Welded Isolating Decoupler for Smaller Pulley Diameter

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Solution Overview

Problem

Existing alternator isolating decouplers are too large and complex, requiring a reduced pulley diameter and simplified manufacturing to meet the needs of smaller automotive engines and increased fuel efficiency, while maintaining functionality.

Innovation Solution

An isolating decoupler design featuring a torsion spring directly connected to a hub by welding and a wrap spring connected to the torsion spring by welding, eliminating the need for additional components and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional components (isolating spring, one way clutch, bearing, pulley, spring carrier) are used, then the device meets functional requirements, but the overall size diameter increases

Engineering Contradiction:
Improvepulley diameterVSAvoidnumber of components
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent combines multiple traditional components into an integrated structure where the torsion spring is directly welded to the hub and the wrap spring is directly welded to the torsion spring, eliminating the need for separate spring carriers and reducing the number of individual parts while maintaining isolating decoupler functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The welded connection structure serves multiple functions simultaneously: it provides structural support, transmits torque, and eliminates the need for separate mounting components, thereby reducing overall device size without compromising performance

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If multiple separate components are used, then the device can be assembled, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent integrates the spring mounting function directly into the hub and spring structure through welding, combining what were previously separate assembly steps into a unified manufacturing process that reduces both assembly complexity and part count

Inventive Principle:
Principle #5Merging (Combining)

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

This design reduces the overall size and complexity of the decoupler, achieving the required functionality with a smaller pulley diameter, lower manufacturing costs, and adjustable spring characteristics for optimal performance.

Implementation Method 1

a torsion spring directly connected to a hub by welding

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a wrap spring directly connected to the torsion spring by welding

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

directly connected to a hub by welding, and a wrap spring directly connected to the torsion spring by welding

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3676506B1Isolating decoupler
Publication Date: 2021.08.11 THE GATES CORP
  • EP3676506B1 patent drawingFigure 1~2
  • EP3676506B1 patent drawingFigure 3
  • EP3676506B1 patent drawingFigure 4~5

AI summary

An isolating decoupler comprising a hub, a pulley journalled to the hub, a torsion spring having a first torsion spring end welded directly to the hub, a wrap spring having a first wrap spring end welded directly to a second torsion spring end, a wrap spring outer surface fictionally engaged with a pulley inner surface, and a wrap spring second end temporarily engagable with the torsion spring first end whereby the frictional engagement between the wrap spring outer surface and the pulley inner surface is progressively released as a torque load increases.