the macroscopic motion output of the ultrasonic motor.

9. An ultrasonic motor characterized by comprising: The patch type ultrasonic motor vibrator of any one of claims 1-7 is included.

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