CN110601597B - A dual-mode composite inchworm ultrasonic motor - Google Patents

Abstract

The invention relates to a dual-mode composite inchworm ultrasonic motor, which belongs to the technical field of piezoelectric driving. The invention comprises a base, a bearing, a vertical plate, a fixed plate, a mode converter, a piezoelectric ceramic sheet, a piezoelectric stack, and a rotor , the output shaft; the modal converter, the piezoelectric ceramic sheet, and the piezoelectric stack constitute the stator assembly of the ultrasonic motor; the number of the piezoelectric ceramic sheet is two, and the number of the piezoelectric stack is two , the output shaft is one; the rotor is fixedly connected to the output shaft, and the output shaft passes through the through hole on the vertical plate and is connected to the vertical plate through a bearing; there are two elliptical fixers on the modal converter, and at the same time there are Two driving feet; a gap for the vibration of the driving feet is provided between the driving feet and the outer arc surface of the rotor. The invention combines the longitudinal vibration of the piezoelectric ceramic sheet and the expansion and contraction vibration of the piezoelectric stack into a small amplitude drive of the rotor by the driving foot, and pushes the rotor to perform forward rotation or reverse rotation under the action of inertia through friction coupling. High utilization rate and flexible use.

Description

A dual-mode composite inchworm ultrasonic motor

technical field

The invention relates to the technical field of piezoelectric driving, in particular to a dual-mode composite inchworm ultrasonic motor.

Background technique

With the continuous development of scientific research and production practice, the indispensable micro-motor servo system in the system largely determines the overall performance of the system. In order to adapt to the small size, fast response, high precision and no magnetic field of modern electronic technology Ultrasonic motor (USM) came into being in response to the requirements of interference and other requirements. The ultrasonic motor uses the inverse piezoelectric effect of piezoelectric materials to convert vibration (mechanical vibration frequency above 20kHz) or quasi-static deformation into mechanical energy, breaking the traditional motor need to be affected by electromagnetic effects. The concept of obtaining speed and torque has been in the spotlight since the 1980s. Ultrasonic motors have high torque density, good controllability, no interference from external magnetic fields, low noise, and can achieve low-speed operation. Weapons and equipment and life science and other fields have very broad application prospects.

In the late 1980s and early 1990s, ultrasonic motors attracted the attention of Chinese scientists, and achieved a series of research results in the design theory, control technology, performance analysis and key technologies of industrialization of micro ultrasonic motors. A variety of ultrasonic motors with complete structures and practical operation have been developed, and some of them have been applied in engineering. The industrial application prospects of ultrasonic motors are favored by large domestic enterprises and traditional motor manufacturers. At present, the main research ideas of domestic and foreign researchers focus on the invention of new motor structures and drive control technologies, but only by combining effective control methods and control strategies can the excellent performance of ultrasonic motors be brought into play.

With the continuous emergence of new materials, new processes and new structures, the types of ultrasonic motors continue to expand, but there are very few ultrasonic motors that can truly realize commercial production. Therefore, it is necessary to design a kind of ultrasonic motor that is close to the actual requirements and is expected to gradually realize batch Production of ultrasonic motors.

In the patent with publication number CN109861582A and the invention titled "An Inertia Rotation Piezoelectric Motor", it is proposed to continuously rotate a tiny angle under the action of a pair of mass blocks in a loosened state to realize a single piezoelectric motor. Rotation movement. The friction damage of the piezoelectric motor is small, and the motion efficiency is increased by 5%-10%. However, this invention has problems such as low efficiency and large friction loss.

The ultrasonic motor has good electrical parameters and mechanical parameters, but the complex structure, high wear consumption and low driving efficiency hinder the further development of the ultrasonic motor. The driving force of the rotor rotation, and the principle of bipedal driving is adopted to improve the driving efficiency of the ultrasonic motor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a dual-mode composite inchworm ultrasonic motor, so as to solve the aforementioned problems existing in the present technology.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

An inchworm-type ultrasonic motor mainly includes a stator assembly and a rotor, and is characterized in that: the ultrasonic motor includes a base 1, a bearing 2, a vertical plate 3, a fixed plate 4, a mode converter 5, a piezoelectric ceramic sheet 6, a pressure The electric stack 7, the elliptical holder 8, the rotor 9, and the output shaft 10; the base 1 is fixedly connected with the vertical plate 3, the mode converter 5 is an integral piece, and the material is an elastic body, and the fixing plate 4 includes The left and right fixed plates press and fix the modal converter 5; the modal converter 5 is provided with an elliptical holder 8 for fixing the piezoelectric stack; A piezoelectric ceramic sheet is pasted on each side, and two piezoelectric stacks are fixed by an elliptical holder on the bottom half.

The piezoelectric ceramic sheet 6 includes a left piezoelectric ceramic sheet A1 and a right piezoelectric ceramic sheet A2, and both the left piezoelectric ceramic sheet A1 and the right piezoelectric ceramic sheet A2 are polarized along the thickness direction.

The piezoelectric stack 7 includes a left piezoelectric stack a1 and a right piezoelectric stack a2, and the piezoelectric stack a1 and the piezoelectric stack a2 glue multiple layers of piezoelectric ceramic sheets polarized along the thickness on each other. Together with electrodes, the total output deformation is the sum of the deformation output of each layer of piezoelectric ceramic sheets.

The piezoelectric ceramic sheet A1 and the piezoelectric ceramic sheet A2 are symmetrically bonded to both sides of the Y-shaped elastic body through conductive epoxy resin glue, the surface plating metal is silver, and the lead method is soldering. The reliability of the soldering process is higher than that of the gluing process, which can improve the working life and working efficiency of the ultrasonic motor.

The piezoelectric stack a1 and the piezoelectric stack a2 are bonded to the inner surface of the elliptical fixing device by using conductive epoxy resin glue.

The included angle between the two elliptical fixing devices is 90 degrees.

Preferably, the bearing adopts a ball bearing.

Furthermore, A friction material is adhered to the surfaces of the two driving feet in contact with the rotor.

Further, the outer arc surface of the rotor is bonded with B friction material.

Compared with the prior art, the present invention adopts the above technical scheme, and has the following technical effects:

The ultrasonic motor proposed by the invention utilizes the longitudinal vibration of the piezoelectric ceramic sheet and the expansion and contraction vibration of the piezoelectric stack to form a micro-amplitude drive of the rotor by the driving foot, and pushes the rotor to rotate clockwise or counterclockwise through friction coupling under the action of inertia. Rotational motion, high energy efficiency and utilization; the structure of the ultrasonic motor has symmetry, which makes the impedance characteristics of the ultrasonic motor also have good symmetry.

Description of drawings

Figure 1 is a schematic diagram of the structure of a dual-mode composite inchworm ultrasonic motor. Label name in the figure: 1-base; 2-bearing; 3-vertical plate; 4-fixed plate; 5-modal converter; 6-piezoelectric ceramic sheet; 7-piezoelectric stack; 8-ellipse holder; 9-rotor; 10-output shaft.

Figure 2 is a schematic diagram of a modal converter. Label name in the figure: A1-left piezoelectric ceramic sheet; A2-right piezoelectric ceramic sheet; a1-left piezoelectric stack; a2-right piezoelectric stack.

FIG. 3 is a schematic diagram of the working mode of the dual-mode composite inchworm ultrasonic motor rotating clockwise when an alternating voltage with an amplitude of 20V _pp is applied.

4 is a schematic diagram of the working mode of the dual-mode composite inchworm ultrasonic motor rotating counterclockwise when an alternating voltage with an amplitude of 20V _pp is applied.

In the figure, the arrows represent the stretching direction of the piezoelectric stack. The dashed line represents the deformation of the modal converter.

Detailed ways

In order to illustrate the technical features of the solution more clearly, the present invention will be described in detail below with reference to the accompanying drawings.

The structure of a dual-mode composite inchworm ultrasonic motor is shown in Figure 1, including 1-base; 2-bearing; 3-vertical plate; 4-fixing plate; 5-mode converter; 6-piezoelectric ceramic sheet ; 7-piezoelectric stack; 8-elliptical holder; 9-rotor; 10-output shaft. The base 1 and the vertical plate 3 are fixedly connected, and the mode converter 5 is an integral piece, and the material is an elastic body.

For the polarized piezoelectric ceramic sheet, the components of the piezoelectric strain constant matrix d are divided into three non-zero components d33, d31, and d15. The piezoelectric ceramic sheet of the ultrasonic motor proposed in this paper works in the d31 transverse vibration mode, and the piezoelectric stack works in the d33 longitudinal working mode.

As shown in FIG. 2 , the stator assembly includes a Y-shaped modal converter 5 , a left piezoelectric ceramic sheet A1 , a right piezoelectric ceramic sheet A2 , a left piezoelectric stack a1 and a right piezoelectric stack a2 ; There are two elliptical holders 8 on the modal converter for fixing two piezoelectric stacks. The modal converter 5 is an integrated structure with two driving feet at the lower end; the piezoelectric ceramic sheet 6 and the piezoelectric stack 7 are used to receive external excitation signals and convert them into ultrasonic vibrations.

The rotor is fixedly connected with the output shaft, the output shaft passes through the through hole on the longitudinal plate, and the output shaft and the through hole are connected through a bearing.

The bottom plate is fixedly connected with the vertical plate.

The two piezoelectric ceramic sheets are polarized along the thickness direction, and are symmetrically glued on both sides of the modal converter through conductive epoxy resin glue. A lead wire is arranged on the surface opposite to the adhesive surface, and the lead wire method is soldering, and a two-phase alternating current signal is applied to the two piezoelectric ceramic sheets through the lead wire.

The piezoelectric stack glues together multiple layers of piezoelectric ceramic sheets polarized along the thickness, and embeds electrodes inside, and the total output deformation is the sum of the deformation output of each layer of piezoelectric ceramic sheets. The piezoelectric stack is bonded to the inner surface of the elliptical fixing device with conductive epoxy resin glue, and the glued surface is plated with silver and provided with lead wires.

The invention also discloses a working mode of the dual-mode composite inchworm ultrasonic motor:

When an alternating voltage is applied to the upper and lower surfaces of the piezoelectric ceramic sheet polarized along the thickness, the piezoelectric ceramic sheet will generate first-order longitudinal vibration. As shown in Figure 3(1), a forward voltage of 20V _pp is applied to the left piezoelectric ceramic sheet A1, and the left piezoelectric ceramic sheet is stretched; a reverse voltage of 20 V _pp is applied to the right piezoelectric ceramic sheet A2, The right piezoelectric ceramic sheet shrinks, the upper half of the modal converter produces the deformation shown by the dotted line in the figure, and the lower half of the modal converter produces the displacement shown by the dotted line in the figure; the left driving foot presses the rotor , forming a friction coupling surface with the outer arc surface of the rotor; the right driving foot is separated from the outer arc surface of the rotor by a certain distance and does not have a contact surface with the rotor. At this time, a reverse voltage is applied to the left piezoelectric stack a1 and the right piezoelectric stack a2 at the same time, the left piezoelectric stack and the right piezoelectric stack are shortened at the same time, and the left driving foot passes through the outer arc surface of the rotor. The formed friction coupling surface uses the friction force to give the rotor a driving force in the upper right direction, which pushes the rotor to rotate clockwise.

As shown in Figure 3(2), apply a reverse voltage of 20V _pp to the left piezoelectric ceramic sheet A1, and the left piezoelectric ceramic sheet shrinks; apply a forward voltage of 20 V _pp to the right piezoelectric ceramic sheet A2, and the right piezoelectric ceramic sheet A2 The side piezoelectric ceramic sheet is elongated, and the upper half of the modal converter produces the deformation shown by the dotted line in the figure, so that the lower half of the modal converter produces the displacement shown by the dotted line in the figure; the left driving foot leaves the rotor. The arc surface is at a certain distance, and there is no contact surface; the right driving foot presses the rotor to form a friction coupling surface with the outer arc surface of the rotor. At this time, a forward voltage is applied to the left piezoelectric stack a1 and the right piezoelectric stack a2 at the same time, the left piezoelectric stack and the right piezoelectric stack are stretched at the same time, and the right driving foot passes through the outer arc with the rotor. The friction coupling surface formed by the surface uses the friction force to give the rotor a driving force, and the direction is the lower right, which pushes the rotor to rotate clockwise.

Figures 3(3) and 3(4) are the repetitive processes of the above two basic working modes. The modal converter moves continuously according to the working modes shown in Figures 3(1) to 3(4), so that the two The driving foot is driven at two points respectively, and the rotor can realize continuous clockwise rotation.

The motion mechanism of the counterclockwise rotational motion is consistent with the motion mechanism of the clockwise rotational motion, only the positive and negative of the applied piezoelectric are changed, and the working mode is shown in Figure 4, which will not be repeated here.

The ultrasonic motor proposed by the invention utilizes the longitudinal vibration of the piezoelectric ceramic sheet and the expansion and contraction vibration of the piezoelectric stack to form a micro-amplitude drive of the rotor by the driving foot, and pushes the rotor to perform forward rotation or reverse rotation under the action of inertia through friction coupling. Rotating motion, high energy efficiency and flexible use. The stator assembly adopts a patch structure, which is easy to process and saves costs.

The present invention has been described by the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only used for illustration and description, and are not intended to limit the present invention to the scope of the described embodiments. It can be understood by those skilled in the art that more variations and modifications can be made according to the teachings of the present invention, which all belong to the protection scope of the present invention.

Claims (5)

1. A bimodal composite inchworm ultrasonic motor comprises a base, a bearing, a modal converter, a piezoelectric ceramic piece, a piezoelectric stack, a rotor and an output shaft, wherein the stator assembly comprises the modal converter, the piezoelectric ceramic piece and the piezoelectric stack;

the mode converter is a Y-type mode integrated piece made of an elastomer; a piezoelectric ceramic piece is respectively adhered to the left side and the right side of the elastic plate at the upper half part of the modal converter, two driving feet are arranged at the lower half part of the modal converter, and the driving feet face the rotor surface and are respectively fixed with one piezoelectric stack; the rotor is a disk metal body, and the outer arc surface of the rotor and the two driving feet form two friction coupling surfaces;

the piezoelectric ceramic piece is polarized along the thickness direction, and the longitudinal vibration of the piezoelectric ceramic piece and the telescopic vibration of the piezoelectric stack are compounded to be driven by a micro amplitude of the rotor, so that the rotor is pushed to rotate;

when alternating voltage is applied to the upper surface and the lower surface of the piezoelectric ceramic sheet polarized along the thickness, the piezoelectric ceramic sheet can generate first-order longitudinal vibration; applying a forward voltage of 20Vp-p to the left piezoelectric ceramic piece, and extending the left piezoelectric ceramic piece; applying reverse voltage of 20Vp-p to the right piezoelectric ceramic piece, shrinking the right piezoelectric ceramic piece, and generating deformation on the upper half part of the modal converter to enable the lower half part of the modal converter to generate displacement; the left driving foot presses the rotor to form a friction coupling surface with the outer arc surface of the rotor; the left driving foot is away from the outer arc surface of the rotor by a certain distance and does not generate a contact surface with the rotor, reverse voltage is simultaneously applied to the left piezoelectric stack and the right piezoelectric stack, the left piezoelectric stack and the right piezoelectric stack are simultaneously shortened, the left driving foot applies a driving force to the rotor by using friction force through a friction coupling surface formed by the left driving foot and the outer arc surface of the rotor, the direction is upward right, and the rotor is pushed to rotate clockwise; applying a reverse voltage of 20Vp-p to the left piezoelectric ceramic piece, and contracting the left piezoelectric ceramic piece; applying a forward voltage of 20Vp-p to the right piezoelectric ceramic piece, extending the right piezoelectric ceramic piece, and generating deformation on the upper half part of the modal converter to enable the lower half part of the modal converter to generate displacement; the left driving foot is away from the outer arc surface of the rotor by a certain distance, and no contact surface is generated; the right side driving foot compresses the rotor to form a friction coupling surface with the outer arc surface of the rotor, forward voltage is applied to the left side piezoelectric stack and the right side piezoelectric stack at the same time, the left side piezoelectric stack and the right side piezoelectric stack extend at the same time, the right side driving foot utilizes friction force to provide driving force for the rotor through the friction coupling surface formed with the outer arc surface of the rotor, and the rotor is pushed to rotate clockwise in the downward right direction.

2. The bimodal compound inchworm ultrasonic motor of claim 1, wherein: the base is vertically connected with the longitudinal plate, and the number of the output shafts is one; the rotor is fixedly connected with the output shaft, and the output shaft penetrates through the through hole in the longitudinal plate and is connected with the longitudinal plate through the bearing.

3. The bimodal compound inchworm ultrasonic motor of claim 1, wherein: the piezoelectric ceramic plates are symmetrically adhered to two sides of the upper half part of the elastic plate of the mode converter through conductive epoxy resin glue, the surface plating layer metal is silver, and the lead mode is tin soldering.

4. The bimodal compound inchworm ultrasonic motor of claim 1, wherein: the fixed die converter also comprises a left fixed plate and a right fixed plate which are used for compressing the fixed die converter; the mode converter is provided with 2 elliptical fixing devices for fixing the piezoelectric stacks, and the included angle of a vertical plane between the two elliptical fixing devices is 90 degrees.

5. The bimodal compound inchworm ultrasonic motor of claim 1, wherein: the piezoelectric stack is used for gluing a plurality of layers of piezoelectric ceramic pieces polarized along the thickness together, electrodes are embedded in the piezoelectric stack, and the total output deformation is the sum of the output deformation of each layer of piezoelectric ceramic piece.

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