Piezoelectric Actuator With Offset Electrodes for Two-Axis Linear and Rotary Motion
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Solution Overview
Problem
Existing piezoelectric actuators are limited in their ability to achieve movements in two axial directions and rotary drive movements, requiring a more complex structure and larger size, which is not suitable for miniaturization in devices like smartphones.
Innovation Solution
A piezoelectric actuator with a single-layer or multi-layer flat plate design featuring electrodes on both sides, offset from each other, allowing for independent oscillating deformations in two axial directions and synchronized electrical activation to generate rotary movements through a stick-slip drive mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a piezoelectric actuator is designed to enable movements in two axial directions and rotary drive movements, then the functionality and versatility are improved, but the structure becomes more complex and the size increases
Solution Approach 1:
The patent merges multiple movement capabilities (two-axis linear movement and rotary movement) into a single piezoelectric actuator structure. The actuator integrates first and second piezoelectric element layers with different electrode arrangements, allowing it to perform both linear movements along x and y axes as well as rotary movements around a z axis, eliminating the need for separate actuators for each function
Solution Approach 2:
The piezoelectric actuator is designed as a universal drive mechanism that can perform multiple functions: linear movement along the x axis through the first piezoelectric element layer, linear movement along the y axis through the second piezoelectric element layer, and rotary movement around the z axis through coordinated activation of both layers. This multi-functional design replaces what would traditionally require multiple separate actuators
2Adaptability or versatility
If a piezoelectric actuator is designed to enable movements in two axial directions and rotary drive movements, then the functionality and versatility are improved, but the size increases
Solution Approach 1:
The actuator employs a nested layer structure where the first and second piezoelectric element layers are stacked one on top of the other. The lower electrodes of the first layer are positioned between the upper electrodes of the first layer and the lower electrodes of the second layer, creating a compact nested arrangement that maximizes functionality within minimal space
Solution Approach 2:
The patent utilizes the vertical dimension by stacking piezoelectric element layers in the thickness direction of the actuator. This vertical stacking allows multiple movement functions to be achieved within a compact footprint, as the different piezoelectric layers operate independently in the vertical dimension while producing horizontal movements and rotation
3Adaptability or versatility
If electrodes are arranged offset on top and bottom surfaces of piezoelectric layers, then two-axis linear movement and rotary movement are enabled, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs asymmetric electrode arrangements where the electrodes on the top surface are offset relative to the electrodes on the bottom surface of each piezoelectric layer. This asymmetric configuration is deliberately designed to generate the desired movement patterns (linear and rotary) when voltage is applied, transforming the manufacturing challenge into a functional feature
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
Enables compact, simple, and efficient two-axis linear and rotary movements with reduced wear and stable performance, suitable for miniaturized devices by utilizing piezoceramic materials and optimized electrode configurations.
Implementation Method 1
an actuator (1) having a piezoelectric material and having the shape of a single-layer or multi-layer flat plate
Implementation Method 2
the actuator is excited to oscillate—in particular in the ultrasonic range—at a mechanical resonance frequency
Implementation Method 3
there is no relative sliding between the actuator and the element to be driven, i.e. there should be static friction conditions between the actuator and the element to be driven
Data Source
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AI summary
The invention relates to an actuator, preferably having piezoelectric material, in the form of a single-layer or multi-layer flat plate, wherein at least one layer has two electrodes spaced from each other by means of a separating area and arranged opposite each other both on the upper face of the at least one layer and on the lower face of the at least one layer, and the electrodes of the upper face are arranged at an offset from the electrodes of the lower face. The invention further relates to a motor, comprising the actuator according to the invention and a movable element to be driven by means of the actuator.