Camshaft Phaser Compliant Sealing Ring
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Solution Overview
Problem
Existing camshaft phasers face challenges in minimizing leakage while accommodating radially inward expansion of the camshaft phaser attachment bolt, which can lead to binding issues due to the need for a larger clearance to ensure proper movement of the valve spool.
Innovation Solution
The camshaft phaser incorporates a compliant sealing ring between the bolt valve bore and the valve sleeve, which isolates the valve sleeve from radial expansion of the camshaft phaser attachment bolt, allowing for radially inward expansion accommodation without increasing clearance, thus minimizing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a larger clearance is provided between the valve spool and camshaft phaser attachment bolt to accommodate radially inward expansion, then proper movement of the valve spool is ensured, but leakage between the interface increases
Solution Approach 1:
A compliant sealing ring is introduced as an intermediary component between the valve spool and the camshaft phaser attachment bolt. This sealing ring accommodates the radially inward expansion of the bolt while maintaining a sealed interface, thus preventing oil leakage without requiring increased clearance that would compromise sealing effectiveness.
Solution Approach 2:
The sealing ring is designed with compliant material properties that allow it to deform and accommodate dimensional changes in the camshaft phaser attachment bolt during tightening. This parameter change approach enables the sealing interface to adapt to bolt expansion while maintaining adequate clearance for valve spool movement.
2Object-generated harmful factors
If clearance is minimized to control leakage, then oil sealing is improved, but radially inward expansion of the camshaft phaser attachment bolt causes binding of the valve spool
Solution Approach 1:
The compliant sealing ring serves as a mediator that decouples the clearance requirement from the sealing effectiveness. It allows the valve spool to move freely with minimal clearance while the sealing ring itself accommodates bolt expansion through deformation, preventing both binding and leakage simultaneously.
Solution Approach 2:
The sealing ring is implemented as a flexible element that can deform radially to accommodate bolt expansion. This flexibility allows the system to maintain tight clearance for precise valve spool movement while the compliant material absorbs dimensional changes without causing binding.
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
This solution effectively prevents oil leakage and maintains the valve sleeve's position, ensuring precise control over the phase relationship between the crankshaft and camshaft while accommodating the attachment bolt's expansion, thereby enhancing the camshaft phaser's operational reliability.
Implementation Method 1
a compliant sealing ring radially between the bolt valve bore and the valve sleeve which engages the bolt valve bore and the valve sleeve, the sealing ring preventing fluid communication through the annular clearance axially between opposing axial sides of the sealing ring and the sealing ring also accommodating radially inward expansion of the camshaft phaser attachment bolt within the annular clearance
Data Source
AI summary
A camshaft phaser includes an input member; an output member defining an advance chamber and a retard chamber with the input member; a camshaft phaser attachment bolt which clamps the camshaft phaser to a camshaft, the camshaft phaser attachment bolt having a bolt valve bore extending along an axis. A valve sleeve is located coaxially within the bolt valve bore such that an annular clearance is provided radially therebetween. A valve spool is located coaxially within the valve sleeve such that the valve spool is moved coaxially between an advance position and a retard position. A compliant sealing ring radially between the bolt valve bore and the valve sleeve prevents fluid communication through the annular clearance axially between opposing axial sides of the sealing ring and isolates the valve sleeve from radial expansion of the camshaft phaser attachment bolt.