CN115224977B - A resonant rotary piezoelectric motor - Google Patents

Abstract

The invention belongs to the technical field of precise driving and positioning, and particularly relates to a resonant rotary piezoelectric motor, which comprises a square base, a stator mechanism and a rotating wheel mechanism; the stator mechanism comprises a driving elastic vibrator, a pair of clamping blocks, a central connecting block, a pre-tightening block and a clamping elastic vibrator, wherein the driving elastic vibrator is arranged above the square base and sequentially connected along the X-axis direction of the square base; the supporting shaft penetrates through the central axial direction of the rotating wheel through the deep groove ball bearing, the clamping foot is fixedly arranged at the lower end of the pre-tightening block, so that the lower end of the clamping foot corresponds to the upper end face of the rotating wheel, the driving and clamping integration of the resonance type rotary piezoelectric motor is realized, single harmonic driving is adopted to work in a resonance state, the energy conversion efficiency is good, compared with other motors of the same type, the contact and separation of the clamping foot and the rotating wheel are abrupt, the rotating wheel is driven by static friction force, sliding friction does not exist between the clamping foot and the rotating wheel, and the motor is stable in operation.

Description

A resonant rotary piezoelectric motor

Technical Field

The present invention belongs to the technical field of precision driving and positioning, and in particular, it relates to a resonant rotary piezoelectric motor.

Background technique

In recent decades, with the increasing demand for actuators in engineering applications, piezoelectric motors have developed rapidly. Piezoelectric motors use the inverse piezoelectric effect of piezoelectric materials to convert input electrical energy into output mechanical energy. Compared with traditional electromagnetic motors, piezoelectric motors have the advantages of small size, fast response, and no electromagnetic interference. At present, piezoelectric motors have been widely used in micro-robots, aerospace equipment, biomedicine, optical measurement and other fields.

There are many types of piezoelectric motor structures. According to their working principles, they can be mainly divided into ultrasonic motors, inchworm motors and inertial impact motors. Among them, ultrasonic motors have the advantages of high frequency, high torque and low noise. However, since the ultrasonic motor uses the friction between the stator and the mover to generate movement, the motor will be accompanied by friction and wear problems when working, so this type of motor is not suitable for long-term work. The inchworm motor works in a quasi-static state and does not generate sliding friction during operation. Therefore, it has the characteristics of large output force, high efficiency and precision. However, the operating frequency of the inchworm motor is lower than that of other types of motors, resulting in a lower output speed. In 2017, Wang et al. designed an inchworm motor with a maximum no-load speed of about 0.0377 rad/s.

Inertial impact motors have the advantages of large stroke, simple structure, high resolution, small size and can be miniaturized. However, since this type of motor uses the inertial impact of the stator to produce a micro-displacement difference in the mover for linear or rotational motion, the retraction step distance of each cycle is different, which affects the stability of the operation of this type of motor.

Therefore, it is necessary to design a resonant rotary piezoelectric motor with an integrated clamp and a simple structure. It uses a single harmonic drive to work in a resonant state and has good energy conversion efficiency. Compared with other motors of the same type, it has the characteristics of large output torque and convenient power supply control. In addition, the contact and separation between the clamp foot and the wheel are sudden, and the rotation of the wheel is driven by static friction, and there is no sliding friction, thereby extending the life of the motor.

Summary of the invention

In order to solve the shortcomings of severe friction and wear of ultrasonic motors, low frequency and speed of inchworm motors, and unstable operation of inertial impact motors, the present invention provides a resonant rotary piezoelectric motor.

The technical solution of the present invention is as follows: a resonant rotary piezoelectric motor,

It includes a square base 1, a stator mechanism 2 and a rotating wheel mechanism 3;

The stator mechanism 2 includes a driving elastic vibrator 21, a pair of clamping blocks 22, a central connecting block 23, a pre-tightening block 24 and a clamping elastic vibrator 25 which are arranged above the square base 1 and are sequentially connected along the X-axis direction of the square base 1;

The driving elastic vibrator 21 is a horizontally arranged rectangle, with two side surfaces of the rectangle arranged vertically, a pair of driving piezoelectric sheets 26 attached to the two side surfaces, and a first mass block 27 is fixedly connected to the extended end of the driving elastic vibrator 21;

The clamped elastic vibrator 25 is a horizontally arranged rectangle, with two side surfaces of the rectangle arranged horizontally, a pair of clamped piezoelectric sheets 28 attached to the two side surfaces, and a second mass block 29 is fixedly connected to the extended end of the clamped elastic vibrator 25;

The wheel mechanism 3 includes a wheel 31, a support shaft 32 and a clamping foot 34. The support shaft 32 passes through the central axial direction of the wheel 31 through a deep groove ball bearing 33 and penetrates the central connecting block 23. The pre-tightening block 24 is floatingly mounted on the central connecting block 23, and the clamping foot 34 is fixedly arranged at the lower end of the pre-tightening block 24, so that the lower end of the clamping foot 34 corresponds to the upper end surface of the wheel 31.

During operation, a harmonic signal is input to a pair of driving piezoelectric sheets 26, driving the elastic vibrator 21 to drive the central connecting block 23 to swing back and forth around the supporting shaft 32 within one vibration cycle, thereby realizing the action of the clamping foot 34 driving the rotating wheel 31 to rotate; a harmonic signal is input to another pair of clamping piezoelectric sheets 28, and the clamping elastic vibrator 25 swings up and down around the rotating wheel 31 within one vibration cycle, thereby realizing the clamping foot 34 clamping and releasing the rotating wheel 31.

Furthermore, the central connecting block 23 is a horizontally arranged convex block, the large end of the convex block is fixedly connected to the pair of clamping blocks 22, and the small end of the convex block is horizontally provided with a pair of threaded holes;

The pre-tightening block 24 comprises a rectangular cavity with an open bottom, so that the pre-tightening block 24 is covered on the small end of the convex block.

A pair of vertical waist-shaped holes are respectively opened on the opposite side walls of the pre-tightening block 24, and the pre-tightening block 24 is fixed to the small end of the convex block by passing the fastening screws 241 through the vertical waist-shaped holes and the threaded holes of the small end of the convex block in sequence;

The pre-tightening screw 242 passes through the upper end of the pre-tightening block 24 and connects the pre-tightening block 24 and the small end of the convex block. A pre-tightening spring 243 is sleeved on the pre-tightening screw 242. The pre-tightening screw 242 and the fastening screw 241 are adjusted so that the pre-tightening block 24 is floatingly installed on the central connecting block 23.

Furthermore, a horizontal clamping foot connecting block 374 is provided on one side of the central connecting block 23 corresponding to the clamping elastic vibrator 25, and a flexible hinge connection is provided between the central connecting block 23 and the clamping foot connecting block 374; the clamping foot 34 is a short cylinder, and the lower end is a spherical arc surface, and the upper end is fixedly connected to the clamping foot connecting block 341.

Furthermore, an inverted U-shaped bracket 2 is fixedly provided above the square base 1 , the upper end of the support shaft 32 is fixedly connected to the upper bottom plate of the U-shaped bracket 2 , and the lower end of the support shaft 32 is fixedly connected to the square base 1 .

Furthermore, each of the driving piezoelectric sheet and the clamping piezoelectric sheet is a lead zirconate titanate piezoelectric ceramic sheet.

Furthermore, the support shaft 32 is a three-section support shaft, and the upper section and the middle section are connected by a flexible hinge, and the middle section and the lower section are connected by a flexible hinge.

Beneficial effects of the present invention:

(1) A resonant rotary piezoelectric motor of the present invention comprises a pair of driving piezoelectric sheets inputting harmonic signals, driving the elastic vibrator to drive the stator mechanism to swing back and forth relative to the support shaft within one vibration cycle so as to realize the action of the clamping foot to complete the rotation of the rotating wheel; inputting harmonic signals to another pair of clamping piezoelectric sheets, causing the clamping elastic vibrator to swing up and down relative to the rotating wheel within one vibration cycle so as to realize the clamping foot to clamp and release the rotating wheel; and simultaneously inputting harmonic signals with equal frequency but different phases to the driving piezoelectric sheets and the clamping piezoelectric sheets respectively, coordinating the bending vibrations of the driving elastic vibrator and the clamping elastic vibrator in vertically staggered directions, so that the clamping foot moves in an elliptical trajectory so as to realize unidirectional continuous rotation of the rotating wheel, and at the same time changing the input phase difference can adjust the motor speed and realize the reverse rotation of the motor;

Therefore, the present invention realizes the driving and clamping of the resonant rotary piezoelectric motor in one, has a simple structure, and adopts single harmonic drive to work in a resonant state, with good energy conversion efficiency. Compared with other motors of the same type, the contact and separation between the clamping foot and the wheel are sudden, and the rotation of the wheel is driven by static friction. There is no sliding friction between the clamping foot and the wheel, which makes the motor run stably and extends the service life of the motor.

(2) The working state of the present invention is a resonant state. When the two electrical signals are cooperatively excited, the wheel will realize unidirectional rotation, and the wheel can be reversed by changing the initial phase of the input electrical signal. When the operating frequency of the motor prototype is 360 Hz and the driving voltage is 280 V, the no-load speed and maximum output torque of the motor are 19.7 r/min and 93.6 N·mm.

Therefore, it has the advantages of large output torque and convenient power supply control.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a resonant rotary piezoelectric motor according to the present invention.

FIG. 2 is a schematic diagram of the structure of the stator mechanism in contact with the rotor of the present invention.

FIG. 3 is a schematic structural diagram of the stator mechanism of the present invention.

FIG. 4 is a schematic diagram of the installation and use of the preload block of the present invention.

FIG. 5 is an exploded schematic diagram of FIG. 4 .

FIG. 6 is a schematic structural diagram of the rotating wheel of the present invention.

FIG. 7 is a schematic structural diagram of a support shaft of the present invention.

FIG8 is a simplified schematic diagram of the contact relationship between the stator mechanism and the rotor in the main view direction of the present invention.

FIG. 9 is a simplified schematic diagram of the contact relationship between the stator mechanism and the rotor in a top view of the present invention.

FIG. 10 is a diagram showing the driving voltage and the input signal of the clamped piezoelectric film according to the present invention.

FIG. 11 is a working principle diagram of the motor of the present invention at t ₀ -t ₁ in FIG. 10 .

FIG. 12 is a working principle diagram of the motor of the present invention at t ₁ -t ₂ in FIG. 10 .

FIG. 13 is a diagram showing the working principle of the motor of the present invention during the period t ₂ -t ₃ in FIG. 10 .

FIG. 14 is a diagram showing the working principle of the motor of the present invention during the period t ₃ -t ₄ in FIG. 10 .

Among them: square base 1, stator mechanism 2, rotating wheel mechanism 3, U-shaped bracket 4, driving elastic vibrator 21, a pair of clamping blocks 22, central connecting block 23, pre-tightening block 24, fastening screw 241, pre-tightening screw 242, pre-tightening spring 243, clamping elastic vibrator 25, a pair of driving piezoelectric sheets 26, a first mass block 27, a pair of clamping piezoelectric sheets 28, a second mass block 29, a rotating wheel 31, a supporting shaft 32, a deep groove ball bearing 33, a clamping foot 34, and a clamping foot connecting block 341.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

Example

As shown in FIG1 and FIG2 , a resonant rotary piezoelectric motor includes a square base 1, a stator mechanism 2 and a rotating wheel mechanism 3;

As shown in FIG3 , the stator mechanism 2 includes a driving elastic vibrator 21, a pair of clamping blocks 22, a central connecting block 23, a pre-tightening block 24 and a clamping elastic vibrator 25 which are arranged above the square base 1 and are sequentially connected along the X-axis direction of the square base 1;

The driving elastic vibrator 21 is a horizontally arranged rectangle, with two side surfaces of the rectangle arranged vertically, a pair of driving piezoelectric sheets 26 attached to the two side surfaces, and a first mass block 27 is fixedly connected to the extended end of the driving elastic vibrator 21;

The clamped elastic vibrator 25 is a horizontally arranged rectangle, with two side surfaces of the rectangle arranged horizontally, a pair of clamped piezoelectric sheets 28 attached to the two side surfaces, and a second mass block 29 fixedly connected to the extended end of the clamped elastic vibrator 25 .

As shown in FIGS. 6 and 7 , the wheel mechanism 3 includes a wheel 31, a support shaft 32 and a clamping foot 34. The support shaft 32 passes through the central axial direction of the wheel 31 through a deep groove ball bearing 33 and passes through the central connecting block 23. The pre-tightening block 24 is floatingly mounted on the central connecting block 23, and the clamping foot 34 is fixedly and vertically provided at the lower end of the pre-tightening block 24, so that the lower end of the clamping foot 34 corresponds to the upper end surface of the wheel 31.

During operation, a harmonic signal is input to a pair of driving piezoelectric sheets 26, driving the elastic vibrator 21 to drive the central connecting block 23 to swing back and forth around the supporting shaft 32 within one vibration cycle, thereby realizing the action of the clamping foot 34 driving the rotating wheel 31 to rotate; a harmonic signal is input to another pair of clamping piezoelectric sheets 28, and the clamping elastic vibrator 25 swings up and down around the rotating wheel 31 within one vibration cycle, thereby realizing the clamping foot 34 clamping and releasing the rotating wheel 31.

As shown in Figures 4 and 5, the central connecting block 23 is a horizontally arranged convex block, the large end of the convex block is fixedly connected to the pair of clamping blocks 22, and the small end of the convex block is horizontally provided with a pair of threaded holes;

The pre-tightening block 24 comprises a rectangular cavity with an open bottom, so that the pre-tightening block 24 is covered on the small end of the convex block.

A pair of vertical waist-shaped holes are formed through the opposite side walls of the pre-tightening block 24, and the pre-tightening block 24 is fixed to the small end of the convex block by fastening screws 241 passing through the vertical waist-shaped holes and the threaded holes in sequence;

The pre-tightening screw 242 passes through the upper end of the pre-tightening block 24 and connects the pre-tightening block 24 and the small end of the convex block. A pre-tightening spring 243 is sleeved on the pre-tightening screw 242.

A horizontal clamping foot connection block 341 is provided on one side of the pre-tightening block 24 corresponding to the clamping elastic vibrator 25 , and the pre-tightening block 24 and the clamping foot connection block 341 are connected by a flexible hinge.

An inverted U-shaped bracket 4 is fixedly provided above the square base 1 , the upper end of the support shaft 32 is fixedly connected to the upper bottom plate of the U-shaped bracket 4 , and the lower end of the support shaft 32 is fixedly connected to the square base 1 .

Each of the driving piezoelectric sheet and the clamping piezoelectric sheet is a lead zirconate titanate piezoelectric ceramic sheet.

The support shaft 32 is a three-section support shaft, and the upper section and the middle section are connected by a flexible hinge, and the middle section and the lower section are connected by a flexible hinge.

FIG8 is a simplified schematic diagram of the contact relationship between the stator mechanism 2 and the rotating wheel 31 of the present invention in the front view direction; FIG9 is a simplified schematic diagram of the contact relationship between the stator mechanism 2 and the rotating wheel 31 of the present invention in the top view direction.

During operation, a harmonic signal is input to a pair of driving piezoelectric sheets 26, and the driving elastic vibrator 21 drives the stator mechanism 2 to swing back and forth relative to the support shaft 32 within one vibration cycle, so that the clamping foot 34 can complete the action of rotating the rotating wheel 31; a harmonic signal is input to another pair of clamping piezoelectric sheets 28, and the clamping elastic vibrator 25 swings up and down relative to the rotating wheel 31 within one vibration cycle, so that the clamping foot 34 clamps and releases the rotating wheel 31; if harmonic signals with equal frequencies but different phases are input to a pair of driving piezoelectric sheets 26 and a pair of clamping piezoelectric sheets 28 at the same time, the bending vibrations of the driving elastic vibrator 21 and the clamping elastic vibrator 25 in vertically staggered directions are coordinated, so that the clamping foot 34 moves in an elliptical trajectory, thereby realizing unidirectional continuous rotation of the rotating wheel 31, and at the same time, changing the input phase difference can adjust the motor speed and realize reverse rotation of the motor.

10 to 14 , at time t ₀ , the clamped elastic vibrator 25 is in the initial position, and the driven elastic vibrator 21 is in the maximum counterclockwise position.

From _t0 to _t1 , the clamping elastic vibrator 25 starts to swing upward from the initial position to the uppermost position, driving the elastic vibrator 21 to swing clockwise from the maximum counterclockwise position to the initial position. During this process, the stator mechanism will swing around the support shaft 32, but the clamping foot 34 is away from the rotating wheel 31, and the rotating wheel 31 remains stationary.

In the time period from _t1 to _t2 , the clamping elastic vibrator 25 swings downward from the uppermost position to the initial position, at which time the clamping foot 34 approaches the rotating wheel 31, and the driving elastic vibrator 21 continues to swing from the initial position to the maximum clockwise position, during which the rotating wheel 31 remains stationary;

In the time period from _t2 to _t3 , the clamped elastic vibrator 25 continues to swing downward to the lowest position, and the driving elastic vibrator 21 swings counterclockwise from the maximum clockwise position to the initial position. In this process, the clamping foot 34 clamps the rotating wheel 31, and the clamping foot 34 swings around the axis under the action of the driving elastic vibrator 21, thereby driving the rotating wheel 31 to rotate counterclockwise by an angle of α; in the time period from _t3 to _t4 , the clamped elastic vibrator 25 swings upward from the lowest position to the initial position, and the driving elastic vibrator 21 continues to swing from the initial position to the maximum counterclockwise position. In this process, the clamping foot 34 and the rotating wheel 31 remain in a clamped state, and the rotating wheel 31 continues to rotate counterclockwise by an angle of β under the action of the driving elastic vibrator 21.

The above four steps are a total rotation of α+β angles for one rotation cycle of the motor. Therefore, continuous use of harmonic signal excitation will enable the motor to rotate continuously, while changing the phase difference of the input signal can achieve reverse rotation of the motor.

It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims (6)

1. A resonant rotary piezoelectric motor, characterized in that: It comprises a square base (1), a stator mechanism (2) and a rotating wheel mechanism (3); The stator mechanism (2) comprises a driving elastic vibrator (21), a pair of clamping blocks (22), a central connecting block (23), a pre-tightening block (24), and a clamping elastic vibrator (25) which are arranged above the square base (1) and are connected in sequence along the X-axis direction of the square base (1); The driving elastic vibrator (21) is a horizontally arranged rectangle, the two side surfaces of the rectangle are arranged vertically, a pair of driving piezoelectric sheets (26) are attached to the two side surfaces, and a first mass block (27) is fixedly connected to the extended end of the driving elastic vibrator (21); The clamped elastic vibrator (25) is a horizontally arranged rectangle, the two side surfaces of the rectangle are arranged horizontally, a pair of clamped piezoelectric sheets (28) are attached to the two side surfaces, and a second mass block (29) is fixedly connected to the extended end of the clamped elastic vibrator (25); The wheel mechanism (3) comprises a wheel (31), a support shaft (32) and a clamping foot (34); the support shaft (32) passes through the central axis of the wheel (31) via a deep groove ball bearing (33) and penetrates the central connecting block (23); the preload block (24) is floatingly mounted on the central connecting block (23), and the clamping foot (34) is fixedly mounted at the lower end of the preload block (24), so that the lower end of the clamping foot (34) corresponds to the upper end surface of the wheel (31); When working, a harmonic signal is input to a pair of driving piezoelectric sheets (26), driving the elastic vibrator (21) to drive the central connecting block (23) to swing back and forth around the support shaft (32) within a vibration cycle, thereby realizing the action of the clamping foot (34) to drive the rotating wheel (31) to rotate; a harmonic signal is input to another pair of clamping piezoelectric sheets (28), causing the clamping elastic vibrator (25) to swing up and down around the rotating wheel (31) within a vibration cycle, thereby realizing the clamping foot (34) to clamp and release the rotating wheel (31). 2. A resonant rotary piezoelectric motor according to claim 1, characterized in that: the central connecting block (23) is a horizontally arranged convex block, the large end of the convex block is fixedly connected to the pair of clamping blocks (22), and the small end of the convex block is horizontally provided with a pair of threaded holes; The pre-tightening block (24) comprises a rectangular cavity with an open bottom, so that the pre-tightening block (24) is covered on the small end of the convex block, and a pair of vertical waist-shaped holes are respectively opened on the opposite side walls of the pre-tightening block (24), and the pre-tightening block (24) is fixed to the small end of the convex block by a fastening screw (241) passing through the vertical waist-shaped holes and the threaded hole on the small end of the convex block in sequence; A pre-tightening screw (242) passes through the upper end of the pre-tightening block (24) and connects the pre-tightening block (24) and the small end of the convex block. A pre-tightening spring (243) is sleeved on the pre-tightening screw (242). The pre-tightening screw (242) and the fastening screw (241) are adjusted so that the pre-tightening block (24) is floatingly mounted on the central connecting block (23). 3. A resonant rotary piezoelectric motor according to claim 1, characterized in that: a horizontal clamping foot connection block (341) is provided on one side of the pre-tightening block (24) corresponding to the clamping elastic vibrator (25), and the pre-tightening block (24) and the clamping foot connection block (341) are connected by a flexible hinge, The clamping foot (34) is in the shape of a short cylinder, and the lower end is a spherical arc surface, and the upper end is fixedly connected to the clamping foot connecting block (341). 4. A resonant rotary piezoelectric motor according to claim 1, characterized in that an inverted U-shaped bracket (4) is fixedly provided above the square base (1), the upper end of the support shaft (32) is fixedly connected to the upper bottom plate of the U-shaped bracket (4), and the lower end of the support shaft (32) is fixedly connected to the square base (1). 5. A resonant rotary piezoelectric motor according to claim 1, characterized in that each of the driving piezoelectric sheet and the clamping piezoelectric sheet is a lead zirconate titanate piezoelectric ceramic sheet. 6. A resonant rotary piezoelectric motor according to claim 1, characterized in that: the support shaft (32) is a three-section support shaft, and the upper section and the middle section are connected by a flexible hinge, and the middle section and the lower section are connected by a flexible hinge.