Spark Plug Metal Terminal Projection for Mark Protection
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Solution Overview
Problem
Existing spark plugs with identifiers on metal terminals face issues with peeling or damage of the mark, leading to reading errors due to external forces, which existing technologies have not adequately addressed.
Innovation Solution
A spark plug design featuring a metal terminal with a projection from the outer edge of the bottom surface, where the Vickers hardness of the projection is 100 HV or higher and the rear end surface area is 3 mm² or greater, positioned on the rear side of the mark, and optionally projecting rearward from the entire circumference, with a gap between the mark and the outer edge to enhance durability and readability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a mark is provided to the bottom surface of the metal terminal, then identification and tracking information can be recorded, but the mark is susceptible to peeling or damage from external forces
Solution Approach 1:
A projection is introduced as an intermediary element between the external environment and the mark on the bottom surface. This projection absorbs external forces (such as impact or insertion forces) before they can reach the mark, thereby protecting the mark from peeling or damage while maintaining its readability function
Solution Approach 2:
The projection is designed to provide beforehand cushioning by positioning itself between potential external force sources and the mark. The projection's structure (with specified hardness ≥100 HV and rear end surface area ≥3 mm²) allows it to absorb and distribute external forces before they can affect the mark, preventing damage in advance
2Strength
If the projection is made with high hardness (≥100 HV) and sufficient rear end surface area (≥3 mm²), then the projection can effectively resist external forces, but the manufacturing complexity increases
Solution Approach 1:
The invention specifies critical parameters for the projection (Vickers hardness ≥100 HV, rear end surface area ≥3 mm²) that balance protective function with manufacturability. These parameter ranges are optimized to provide sufficient strength for protection while remaining achievable through conventional metal forming and heat treatment processes
Solution Approach 2:
The projection is designed with localized quality features: the rear end surface is specifically engineered to have sufficient area (≥3 mm²) and hardness (≥100 HV) to absorb external forces, while other portions of the metal terminal can have different properties optimized for their specific functions. This localized approach allows targeted strengthening without requiring the entire component to be manufactured to the same high specifications
Data Source
AI summary
The spark plug includes: an insulator having an axial hole formed along an axial line; and a metal terminal provided on a rear side of the axial hole of the insulator. The metal terminal has, at a rear end portion thereof, a bottom surface facing rearward and a projection projecting rearward from an outer edge of the bottom surface, and a mark is provided to at least a part of the bottom surface. The Vickers hardness of the projection is 100 HV or higher. A rear end surface of the projection is positioned on a rear side with respect to a rear end of the mark. An area of the rear end surface is 3 mm2 or greater.