阅读说明：本技术 圆形双纵振夹心式激励双足直线超声电机及其定子 (Circular double-longitudinal-vibration sandwich type excitation double-foot linear ultrasonic motor and stator thereof ) 是由 王寅 李佳音 陈紫嫣 于 2020-04-30 设计创作，主要内容包括：本发明公开了圆形双纵振夹心式激励双足直线超声电机及其定子,定子包括一对称杆和四组压电陶瓷片组；该对称杆包括一圆柱座和两端直杆；该圆柱座设有中心圆柱孔,该圆柱座的上下侧线处设为驱动足；该两端直杆固设在圆柱座两侧,该端直杆上设有端部圆柱孔；该每一端直杆外还配设有两金属块,该两金属块间、端直杆末端面和金属块间都设一组压电陶瓷片组；该压电陶瓷片组的各个压电陶瓷片之间,及,压电陶瓷片组与对称杆之间都装有作为电极的铜片；另配设预紧螺栓穿过金属块、压电陶瓷片、铜片并螺接在端直杆内以将它们固接构成一个整体；该对称杆相对两基准面都轴向对称设置。它具有如下优点：输出效率高、驱动力大,结构紧凑、控制性能好、成本低。(The invention discloses a circular double longitudinal vibration sandwich type excitation double-foot linear ultrasonic motor and a stator thereof, wherein the stator comprises a symmetric rod and four groups of piezoelectric ceramic sheet groups; the symmetrical rod comprises a cylindrical seat and straight rods at two ends; the cylindrical seat is provided with a central cylindrical hole, and the upper side line and the lower side line of the cylindrical seat are provided with driving feet; the straight rods at the two ends are fixedly arranged at the two sides of the cylindrical seat, and the straight rods at the ends are provided with cylindrical holes at the end parts; two metal blocks are also arranged outside each end straight rod, and a group of piezoelectric ceramic sheet groups are arranged between the two metal blocks, the end surface of each end straight rod and the metal blocks; copper sheets used as electrodes are arranged among the piezoelectric ceramic sheets of the piezoelectric ceramic sheet group and between the piezoelectric ceramic sheet group and the symmetrical rods; in addition, a pre-tightening bolt is arranged to penetrate through the metal block, the piezoelectric ceramic piece and the copper sheet and is screwed in the straight end rod so as to fixedly connect the metal block, the piezoelectric ceramic piece and the copper sheet into a whole; the symmetrical rods are arranged axially symmetrically with respect to both reference planes. It has the following advantages: high output efficiency, large driving force, compact structure, good control performance and low cost.)

1. The circular double-longitudinal-vibration sandwich type excitation double-foot linear ultrasonic motor comprises a stator, a rotor and a clamping device for connecting the stator and the rotor; the method is characterized in that: the stator comprises a symmetrical rod made of metal and four groups of piezoelectric ceramic sheet groups, wherein each group of piezoelectric ceramic sheet group comprises four piezoelectric ceramic sheets for longitudinal vibration; the symmetrical rod comprises a cylindrical seat and straight rods at two ends; the cylindrical seat is defined with a first reference surface and a second reference surface which are perpendicular to each other and pass through the axis of the cylindrical seat, the axis of the cylindrical seat is provided with a central cylindrical hole which penetrates through the axis, and the upper side line and the lower side line of the peripheral wall of the cylindrical seat, which are positioned on the first reference surface, are provided with driving feet; the straight rods at the two ends are fixedly arranged at the two sides of the cylindrical seat, the straight rods at the two ends are provided with end cylindrical holes which are parallel to the central cylindrical hole and penetrate through the central cylindrical hole, and the axis of each end cylindrical hole is positioned on a second reference surface; the end straight rod is also provided with two metal blocks which are arranged outside the end straight rod at intervals inside and outside, a group of piezoelectric ceramic sheet groups is arranged between the two metal blocks, a group of piezoelectric ceramic sheet groups is also arranged between the end face of the end straight rod and the metal blocks, the polarization directions of every two adjacent piezoelectric ceramic sheets are opposite, and each piezoelectric ceramic sheet is polarized along the thickness direction; copper sheets used as electrodes are arranged among the piezoelectric ceramic sheets of the piezoelectric ceramic sheet group and between the piezoelectric ceramic sheet group and the symmetrical rods; in addition, a pre-tightening bolt is arranged to penetrate through the metal block, the piezoelectric ceramic piece and the copper sheet and is screwed in the straight end rod so as to fixedly connect the metal block, the piezoelectric ceramic piece and the copper sheet into a whole; the symmetry bar is disposed axially symmetrically with respect to both the first reference plane and the second reference plane.

2. The circular dual longitudinal vibration sandwich type excitation biped linear ultrasonic motor according to claim 1, characterized in that: the distance L between the center of the driving foot and the center of the symmetric rod is 1/2 longitudinal vibration wavelength.

3. The circular dual longitudinal vibration sandwich type excitation biped linear ultrasonic motor according to claim 1, characterized in that: the first reference surface is arranged along the up-down direction, the second reference surface is arranged along the left-right direction, and the axis of the cylindrical seat is arranged along the front-back direction; the end straight rod and the metal block are cuboids, and the front side wall and the rear side wall of the end straight rod, the metal block and the cylindrical seat are aligned.

4. The circular dual longitudinal vibration sandwich excitation biped linear ultrasonic motor according to claim 3, characterized in that: the end straight rod is aligned with the peripheral side wall of the metal block.

5. The circular dual longitudinal vibration sandwich type excitation biped linear ultrasonic motor according to claim 1, characterized in that: the two drive feet are rectangular or circular in cross-section.

6. The circular dual longitudinal vibration sandwich type excitation biped linear ultrasonic motor according to claim 1, characterized in that: the end cylindrical bore diameter is 1/3-2/3 of the central cylindrical bore.

7. The circular dual longitudinal vibration sandwich type excitation biped linear ultrasonic motor according to claim 1, characterized in that: the mounting hole that runs through about this metal block, thin copper sheet center all are equipped with, and this end straight-bar is terminal end face center is concave to be equipped with the mounting groove, and this mounting groove leads to tip cylinder hole, this pretension bolted connection this mounting hole and mounting groove.

8. The circular dual longitudinal vibration sandwich type excitation biped linear ultrasonic motor according to claim 1, characterized in that: the symmetric rod and the driving foot are machined from a single piece of metal material.

9. The circular dual longitudinal vibration sandwich excitation bipedal linear ultrasonic motor according to any one of claims 1 to 8, wherein: the two end straight rods are respectively a first end straight rod and a second end straight rod; applying sinusoidal voltage to the piezoelectric ceramic sheet group on the first end straight rod, and synchronously expanding or contracting each pair of piezoelectric ceramic sheets to excite longitudinal vibration; the piezoelectric ceramic sheet group on the second end straight rod applies cosine voltage with the same frequency and the phase difference of 90 degrees with the cosine voltage, and two longitudinal vibration modes excited by the stator are superposed, so that mass points on the contact surface of the stator and the rotor do elliptic motion, and the rotor is pushed to move.

10. Circular two longitudinal vibration sandwich type excitation biped linear ultrasonic motor stator which is characterized in that: the device comprises a symmetrical rod made of metal and four groups of piezoelectric ceramic sheet groups, wherein each group of piezoelectric ceramic sheet group comprises four piezoelectric ceramic sheets for longitudinal vibration; the symmetrical rod comprises a cylindrical seat and straight rods at two ends; the cylindrical seat is defined with a first reference surface and a second reference surface which are perpendicular to each other and pass through the axis of the cylindrical seat, the axis of the cylindrical seat is provided with a central cylindrical hole which penetrates through the axis, and the upper side line and the lower side line of the peripheral wall of the cylindrical seat, which are positioned on the first reference surface, are provided with driving feet; the straight rods at the two ends are fixedly arranged at the two sides of the cylindrical seat, the straight rods at the two ends are provided with end cylindrical holes which are parallel to the central cylindrical hole and penetrate through the central cylindrical hole, and the axis of each end cylindrical hole is positioned on a second reference surface; the end straight rod is also provided with two metal blocks which are arranged outside the end straight rod at intervals inside and outside, a group of piezoelectric ceramic sheet groups is arranged between the two metal blocks, a group of piezoelectric ceramic sheet groups is also arranged between the end face of the end straight rod and the metal blocks, the polarization directions of every two adjacent piezoelectric ceramic sheets are opposite, and each piezoelectric ceramic sheet is polarized along the thickness direction; copper sheets used as electrodes are arranged among the piezoelectric ceramic sheets of the piezoelectric ceramic sheet group and between the piezoelectric ceramic sheet group and the symmetrical rods; in addition, a pre-tightening bolt is arranged to penetrate through the metal block, the piezoelectric ceramic piece and the copper sheet and is screwed in the straight end rod so as to fixedly connect the metal block, the piezoelectric ceramic piece and the copper sheet into a whole; the symmetry bar is disposed axially symmetrically with respect to both the first reference plane and the second reference plane.

Technical Field

The invention relates to the technical field of ultrasonic motors, in particular to a circular double-longitudinal-vibration sandwich type excitation double-foot linear ultrasonic motor and a stator thereof.

Background

The linear ultrasonic motor utilizes the inverse piezoelectric effect of a piezoelectric material to excite the micro-amplitude vibration of an elastic body, and transmits kinetic energy to a rotor through the friction effect between the stator and the rotor so as to output motion. The linear ultrasonic motor has the advantages of good control performance, stepping and servo work, simple structure, low speed, large torque, quick response and the like, and has wide application prospect. In the existing linear ultrasonic motor, a stator structure has a patch structure and a sandwich structure according to the assembly mode of piezoelectric ceramics and an elastic body, the sandwich structure is disclosed as the publication number CN101072000A, the patent application name is the technical scheme of the single-drive-foot sandwich transducer type longitudinal bending linear ultrasonic motor, although the idle problem of vibration energy is solved by adopting a quadrangular body with the section gradually reduced from two ends to the middle part, only one rotor of one drive foot moves and outputs, and the working efficiency is low.

Disclosure of Invention

The invention provides a circular double longitudinal vibration sandwich type excitation double-foot linear ultrasonic motor and a stator thereof, which overcome the defects of a linear ultrasonic motor in the background technology.

One of the technical schemes adopted by the invention for solving the technical problems is as follows: the circular double-longitudinal-vibration sandwich type excitation double-foot linear ultrasonic motor comprises a stator, a rotor and a clamping device for connecting the stator and the rotor; the stator comprises a symmetrical rod made of metal and four groups of piezoelectric ceramic sheet groups, wherein each group of piezoelectric ceramic sheet group comprises four piezoelectric ceramic sheets for longitudinal vibration; the symmetrical rod comprises a cylindrical seat and straight rods at two ends; the cylindrical seat is defined with a first reference surface and a second reference surface which are perpendicular to each other and pass through the axis of the cylindrical seat, the axis of the cylindrical seat is provided with a central cylindrical hole which penetrates through the axis, and the upper side line and the lower side line of the peripheral wall of the cylindrical seat, which are positioned on the first reference surface, are provided with driving feet; the straight rods at the two ends are fixedly arranged at the two sides of the cylindrical seat, the straight rods at the two ends are provided with end cylindrical holes which are parallel to the central cylindrical hole and penetrate through the central cylindrical hole, and the axis of each end cylindrical hole is positioned on a second reference surface; the end straight rod is also provided with two metal blocks which are arranged outside the end straight rod at intervals inside and outside, a group of piezoelectric ceramic sheet groups is arranged between the two metal blocks, a group of piezoelectric ceramic sheet groups is also arranged between the end face of the end straight rod and the metal blocks, the polarization directions of every two adjacent piezoelectric ceramic sheets are opposite, and each piezoelectric ceramic sheet is polarized along the thickness direction; copper sheets used as electrodes are arranged among the piezoelectric ceramic sheets of the piezoelectric ceramic sheet group and between the piezoelectric ceramic sheet group and the symmetrical rods; in addition, a pre-tightening bolt is arranged to penetrate through the metal block, the piezoelectric ceramic piece and the copper sheet and is screwed in the straight end rod so as to fixedly connect the metal block, the piezoelectric ceramic piece and the copper sheet into a whole; the symmetry bar is disposed axially symmetrically with respect to both the first reference plane and the second reference plane.

In one embodiment: the distance L between the center of the driving foot and the center of the symmetric rod is 1/2 longitudinal vibration wavelength.

In one embodiment: the first reference surface is arranged along the up-down direction, the second reference surface is arranged along the left-right direction, and the axis of the cylindrical seat is arranged along the front-back direction; the end straight rod and the metal block are cuboids, and the front side wall and the rear side wall of the end straight rod, the metal block and the cylindrical seat are aligned.

In one embodiment: the end straight rod is aligned with the peripheral side wall of the metal block.

In one embodiment: the two drive feet are rectangular or circular in cross-section.

In one embodiment: the end cylindrical bore diameter is 1/3-2/3 of the central cylindrical bore.

In one embodiment: the mounting hole that runs through about this metal block, thin copper sheet center all are equipped with, and this end straight-bar is terminal end face center is concave to be equipped with the mounting groove, and this mounting groove leads to tip cylinder hole, this pretension bolted connection this mounting hole and mounting groove.

In one embodiment: the symmetric rod and the driving foot are machined from a single piece of metal material.

In one embodiment: the two end straight rods are respectively a first end straight rod and a second end straight rod; applying sinusoidal voltage to the piezoelectric ceramic sheet group on the first end straight rod, and synchronously expanding or contracting each pair of piezoelectric ceramic sheets to excite longitudinal vibration; the piezoelectric ceramic sheet group on the second end straight rod applies cosine voltage with the same frequency and the phase difference of 90 degrees with the cosine voltage, and two longitudinal vibration modes excited by the stator are superposed, so that mass points on the contact surface of the stator and the rotor do elliptic motion, and the rotor is pushed to move.

The second technical scheme adopted by the invention for solving the technical problems is as follows: the circular double longitudinal vibration sandwich type excitation double-foot linear ultrasonic motor stator comprises a symmetrical rod made of metal and four groups of piezoelectric ceramic sheet groups, wherein each group of piezoelectric ceramic sheet group comprises four piezoelectric ceramic sheets for longitudinal vibration; the symmetrical rod comprises a cylindrical seat and straight rods at two ends; the cylindrical seat is defined with a first reference surface and a second reference surface which are perpendicular to each other and pass through the axis of the cylindrical seat, the axis of the cylindrical seat is provided with a central cylindrical hole which penetrates through the axis, and the upper side line and the lower side line of the peripheral wall of the cylindrical seat, which are positioned on the first reference surface, are provided with driving feet; the straight rods at the two ends are fixedly arranged at the two sides of the cylindrical seat, the straight rods at the two ends are provided with end cylindrical holes which are parallel to the central cylindrical hole and penetrate through the central cylindrical hole, and the axis of each end cylindrical hole is positioned on a second reference surface; the end straight rod is also provided with two metal blocks which are arranged outside the end straight rod at intervals inside and outside, a group of piezoelectric ceramic sheet groups is arranged between the two metal blocks, a group of piezoelectric ceramic sheet groups is also arranged between the end face of the end straight rod and the metal blocks, the polarization directions of every two adjacent piezoelectric ceramic sheets are opposite, and each piezoelectric ceramic sheet is polarized along the thickness direction; copper sheets used as electrodes are arranged among the piezoelectric ceramic sheets of the piezoelectric ceramic sheet group and between the piezoelectric ceramic sheet group and the symmetrical rods; in addition, a pre-tightening bolt is arranged to penetrate through the metal block, the piezoelectric ceramic piece and the copper sheet and is screwed in the straight end rod so as to fixedly connect the metal block, the piezoelectric ceramic piece and the copper sheet into a whole; the symmetry bar is disposed axially symmetrically with respect to both the first reference plane and the second reference plane.

Compared with the background technology, the technical scheme has the following advantages: high output efficiency, large driving force, compact structure, good control performance and low cost.

Drawings

The invention is further described with reference to the following figures and detailed description.

Fig. 1 is an overall assembly view of a stator according to the present embodiment.

Fig. 2 is a schematic view of the matching structure of the symmetric rod, the ceramic plate and the thin copper sheet of the stator according to the present embodiment.

Fig. 3 is a schematic structural diagram of any two opposite-polarity ceramic plates in each group of piezoelectric ceramic plate groups of the stator according to the embodiment.

Fig. 4 is a modal analysis diagram of the stator of the present embodiment at a frequency of 28.238 kHz.

Fig. 5 is a modal analysis diagram of the stator of the present embodiment at a frequency of 27.437 kHz.

Detailed Description

Referring to fig. 1 and 2, the circular double longitudinal vibration sandwich type excitation biped linear ultrasonic motor includes a stator, a mover and a clamping device connecting the stator and the mover, and the clamping device and the mover can refer to the prior art.

The stator comprises a symmetrical rod 1 and four groups of piezoelectric ceramic sheet groups 3, 4, 5 and 6, wherein the symmetrical rod 1 comprises a cylindrical seat 11 and straight rods 12 at two ends. The axis of the cylindrical seat 11 is arranged in the front-back direction, the cylindrical seat 11 defines a first reference surface and a second reference surface which both pass through the axis of the cylindrical seat 11, the first reference surface and the second reference surface are vertical, the first reference surface is arranged in the up-down direction, and the second reference surface is arranged in the left-right direction; a central cylindrical hole 111 penetrating along the axis is arranged at the axis of the cylindrical seat 11; the driving feet 13 are arranged at the upper and lower lateral lines of the outer peripheral wall of the cylindrical seat 11 on the first reference surface, the sections of the two driving feet 13 are rectangular or circular, and the structure can ensure that the driving feet are fully contacted with the guide rail plane of the clamping component so as to improve the working stability of the linear ultrasonic motor; the distance L between the center of the driving foot and the center of the symmetric rod 1 is 1/2 longitudinal vibration wavelength. The end straight rods 12 are cuboids, the thickness (front-back distance) of each cuboid is equal to the axial distance of the cylindrical seat 11, the two end straight rods 12 are symmetrically and fixedly arranged on the left side and the right side of the cylindrical seat 11 in a left-right mode and are aligned in a front-back mode, end cylindrical holes 121 penetrating in the front-back direction are formed in the two end straight rods 12, and the axial lines of the end cylindrical holes 121 are located on a second reference surface; the two end straight rods 12 are axially and symmetrically arranged relative to the first reference surface, and the end straight rods 12 are also axially and symmetrically arranged relative to the second reference surface. The end cylindrical hole 121 has a diameter one-half of that of the central cylindrical hole 111, which further reduces the modal frequency difference.

Each end straight rod 12 is also provided with two metal blocks 14 in a cuboid structure, the thickness (front-back distance) of each cuboid is equal to the axial distance of the cylindrical seat 11, the two metal blocks 14 are sequentially arranged outside the tail end surface of the end straight rod 12 in an internal-external sequence, installation intervals are formed between the two metal blocks 14 and between the tail end surface of the end straight rod 12 and the metal blocks 14, each installation interval is internally provided with a group of piezoelectric ceramic piece groups, and each group of piezoelectric ceramic piece groups comprises four piezoelectric ceramic pieces 7 which longitudinally vibrate. Thin copper sheets 8 serving as electrodes are arranged between the piezoelectric ceramic sheets 7 of the piezoelectric ceramic sheet groups 3, 4, 5 and 6 and between the piezoelectric ceramic sheet groups and the symmetrical rod 1 (between the piezoelectric ceramic sheet groups and the tail end face of the end straight rod 12 and between the piezoelectric ceramic sheet groups and the end face of the metal block), and the number of grounding copper sheets in the thin copper sheets 8 is ten; in addition, a pre-tightening bolt 2 is arranged to penetrate through the metal block 13, the piezoelectric ceramic piece 7 and the thin copper sheet 8 and is screwed in the end straight rod 12 so as to fixedly connect the metal block 13, the piezoelectric ceramic piece 7, the thin copper sheet 8 and the symmetrical rod 12 to form a whole, and the peripheral side walls of the metal block 13, the piezoelectric ceramic piece 7 and the thin copper sheet 8 are aligned. The polarization directions of every two adjacent piezoelectric ceramic pieces 7 are opposite, each piezoelectric ceramic piece is polarized along the thickness direction, and the electric domain, namely the polarization direction, is represented by "+" - ". Has the structure that: the centers of the metal block 14 and the thin copper sheet 8 are provided with mounting holes which are penetrated left and right, the center of the tail end surface of the end straight rod 12 is concavely provided with a mounting groove, the mounting groove is communicated to the end cylindrical hole 121, and the pre-tightening bolt 2 is connected with the mounting holes and the mounting groove.

The stator is axially symmetrically disposed with respect to both the first reference plane and the second reference plane. This symmetrical pole 1 and drive foot adopt a monoblock metal material processing to form to reduce energy loss, simple structure workable.

The mode analysis by ANSYS (ANSYS is a large general finite element analysis software developed by ANSYS corporation, usa) is shown in fig. 4 and 5, and the up-and-down and left-and-right movement of the stator of the motor can be observed through the mode analysis diagram, and the stator can be moved left and right by changing the phase difference of two working modes of the stator to be-pi/2, as shown in fig. 5. According to the frequency 28.238kHz of modal analysis, the up-and-down moving distance of the stator driving foot is maximum, as shown in FIG. 4; the frequency was 27.437kHz and the stator drive foot moved the greatest distance to the left and right as shown in FIG. 5.

The working principle of the circular double longitudinal vibration sandwich type excitation biped linear ultrasonic motor in the embodiment is described as follows: the longitudinal vibration of the piezoelectric ceramics is utilized to push the rotor to output linear displacement. As shown in fig. 3, when a sinusoidal voltage is applied to the piezoelectric ceramic sheet groups 3 and 4, each pair of longitudinal vibration ceramic sheets synchronously expands or contracts to excite longitudinal vibration; cosine voltages with the phase difference of 90 degrees with the same frequency are applied to the piezoelectric ceramic sheet groups 5 and 6, and two longitudinal vibration modes excited by the stator are superposed, so that mass points on the contact surface of the stator and the rotor do elliptic motion, and the rotor is pushed to move. When the applied voltage is reversed, the elliptical trajectory is reversed in direction, thereby enabling the mover to move bidirectionally. The central cylindrical hole 111 in the middle of the symmetrical rod can improve the amplitude and the vibration speed of the driving foot part, and the end cylindrical holes 121 of the straight rods at the two ends can further reduce the modal frequency difference, so that the performance of the motor is greatly improved.

This embodiment's supersound motor combines sandwich structure, cylinder seat structure, cylinder hole structure and symmetrical structure together, wherein: firstly, piezoelectric ceramics of an ultrasonic motor with a sandwich structure are pre-tightened by adopting a threaded structure, the piezoelectric ceramics work in a d33 mode, and the piezoelectric ceramics are always in a compressive stress state in the working process of the motor, so that the motor has the characteristic of pressure resistance, the motor can apply quite large pre-tightening force, the piezoelectric ceramics of the motor can fully exert the advantage of large output density, the output performance of the ultrasonic motor can be effectively improved, and the ultrasonic motor with the sandwich structure can stably work in various extreme environments, such as outer space with vacuum, high and low temperature, strong electromagnetic interference and other extreme environments; the structure that the cylindrical seat is matched with the cylindrical hole is adopted, the contact area of the driving foot of the ultrasonic motor is large, the ultrasonic motor is wear-resistant, the ultrasonic motor is suitable for working occasions with long service life and high thrust, the working effect is more gentle, and the damage to the rotor is small; the piezoelectric ceramic is used for exciting the longitudinal vibration mode and the bending vibration mode of the elastic body, wherein the linear ultrasonic motor utilizing the structural longitudinal vibration mode has higher thrust and efficiency; and fourthly, through the design of simultaneously exciting the double driving feet after the two longitudinal vibration ultrasonic vibrators are connected, vibration energy is fully utilized, and the working mode distortion caused by asymmetric clamping is avoided due to the strict symmetrical structure of the symmetrical rod.

The above description is only a preferred embodiment of the present invention, and therefore should not be taken as limiting the scope of the invention, which is defined by the appended claims and their equivalents.