Cam Phaser Rotor Vane Locking Mechanism Design
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Solution Overview
Problem
Cam phasers with locking mechanisms at the rotor vane lead to material weakening and potential deformations, causing noise and reducing lifespan due to mechanical impact, and shifting the mechanism inwardly increases force on the locking mechanism.
Innovation Solution
The locking mechanism is arranged at the rotor vane radially outward and spaced from the stator walls, with a bore in one vane to house a locking element, allowing for balanced and noise-free operation by preventing mechanical impact and using different bore volumes and cross-sections to compensate for imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the locking mechanism is arranged at the rotor vane, then the rotor can be locked in reference to the stator, but the material at the vane is weakened and deformations may occur upon impact
Solution Approach 1:
The locking mechanism is extracted from the rotor vane and relocated to the stator wall. The locking element is now part of the stator structure rather than the rotor vane, eliminating the weakening effect on the vane material while maintaining the locking function. The locking element protrudes from the stator wall into the pressure chamber to engage with the rotor vane.
Solution Approach 2:
A locking element serves as an intermediary component between the stator and rotor. This locking element with its protruding locking surface provides the locking function without being integrated into the rotor vane structure, thus preventing material weakening while enabling reliable locking when the vane impacts the stator wall.
2Strength
If the rotor vane is embodied in a reinforced fashion to avoid deformations, then deformations are prevented, but imbalance in the cam phaser increases causing noise and reduced life span
Solution Approach 1:
The locking function is extracted from the rotor vane structure and placed in the stator wall. This eliminates the need to reinforce the rotor vane with additional material, thereby maintaining balanced mass distribution in the rotating assembly and preventing noise and reduced lifespan associated with imbalance.
3Strength
If the locking mechanism is shifted radially inwardly towards the hub, then the locking mechanism is protected from impact, but stronger forces are subjected on the locking mechanism due to lower lever effect
Solution Approach 1:
The locking element is positioned in the axial dimension protruding from the stator wall into the pressure chamber, rather than being located radially inward. This axial positioning allows the locking surface to engage the rotor vane at a radial position that maintains a favorable lever effect, reducing the forces on the locking mechanism while still protecting it from direct impact.
4Strength
If the locking mechanism is arranged at the rotor vane radially outward, then mechanical impact load is prevented, but the locking mechanism needs to be spaced from stator walls requiring precise positioning
Solution Approach 1:
The stator wall incorporates a specifically designed locking element with a protruding locking surface at the precise location where the rotor vane impacts during normal operation. This localized feature provides the necessary spacing and positioning, guiding the rotor vane to engage at the correct radial distance without requiring complex overall spacing mechanisms.
Data Source
AI summary
A cam phaser for transferring rotational energy from a crankshaft (16) to a camshaft (12) of an internal combustion engine (2), having a stator (20) for torque-proof connection to one of the shafts (12, 16) and a rotor (22) received rotationally in the stator (20) for torque-proof connection to the other shaft (12, 16), with first and second chambers being formed in the stator (20), engaged by first and second vanes (26) of the rotor (22). A bore (42) is provided in the first vane (26), in which a locking element (40) can be received for blocking a rotary motion of the rotor (22) relative to the stator (20). Here in an impact position of the second vane (26) at a wall (30) of the second chamber, the first vane (26) is arranged spaced apart from a wall (30) of the first chamber (44).