Bidirectional Overrunning Decoupler with Centrifugal Locking
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Solution Overview
Problem
Existing overrunning accessory decouplers for serpentine drives only transmit torque in one direction, preventing their use with alternator/generator starters or starter assist devices, which limits their application in engine starting systems.
Innovation Solution
An overrunning accessory decoupler with a locking mechanism that allows torque transfer in both directions, either through a centrifugal force-controlled mechanism or an electromagnet, enabling the decoupler to lock or unlock the pulley and hub for bidirectional torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a one way clutch is used in the decoupler to dampen torsional vibrations, then vibration damping is improved, but torque transmission in the reverse direction is prevented
Solution Approach 1:
The patent applies the dynamics principle by making the clutch mechanism changeable between two states: a one-way clutch state for vibration damping and a locked state for bidirectional torque transmission. The clutch can dynamically switch between allowing free rotation in one direction (for damping) and locking to transmit torque in both directions (for starter operation), resolving the contradiction between vibration damping and torque transmission capability
Solution Approach 2:
The patent applies parameter changes by modifying the operational parameters of the clutch mechanism. By changing the engagement state of the clutch (from engaged to disengaged), the system transitions between vibration damping mode and bidirectional torque transmission mode, allowing the same component to serve multiple functions under different operating conditions
2Adaptability or versatility
If a locking mechanism is added to enable bidirectional torque transmission, then adaptability for starter applications is improved, but device complexity increases
Solution Approach 1:
The patent applies the merging principle by combining the locking mechanism with the existing one-way clutch structure. The locking mechanism is integrated into the clutch assembly, sharing common components such as the clutch plates, springs, and housing. This integration allows bidirectional torque transmission capability to be added without proportionally increasing overall device complexity, as the locking function merges with the existing vibration damping mechanism
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
Enables the use of overrunning accessory decouplers with alternator/generator starters by allowing torque transmission from the accessory to the engine drive, facilitating engine starting and providing conventional vibration damping and isolation functions.
Implementation Method 1
an isolator spring acting between the pulley and the hub to dampen torsional vibrations therebetween
Implementation Method 2
the decoupler includes a locking mechanism that is controlled by centrifugal forces developed in the decoupler to lock the decoupler
Implementation Method 3
the decoupler includes a locking mechanism with an electromagnet that can be energized to lock the decoupler
Data Source
AI summary
An overrunning accessory decoupler with a locking mechanism provides the desired overrunning accessory decoupler functionality and also permits torque to be transferred from the accessory to which the decoupler is installed to the drive of the engine when desired. In one embodiment, the decoupler includes a locking mechanism that is controlled by centrifugal forces developed in the decoupler to lock the decoupler to permit the accessory to transfer torque to the drive to start or boost the engine. In another embodiment, the decoupler locking mechanism includes an electromagnet that can be energized to lock and/or unlock the decoupler.