Welded Isolating Decoupler for Belt Chirp and Vibration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Diesel and gasoline engine accessory drive systems experience increased belt chirp noise and reduced belt life due to higher crankshaft vibrations and alternator inertia, which existing crankshaft isolators and decouplers fail to adequately address.
Innovation Solution
An isolating decoupler design featuring a shaft with an inner race of at least one bearing, a torsion spring with one end welded to a one-way clutch and the other end welded to a pulley, which reduces axial length and facilitates use in smaller engine compartments, effectively managing vibrations and belt slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional isolator decouplers are assembled with interference or press fits between components, then mechanical connections are achieved, but the device complexity increases and manufacturing precision requirements increase
Solution Approach 1:
The patent combines multiple connection functions into a single welded structure. The torsion spring is welded directly to both the shaft and the pulley, eliminating the need for separate interference fits, press fits, or mechanical fasteners. This merging of connection methods reduces assembly complexity while maintaining connection reliability through the permanent welded joints.
Solution Approach 2:
The patent replaces traditional mechanical connection systems (interference fits, press fits, tang and groove engagements) with welding. This substitution eliminates the need for precise mechanical tolerances and complex assembly procedures, reducing both device complexity and manufacturing precision requirements while maintaining connection reliability.
2Ease of manufacture
If isolator decouplers use discrete components with mechanical connections, then assembly is easier, but the axial length increases making it unsuitable for smaller engine compartments
Solution Approach 1:
The patent merges the shaft, torsion spring, and pulley into a more compact integrated structure through welding. The torsion spring is welded directly to the shaft and pulley, eliminating the need for separate mounting features, retaining rings, or mechanical fasteners that would increase axial length. This integration maintains ease of manufacture through straightforward welding processes while reducing the overall axial dimension.
Solution Approach 2:
The patent employs a nested arrangement where the torsion spring is positioned between the shaft and pulley in a compact configuration. The welded connections allow the components to be closely spaced and integrated, similar to nested dolls, reducing the axial length while maintaining the functional separation and ease of assembly through welding.
3Strength
If welds are used to join torsion spring to one-way clutch and pulley, then connection strength increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent replaces mechanical connection systems that require precise tolerances (interference fits, press fits) with welding. While welding does require precision, it eliminates the need for maintaining precise clearance fits and mechanical tolerances throughout the assembly. The welded joints provide superior connection strength while the precision requirements are concentrated in the welding process itself rather than in multiple mechanical interfaces.
Solution Approach 2:
The patent combines multiple precision mechanical interfaces into single welded joints. Instead of requiring precise fits between multiple discrete components (shaft to bearing, bearing to housing, pulley to shaft), the welded construction consolidates these connections into fewer weld zones, reducing the cumulative precision requirements while maintaining overall connection strength.
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 design significantly reduces belt chirp noise and extends belt life by effectively filtering out engine vibrations and controlling belt slip, enhancing the operational efficiency of engine accessory drive systems.
Implementation Method 1
a torsion spring engaged between the one-way clutch and the pulley
Implementation Method 2
a one-way clutch engaged with the shaft
Implementation Method 3
a pulley journalled to the shaft on at least one bearing
Implementation Method 4
the torsion spring having an end welded to the one-way clutch and having another end welded to the pulley
Data Source
AI summary
An isolating decoupler comprising a shaft, a pulley journalled to the shaft on at least one bearing, a one-way clutch engaged with the shaft, a torsion spring engaged between the one-way clutch and the pulley, the shaft comprises an inner race of the at least one bearing, and the torsion spring having an end welded to the one-way clutch and having another end welded to the pulley.