Vane Cam Phaser Bias Spring for Intermediate Locking
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Solution Overview
Problem
Vane-type camshaft phasers lack a mechanical means to reliably lock the rotor at an intermediate position, leading to unacceptably high locking failures due to the absence of a mechanical stop, especially when oil pressure is low.
Innovation Solution
A toroidal bias spring system is introduced, where the spring is grounded to the stator and variably grounded to the rotor, disengaging during phase-advance and engaging during phase-retard to increase locking reliability at an intermediate position, allowing the lock pin to oscillate and re-engage with a mid-range pin seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If no mechanical stop is provided for intermediate position locking, then the rotor range of rotational authority can be increased, but locking reliability deteriorates due to absence of mechanical positioning means
Solution Approach 1:
A toroidal bias spring is introduced as an intermediary mechanical element between the rotor and stator. The spring provides a mechanical positioning force that assists the lock pin in engaging the pin seat at intermediate positions, thereby improving locking reliability without restricting the rotor's range of rotational authority. The spring engages the rotor at specific positions to provide the necessary mechanical means for reliable locking.
2Reliability
If a mechanical stop is added to position the rotor for intermediate locking, then locking reliability improves, but device complexity increases
Solution Approach 1:
The toroidal bias spring serves multiple functions: it provides the mechanical positioning force for intermediate locking, assists the lock pin in engaging the pin seat, and maintains rotor positioning without requiring separate mechanical stops or complex positioning mechanisms. This multi-functionality improves locking reliability while minimizing the increase in device complexity.
3Use of energy by moving object
If oil pressure is low, then the ability to maintain rotor position deteriorates, but locking failures increase without mechanical assistance
Solution Approach 1:
The toroidal bias spring provides beforehand mechanical assistance to the locking mechanism. When oil pressure is low or unavailable, the spring has already been positioned to provide the necessary mechanical force to assist the lock pin in engaging the pin seat, thereby preventing locking failures before they occur rather than relying solely on oil pressure.
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 bias spring system enhances the reliability of rotor locking at an intermediate position by decelerating the rotor during phase-retard, ensuring consistent alignment of the lock pin with the pin seat, even under low oil pressure conditions, thereby reducing locking failures.
Implementation Method 1
A toroidal bias spring system is introduced, where the spring is grounded to the stator and variably grounded to the rotor, disengaging during phase-advance and engaging during phase-retard to increase locking reliability at an intermediate position
Data Source
AI summary
A vane-type camshaft phaser for varying the timing of combustion valves in an internal combustion engine. The phaser includes a seat formed in the sprocket at the appropriate position of intermediate rotor rotation and a locking pin slidably disposed in a vane of the rotor for engaging the seat to lock the rotor to the stator at the intermediate position. A bias spring system disposed on a cover plate urges the rotor toward the intermediate locking position from any position retarded of the locking position but does not engage the rotor during valve timing-advance motion thereof from the intermediate locking position.