Vane Cam Phaser Staged Locking Pin Intermediate Position
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Solution Overview
Problem
Prior art vane-type camshaft phasers lack a reliable mechanical means to position the rotor for locking at an intermediate position, leading to unreliable locking due to manufacturing tolerances affecting the alignment of locking pins and their seats, resulting in significant rotational lash.
Innovation Solution
A staged dual locking pin system with a pre-loaded bias spring that urges the rotor toward an intermediate locking position, featuring a primary locking pin and a secondary locking pin with non-coaxial seats, allowing multiple opportunities for the secondary pin to engage its seat and define the rotary lash, reducing the criticality of manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single locking pin system is used, then the device complexity is reduced, but the locking reliability at intermediate positions deteriorates due to manufacturing tolerances affecting alignment
Solution Approach 1:
The locking pin system is segmented into two distinct locking pins: a primary locking pin for initial engagement and a secondary locking pin for final precise positioning. This segmentation allows each pin to perform a specific function in the locking sequence, improving reliability without requiring the entire system to be perfectly aligned, thus resolving the contradiction between simplicity and reliability.
Solution Approach 2:
The primary locking pin performs a preliminary action by engaging first to establish a rough locked position. This preliminary engagement creates favorable conditions for the secondary locking pin to then achieve precise alignment with its seat, ensuring reliable locking at intermediate positions while maintaining manufacturing feasibility.
2Reliability
If precise alignment of locking pins and seats is required, then locking reliability improves, but manufacturing precision requirements and costs increase
Solution Approach 1:
The primary locking pin performs a preliminary engagement action that establishes a rough locked position without requiring precise alignment. This preliminary action creates favorable conditions for the secondary locking pin to then achieve precise alignment with its seat, ensuring reliable locking at intermediate positions while maintaining manufacturing feasibility.
Solution Approach 2:
The system utilizes the dynamic sequence of pin engagement where the primary pin engages first followed by the secondary pin. This dynamic sequencing allows the system to accommodate manufacturing tolerances in the primary pin alignment while maintaining precise locking through the secondary pin's subsequent engagement.
3Reliability
If dual locking pins are used, then locking reliability improves, but the device complexity increases
Solution Approach 1:
The locking pin system is segmented into two distinct locking pins: a primary locking pin for initial engagement and a secondary locking pin for final precise positioning. This segmentation allows each pin to perform a specific function in the locking sequence, improving reliability without requiring the entire system to be perfectly aligned, thus resolving the contradiction between simplicity and reliability.
Solution Approach 2:
Both locking pins are integrated into the same rotor assembly and work together as a unified locking mechanism. The primary and secondary pins serve complementary functions within the same system, achieving reliable intermediate position locking without requiring separate independent systems, thus limiting the increase in complexity.
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 reliably minimizes rotational lash in the camshaft phaser, ensuring consistent locking at the intermediate position, reducing manufacturing costs and improving locking reliability.
Implementation Method 1
A pre-loaded bias spring urges the rotor toward an intermediate locking position from any rotational position retarded of the locking position
Data Source
AI summary
A vane-type camshaft phaser including a bias spring to urge the rotor toward an intermediate locking position from any rotational position retarded of the locking position. The rotor comprises non-coaxially acting primary and secondary locking pins for mating with primary and secondary locking pin seats in the phaser stator. The primary seat is elongated and is readily located by the primary locking pin to provide a first limit to the rotor phase angle authority in the retard direction. Camshaft torque reversals cause the rotor phase angle to dither. With each torque reversal the secondary locking pin passes over its seat, allowing multiple opportunities for re-engagement. The clearance of the secondary locking pin to its seat defines the rotary lash in the phaser.