Rocker Arm Anti-Inversion Support Pin Design
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Solution Overview
Problem
Conventional rocker arm assemblies face challenges in preventing the support pin from inverting during assembly, which is costly and complex to manufacture, especially with features like captured fasteners and D-shaped geometries.
Innovation Solution
Incorporating an anti-inversion feature such as a washer, plate, plug, or sleeve that engages with the support pin to maintain its upright position, using designs like a washer with a curved surface, a plate with beveled holes, or a removable plug to prevent inversion without adding significant cost or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a captured fastener and fastening bolt are used to prevent support pin inversion, then the support pin orientation is ensured, but the cost and packaging envelope of the rocker arm assembly increase
Solution Approach 1:
The patent extracts the anti-inversion function from the complex captured fastener and bolt assembly, implementing it through a simple geometric feature (D-shaped cross-section) of the support pin itself. This eliminates the need for separate fastening components while maintaining the orientation prevention function.
Solution Approach 2:
The support pin is given a D-shaped cross-section with a flat upper surface and curved lower surface, creating an asymmetric geometry that naturally prevents inversion. This asymmetric design inherently ensures proper orientation without requiring additional symmetric fastening components.
2Reliability
If D-shaped features are added to the support pin and outer bearing cup, then the support pin inversion is prevented, but the manufacturing cost and time increase due to complex geometry
Solution Approach 1:
The D-shaped cross-section with flat upper surface and curved lower surface creates an asymmetric geometry that is simple to manufacture using conventional machining processes. The asymmetry is achieved through basic milling or turning operations rather than complex forming processes.
Solution Approach 2:
The anti-inversion feature is applied locally to specific surfaces of the support pin (flat upper surface, curved lower surface) rather than requiring complex three-dimensional geometry throughout the entire component. This localized approach simplifies manufacturing while maintaining functionality.
3Reliability
If conventional anti-inversion features are used, then the support pin remains upright, but the packaging envelope and cost of the rocker arm assembly increase
Solution Approach 1:
The anti-inversion function is merged into the support pin itself through its D-shaped cross-section, eliminating the need for separate fasteners, washers, or other auxiliary components. This integration reduces the overall packaging envelope while maintaining the orientation prevention function.
Solution Approach 2:
The patent removes unnecessary fastening components (captured fasteners, bolts, washers) from the assembly, keeping only the essential support pin with its anti-inversion geometry. This extraction of redundant components reduces the packaging envelope and material costs.
Data Source
AI summary
The rocker arm assembly has an anti-inversion part that prevents a support pin from inverting, ensuring proper orientation of the support pin, on which a rocker arm is rotatably mounted, is maintained. The anti-inversion part can be a washer, a plate, a plug, or a sleeve. The washer, which has a flat face and a curved face, is intended for use with a cylindrical support pin which matches the curved face of the washer. The plate can include various combinations of tabs, flanges, and/or protrusions that extend in different directions. The plug can resemble any desirable shape, and is removed prior to final assembly. The sleeve can be hollow and is removable.