Alternator Decoupler With Resilient Biasing For Damping Control
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Solution Overview
Problem
Decouplers for alternators face challenges in maintaining compactness while ensuring consistent damping to prevent resonance and extend spring life, as excessive or insufficient damping can lead to premature failure or inadequate isolation of torsional vibrations.
Innovation Solution
A decoupler design incorporating a hub, pulley, one-way clutch, isolation spring, and a damping member with a biasing member having a transition portion with bends to engage frictionally with the pulley or hub, allowing for adjustable damping force to mitigate resonance and maintain consistent damping torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If damping is increased to reduce resonance and extend spring life, then reliability improves, but device complexity increases and manufacturing precision becomes more difficult to control
Solution Approach 1:
The biasing member incorporates a resilient transition portion with bends that allows dynamic adjustment of damping force. The transition portion flexes to accommodate variations in damping member position while maintaining consistent damping force, making the system adaptive rather than static.
Solution Approach 2:
The design changes the physical configuration of the biasing member by incorporating bends in the transition portion. This geometric modification allows the same component to provide both structural support and resilient damping force adjustment, changing the mechanical parameters of the system.
2Reliability
If damping is increased to prevent resonance, then spring life extends, but torsional vibration isolation deteriorates due to excessive damping
Solution Approach 1:
The resilient transition portion enables the damping force to dynamically adapt to operating conditions. When resonance occurs, the transition portion flexes to maintain optimal damping force without excessive magnitude, preventing both under-damping (resonance) and over-damping (excessive isolation).
Solution Approach 2:
The biasing member with resilient transition portion creates a feedback mechanism where the damping force automatically adjusts based on the relative position and movement between the pulley and hub. The transition portion flexes in response to damping member position, providing self-regulating damping control.
3Reliability
If damping member position is adjusted to optimize damping force, then reliability improves, but manufacturing precision requirements increase due to tolerance stack up
Solution Approach 1:
The resilient transition portion replaces rigid positioning requirements with flexible, force-based positioning. Instead of requiring precise manufacturing tolerances to achieve correct damping member positioning, the transition portion naturally flexes to the appropriate position based on force equilibrium, making the system insensitive to manufacturing variations.
Solution Approach 2:
The design changes from a rigid dimensional relationship (requiring precise tolerances) to a flexible force-based relationship. The bends in the transition portion allow the system to accommodate dimensional variations while maintaining consistent damping force through elastic deformation.
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 decoupler effectively reduces resonance and extends the life of the spring by providing a consistent damping force, ensuring the alternator operates efficiently while maintaining a compact design.
Implementation Method 1
a damping member (64) that is positioned to frictionally engage a friction surface (60) on one of the pulley (24) and the hub (22)
Data Source
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AI summary
In an aspect, a decoupler is provided, comprising a hub defining an axis, a pulley, a one way clutch and an isolation spring that act in series, a damping member that frictionally engages a friction surface the pulley or the hub, and a biasing member that urges the damping member into the friction surface. The biasing member has a mounting portion having an axially extending first mounting surface that is fixedly engaged with a second axially extending mounting surface on the other of the pulley and hub and an engagement portion resiliently connected to the mounting portion by a transition portion having at least one bend that urges the engagement portion into engagement with the damping member with a selected force. The at least one bend resiliently permits axial movement of the damping member engagement portion independent of the mounting portion.