Camshaft Phaser Spring Retainer Tab for Bias Spring Slip Prevention
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Solution Overview
Problem
Slippage of the bias spring relative to its attachment interface in camshaft phasers can be detrimental to the function of the camshaft phaser, affecting engine performance, efficiency, and emissions.
Innovation Solution
A spring retainer assembly with a disk portion and an axially extending portion that includes a retention tab and torsional fixing region, designed to prevent rotational slipping of the bias spring by engaging with the spring legs and landings, allowing for precise angular position tracking and biasing of the rotor relative to the stator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bias spring is attached to the spring retainer using only a torsional fixing region, then the attachment is simple and allows rotational movement, but rotational slippage occurs which is detrimental to camshaft phaser function
Solution Approach 1:
The attachment interface is segmented into two distinct functional regions: a torsional fixing region with spring landings for normal operation, and a retention tab with engagement features for preventing slippage. This segmentation allows each region to perform its specific function optimally without compromising the other.
Solution Approach 2:
The retention tab acts as an intermediary element between the bias spring and the spring retainer. It provides an additional engagement interface that mediates the attachment relationship, preventing rotational slippage while allowing the torsional fixing region to maintain its primary function.
2Reliability
If the retention tab is positioned to engage the bias spring leg, then rotational slippage is prevented, but the spring leg may form an angle with the spring landing during engagement
Solution Approach 1:
The design accommodates dynamic changes in spring leg orientation during engagement. The retention tab is positioned and dimensioned to allow the spring leg to transition from a parallel alignment with the spring landing to an angled position during slippage prevention, maintaining functional integrity throughout the movement.
Solution Approach 2:
The geometric parameters of the retention tab (position, height, curvature) are optimized to accommodate the changing orientation of the spring leg. The tab's curved surface and strategic positioning allow the spring leg to engage at varying angles while maintaining secure retention.
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 effectively limits rotational slipping of the bias spring, ensuring accurate engine valve timing and improved performance by maintaining the biasing force and angular position precision, thus enhancing engine efficiency and reducing emissions.
Implementation Method 1
The axially extending portion has a torsional fixing region defined by at least two straight spring landings, each one of the at least two straight spring landings configured to receive a corresponding one of the at least two straight spring legs in order to torsionally attach the bias spring to the torsional fixing region.
Data Source
AI summary
A spring retainer for a camshaft phaser is provided that includes an axially extending portion and a disk portion. The disk portion has an axially extending retention tab that is formed integrally therewith. The axially extending portion includes a torsional fixing region configured to torsionally attach a bias spring to the spring retainer. In a first installed position, the retention tab is spaced apart from a straight side of the bias spring. In a second rotationally slipped position, the retention tab is configured to be engaged with the straight side of the bias spring. The spring retainer can be utilized as a timing wheel that is configured to cooperate with a camshaft position sensor to provide an angular position of a camshaft.