Piezo Stack Contacting Component with Force Decoupling
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Solution Overview
Problem
Piezo stacks in fuel injectors experience expansion cracks due to cyclic loading, leading to disruptions in electrical contacting and reduced service life, as existing contacting methods are sensitive to mechanical loads and require precise positioning to maintain insulation and contact reliability.
Innovation Solution
A contacting component with an electrically conductive meandering structure and a force-decoupling connecting element, where the meandering structure is directly attached to the piezo stack and the connecting element is spaced apart, allowing for reliable long-term contact without transmitting external forces to the meandering structure, ensuring stable electrical connection and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contacting element is directly connected to the piezo stack, then electrical contact is established, but the contacting becomes sensitive to external forces such as axial forces, radial forces, lateral forces and torsional forces
Solution Approach 1:
The contacting element is divided into two functionally independent parts: a first contacting element that makes electrical contact with the piezo stack, and a second contacting element that extends beyond the piezo stack for external connection. This segmentation allows the first element to remain isolated from external forces while the second element handles external connections, resolving the contradiction between establishing electrical contact and avoiding force sensitivity.
Solution Approach 2:
The patent introduces an insulating structure as an intermediary between the first contacting element and the external environment. This insulating structure protects the first contacting element from external forces and mechanical loads while allowing it to maintain reliable electrical contact with the piezo stack, effectively mediating between the electrical contact function and the force isolation requirement.
2Device complexity
If the contacting element is positioned close to the piezo stack end faces, then insulation spacing is reduced, but precise positioning is required to ensure reliable insulation
Solution Approach 1:
The insulating structure is designed to automatically provide the necessary insulation spacing between the contacting element and the piezo stack end faces. By integrating the insulating function into the contacting element's structure itself, the system eliminates the need for separate positioning adjustments or additional insulation components, achieving reliable insulation without demanding high positioning precision.
3Strength
If the contacting element is made robust to withstand external forces, then mechanical strength is improved, but the contacting becomes more sensitive to mechanical loads on the contact points
Solution Approach 1:
The contacting element is segmented into a first contacting element for electrical contact and a second contacting element for external connection. This allows the second element to be made robust for withstanding external forces, while the first element remains isolated from these forces, preventing mechanical loads from being transmitted to the contact points on the piezo stack.
Solution Approach 2:
The insulating structure acts as a mediator that physically isolates the first contacting element from external forces. This allows the overall contacting assembly to be mechanically robust while protecting the critical contact points from mechanical loads, resolving the contradiction between strength and force sensitivity.
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 robust and reliable electrical contacting system for piezo stacks, preventing detachment under external forces and maintaining contact integrity over a large number of cycles, thereby enhancing the service life and operational stability of piezo components.
Implementation Method 1
The piezoelectric effect has the effect here that the piezoceramic expands. The sum of the expansions of the individual piezo stack layers yields the stroke of the piezo stack as a whole.
Data Source
AI summary
A piezo component with a contacting component for electrically contacting a piezo stack. The contacting component has an electrically conductive meandering structure for bringing the contacting component into electric contact with inner electrodes of the piezo stack and an electrically conductive contacting device for electrically contacting the contacting component from outside the piezo stack. The meandering structure and the contacting device are arranged at a distance from each other, and a connection element is provided in order to connect the contacting device and the meandering structure in an electrically conductive manner and simultaneously decouple forces between the contacting device and the meandering structure.