Laminated Piezoelectric Element Stress Dispersion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional laminated piezoelectric elements face challenges in maintaining displacement quantity under high pressure and continuous operation due to stress on external electrodes, leading to potential cracks and reduced reliability.
Innovation Solution
Incorporating a low rigidity layer with metal or ceramic portions separated by voids, which are integrated with piezoelectric and internal electrodes, to absorb stress and concentrate cracks, thereby reducing the likelihood of electrical shorts and maintaining displacement quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a higher electric field is applied to ensure large displacement quantity, then the displacement quantity is improved, but the stress on external electrodes increases leading to cracks and reduced reliability
Solution Approach 1:
The external electrode is divided into multiple separate conductors that are connected to different portions of the electrode. This segmentation allows the electrode structure to accommodate stress and cracks in individual regions without compromising the entire electrode, thereby maintaining reliability while enabling higher electric fields for larger displacement quantities.
Solution Approach 2:
Multiple conductors are预先 distributed across the external electrode surface to provide redundant electrical pathways. When cracks occur under high stress conditions, these pre-positioned conductors ensure continuous electrical connection, cushioning against the harmful effects of electrode degradation and maintaining system reliability.
2Reliability
If multiple conductors are connected to the external electrode to suppress displacement reduction, then reliability is improved, but the device complexity increases
Solution Approach 1:
Multiple conductors are merged into a single integrated external electrode structure that functions as a unified component. This combining approach maintains the reliability benefits of multiple conductors while simplifying the overall device structure by eliminating the need for separate complex multi-conductor assemblies.
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 low rigidity layer effectively disperses stress, reduces crack occurrence in critical areas, and ensures stable voltage application to internal electrodes, enhancing the reliability and durability of laminated piezoelectric elements.
Implementation Method 1
a low rigidity layer that is low in rigidity in comparison with the piezoelectric layers and the internal electrodes... effectively disperses stress
Implementation Method 2
a plurality of piezoelectric layers and a plurality of internal electrodes laminated alternately... ensure stable voltage application to internal electrodes
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
There are some cases where cracks occur at a plurality of areas on an external electrode when a displacement quantity of a laminated piezoelectric element is large. In such cases, there is a possibility of a voltage not being applied to a portion of the laminated structure due to the cracks caused by a long time drive to cause a reduction in the displacement quantity. A low rigidity layer is arranged on the laminated structure to form a plurality of portions divided by the low rigidity layer in a laminating direction. Each portion is provided with power feeding members on the anode side and the cathode side. Thus, a voltage can be stably supplied to each internal electrode.