Segmented Piezo-Electrical Plate Ultrasonic Motor
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Solution Overview
Problem
Existing ultrasonic motors experience high mechanical losses due to the requirement of high electrical voltage for bending piezo-electrical plates, leading to reduced maximum speed and force, and decreased performance and efficiency.
Innovation Solution
An ultrasonic motor design featuring a rectangular piezo-electrical plate with divided generators for acoustic longitudinal and bending standing waves, where the piezo-electrical plate is divided into three parts along its length, with each part being electrically connected to an excitation device, and the generators are further divided into sub-generators for independent control, allowing for efficient excitation with two-phase or single-phase voltage, reducing mechanical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high electrical voltage is applied to bend the piezo-electrical plate over its height, then the acoustic bending standing wave is generated, but high mechanical losses arise and the maximum speed and force are reduced
Solution Approach 1:
The piezo-electrical plate is divided into three distinct parts along its longitudinal direction: a central part for generating acoustic longitudinal standing waves and two peripheral parts for generating acoustic bending standing waves. Each part has its own excitation electrodes and can be independently controlled, allowing separate optimization of wave generation mechanisms to reduce mechanical losses while maintaining force output.
Solution Approach 2:
The invention changes the excitation parameters by applying different voltages and phases to different parts of the piezo-electrical plate. The central part receives excitation for longitudinal waves while peripheral parts receive excitation for bending waves, with the ability to independently adjust voltage magnitude and phase to optimize the balance between force generation and mechanical loss reduction.
2Speed
If high electrical voltage is applied to bend the piezo-electrical plate, then the acoustic bending standing wave is generated, but the maximum speed of movement is reduced
Solution Approach 1:
By segmenting the piezo-electrical plate into central and peripheral parts with separate excitation systems, the invention enables independent optimization of wave generation. The central part generates longitudinal waves for efficient force transmission, while peripheral parts generate bending waves for motion actuation, reducing the total electrical energy required compared to using high voltage for bending the entire plate.
Solution Approach 2:
The invention merges two different wave generation mechanisms (longitudinal standing waves from the central part and bending standing waves from peripheral parts) into a single integrated actuator system. This combination allows the motor to achieve both force generation and motion actuation simultaneously with reduced electrical energy consumption compared to traditional single-mechanism designs.
3Productivity
If the piezo-electrical plate is bent over its height to generate acoustic bending standing wave, then the element to be driven is actuated, but the efficiency of the motor is reduced
Solution Approach 1:
The piezo-electrical plate is segmented into functionally distinct regions: a central part for longitudinal wave generation with high efficiency, and peripheral parts for bending wave generation. This segmentation allows each region to operate in its optimal mode, maximizing overall motor efficiency while minimizing mechanical losses that would occur if the entire plate were bent.
Solution Approach 2:
The invention optimizes motor efficiency by changing the excitation parameters applied to different parts of the actuator. By applying appropriate voltage magnitudes and phases to the central and peripheral parts independently, the system achieves optimal wave generation efficiency and minimizes mechanical losses, thereby improving overall productivity.
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 design achieves higher maximum speed and force with reduced mechanical losses, requiring less electrical energy and improving the overall performance and efficiency of the motor compared to prior art.
Implementation Method 1
the piezo-electrical plate is along its longitudinal direction, i.e. in the direction of the greatest extension of the piezo-electrical plate divided into three parts, where the central or middle part forms a generator for an acoustic longitudinal standing wave, and the peripheral parts bordering the central part form generators for an acoustic bending standing wave
Implementation Method 2
At least one friction element is arranged on at least one side surface of the ultrasonic actuator and is in operative or frictional contact with the element to be driven
Data Source
AI summary
An exemplary ultrasonic motor includes an ultrasonic actuator, functioning as a waveguide resonator, formed as a rectangular piezo-electrical plate having two main surfaces and side surfaces that join the main surfaces together, an element to be driven and an electrical excitation device. At least one friction element is arranged on at least one side surface of the ultrasonic actuator and is in frictional contact with the element to be driven. The piezo-electrical plate is divided into three parts. The central part forms a generator for an acoustic longitudinal standing wave, and the peripheral parts bordering the central part form generators for an acoustic bending standing wave. Each generator is electrically connected to the electrical excitation device-can be electrically controlled, and can be divided into two equally-sized and electrically individually controllable sub-generators. Each sub-generator has layers of excitation electrodes, layers of general electrodes, and layers of piezo-ceramics arranged therebetween.