Spherical Latch Interface for Rocker Arm Assembly
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Solution Overview
Problem
Current rocker arm designs for internal combustion engines face challenges in fitting specific engine head designs due to increased width, requiring expensive manufacturing processes and complex latch mechanisms, which affect lash alignment and efficiency.
Innovation Solution
A switching rocker arm assembly with increased manufacturing tolerances, featuring a latch with a complementary indentation in the latch seat to compensate for mechanical lash, allowing for efficient operation and fitting in engine heads with obstructions, utilizing a diamond-like carbon coating for reduced friction and increased durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional rocker arm designs are used to fit specific engine head designs, then manufacturing precision and complex latch mechanisms are required, but this increases device complexity and manufacturing cost
Solution Approach 1:
The patent changes the geometric parameters of the latch interface, specifically providing the latch pin with a spherical head and the latch seat with a complementary spherical indentation. This parameter change allows the latch mechanism to accommodate variations in engine head designs through self-alignment, eliminating the need for complex adjustment mechanisms while maintaining adaptability.
Solution Approach 2:
The spherical latch pin and complementary spherical indentation create a self-aligning, self-adjusting latch mechanism. The spherical geometry enables automatic centering and alignment during assembly, eliminating the need for precise pre-alignment or complex positioning mechanisms, thereby reducing device complexity while maintaining adaptability to different engine head designs.
2Ease of manufacture
If manufacturing tolerances are increased to reduce cost, then production efficiency improves, but mechanical lash alignment deteriorates
Solution Approach 1:
The patent changes the geometric parameters of the latch interface from flat surfaces to spherical surfaces. The spherical geometry provides a self-aligning feature that compensates for variations in manufacturing tolerances, ensuring consistent lash alignment even when tolerance ranges are widened. This allows easier manufacturing while maintaining precision.
Solution Approach 2:
The spherical latch interface design incorporates built-in compensation for manufacturing variations. The curved surfaces provide a cushioning effect that absorbs tolerance stack-ups, ensuring that lash alignment remains within acceptable ranges even when individual component tolerances are looser than traditional designs require.
3Adaptability or versatility
If rocker arm width is increased to accommodate certain engine head designs, then adaptability improves, but the ability to fit in engine heads with obstructions deteriorates
Solution Approach 1:
The patent changes the geometry of the latch interface to spherical surfaces, which allows for a more compact rocker arm design. The spherical latch pin and indentation provide the necessary adaptability to different engine head designs without requiring increased rocker arm width, as the self-aligning feature compensates for design variations.
Solution Approach 2:
The latch interface uses asymmetric spherical geometry where the curved surfaces are strategically positioned to provide adaptability in one direction while minimizing the width in the perpendicular direction. This allows the rocker arm to accommodate engine head design variations without increasing overall width, enabling it to fit in engine heads with obstructions.
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 enables a compact, durable, and efficient rocker arm system that maintains predefined lash, reduces mass and moment of inertia, and achieves robust performance across various engine conditions, including high speed and low speed operations, while minimizing wear and assembly issues.
Implementation Method 1
utilizing a diamond-like carbon coating for reduced friction and increased durability
Data Source
AI summary
A novel latch seat for a switching rocker arm assembly used in variable valve actuation (VVA) systems for internal combustion engines. The seat is formed interactively in the assembled switching rocker arm using a novel fixture and press. The press interactively creates a curved dimple of the correct curvature, position and depth while measuring several lash dimensions. Since the latch seat is formed on the assembled rocker arm assembly, the latch seat depth is designed to account for the inaccuracies in the rocker arm assembly parts which create lash. Therefore all of the parts may be made with less precision since the latch seat is sized to compensate for the inaccuracies of all of the parts. The rocker arm assembly parts now may be manufactured to less stringent standards, but result in a rocker arm assembly with same accuracy of rocker arm assemblies manufactured to previous standards.