Partial DLC Coating on Piston Pin Angular Sector
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Solution Overview
Problem
Tightly-assembled piston pins in engines experience uneven wear and high friction, leading to seizing issues and increased costs due to the need for uniform DLC coatings that wear down quickly, especially in high-load applications.
Innovation Solution
Applying a DLC anti-seize coating only on specific angular sectors of the piston pin corresponding to high-stress areas, optimizing coating thickness and distribution to reduce friction and extend pin lifetime, while simplifying the coating process and reducing implementation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform DLC coating is applied on the entire pin surface, then friction is reduced and seizing resistance is improved, but coating thickness and hardness are compromised due to excessive wear in non-contact areas
Solution Approach 1:
The patent applies DLC coating only to the angular sector of the pin that is subject to contact stress (typically the upper half or specific wedge area), while leaving other areas uncoated or with different coating characteristics. This localized coating approach ensures that the coating thickness is preserved in areas where it is actually needed for seizing resistance, while avoiding unnecessary coating material in non-contact areas where it would be wasted and subject to meaningless wear.
2Reliability
If a DLC coating is applied on the entire pin, then friction is decreased, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent segments the pin surface into different functional zones: a coated angular sector subject to contact stress and uncoated or differently coated areas. This segmentation is achieved through masking techniques during the DLC deposition process, where specific angular sectors are protected from coating while others receive the coating. This reduces overall coating material usage and simplifies the manufacturing process by focusing treatment only on necessary areas.
3Duration of action of stationary object
If a thick DLC coating is applied to increase seizing resistance, then pin lifetime is extended, but coating deposition time and cost increase
Solution Approach 1:
The patent applies DLC coating partially rather than uniformly across the entire pin surface. By limiting the coating to the angular sector subject to contact stress (typically 180 degrees or less), the deposition time is significantly reduced compared to coating the entire 360-degree surface, while still achieving sufficient seizing resistance in the critical areas. This partial action approach extends pin lifetime where needed without the excessive time cost of full-surface coating.
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 partial DLC coating significantly decreases friction, increases pin resistance, and extends the coating's lifespan, allowing for higher load capacity and reduced assembly complexity, while also optimizing engine performance and reducing mass.
Implementation Method 1
The invention relates to a piston pin (1) provided with a DLC-type anti-seize coating (4) over a limited angular sector (S)
Data Source
AI summary
The piston pin has an anti-seize coating limited to an angular sector corresponding at least to a friction area submitted to a contact pressure along a preferential direction.