Bimorphic Piezoelectric Actuator Using d14 Shear Ceramics
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Solution Overview
Problem
Current piezoelectric actuators face challenges in achieving larger deformation while maintaining a smaller size and higher output power, particularly with d15 ceramic members requiring increased height and voltage, which complicates electrical connections and miniaturization.
Innovation Solution
A piezoelectric actuator utilizing d14 ceramic members attached to a metal block to form a bimorph structure, enabling face shear or face resonance deformation, which generates an elliptical motion and increases output power without the need for elevated driving voltage, and includes a unique electrode configuration for efficient electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the height of d15 piezoelectric ceramic member is increased to increase shear deformation, then the shear deformation increases, but the distance between electrodes increases requiring elevated driving voltage
Solution Approach 1:
The patent changes the piezoelectric material parameter from d15 to d14 type ceramic, which fundamentally alters the deformation mechanism. The d14 ceramic undergoes face shear deformation where the deformation amount is proportional to the applied voltage and can be enhanced by increasing the ceramic height without requiring higher driving voltage, thus resolving the contradiction between increasing shear deformation and maintaining driving voltage levels
Solution Approach 2:
The patent employs a composite structure consisting of d14 piezoelectric ceramic members attached to a metal block (such as aluminum or copper). This composite configuration allows the piezoelectric ceramic to generate shear deformation while the metal block provides structural support and heat dissipation, enabling the system to achieve large deformation with moderate driving voltage
2Force
If the height of d15 piezoelectric ceramic member is increased to increase shear deformation, then the shear deformation increases, but the device size increases complicating miniaturization
Solution Approach 1:
By switching to d14 piezoelectric ceramic with face shear deformation characteristics, the patent achieves a more efficient deformation mechanism where the deformation amount is directly proportional to the ceramic height. This allows for optimized dimensional design that can achieve large deformation without excessive size increase, facilitating miniaturization
Solution Approach 2:
The patent utilizes the thickness dimension of the d14 piezoelectric ceramic member to generate shear deformation. By applying voltage across the thickness direction, the ceramic undergoes shear deformation in the plane parallel to the electrodes, effectively using the thickness dimension to produce lateral deformation without increasing the overall device footprint
3Force
If d15 piezoelectric ceramic member is used for shear deformation, then shear deformation is generated, but electrical connection to driving electrode becomes difficult
Solution Approach 1:
The patent inverts the electrode configuration approach by placing electrodes on the large-area side surfaces of the d14 piezoelectric ceramic member rather than on the small top and bottom surfaces. This inversion makes electrical connection straightforward as the electrodes can be easily accessed and connected to the side surfaces where the ceramic is mounted on the metal block
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 d14 ceramic actuator achieves enhanced displacement and speed, suitable for miniature piezoelectric motors with high output power, suitable for applications requiring small size, high precision, and low power consumption.
Implementation Method 1
a piezoelectric actuator which includes a pair of d14 piezoelectric ceramic members 10, a metal block 20 and an output head 30... a first pair of ceramic members, each comprising... wherein the first driving surface is coated with a first electrode and a second electrode arranged side-by-side with each other... the first pair of ceramic members are polarized along a polarization direction orthogonal to the thickness direction and attached at the second driving surfaces thereof to the two side surfaces of the metal block
Implementation Method 2
By applying a driving voltage, this pair of d14 ceramic members can be made to cooperatively undergo either a face shear deformation or a face resonance deformation, which in turn drives the metal block and the output head located thereon to generate an elliptical motion
Data Source
AI summary
The present invention relates to a shear deformation-type bimorphic piezoelectric actuator. The actuator includes at least a pair of shear deformation-type piezoelectric ceramic members which are polarized in the height direction thereof, coated with metal electrodes on both sides thereof and attached to opposite sides of a metal block to constitute a piezoelectric bimorph. The ceramic members are forced to undergo a face shear deformation or a resonance deformation upon receiving a driving voltage, whereby the metal block and the output head mounted thereon are driven to generate an elliptical motion, which in turn drives a rotor or a carriage to move. Taking advantage of the small dimension of the ceramic members and the enhanced displacement attributed to the piezoelectric bimorph structure, the piezoelectric actuator disclosed herein is suitable for manufacturing a miniature piezoelectric motor with high power output.