CN102931873B - A kind of small all-in-one parallel rotation ultrasonic motor - Google Patents

Abstract

The invention relates to a small integrated parallel rotating ultrasonic motor, which belongs to the technical field of ultrasonic motors. It includes a stator (1) and a mover (2) as a bearing. The stator (1) is composed of N (N≥3) composite oscillators connected in parallel. The composite oscillators are connected through flexible support elements, and the composite oscillators surround the moving The sons are placed symmetrically along the circumferential direction; each composite vibrator is composed of two Langevin vibrators intersecting each other at a certain angle; at the same time, the heads of the two Langevin vibrators are joined together to form the driving foot (13) of the composite vibrator, And the Langevin vibrators are all on the same plane; each Langevin vibrator is composed of an elastomer (11) and a piezoelectric ceramic sheet (12), the positive electrode of the piezoelectric ceramic sheet faces outward, and the negative electrode points to the elastic The substrate surface of body (11). The invention not only has high energy density and compact structure, but also can provide relatively large output torque in the case of being very thin in the longitudinal dimension.

Description

A Small Integrated Parallel Rotating Ultrasonic Motor

technical field

The invention relates to a rotary ultrasonic motor which is composed of a plurality of composite oscillators which are integrally connected in parallel circumferentially and symmetrically, and belongs to the field of ultrasonic motors.

Background technique

The linear ultrasonic motor is a new type of micro-motor developed and applied rapidly in the 1980s. It uses the inverse piezoelectric effect of the piezoelectric element and the ultrasonic vibration of the elastic body, and through the friction between the stator and the mover, the elastic The micro-vibration of the body is converted into the macroscopic linear (rotational) motion of the mover, which directly pushes the load. At present, the development of domestic linear ultrasonic motor is very fast. On the China Patent Network, there are many patents on linear ultrasonic motors. Among them, the rod structure linear ultrasonic motor has attracted much attention because the stator of the motor is composed of Langevin oscillators. The Langevin oscillator uses longitudinal vibration and has clear nodes. It has high energy transfer efficiency and facilitates gripping. The patent [200810124426.2] proposes a K-shaped linear ultrasonic motor based on the principle of a continuous horn. The stator of the motor is composed of two symmetrical Langevin vibrators. The patent [201010556088.7] proposes a flexible clamping technology based on linear ultrasonic motors, which connects all piezoelectric vibrators through flexible arc segments, and connects the vibrators to fixed ends with circular through holes through flexible arc segments , thus simplifying the clamping structure. With the application research of linear ultrasonic motors in robotics, aerospace and other fields in recent years, the problems of linear ultrasonic motors have gradually been exposed. One of them is that the output force of a single motor is insufficient. In some applications that require large output force Occasions cannot meet the requirements, which prompts the research on high-thrust linear ultrasonic motors. At present, the research on high-thrust linear ultrasonic motors mainly focuses on two aspects:

One is to increase the volume of the linear ultrasonic motor. However, according to the characteristics of the linear ultrasonic motor, the motor can have a greater advantage in the case of a small volume. After the motor volume becomes larger, the output force does not increase much, and the application of the ultrasonic motor generally has restrictions on the volume, so only Increasing the size of the motor does not solve the problem.

The second is to use the linear ultrasonic motor in parallel. In the case of keeping the volume of a single motor unchanged, increasing the number of driving motors to improve the overall output force can be better than increasing the volume of the motor. At present, the parallel connection of linear ultrasonic motors mostly adopts the assembly of multiple small motor platforms into a parallel platform, which is cumbersome to clamp and has a low thrust-to-weight ratio.

The research on the parallel performance of linear ultrasonic motors has higher requirements on linear ultrasonic motors. Since the domestic research on ultrasonic motors started relatively late, this kind of research is currently dominated by foreign countries. In 1998, Kurosawa proposed a linear ultrasonic motor parallel scheme, which uses three linear ultrasonic motors to drive a large disc at the same time, and is used in the precision drive system of large astronomical telescopes; German Mracek et al. Coordinated operation has also done some preliminary research, mainly by changing the driving mode of parallel linear ultrasonic motors to study the overall output new energy of linear ultrasonic motors under parallel conditions.

Domestic research on parallel connection of ultrasonic motors uses the relatively mature 60 traveling wave motors. This scheme changes the motor from single stator and single rotor to dual stators and dual rotors in parallel output. Through experiments, it is obtained that the same size single stator rotary Compared with the performance of traveling wave ultrasonic motor, the torque and idling speed are more than doubled.

Although there has been some research and application on the parallel connection of ultrasonic motors, none of them are systematic and in-depth. In particular, there is no systematic theory to solve the problem of unsatisfactory efficiency of split parallel connection of multiple linear ultrasonic motors.

Contents of the invention

The present invention aims at the deficiencies of the above problems, and proposes a high energy density, multi-vibrator integrated parallel rotary ultrasonic motor, which can still provide a small integrated parallel rotary ultrasonic motor with a relatively large output torque in the case of a very thin longitudinal dimension. .

The technical solution proposed by the present invention to solve the above technical problems is: a small-sized integrated parallel rotary ultrasonic motor, including a stator (1) and a mover (2) as a bearing, and the stator is composed of N (N≥3) composite The oscillators are connected in parallel, the composite oscillators are connected through flexible support elements (3), and the composite oscillators are placed symmetrically around the mover (2) along the circumferential direction; each composite oscillator consists of two Langevin oscillators at a certain angle to each other The two Langevin vibrator heads are combined to form the driving foot (13) of the composite vibrator at the same time, and the Langevin vibrators are all on the same plane; each Langevin vibrator is composed of an elastic body ( 11) and a piezoelectric ceramic sheet (12), the positive electrode of the piezoelectric ceramic sheet faces outward, and the negative electrode points to the surface of the base body of the elastomer (11).

Preferably: the stator is excited in parallel with the same frequency.

Preferably: the Langevin vibrator on the same side of each composite vibrator is a group, and the two groups of ceramic plates are respectively applied with sinusoidal excitation signals of the same frequency, equal voltage, and π/2 phase difference, and simultaneously excite the longitudinal vibration mode of the motor state and bending mode.

Preferably: the flexible supporting element is composed of a flexible hinge (31) for fixing the stator and applying preload and a fixed end (32) for fixing the entire motor; the flexible hinge (31) is designed on the elastic body (11 ) at the longitudinal vibration node, and the fixed end is arranged on the outer side of the flexible hinge, and there is a composite vibrator alternately between the fixed ends.

Preferably: the N driving feet form a circle in the plane with the moving direction of the mover, and the diameter of the mover is larger than the diameter of the circle.

Preferably: the intersection angle of the two Langevin oscillators of each composite oscillator is between 0°-180°.

A small-sized integrated parallel rotary ultrasonic motor of the present invention has the following beneficial effects compared with the prior art: since the present invention includes a stator (1) and a mover (2) as a bearing, the stator consists of N (N≥ 3) Composite vibrators are connected in parallel, the composite vibrators are connected through flexible supporting elements (3), and the composite vibrators are placed symmetrically around the mover (2) along the circumferential direction. Meanwhile, for linear ultrasonic motors, there are mainly plate structures and There are two types of rod structure. The plate structure linear ultrasonic motor is flat and simple in structure, and can play a role in specific occasions. The rod structure linear ultrasonic motor can generate large output force and high output efficiency by using the Langevin vibrator. The important thing is that the Langevin vibrator has a clear longitudinal vibration node, which is beneficial to the clamping and preloading of the motor. Therefore, the present invention combines the characteristics of these two linear ultrasonic motors, and proposes to design a linear ultrasonic motor by using multiple Langevin vibrators. On the one hand, the main structure of the motor is a Langevin vibrator with a rod structure, and on the other hand, its appearance structure is a ring-shaped plate structure, so the present invention has the following characteristics: (1) Multiple composite vibrators are connected in parallel in the circumferential direction, and the horizontal structure is compact , high space utilization; (2) The integrated parallel structure ensures that the parallel motors have similar excitation frequencies, improves parallel efficiency, and has better output characteristics; (3) The circumferential symmetrical arrangement ensures the stability of the structure and the applied The uniformity of the preload, the longitudinal dimension is the same as that of a single composite vibrator. In summary, the present invention has the outstanding advantages of compact structure, high space utilization rate, excellent parallel connection efficiency, large torque output, stable performance and thin longitudinal dimension.

Description of drawings

Figure 1 is a schematic diagram of the structure of a small integrated parallel rotating ultrasonic motor.

Figure 2 is a schematic diagram of polarization and signal loading of a single stator piezoelectric ceramic sheet. Figure 2(b) is a k-k cross-sectional view of Figure 2(a).

Fig. 3 is a schematic diagram of the working mode of the elliptical parabolic linear ultrasonic motor system. Wherein, FIG. 3( a ) is a schematic diagram of a stator in a symmetrical working mode, and FIG. 3( b ) is a schematic diagram of a stator in an antisymmetrical working mode.

The names of the symbols in the figure: 1 is the stator, 2 is the mover, 3 is the flexible supporting element, 11 is the elastic body, 12 is the ceramic sheet, 13 is the driving foot, 31 is the flexible hinge, and 32 is the fixed end.

detailed description

The accompanying drawing discloses a schematic structural view of a preferred embodiment of the present invention without limitation, and the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings.

Example

A small integrated parallel rotary ultrasonic motor of this embodiment is shown in Figure 1-3, including a stator 1 and a mover 2 as a bearing, the stator is composed of N composite oscillators connected in parallel, N≥3, the composite The vibrator is connected through the flexible support element 3, and the composite vibrator is placed symmetrically around the mover 2 in the circumferential direction. Therefore, the force of the N composite vibrators on the mover is naturally balanced, and the entire stator can be processed in an integrated manner by wire cutting to ensure that the clamping of each composite vibrator is achieved without disturbing its vibration modal frequency, and the stator can also be made to move. The sub has a certain pre-pressure. Each composite vibrator is composed of two Langevin vibrators crossing each other at a certain angle, and the intersection angle of the two Langevin vibrators of each composite vibrator is between 0°-180°; The heads of the Jiewen vibrator are connected together to form the driving foot 13 of the composite vibrator, and the Langevin vibrators are all on the same plane; each Langevin vibrator is composed of an elastic body 11 and a piezoelectric ceramic sheet 12, the The positive electrode of the piezoelectric ceramic sheet faces outward, and the negative electrode points to the surface of the base body of the elastic body 11 .

The stator adopts the parallel excitation method of the same frequency excitation. That is, the Langevin oscillators on the same side of each composite oscillator are a group, that is to say, since the composite oscillator is composed of two Langevin oscillators, the two Langevin oscillators can be arranged clockwise along the stator The direction is divided into the first Langevin oscillator and the second Langevin oscillator. All the first Langevin oscillators form a group, and the remaining second Langevin oscillators form a group. The two groups of ceramic plates are respectively applied with the same frequency. , Equal voltage, sinusoidal excitation signal with π/2 phase difference, simultaneously excite the longitudinal vibration mode and bending vibration mode of the motor.

The flexible support element is composed of a flexible hinge 31 for fixing the stator and applying a preload and a fixed end 32 for fixing the entire motor; the flexible hinge 31 is designed at the longitudinal vibration node of the elastic body 11, and the fixed The ends are arranged on the outer side of the flexible hinge, and there is a composite vibrator between the fixed ends; the fixed end is a rectangular clamp with a through hole, and the motor is assembled on the external device through screws.

The N driving feet form a circle in the plane with the moving direction of the mover, and the diameter of the mover is larger than the diameter of the circle, so that pre-pressure can be applied through the slight deformation of the flexible hinge. Therefore, this motor does not have a special device for applying preload, and its structure is relatively simple.

Fig. 2 is a schematic diagram of the polarization and signal loading of the piezoelectric ceramic sheet. Each composite vibrator is composed of two Langevin vibrators crossing at a certain angle, applying a sinusoidal signal of the same frequency with a phase difference of π/2, and using the d ₃₁ effect of the piezoelectric ceramic sheet to simultaneously excite the two piezoelectric vibrators to respectively excite the two piezoelectric vibrators of the stator. The superposition of these two vibration modes makes the particles on the end surface of the driving foot produce elliptical motion to push the mover to perform continuous rotational motion. When the excitation signals are opposite, the reverse linear motion of the mover can be realized. The N composite oscillators adopt the same driving mode (same frequency, same phase) to drive the movers to move in the same direction, which improves the output force and output power, and improves the space utilization rate.

The working modes of the small integrated parallel rotating ultrasonic motor mentioned above: the two working modes of each composite vibrator are shown in Fig. 3 . When the two Langevin oscillators of the composite oscillator vibrate longitudinally in the same phase, the symmetrical mode of the composite oscillator is excited; when the two Langevin oscillators vibrate in opposite phases to each other, the antisymmetric mode of the composite oscillator is excited. Two sine signals with a phase difference of π/2 are used to simultaneously excite the two Langevin oscillators of the composite oscillator, and two vibrations of the composite oscillator with the same frequency and a phase difference of π/2 are used to drive the foot mass on the composite oscillator to perform elliptical motion. When the motor is working, the N composite oscillators adopt the same driving mode (same frequency, same phase) to drive the movers to move in the same direction. The mover is a cylindrical structure, which is in contact with the compound vibrator at the driving foot. The n driving feet form a circle in the plane with the moving direction of the mover, and the diameter of the cylindrical mover is larger than the diameter of the circle. Since the diameter of the cylindrical mover is larger than the diameter of the circle, a preload is created between the stator and the mover. Figure 3a shows that the two piezoelectric vibrators of the composite vibrator perform longitudinal stretching vibration in the same direction, which is synthesized into up and down motion at the driving foot. Figure 3b shows that the two piezoelectric vibrators of the composite vibrator do reverse longitudinal stretching vibrations, which are synthesized into left and right motions at the driving feet.

The preferred specific embodiments of the present invention described above in conjunction with the accompanying drawings are only used to illustrate the implementation of the present invention, rather than as a limitation to the foregoing invention purpose and the content and scope of the appended claims. Any simple modifications, equivalent changes and modifications made in the embodiments still belong to the technical and rights protection scope of the present invention.

Claims (4)

1. a small all-in-one parallel rotation ultrasonic motor, comprise stator (1) and the mover (2) as bearing, it is characterized in that: described stator is composed in parallel by N number of composite oscillator, N >=3, described composite oscillator is connected by flexible supporting element (3), and composite oscillator is placed around mover (2) is circumferentially symmetrical simultaneously; Described each composite oscillator is made up of two angled crossing one another of Langevin-type transducer; These two Langevin-type transducer heads combine as a whole driving foot (13) forming composite oscillator simultaneously, and described Langevin-type transducer is all in same plane; Each Langevin-type transducer is made up of elastomer (11) and piezoelectric ceramic piece (12), and outwardly, negative pole points to the matrix surface of elastomer (11) to the positive pole of described piezoelectric ceramic piece; Described stator adopts the parallel connection excitement mode with excitation frequently; Described flexible supporting element is by the flexible hinge (31) for fixed stator and applying precompression and form for the stiff end (32) of fixing whole motor; Described flexible hinge (31) design is at elastomer (11) longitudinal vibration nodal section place, and described stiff end is arranged on the outside of described flexible hinge, and simultaneously alternate between described stiff end have a composite oscillator.

2. small all-in-one parallel rotation ultrasonic motor according to claim 1, it is characterized in that: the Langevin-type transducer of the same side of described each composite oscillator is one group, two groups of potsherds apply same frequency respectively, Deng voltage, the sinusoidal excitation signal of pi/2 phase difference, inspires longitudinal vibration mode and the bending vibration modes of motor simultaneously.

3. small all-in-one parallel rotation ultrasonic motor according to claim 1, is characterized in that: described N number of driving foot is to form a circle in the plane of the mover direction of motion, and the diameter of described mover is greater than this diameter of a circle.

4. small all-in-one parallel rotation ultrasonic motor according to claim 1, is characterized in that: the intersecting angle of two Langevin-type transducers of described each composite oscillator is between 0 °-180 °.