Rotary travelling wave ultrasonic motor adopting brand new pre-pressure applying mode

Abstract

The invention relates to a rotary travelling wave ultrasonic motor adopting a brand new pre-pressure applying mode, which comprises a rigid rotor assembly. One side of the rigid rotor assembly is installed on a motor base through a bearing, and the other side of the rigid rotor assembly is sequentially provided with a stator assembly, a stator supporting frame and a pre-pressure shell; the rigid rotor assembly comprises a rigid rotor and a friction plate which are sequentially connected; the stator assembly comprises a stator, a piezoceramic plate and a flexible printed board which are sequentially connected; a waveform spring is further installed between the pre-pressure shell and the stator supporting frame; the rotary travelling wave ultrasonic motor adopting brand new pre-pressure applying mode has the advantages of a large hollow ratio, a high overload resistance, a good low-speed stability, a good low-temperature startability, etc., and the output performance consistency of the motor during the whole life is good; the application of the hollow ultrasonic motor in the large hollow ratio is expanded, such as used for a large hollow ratio optical lens to drive a lens and a waveplate.

Description

technical field [0001] The invention relates to a rotating traveling wave ultrasonic motor adopting a new pre-pressure application method, which belongs to the technical field of ultrasonic motors. Background technique [0002] Various hollow rotating traveling wave ultrasonic motors in the prior art lack a hollow rotating traveling wave ultrasonic motor with a large hollow ratio and a large torque ratio. [0003] In the prior art, a rotating traveling wave ultrasonic motor with an annular stator without a web structure and a super large hollow ratio, its stator assembly and structure are as follows figure 1 shown. During the installation and use of this hollow ultrasonic motor with ring-shaped stator webless structure, it at least includes a metal or plastic casing that limits the circumferential rotation of the stator, a wave spring or disc spring that applies preload, a rotor, and a roller for the rotor. Balls, etc., the stator of this hollow ultrasonic motor is usually...

AI Technical Summary

Problems solved by technology

Its disadvantages: the stator positioning mechanism is complex; the production and installation of rollers or balls require high technical requirements; the motor cannot provide large torque, and the torque is relatively low

The existing hollow rotary ultrasonic motor with a stator web structure has a larger output torque than the ultra-large hollow ratio rotary traveling wave ultrasonic motor with a ring-shaped stator without a web structure, but it also has many shortcomings. Disadvantages: First, because the stator is fixed by screws or threads, the diameter of the through hole in the motor cannot be designed to be very large, resulting in the overall hollow ratio of the motor is still relatively small, which cannot be used for some applications that require larger through holes. application occasions; secondly, since the preload is mainly provided by the deformation of the flexible rotor or stator web, the structural design and rigidity design of the flexible rotor or stator web have higher requirements, and the design is more difficult; thirdly, because the stator and rotor provide The deformation of the motor is usually small, and the wear of the friction material is extremely sensitive to the influence of the pre-pressure. After the friction material is worn, the pre-pressure of the motor changes significantly, so the output performance of the motor at the end of its life is extremely reduced due to the wear of the friction material.

The existing solid-shaft rotary traveling wave ultrasonic motor with stator and web structure is very common, and has been successfully applied in automobiles (steering wheel power system), medical injection (nuclear magnetic resonance instrument), aerospace (my country's Chang'e three No.), etc., but there are also shortcomings: First, because the rotor usually needs to be designed as a flexible web structure, it is easy to fatigue and crack under the influence of high-frequency vibration of the stator, so it is usually necessary to set vibration-damping rubber on the rotor web Reduce the vibration of the rotor web; second, the pre-pressure is mainly provided by the deformation of the flexible rotor or stator web, so the structural design and stiffness design of the flexible rotor or stator web have high requirements, and the design is more difficult; the third is Since the deformation provided by the stator and rotor is usually small, the wear of the friction material is extremely sensitive to the effect of the preload. After the friction material wears, the preload of the motor changes significantly. Therefore, the output performance of the motor at the end of its life is extremely reduced due to the wear of the friction material.

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