Stator double-face excitation traveling wave type rotary ultrasonic motor

Abstract

The invention discloses a stator double-face excitation traveling wave type rotary ultrasonic motor, and belongs to the technical field of ultrasonic motors, the stator double-face excitation traveling wave type rotary ultrasonic motor specifically comprises a base, a stator and a rotor, the stator comprises a cylinder wall and a cylinder bottom, the stator is provided with an upper end and a lower end, the cylinder bottom is provided with an upper side face and a lower side face, and the upper side face and the lower side face are each provided with a plurality of positioning grooves; a piezoelectric ceramic stack is mounted in each positioning groove, each piezoelectric ceramic stack is excited by power supplies with different phases to form an excitation unit, and the polarization direction of the piezoelectric ceramic stack of each excitation unit is parallel to the circumferential direction of the stator; according to the invention, the plurality of piezoelectric ceramic stacks are arranged on the upper side surface and the lower side surface, the upper side surface and the lower side surface are excited at the same time, and each piezoelectric ceramic stack is excited by a power supply with a corresponding phase, so that the input power of the motor is effectively increased, and the output mechanical power of the stator during vibration is further improved; according to the invention, the stator can operate in a non-resonance state, so that the rotating speed operation range of the motor is expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic motors, and in particular to a stator double-sided excitation traveling wave type rotary ultrasonic motor. Background Art

[0002] An ultrasonic motor (USM) utilizes the inverse piezoelectric effect of piezoelectric materials to induce micro-vibrations in the stator at ultrasonic frequencies, thereby creating a specific motion trajectory on the stator surface and achieving electromechanical energy conversion through friction. Based on their driving principles, UMSs can be categorized into standing wave, traveling wave, and composite types. Traveling wave UMSs utilize waves excited in the stator to induce elliptical vibrations on the surface of the elastic body, which in turn drives the particles.

[0003] Traditional traveling wave rotary ultrasonic motors typically use a constant-amplitude alternating voltage signal in the ultrasonic frequency band with a phase difference of 90° to excite two sets of piezoelectric ceramic plates attached to the bottom of a disc-shaped stator, which are spatially spaced 1 / 4 of the traveling wave wavelength apart. This in turn generates two standing waves in the stator that differ in time by 90° electrical angle and in space by 90° mechanical angle. These two standing waves eventually combine on the side of the stator to form a traveling wave that propagates along the circumference of the stator. Finally, friction drives the rotor to rotate and output mechanical power. This type of motor has the advantages of simple structure, fast response speed, high positioning accuracy, no external electromagnetic radiation, and no external electromagnetic interference. The above-mentioned traveling wave rotary ultrasonic motor has the disadvantage of low output mechanical power, and the stator needs to operate in a resonant state, so the motor's speed range is also greatly limited.

[0004] In view of this, the inventors of this case conducted in-depth research on the above-mentioned issues, which led to the creation of this case. Summary of the Invention

[0005] The object of the present invention is to provide a stator double-sided excited traveling wave rotary ultrasonic motor, which uses multiple piezoelectric stacks to excite the stator. Each piezoelectric ceramic stack is excited by a power supply with a different phase, which can increase the mechanical power output during stator vibration and at the same time increase the displacement of the stator side in a non-resonant state, thereby realizing the operation of the motor in the stator non-resonant state, thereby effectively expanding the motor's speed operating range.

[0006] In order to achieve the above object, the present invention adopts such technical solution: A stator double-sided excitation traveling wave rotary ultrasonic motor includes a base, a stator and a rotor, the stator having a cylindrical structure, the stator including an integrally connected cylinder wall and a cylinder bottom, and the stator having an upper end and a lower end, the cylinder bottom having an upper side surface and a lower side surface, the stator is arranged above the base, the upper end is connected to the rotor, the upper side surface and the lower side surface of the cylinder bottom are both provided with a plurality of positioning grooves, a piezoelectric ceramic stack is installed in each of the positioning grooves, each piezoelectric ceramic stack is excited by a power supply of different phases to form an excitation unit, the polarization direction of the piezoelectric ceramic stack of each excitation unit is parallel to the circumferential direction of the stator, the base extends upward along the direction of the stator with a positioning step, the lower end is provided with a groove matching the positioning step at a position corresponding to the positioning step, and the positioning step is adapted to the groove.

[0007] Furthermore, voltage excitation is applied to the piezoelectric ceramic stack of each of the excitation units to excite symmetric vibration modes and antisymmetric vibration modes of the excitation unit, and each of the excitation units is deformed and displaced along the circumferential direction of the stator.

[0008] Furthermore, the number of the positioning grooves on the upper side and the number of the positioning grooves on the lower side are both 2n, where n is a natural number greater than or equal to 1.

[0009] Furthermore, two adjacent piezoelectric ceramic stacks on the upper side and two adjacent piezoelectric ceramic stacks on the lower side are each a group, and the corresponding upper side and lower side are evenly divided into n regions along the circumferential direction, and the length of each region along the circumferential direction is one traveling wave wavelength.

[0010] Furthermore, the n groups of piezoelectric ceramic stacks uniformly arranged on the lower side are spatially spaced apart from the n groups of piezoelectric ceramic stacks uniformly arranged on the upper side by a distance of 1 / 4 of the wavelength of the traveling wave along the circumferential direction.

[0011] Furthermore, the piezoelectric ceramic stacks are excited by an AC power supply of the same amplitude and frequency, the excitation power supplies of two adjacent piezoelectric ceramic stacks arranged on the same side of the bottom of the cylinder have a phase difference of 180°, and the excitation power supplies of the piezoelectric ceramic stack on the upper side and the piezoelectric ceramic stack on the lower side have a uniform phase difference of 90°.

[0012] Furthermore, a friction layer is installed on the side of the rotor in contact with the stator, and a spring, a pressure cover and a locking nut are provided on the side of the rotor away from the stator. The spring and the pressure cover are connected and pressed against the rotor through the locking nut.

[0013] Furthermore, a plurality of tooth grooves are evenly arranged on the cylinder wall along the circumferential direction.

[0014] Furthermore, the base and the rotor are hollow and / or solid structures, and the stator is a hollow structure.

[0015] By adopting the aforementioned design scheme, the beneficial effects of the present invention are as follows: by arranging a plurality of piezoelectric ceramic stacks on the upper and lower sides and simultaneously exciting the upper and lower sides of the stator, each piezoelectric ceramic stack is excited by a power supply of a corresponding phase, effectively increasing the input power of the motor, thereby increasing the mechanical power output of the stator during vibration; at the same time, compared with traditional piezoelectric ceramic sheets, the piezoelectric ceramic stack has a larger displacement deformation under the excitation of the same amplitude voltage. Therefore, the present invention can realize the operation of the stator in a non-resonant state, thereby expanding the speed operating range of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 is a cross-sectional view of the present invention; In the figure: base 1, positioning step 11, stator 2, upper end 21, lower end 22, groove 221, cylinder wall 23, tooth groove 231, cylinder bottom 24, upper side 241, lower side 242, positioning groove 243, piezoelectric ceramic stack 3, rotor 4, friction layer 5. DETAILED DESCRIPTION

[0017] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0018] Reference Figures 1 to 2 : A stator double-sided excitation traveling wave rotary ultrasonic motor includes a base 1, a stator 2, and a rotor 4. The stator 2 includes an integrally connected cylinder wall 23 and a cylinder bottom 24, and the stator 2 has an upper end 21 and a lower end 22. The cylinder bottom 24 has an upper side surface 241 and a lower side surface 242. The stator 2 is disposed above the base 1, with the upper end 21 in contact with the rotor 4. Furthermore, the stator 2 has a cylindrical hollow structure, and the base 1 and the rotor 4 have hollow and / or solid structures. The base 1 has a positioning step 11 extending upwardly in the direction of the stator 2. The lower end 22 has a groove 221 corresponding to the position of the positioning step 11, which matches the positioning step 11. The positioning step 11 is adapted to the groove 221. Preferably, in this embodiment, the base 1 and the rotor 4 adopt a hollow metal matrix.

[0019] Both the upper side 241 and the lower side 242 are provided with a plurality of positioning slots 243. A piezoelectric ceramic stack 3 is mounted in each positioning slot 243 and bonded to the positioning slots 243 of the stator 2 using an adhesive. Each piezoelectric ceramic stack 3 is excited by a power source with a different phase, forming an excitation unit. The polarization direction of the piezoelectric ceramic stack 3 in each excitation unit is parallel to the circumferential direction of the stator 2. Voltage excitation is applied to the piezoelectric ceramic stack 3 of each excitation unit via a wire to stimulate the unit's symmetric and antisymmetric vibration modes, causing each excitation unit to deform and displace along the circumference of the stator 2. Simultaneously exciting the upper side 241 and lower side 242 of the stator effectively increases the motor's input power, thereby increasing the motor's mechanical power output during vibration. Using the piezoelectric ceramic stack 3 as the excitation unit effectively increases the deformation of the stator 2 under the same amplitude voltage excitation, enabling the motor to output mechanical power in a non-resonant state, broadening the motor's speed operating range while fully utilizing the space of the stator 2. This design offers the advantages of a rational design, a clear structure, and ease of implementation. It should be noted that the design of piezoelectric ceramic stacks 3 with different phases, by applying modal forces at different phases, can achieve multiple vibration modes to accommodate varying operating conditions and load variations, greatly expanding the motor's application range and adaptability. This design can generate more powerful vibration and driving force, resulting in a motor with higher output power, speed, and precision, making it suitable for high-end equipment and precision instruments with high motor performance requirements.

[0020] Furthermore, the number of positioning grooves 243 on the upper side 241 and the number of positioning grooves 243 on the lower side 242 are both 2n, where n is a natural number greater than or equal to 1. Two adjacent piezoelectric ceramic stacks 3 on the upper side 241 and two adjacent piezoelectric ceramic stacks 3 on the lower side 242 form a group, and the corresponding upper side 241 and lower side 242 are evenly divided into n regions along the circumferential direction, with the length of each region along the circumferential direction being one traveling wave wavelength.

[0021] The n groups of piezoelectric ceramic stacks 3 uniformly arranged on the lower side 242 are spatially spaced apart from the n groups of piezoelectric ceramic stacks 3 uniformly arranged on the upper side 241 by a distance of 1 / 4 of the wavelength of the traveling wave along the circumferential direction.

[0022] The piezoelectric ceramic stacks 3 are excited by an AC power supply of the same amplitude and frequency. The excitation power supplies of two adjacent piezoelectric ceramic stacks 3 arranged on the same side of the cylinder bottom 24 are 180° out of phase with each other. The excitation power supplies of the piezoelectric ceramic stacks 3 on the upper side 241 and the piezoelectric ceramic stacks 3 on the lower side 242 are uniformly 90° out of phase with each other.

[0023] Furthermore, a friction layer 5 is installed on the side of the rotor 4 that contacts the stator 2, and a spring (not shown in the figure), a pressure cover (not shown in the figure) and a locking nut (not shown in the figure) are provided on the side of the rotor 4 away from the stator 2. The spring and the pressure cover are connected and pressed on the rotor 4 through the locking nut.

[0024] A plurality of tooth slots 231 are evenly arranged on the cylinder wall 23 along the circumferential direction. This structure can effectively amplify the deformation of the stator 2. At the same time, the tooth slots 231 can accommodate debris generated by friction, thereby improving the stability of the motor during operation.

[0025] It should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A traveling wave rotary ultrasonic motor with double-sided stator excitation, comprising a base, a stator, and a rotor, characterized in that: The stator has a cylindrical structure, and includes a cylindrical wall and a cylindrical bottom connected as an integral part. The stator has an upper end and a lower end, and the cylindrical bottom has an upper side and a lower side. The stator is arranged above the base, and the upper end is connected to the rotor. The upper side and the lower side of the cylindrical bottom are both provided with a plurality of positioning grooves, and a piezoelectric ceramic stack is installed in each of the positioning grooves. Each piezoelectric ceramic stack is excited by a power supply of different phases to form an excitation unit. The polarization direction of the piezoelectric ceramic stack of each excitation unit is parallel to the circumferential direction of the stator. The base extends upward along the direction of the stator with a positioning step, and the lower end is provided with a groove matching the positioning step at a position corresponding to the positioning step, and the positioning step is adapted to the groove.

2. The stator double-sided excitation traveling wave type rotary ultrasonic motor according to claim 1, characterized in that: Voltage excitation is applied to the piezoelectric ceramic stack of each of the excitation units to excite a symmetric vibration mode and an antisymmetric vibration mode of the excitation unit, and each of the excitation units is deformed and displaced along the circumferential direction of the stator.

3. The stator double-sided excitation traveling wave type rotary ultrasonic motor according to claim 1, characterized in that: The number of the positioning grooves on the upper side and the number of the positioning grooves on the lower side are both 2n, where n is a natural number greater than or equal to 1.

4. The stator double-sided excitation traveling wave type rotary ultrasonic motor according to claim 3, characterized in that: The two adjacent piezoelectric ceramic stacks on the upper side and the two adjacent piezoelectric ceramic stacks on the lower side are each a group, and the corresponding upper side and lower side are evenly divided into n areas along the circumferential direction, and the length of each area along the circumferential direction is one traveling wave wavelength.

5. The stator double-sided excitation traveling wave type rotary ultrasonic motor according to claim 4, characterized in that: The n groups of piezoelectric ceramic stacks uniformly arranged on the lower side are spatially spaced apart from the n groups of piezoelectric ceramic stacks uniformly arranged on the upper side by a distance of 1 / 4 of the wavelength of the traveling wave along the circumferential direction.

6. The stator double-sided excitation traveling wave type rotary ultrasonic motor according to claim 4, characterized in that: The piezoelectric ceramic stacks are excited by an AC power supply of the same amplitude and frequency. The phases of the excitation power supplies of two adjacent piezoelectric ceramic stacks arranged on the same side of the bottom of the cylinder are 180° apart, and the phases of the excitation power supplies of the piezoelectric ceramic stacks on the upper side and the piezoelectric ceramic stacks on the lower side are uniformly 90° apart.

7. The stator double-sided excitation traveling wave type rotary ultrasonic motor according to claim 4, characterized in that: A friction layer is installed on the side of the rotor that contacts the stator, and a spring, a pressure cover and a locking nut are provided on the side of the rotor away from the stator. The spring and the pressure cover are connected and pressed onto the rotor through the locking nut.

8. The stator double-sided excitation traveling wave type rotary ultrasonic motor according to claim 1, characterized in that: A plurality of tooth grooves are evenly arranged on the cylinder wall along the circumferential direction.

9. The stator double-sided excitation traveling wave type rotary ultrasonic motor according to claim 1, characterized in that: The base and the rotor are hollow and / or solid structures, and the stator is a hollow structure.

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