Parallelogram Ultrasonic Actuator for Low-Power Torque Generation

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Solution Overview

Problem

Existing ultrasonic actuators for ultrasonic motors face challenges in achieving a simple construction, low energy consumption, and reliable operation while being suitable for mass production and miniaturization, with previous designs either being complex and expensive or requiring high electrical power.

Innovation Solution

An ultrasonic actuator with a non-right-angled parallelogram inscribed in its base area, featuring an octagonal base and top surface with isosceles trapezoidal sides, allowing for efficient deformation excitation and reduced material usage, combined with a holding device for stable rotor contact, enabling low energy consumption and scalable manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a rectangular piezoelectric plate is used as the resonator, then the design is simple and manufacturing is easy, but relatively high electrical power is required resulting in increased energy consumption

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidelectrical power consumption
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent applies asymmetry by using a parallelogram-shaped resonator instead of a conventional rectangular plate. This asymmetric geometry modifies the vibration modes and mechanical coupling, enabling more efficient energy transfer to the rotor while maintaining simple manufacturing processes. The parallelogram shape creates favorable stress distributions that reduce the electrical power required for actuation.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If complex composite vibrators with piezoelectric excitation plates are used, then operational stability is improved, but the design becomes complicated and manufacturing cost increases

Engineering Contradiction:
Improveoperational stabilityVSAvoiddesign complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the resonator body and the piezoelectric excitation structure into a single integrated parallelogram-shaped component. This eliminates the need for separate piezoelectric plates glued to a resonating body, simplifying both design and manufacturing while maintaining operational stability. The integrated design reduces assembly steps and potential failure points from material bonding.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If the inscribed parallelogram has right angles, then the structure is simpler, but no torque can be generated to rotate the ultrasonic actuator

Engineering Contradiction:
Improvegeometric simplicityVSAvoidtorque generation capability
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The patent deliberately introduces geometric asymmetry by using a parallelogram with non-right angles. This asymmetry is essential for generating torque because it creates unequal force distributions during ultrasonic vibration, producing a rotational moment. The specific angular deviation from 90 degrees enables the conversion of linear vibration into rotational motion while maintaining manufacturing simplicity.

Inventive Principle:
Principle #4Asymmetry

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 solution provides a simple, energy-efficient ultrasonic actuator that supports reliable motor operation with high positioning accuracy and robustness against external influences, suitable for miniaturized devices with low energy consumption.

Implementation Method 1

the plate comprises an electromechanical material and electrodes for exciting periodic deformations of the plate are arranged on its base and on its top surface opposite the base

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3994737B1An ultrasonic actuator and a motor having such an ultrasonic actuator
Publication Date: 2024.05.15 PHYSIK INSTRUMENTE (PI) GMBH & CO KG
  • EP3994737B1 patent drawingFigure 1~2B
  • EP3994737B1 patent drawingFigure 3
  • EP3994737B1 patent drawingFigure 4

AI summary

The invention relates to an ultrasonic actuator (1) in the form of a plate (2) having a base (3), a cover surface (4) which is geometrically similar to the base, and a lateral surface (5) which interconnects the base and the cover surface, wherein the plate comprises an electromagnetic material and electrodes (6, 6', 7, 7') for inciting periodic deformations of the plate are arranged on the base of the plate and on the cover surface of the plate opposite the base, and the base (3) comprises at least two faces (8, 8') which are arranged in parallel with one another and form contact portions (50, 50') of the lateral surface (5), and the two faces of the base arranged in parallel with one another, together with connecting lines (9, 9') which interconnect the respective end points of the faces (8, 8') arranged in parallel, form a parallelogram (10) inscribed in the base, in which parallelogram an angle different from 90° is enclosed between adjacent faces. The invention also relates to a motor having such an ultrasonic actuator.