Valve Stem Seal Hook Hasps for High-Pressure Guide Attachment
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Solution Overview
Problem
Existing valve-stem seals for internal combustion engines are prone to damage when attached to the valve-stem guide and do not effectively manage high back pressures, leading to potential detachment and increased engine oil consumption.
Innovation Solution
A sealing device comprising an elastic ring and a rigid ring with hook hasps, where the hook hasps have a thin root portion for flexibility and are engaged into recesses on the guide, preventing damage and ensuring secure attachment under high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid ring with locking convex portion is used to prevent detachment under high pressure, then the reliability of sealing device is improved, but the outer peripheral surface of the guide may be damaged during attachment
Solution Approach 1:
The locking convex portion is segmented into multiple hook hasps distributed around the rigid ring, allowing gradual engagement with the guide recesses rather than a single rigid locking action, thereby reducing impact damage to the guide surface
Solution Approach 2:
The hook hasps incorporate a thin portion at the root with different material properties (higher flexibility) compared to other parts of the hasp, allowing localized deformation during attachment to accommodate surface variations without damaging the guide
Solution Approach 3:
The hook hasps are designed with varying thickness parameters, with the root portion being thinner to provide flexibility and the distal end being thicker for strength, allowing the structure to adapt its mechanical properties during the attachment process
2Reliability
If the hook hasps are made rigid to ensure secure locking, then the reliability is improved, but the flexibility during attachment is reduced causing potential damage
Solution Approach 1:
Different portions of the hook hasp have different structural qualities - the root portion is thin and flexible for easy engagement, while the distal end is thick and rigid for secure locking, combining both requirements in a single component
Solution Approach 2:
The hook hasps transition from a flexible state during attachment (when the thin root portion bends) to a rigid locked state after engagement, dynamically adapting their mechanical properties to each phase of the operation
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 sealing device effectively prevents damage to the guide's surface and maintains secure attachment even under high back pressures, reducing engine oil consumption and white smoke generation.
Implementation Method 1
a thin portion being formed at the root portion of the hook hasp, the thin portion being thinner than other parts of the hook hasp. When the sealing device is mounted on the guide for the rod, the hook hasps of the rigid-ring cylindrical part are slid on the outer peripheral surface of the guide. At this time, since the hook hasps, particularly the thin portions, are bent, they are unlikely to damage the outer peripheral surface of the guide.
Data Source
AI summary
A sealing device seals a rod having a cylindrical part and a cylindrical guide that guides reciprocation of the rod in an axial direction of the rod. The sealing device includes an elastic ring formed of an elastic material, and a rigid ring formed of a rigid material fixed to the elastic ring for reinforcing the elastic ring. The elastic ring includes a lip with which an outer peripheral surface of the rod is in slidable contact. The rigid ring includes a rigid-ring cylindrical part located radially outside an end portion of the guide. The rigid-ring cylindrical part includes multiple hook hasps engaged into at least one recess formed on an outer peripheral surface of the guide. Each of the multiple hook hasps includes a root portion and a distal end portion located radially inward of the root portion and fitted into the recess. A thin portion is formed at the root portion of the hook hasp, the thin portion being thinner than other parts of the hook hasp.