Multilayer Coil Asymmetric Positioning for Crack Prevention
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Solution Overview
Problem
Multilayer coil components face issues with crack occurrence and characteristic deterioration due to excessive firing during the sintering process, leading to disconnection of the coil and decreased inductance when subjected to external forces, especially when the coil axis is orthogonal to the principal surfaces.
Innovation Solution
The multilayer coil component is designed with a coil axis along a direction orthogonal to the principal surfaces, creating a larger gap between the coil and the first principal surface, which reduces the likelihood of external force acting on the excessively fired region, and through-hole conductors that do not overlap terminal electrodes, minimizing stray capacitance and maintaining the coil's inner diameter, thereby preventing crack formation and maintaining inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coil is positioned close to the first principal surface to reduce the gap, then the inner diameter of the coil increases and characteristics improve, but the excessively fired region becomes susceptible to external forces causing cracks and coil disconnection
Solution Approach 1:
The patent positions the coil such that its axis extends in the first direction (perpendicular to principal surfaces) rather than parallel to them. This spatial reconfiguration places the excessively fired region away from the first principal surface where external forces are applied, while maintaining an acceptable gap distance. The coil is disposed at a position where the gap to the first principal surface is larger than the gap to the second principal surface, effectively using the third dimension (depth into the element body) to resolve the conflict between mechanical reliability and electrical characteristics.
2Volume of moving object
If the coil axis is oriented orthogonal to the principal surfaces to maintain compact structure, then the device footprint is reduced, but the gap between the coil and first principal surface decreases causing characteristic deterioration
Solution Approach 1:
The patent employs asymmetric positioning of the coil within the element body. The gap between the coil and the first principal surface is intentionally made larger than the gap between the coil and the second principal surface. This asymmetric configuration allows the coil axis to be orthogonal to the principal surfaces (maintaining compact structure) while creating sufficient distance from the stress-prone first principal surface region, thereby preserving coil characteristics and preventing deterioration.
3Strength
If the metal component functions as an accelerator during sintering to enhance sinterability near the coil, then the bonding strength improves, but the region becomes excessively fired leading to crack formation under external force
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of fired regions within the element body. The metal component serves as an accelerator during sintering, but the coil is positioned such that the excessively fired region is located away from the first principal surface. This localized approach ensures strong bonding where needed while preventing excessive firing in regions susceptible to external forces, thereby maintaining structural stability.
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
This configuration effectively controls crack occurrence and maintains the coil's characteristics by ensuring the coil is away from the primary stress point, reducing direct current resistance and preserving the self-resonant frequency, thus enhancing the overall performance of the multilayer coil component.
Implementation Method 1
In a multilayer coil component manufacturing process (firing process), a metal component for forming the coil conductor may function as an accelerator at a time when the element body is sintered
Data Source
AI summary
A coil is disposed in an element body such that a gap between the coil and a first principal surface is larger than a gap between the coil and a second principal surface, and has a coil axis along a direction intersecting with a direction in which the first principal surface and the second principal surface oppose each other. A terminal electrode is disposed on the element body such that at least a part of the first principal surface and a part of the second principal surface are exposed. The coil includes a plurality of coil conductors separated from each other in a direction along the coil axis and a through-hole conductor connecting the coil conductors adjacent to each other in the direction along the coil axis. The through-hole conductor does not overlap the plurality of terminal electrodes when viewed from the direction along the coil axis.