Annular Spring Support Isolator Decoupler for Belt Chirp Noise
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Solution Overview
Problem
Diesel and gasoline engine accessory drive systems experience increased belt chirp noise and reduced belt operating life due to higher crankshaft vibrations and alternator inertia, which existing isolator decouplers fail to adequately address.
Innovation Solution
An isolator decoupler with an annular spring support member having a spring support member outside surface, independently movable from a spring carrier, limits torsion spring radial contraction and provides uniform support to prevent overstress, comprising a shaft, pulley, one-way clutch, and torsion spring with the annular spring support member radially supporting the spring ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional isolator decouplers are used with fixed spring support, then the structure is simple, but the spring experiences overstress and non-uniform support during engine transients
Solution Approach 1:
The annular spring support member is made independently movable relative to the spring carrier through radial grooves, allowing it to dynamically adjust its position in response to varying loads during engine and alternator transients. This dynamic capability enables the support member to maintain uniform support on the spring ends, preventing overstress while adapting to changing operational conditions.
2Reliability
If the annular spring support member is made independently movable, then uniform spring support is achieved, but the manufacturing complexity increases
Solution Approach 1:
The isolator decoupler is divided into distinct movable components: the annular spring support member separated from the spring carrier, each with specific radial grooves. This segmentation allows independent movement and adjustment of the support member while maintaining manufacturability through standardized groove features that guide the movement and simplify assembly procedures.
3Strength
If discrete components and welding are used for assembly, then strong mechanical connections are achieved, but the manufacturing precision and assembly complexity increase
Solution Approach 1:
The annular spring support member acts as an intermediary element between the spring carrier and the spring ends. It provides a mediating interface that distributes loads uniformly across the spring ends through its independently movable capability, eliminating the need for precise welding or interference fits while maintaining strong mechanical connections through controlled radial movement guided by grooves.
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 effectively reduces belt chirp noise and enhances the operating life of the engine accessory drive system by minimizing spring overstress and maintaining uniform support during engine and alternator transients.
Implementation Method 1
a torsion spring having a first end attached to the pulley and a second end attached to the spring carrier
Implementation Method 2
a one-way clutch engaged with the shaft, a spring carrier engaged with the one-way clutch
Data Source
AI summary
An isolator decoupler comprising a shaft, a pulley journalled to the shaft, a one-way clutch engaged with the shaft, a spring carrier engaged with the one-way clutch, the spring carrier having a spring carrier surface, a torsion spring having a first end laser welded to the pulley and a second end laser welded to the spring carrier, the torsion spring having a volute with a width w, an annular spring support member having a spring support member outside surface, the annular spring support member independently moveable from the spring carrier and independently moveable from the shaft, a gap g between the annular spring support member and the spring carrier, the gap g being less than the width w, the first end comprising a first end coil, the first end coil bearing upon the spring support member outside surface, the first end coil laser welded to the spring support member outside surface, a torsion spring radial contraction limited by engagement with the spring carrier surface, and the gap g and the width w have a relationship (w−2r)>(g+c1+c2) were g>0.