Camshaft Adjuster Central Locking Mechanism
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Solution Overview
Problem
Camshaft adjusting devices face issues with incomplete pressure medium filling at startup, leading to uncontrolled rotor movements and increased wear, and existing locking solutions are costly and prone to failure if not properly locked.
Innovation Solution
Incorporating a check valve outside the locking pin in the rotor hub, which allows pressure medium to flow into enlarging chambers without reversing, and using two valve devices to facilitate fluidic connections between working chambers, enabling automatic rotation to the central locking position using alternating torques, thus preventing backflow and ensuring cost-effective, fail-safe locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple spring-loaded locking pins are used to lock the rotor in the central position, then the rotor can be locked reliably during startup, but the device complexity and manufacturing costs increase
Solution Approach 1:
The invention extracts the check valve function from the locking pin structure and places it in the rotor hub. This separation simplifies the locking pin to a pure locking element while the check valve independently controls pressure medium flow. The locking pin no longer needs to incorporate complex valve mechanisms, reducing manufacturing complexity while maintaining reliable locking through the combination of mechanical locking and fluidic control.
Solution Approach 2:
The rotor hub is given a multi-functional role by incorporating the check valve into it. The rotor hub not only supports the rotor structure but also houses the check valve that controls pressure medium flow to the working chambers. This consolidation reduces the overall number of components needed and simplifies the locking device structure while maintaining reliable operation.
2Reliability
If locking pins are integrated with check valves inside the locking pin structure, then the locking mechanism can control pressure medium flow, but the manufacturing difficulty and structural complexity increase
Solution Approach 1:
The check valve is extracted from the locking pin and relocated to the rotor hub. This extraction simplifies the locking pin manufacturing process significantly, as the locking pin becomes a simpler mechanical component without integrated valve mechanisms. The check valve is manufactured separately and installed in the rotor hub, where it can control pressure medium flow to the working chambers without complicating the locking pin fabrication process.
3Ease of operation
If the rotor is not locked in the central position during startup, then the camshaft adjuster can operate freely, but uncontrolled rotor movements occur leading to increased wear and noise
Solution Approach 1:
The locking pins are designed to automatically lock the rotor in the central position during the startup phase before pressure medium is fully supplied to the working chambers. This preliminary locking action prevents uncontrolled rotor movements and associated wear and noise. Once the engine is running and pressure medium is available, the check valves control the pressure to automatically rotate the rotor to the desired position, at which point the locking pins release to allow normal operation.
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 provides a cost-effective and fail-safe central locking mechanism that prevents uncontrolled rotor movements and wear, ensuring reliable operation by utilizing active torques to automatically rotate the rotor to the central locking position, enhancing the camshaft adjuster's reliability and reducing noise.
Implementation Method 1
the check valve is provided outside the locking pin in the rotor. Due to the check valve, the pressure medium is able to flow into the enlarging working chamber without it being able to be forced back out of this working chamber
Data Source
AI summary
A vane cell adjuster includinga central locking device for locking the rotor in a central locking position, whereinthe central locking device has at least two spring-loaded locking pins which can be locked in a stator-fixed locking slotted guide and which, during a rotation of the rotor from the direction of an “early” or “late” stop position, lock into the central locking position from different directions in the locking slotted guide, whereina locking pin forms a valve unit with the respective accommodation chamber, whereinin a first switch position of the valve unit, at least one first pressure medium line is connected to allow free flow to a second pressure medium line, andin a second switch position of the valve unit, the first pressure medium line is connected to allow flow via a check valve to the second pressure medium line, whereinthe check valve is provided in the rotor outside of the locking pin.