Piezoceramic Surface Actuator with High Width-to-Thickness Ratio
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Solution Overview
Problem
Existing piezoceramic surface actuators face challenges in achieving high strains at low operating voltages, particularly due to inhomogeneous electric field distribution, high electromechanical loading, and the limitations of thickness affecting operating voltage, which reduces their work capacity and service life.
Innovation Solution
A plate-shaped piezoceramic surface actuator with a greater width of piezoceramic plates than its thickness, embedded in a plastic, featuring thin electrodes sintered into the ceramic body for a monolithic structure and electrically conducting elastic contact areas to ensure reliable contacting and mechanical stabilization, allowing for reduced operating voltages and increased strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the thickness of piezoceramic plates is increased to reduce operating voltage, then the operating voltage decreases, but the strain capability and work capacity are reduced
Solution Approach 1:
The patent transitions from traditional thick stack actuators to thin plate-shaped actuators with a much greater width-to-thickness ratio. By changing the geometric dimensions and operating in a different dimensional regime (thin plates rather than thick stacks), the actuator achieves low operating voltage while maintaining high strain capability and work capacity through the plate's lateral dimensions rather than thickness.
Solution Approach 2:
The patent changes the geometric parameters of the piezoceramic structure, specifically using a width-to-thickness ratio greater than 10:1. This parameter change allows the actuator to operate at low voltages while maintaining high strain capability, as the electric field distribution and mechanical leverage are optimized for thin plate geometry rather than thick stack geometry.
2Stability of the object's composition
If conventional thick stack actuators are used, then structural stability is achieved, but inhomogeneous electric field distribution and high electromechanical loading occur
Solution Approach 1:
By transitioning from thick stack geometry to thin plate geometry with width-to-thickness ratio > 10:1, the patent achieves more homogeneous electric field distribution across the piezoceramic material. This dimensional change reduces field concentration effects and electromechanical loading peaks that occur in thick stacks, thereby improving reliability and service life while maintaining structural stability through the plate's geometry.
3Speed
If piezoceramic materials are used for high stiffness and frequency response, then performance is improved, but brittleness and susceptibility to breakage increase
Solution Approach 1:
The patent embeds the thin piezoceramic plates in a plastic matrix, creating a composite structure. This composite approach maintains the high stiffness and frequency response characteristics of the piezoceramic while the surrounding plastic provides mechanical protection, stress distribution, and resistance to breakage, effectively combining the advantages of both materials.
Solution Approach 2:
By using thin plate-shaped piezoceramic elements rather than thick blocks, the patent creates a more flexible and less brittle structure. The thin geometry reduces stress concentrations and the likelihood of catastrophic failure while maintaining the high frequency response capability. The plates can better accommodate mechanical stresses without fracturing.
4Ease of manufacture
If discrete actuators are used, then ease of manufacture is achieved, but efficiency decreases with increasing length
Solution Approach 1:
The patent segments the piezoceramic structure into multiple thin plates separated by electrodes, creating a plate-shaped actuator with width-to-thickness ratio > 10:1. This segmentation allows the actuator to maintain high efficiency over larger lateral dimensions while remaining manufacturable through conventional ceramic processing techniques. The segmented plate structure optimizes the balance between manufacturing ease and operational efficiency.
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 enables high strains at lower operating voltages with improved mechanical stability and extended service life by maintaining homogeneous electric fields and reducing the influence of thickness on voltage requirements, while also allowing for tensile and compressive loading.
Implementation Method 1
The function of piezoceramics is based on the piezoelectric effect, which describes the interaction between the mechanical state and the electrical state of a special class of crystals. The opposite of this effect is known as the inverse piezoelectric effect, in which the crystal changes its shape under the influence of an electric field.
Implementation Method 2
producing a monolithic cuboidal ceramic block comprising a plurality of piezoceramic plates respectively separated from one another by a positive or negative electrode, wherein the positive and negative electrodes alternate and are constructed integrally with the piezoceramic plates
Data Source
AI summary
A piezoceramic surface actuator comprising multilayer plates each having a plurality of piezoceramic plates separated from one another by in each case a positive or negative electrode. The positive and negative electrodes alternate and are constructed integrally with the piezoceramic plates, and have collector electrode surfaces for the positive and negative electrodes, which are connected to the associated positive or negative electrodes in a conducting manner and are arranged on two exterior sides of the surface actuator that are opposite from one another. The multilayer plates are plate-shaped and have a much greater width of the piezoceramic plates, defined by the distance between the opposite collector electrode surfaces, than the thickness of the multilayer plates. The collector electrode surface in each case contacts the positive or negative electrodes of the neighboring multilayer plates.