Multi-flap Ultrasonic Motor Outer Rotor Design
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Solution Overview
Problem
Current standing wave ultrasonic motors with inner-rotor flap structures face challenges in batch production precision, power generation, and complexity, making them unsuitable for practical applications.
Innovation Solution
A multi-flap standing wave ultrasonic motor with a circular-distributed flap structure and outer rotor design, incorporating a control circuit board and sensor, uses piezoelectric ceramics and elastomer flaps to simplify the system and enhance torque generation, featuring a compact and flat design that allows for easy assembly and integration with other loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an inner-rotor flap structure is used, then the motor can generate torque, but the structure becomes complex and processing precision cannot be ensured in batch production
Solution Approach 1:
The patent inverts the traditional inner-rotor structure to an outer-rotor structure. The flaps are positioned on the outer circumference of the rotor rather than the inner circumference, which simplifies the overall structure and makes batch production more feasible while still generating torque through the interaction between flaps and rotor teeth
Solution Approach 2:
The rotor is divided into discrete components: a rotor ring with teeth, a flange, and a shaft, connected through standardized fastening structures. This segmentation allows for modular manufacturing and assembly, reducing structural complexity while maintaining torque generation capability
2Ease of operation
If an integrated multi-flap structure is used, then the motor can operate, but the structure is complex and difficult to process
Solution Approach 1:
The flaps are designed as separate, identical components that can be individually manufactured and then assembled onto the rotor ring. This segmentation allows each flap to be processed independently using simple techniques, avoiding the need for complex integrated structure processing while maintaining operational functionality
Solution Approach 2:
The flaps are made from elastic sheet material with specific dimensional parameters (width, thickness, length) that can be precisely controlled during manufacturing. By optimizing these parameters, the flaps achieve the necessary flexibility and strength for operation while being easy to process in batch production
3Force
If the flap outer diameter is greater than the rotor inner diameter, then preload can be generated, but friction loss and noise may increase
Solution Approach 1:
The flap contact area with the rotor is designed to be localized to specific regions rather than spanning the entire circumference. The flaps contact only the necessary portion of the rotor teeth, generating sufficient preload while minimizing the total contact area and thus reducing friction losses and noise
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The motor achieves high torque at low speeds with reduced processing complexity and noise, enabling efficient energy transfer and precise operation, while maintaining compactness and ease of integration with circuit boards.
Implementation Method 1
employ the inverse piezoelectric effect of piezoelectric ceramic and friction coupling between a stator and a rotor to achieve energy conversion from electrical energy to torque output of the motor
Implementation Method 2
The flaps are made of an elastic sheet material, and are in linear contact with the inner surface of the rotor, so that the flaps are bent to form the preload
Implementation Method 3
employ the inverse piezoelectric effect of piezoelectric ceramic and friction coupling between a stator and a rotor to achieve energy conversion from electrical energy to torque output of the motor
Data Source
AI summary
Provided is a multi-flap standing wave type ultrasonic motor, including a rotor part, a stator part, a control circuit board, and a fixing attachment. The rotor part includes a flange, a rotor ring, and a shaft. The shaft and the flange are joined together by using a first screw and the flange and the rotor ring are joined together by using a second screw. The stator part includes a piezoelectric ceramics, an excitation ring, and flaps. The piezoelectric ceramics and the excitation ring are fixed with glue, the flaps and the excitation ring are connected through welding, and form an angle with the radial direction of the excitation ring. The stator part is sleeved on a support, is attached to a pressure plate and is connected, through an upright, to a locking plate, and to a substrate of the control circuit board to form a fixing attachment. The flaps are an elastomer and a preload provider. The inner diameter of the rotor ring is less than the outer diameter of the flaps. Adopted is a circular-distributed flap structure, an outer rotor design, an integrated design of motor and control, and a sensor, thereby simplifying the system structure. By adopting circular-distributed assembled flaps, the processing difficulty of the flaps is reduced.