CN116827165A - Longitudinal-bending mode conversion type rotary ultrasonic motor based on Langerhan transducer - Google Patents

Abstract

The invention discloses a longitudinal-bend mode conversion rotary ultrasonic motor based on a Lanjiewen transducer, which includes a stator, a rotor, an output shaft, a first bearing, a second bearing, a preload nut and a preload spring; a drive The module includes a drive ring, connection components and 2n Langevin transducers. All Lanjiewen transducers work in the longitudinal vibration mode, and take advantage of the high electromechanical conversion efficiency of piezoelectric ceramic sheets in the d33 working mode, which can effectively improve the driving performance and working efficiency of the ultrasonic motor. The ultrasonic motor of the present invention solves the problem that traditional annular patch-type piezoelectric ceramics are difficult to process. The motor has flexible design dimensions, large output torque, and long working life. It can be widely used in aerospace, precision manufacturing, medical equipment, etc. field.

Description

Longitudinal-bending mode conversion rotary ultrasonic motor based on Lanjiewen transducer

Technical field

The invention relates to the fields of ultrasonic motor technology and piezoelectric precision drive technology, and in particular to a longitudinal-bending mode conversion rotary ultrasonic motor based on a Lanjievin transducer.

Background technique

Rotary ultrasonic motors are the type of ultrasonic motors that have been studied for the longest time and are the most studied. They have made great progress after years of development. Traveling wave rotary ultrasonic motors are the most typical type of rotary ultrasonic motors and have been successfully used in civilian fields such as automatic focusing, automobiles, robots, and nuclear magnetic resonance. With the rapid development of high-precision fields such as aerospace, precision manufacturing, and precision optics, the demand for rotating traveling wave ultrasonic motors has become increasingly obvious. Especially in precision space mechanisms such as control moment gyros, laser pointing mechanisms, and space manipulators, ultrasonic motors must have the characteristics of low speed and high torque, long life, compact structure, and high energy conversion efficiency. However, traditional traveling wave rotating ultrasonic motors have the characteristics of low speed and high torque, long life, compact structure, and high energy conversion efficiency. The use of patch-type piezoelectric ceramics results in a relatively low energy utilization rate. Ceramics are prone to fatigue damage under alternating stress. The output torque increases into a bottleneck. Large-size annular piezoelectric ceramics are difficult to process. Therefore, there is an urgent need to find feasible optimizations. Or alternative design solutions can be used to promote the efficient and stable service of rotary ultrasonic motors in high-precision equipment and institutions.

Contents of the invention

The technical problems to be solved by the present invention are to address the low energy utilization efficiency of existing traveling wave rotary ultrasonic motors in the background technology due to the use of patch type piezoelectric ceramics, the ceramics are easily broken under long-term alternating stress, and the large size Due to the difficulty of processing annular multi-zone piezoelectric ceramics and the short stable operation time of the motor, a longitudinal-bending mode conversion rotary ultrasonic motor based on Lanjiewen transducer is provided.

The present invention adopts the following technical solutions to solve the above technical problems:

The longitudinal-bending mode conversion rotary ultrasonic motor based on Lanjiewen transducer includes a stator, a rotor, an output shaft, a first bearing, a second bearing, a preload nut and a preload spring;

The stator includes a base body, a driving module and a fixed bracket;

The base body is a hollow cylinder with openings at both ends;

The output shaft is coaxially connected to the inner rings of the first bearing and the second bearing respectively; the outer rings of the first bearing and the second bearing are coaxially connected to the inner wall of the base body, so that the output shaft and the base body Coaxial and the two ends of the output shaft protrude from both ends of the base body respectively;

The drive module includes a drive ring, a connecting component and 2n Langevin transducers, where n is an even number greater than or equal to 2;

The gear ring is in the shape of a ring, and its upper end surface is evenly provided with q driving teeth in the circumferential direction, where q is a natural number greater than or equal to 3;

The Lanjiewen transducer includes a front beam, a rear beam, pre-tightening bolts and p piezoelectric ceramic sheets, where p is an even number greater than or equal to 2;

The front beam has a variable cross-section structure, its cross-section gradually becomes smaller from bottom to top, and a threaded blind hole is provided in the center of the lower end surface to match the pre-tightening bolt;

The rear beam is a column with a through hole along the axis for the preload bolt to pass through;

The piezoelectric ceramic sheet and the back beam have the same cross-sectional shape, are polarized along the thickness direction, and have a through hole in the center for the preload bolt to pass through;

The pretightened bolts pass through the rear beam and p piezoelectric ceramic sheets in sequence and are threadedly connected to the threaded blind holes of the front beam, clamping the p piezoelectric ceramic sheets between the rear beam and the front beam; adjacent piezoelectric The polarization direction of the ceramic piece is opposite;

The 2n Lanjiewen transducers are evenly arranged in the circumferential direction on the lower end face of the gear ring, the upper end of the front beam is fixedly connected to the lower end face of the gear ring, and the axis of the rear beam is perpendicular to the lower end face of the gear ring;

The connection assembly includes 2n connection plates; the 2n connection plates are arranged one-to-one between the 2n Lanjievin transducers, and the connecting plate and the Lanjievin transducers on both sides are connected through flexible hinges. ;

The connecting component is fixedly connected to the base body through a fixed bracket, so that the ring ring is sleeved outside the output shaft above the base body and coaxial with the output shaft, and the base body is surrounded by 2n Lanjiewen transducers;

The rotor is in the shape of a disk, with a through hole in the center that matches the output shaft, and a friction layer on the lower end surface; the rotor is sleeved on the output shaft, and its friction layer and each drive on the ring gear The teeth offset each other, and the rotor is keyed to the output shaft through the through hole in its center, so that the rotor is circumferentially fixed to the output shaft and can slide freely relative to the output shaft in the axial direction;

The upper end of the output shaft is provided with threads that match the preload nut;

The preload nut is threadedly connected to the upper end of the output shaft; the preload spring is sleeved outside the output shaft between the preload nut and the rotor, with one end offset against the preload nut and the other end offset against the rotor; The tightening nut is used to adjust the preload between the friction layer of the rotor and each drive tooth on the ring gear.

As a further optimization solution of the present invention's longitudinal-bend mode conversion type rotary ultrasonic motor based on Lanjiewen transducer, the friction layer is made of alumina ceramic material or zirconia material, and is adhered to the rotor through epoxy resin. Lower end face.

As a further optimization solution of the present invention's longitudinal-bend mode conversion rotary ultrasonic motor based on Lanjiewen transducer, the q=2mn, m is a natural number greater than or equal to 1.

As a further optimization solution of the present invention's longitudinal-bend mode conversion rotary ultrasonic motor based on Lanjiewen transducer, n is set to 4.

Compared with the existing technology, the present invention adopts the above technical solution and has the following technical effects:

1. This invention utilizes the excellent electromechanical energy conversion characteristics of the Lanjiewen transducer to effectively enhance the longitudinal amplitude of the ring gear. When the same preload is applied, the friction between the ring gear and the rotor is greater, and the motor can output more energy. large torque;

2. The present invention is not limited to the problem of difficult processing of patch-type annular multi-zone polarized piezoelectric ceramics. It changes the patch form into a sandwich form, takes full advantage of the large d33 coefficient of piezoelectric ceramics, and improves the electromechanical conversion of the motor. Efficiency, improving the mechanical output characteristics of the motor;

3. The stress concentration generated when the single-polarized zoned sandwich piezoelectric ceramic piece vibrates is smaller than that of the patch-type piezoelectric ceramic multi-polarized zoned vibration, which reduces the probability of fatigue damage of the piezoelectric ceramic, so it can greatly extend the operating time of the motor. The working life of piezoelectric ceramic discs under harsh working conditions;

4. All Lanjevin transducers are independent of each other and will not affect each other except when preloading is applied, and there will be no coupling phenomenon when the structure vibrates;

5. The present invention improves the cracking problem of traditional patch-type traveling wave rotary ultrasonic motors due to long-term operation of piezoelectric ceramics, and the size of the motor is not limited to the shape and size of the ceramics, and the design is flexible and versatile. It has strong adaptability and can effectively improve the stable service capability of ultrasonic motors in high-precision fields.

Description of the drawings

Figure 1 is a schematic cross-sectional view of the present invention;

Figure 2 is a schematic structural diagram of the driving module in the present invention;

Figure 3 is a schematic diagram of the polarization direction arrangement mode 1 of the piezoelectric ceramic sheets in the present invention;

Figure 4 is a schematic diagram of the driving mode in polarization configuration mode 1 of the present invention;

Figure 5 is a schematic diagram of the polarization direction arrangement mode 2 of the piezoelectric ceramic sheet in the present invention;

Figure 6 is a schematic diagram of the driving mode in polarization configuration mode 2 of the present invention;

Figure 7 is a schematic diagram of the vibration shape during operation of the present invention.

In the figure, 1-base body, 2-rotor, 3-output shaft, 4-first bearing, 5-second bearing, 6-ring gear, 7-front beam, 8-piezoelectric ceramic sheet, 9-rear beam, 10 - Preload bolt, 11 - Key between rotor and output shaft, 12 - Preload nut, 13 - Preload spring, 14 - Flexible hinge, 15 - Drive tooth, 16 - Connecting plate.

Implementation

The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings:

The invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, components are exaggerated for clarity.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components and/or sections, these elements, components and/or sections are not limited by these terms. These terms are only used to distinguish elements, components and/or parts from each other. Thus, a first element, component or section discussed below could be a second element, component or section without departing from the teachings of the present invention.

As shown in Figure 1, the present invention discloses a longitudinal-bend mode conversion rotary ultrasonic motor based on a Lanjievin transducer, including a stator, a rotor, an output shaft, a first bearing, a second bearing, and a preload nut. and preload springs;

The stator includes a base body, a driving module and a fixed bracket;

The base body is a hollow cylinder with openings at both ends;

The output shaft is coaxially connected to the inner rings of the first bearing and the second bearing respectively; the outer rings of the first bearing and the second bearing are coaxially connected to the inner wall of the base body, so that the output shaft and the base body Coaxial and the two ends of the output shaft protrude from both ends of the base body respectively;

As shown in Figure 2, the drive module includes a drive ring, a connecting component and 2n Langevin transducers, where n is an even number greater than or equal to 2;

The gear ring is in the shape of a ring, and its upper end surface is evenly provided with q driving teeth in the circumferential direction, where q is a natural number greater than or equal to 3;

The Lanjiewen transducer includes a front beam, a rear beam, pre-tightening bolts and p piezoelectric ceramic sheets, where p is an even number greater than or equal to 2;

The front beam has a variable cross-section structure, its cross-section gradually becomes smaller from bottom to top, and a threaded blind hole is provided in the center of the lower end surface to match the pre-tightening bolt;

The rear beam is a column with a through hole along the axis for the preload bolt to pass through;

The piezoelectric ceramic sheet and the back beam have the same cross-sectional shape, are polarized along the thickness direction, and have a through hole in the center for the preload bolt to pass through;

The pretightened bolts pass through the rear beam and p piezoelectric ceramic sheets in sequence and are threadedly connected to the threaded blind holes of the front beam, clamping the p piezoelectric ceramic sheets between the rear beam and the front beam; adjacent piezoelectric The polarization direction of the ceramic piece is opposite;

The 2n Lanjiewen transducers are evenly arranged in the circumferential direction on the lower end face of the gear ring, the upper end of the front beam is fixedly connected to the lower end face of the gear ring, and the axis of the rear beam is perpendicular to the lower end face of the gear ring;

The connection assembly includes 2n connection plates; the 2n connection plates are arranged one-to-one between the 2n Lanjievin transducers, and the connecting plate and the Lanjievin transducers on both sides are connected through flexible hinges. ;

The connecting component is fixedly connected to the base body through a fixed bracket, so that the ring ring is sleeved outside the output shaft above the base body and coaxial with the output shaft, and the base body is surrounded by 2n Lanjiewen transducers;

The rotor is in the shape of a disk, with a through hole in the center that matches the output shaft, and a friction layer on the lower end surface; the rotor is sleeved on the output shaft, and its friction layer and each drive on the ring gear The teeth offset each other, and the rotor is keyed to the output shaft through the through hole in its center, so that the rotor is circumferentially fixed to the output shaft and can slide freely relative to the output shaft in the axial direction;

The upper end of the output shaft is provided with threads that match the preload nut;

The preload nut is threadedly connected to the upper end of the output shaft; the preload spring is sleeved outside the output shaft between the preload nut and the rotor, with one end offset against the preload nut and the other end offset against the rotor; The tightening nut is used to adjust the preload between the friction layer of the rotor and each drive tooth on the ring gear.

The base body can be fixedly connected to the outer shell of the rotating ultrasonic motor, as shown in Figure 1, and the outer shell can be fixed to the outside world.

The q is preferably 2mn, m is a natural number greater than or equal to 1; n is preferably 4.

The friction layer is made of alumina ceramic material or zirconium oxide material, and is glued to the lower end surface of the rotor through epoxy resin. The friction layer has high hardness and high wear resistance, forming a large friction coefficient with the drive tooth surface, which can effectively enhance the working life of the motor base-rotor friction contact surface.

In order to obtain the spatially closed motion trajectory of all driving teeth on the ring gear so that the motor has the ability to drive the rotor to continuously rotate in the circumferential direction, the phase difference between the longitudinal vibrations of adjacent Lanjievin transducers is 90°.

All Lanjevin transducers are independent of each other, will not interfere with each other when applying preload force, and will not produce significant mutual influence and coupling phenomena during vibration.

There are two options for the driving method of the present invention:

The first type, as shown in Figure 3, 2n Lanjievin transducers are divided into 2 groups, namely A and B. The two Lanjievin transducers arranged in sequence along the circumferential direction are respectively affiliated to Groups A and B follow the same analogy cycle, with n Lanjievin transducers forming a group; in group A, the polarization directions of the piezoelectric ceramic sheets stacked in pairs in adjacent Lanjievin transducers are opposite, that is, The positive-to-positive polarization direction configuration and the negative-to-negative polarization direction configuration alternate in sequence; in group B, the polarization directions of the stacked piezoelectric ceramic sheets in adjacent Lanjiewen transducers are opposite, that is, the positive-to-positive polarization direction. The directional configurations alternate sequentially with negative-on-negative polarization directional configurations. As shown in Figure 4, the signal generator at this time selects two electrical signals with a phase difference of π/2 and applies them to the electrode sheets for driving.

The second type, as shown in Figure 5, 2n Lanjievin transducers are divided into 4 groups, namely groups C, D, E, and F. The 4 Lanjievin transducers arranged in sequence along the circumferential direction are respectively Belonging to groups C, D, E, F and so on, the polarization direction configuration of the piezoelectric ceramic sheets in all Lanjiewen transducers is the same, that is, all piezoelectric ceramic sheet poles stacked in pairs Orientation positive to positive or negative to negative configuration. As shown in Figure 6, the signal generator at this time selects four electrical signals with a phase difference of π/2 and applies them to the electrode sheets for driving.

As shown in Figure 7, when the Lanjiewen transducer works in the first-order longitudinal vibration state, by implementing the above-mentioned polarization configuration principles and driving methods, the bending vibration mode can be obviously generated on the ring ring. Under the alternating action of signals, all drive teeth can produce a closed motion trajectory, thereby converting the motion of the drive teeth into the rotation of the flexible rotor through frictional contact, and finally output torque through the output shaft.

It can be understood by one of ordinary skill in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in general dictionaries are to be understood to have meanings consistent with their meaning in the context of the prior art, and are not to be taken in an idealized or overly formal sense unless defined as herein. explain.

The above-mentioned specific embodiments further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (4)

1. Longitudinal-bend mode conversion rotary ultrasonic motor based on Lanjiewen transducer, which is characterized by including a stator, a rotor, an output shaft, a first bearing, a second bearing, a preload nut and a preload spring; The stator includes a base body, a driving module and a fixed bracket; The base body is a hollow cylinder with openings at both ends; The output shaft is coaxially connected to the inner rings of the first bearing and the second bearing respectively; the outer rings of the first bearing and the second bearing are coaxially connected to the inner wall of the base body, so that the output shaft and the base body Coaxial and the two ends of the output shaft protrude from both ends of the base body respectively; The drive module includes a drive ring, a connecting component and 2n Langevin transducers, where n is an even number greater than or equal to 2; The gear ring is in the shape of a ring, and its upper end surface is evenly provided with q driving teeth in the circumferential direction, where q is a natural number greater than or equal to 3; The Lanjiewen transducer includes a front beam, a rear beam, pre-tightening bolts and p piezoelectric ceramic sheets, where p is an even number greater than or equal to 2; The front beam has a variable cross-section structure, its cross-section gradually becomes smaller from bottom to top, and a threaded blind hole is provided in the center of the lower end surface to match the pre-tightening bolt; The rear beam is a column with a through hole along the axis for the preload bolt to pass through; The piezoelectric ceramic sheet and the back beam have the same cross-sectional shape, are polarized along the thickness direction, and have a through hole in the center for the preload bolt to pass through; The pretightened bolts pass through the rear beam and p piezoelectric ceramic sheets in sequence and are threadedly connected to the threaded blind holes of the front beam, clamping the p piezoelectric ceramic sheets between the rear beam and the front beam; adjacent piezoelectric The polarization direction of the ceramic piece is opposite; The 2n Lanjiewen transducers are evenly arranged in the circumferential direction on the lower end face of the gear ring, the upper end of the front beam is fixedly connected to the lower end face of the gear ring, and the axis of the rear beam is perpendicular to the lower end face of the gear ring; The connection assembly includes 2n connecting plates; the 2n connecting plates are arranged between the 2n Lanjievin transducers in one-to-one correspondence, and the connecting plate and the Lanjievin transducers on both sides are connected through flexible hinges. ; The connecting component is fixedly connected to the base body through a fixed bracket, so that the ring ring is sleeved outside the output shaft above the base body and coaxial with the output shaft, and the base body is surrounded by 2n Lanjiewen transducers; The rotor is in the shape of a disc, with a through hole in the center that matches the output shaft, and a friction layer on the lower end surface; the rotor is sleeved on the output shaft, and its friction layer and each drive on the gear ring The teeth offset each other, and the rotor is keyed to the output shaft through the through hole in its center, so that the rotor is circumferentially fixed to the output shaft and can slide freely relative to the output shaft in the axial direction; The upper end of the output shaft is provided with threads that match the preload nut; The preload nut is threadedly connected to the upper end of the output shaft; the preload spring is sleeved outside the output shaft between the preload nut and the rotor, with one end offset against the preload nut and the other end offset against the rotor; The tightening nut is used to adjust the preload between the friction layer of the rotor and each drive tooth on the ring gear. 2. The longitudinal-bend mode conversion rotary ultrasonic motor based on the Lanjiewen transducer according to claim 1, characterized in that the friction layer is made of alumina ceramic material or zirconia material, and is made of epoxy resin. Glue on the lower end face of the rotor. 3. The longitudinal-bend mode conversion rotary ultrasonic motor based on the Lanjievin transducer according to claim 1, characterized in that, the q=2mn, m is a natural number greater than or equal to 1. 4. The longitudinal-bend mode conversion rotary ultrasonic motor based on the Lanjiewen transducer according to claim 1, characterized in that the n is 4.