Radial Decoupling Pulley Assembly for Torque Spike Reduction

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Solution Overview

Problem

Existing pulley systems in automobile accessory drives face issues such as speed transitions causing undesirable effects like belt jump, wear, and noise due to periodic torque pulses, and overrunning alternator decouplers introduce additional costs, complexity, and susceptibility to contamination or heat, while also having noise and torque consistency issues.

Innovation Solution

A pulley assembly with a radially oriented one-way clutch mechanism that allows one-way relative motion between the input shaft and the driven sheave, engaging and disengaging to maintain momentum in the predominant direction of rotation during speed transitions, reducing torque reversals and improving operational smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an overrunning alternator decoupler (OAD) is installed to dampen torque variations and speed transitions, then noise and component wear are reduced, but device complexity and packaging space increase

Engineering Contradiction:
Improvenoise and component wearVSAvoiddevice complexity and packaging space
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the decoupling function with the alternator pulley assembly itself, integrating the one-way clutch mechanism directly into the pulley structure. This merging eliminates the need for a separate OAD component, reducing overall device complexity and packaging space while maintaining the noise and wear reduction benefits through the integrated one-way clutch mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pulley assembly is designed to perform multiple functions: it serves as both the driving element for the alternator and incorporates the decoupling mechanism. The one-way clutch mechanism provides both the decoupling function during overrunning conditions and maintains normal torque transmission during standard operation, making the system multi-functional and reducing the need for additional specialized components.

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

2Object-affected harmful factors

If a one-way clutch mechanism is implemented to decouple the driven shaft during torque reversals, then belt wear and noise are reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvebelt wear and noiseVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The one-way clutch mechanism is divided into discrete, modular components including clutch plates, springs, and retainers that can be manufactured separately using standard machining processes. This segmentation allows each component to be produced independently with conventional manufacturing methods, then assembled into the pulley assembly, reducing overall manufacturing complexity while achieving the benefit of reduced belt wear and noise through effective torque reversal decoupling.

Inventive Principle:
Principle #1Segmentation

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 pulley assembly effectively reduces noise, heat generation, and torque spikes, enhances packaging efficiency, and maintains consistent overrun torque, addressing the limitations of existing systems while minimizing additional costs and complexity.

Implementation Method 1

a first inclined feature and a second inclined feature that define a friction clutching mechanism

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a compression spring that bears against the second inclined feature

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

an upper ramp component and a lower ramp component that define a radially oriented one-way clutch mechanism

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3129671B1Pulley assembly with radially oriented decoupling mechanism
Publication Date: 2019.05.15 DAYCO IP HOLDINGS LLC
  • EP3129671B1 patent drawingFigure 1
  • EP3129671B1 patent drawingFigure 2
  • EP3129671B1 patent drawingFigure 3

AI summary

A pulley assembly with a radially oriented decoupling mechanism is disclosed. The pulley assembly includes a pulley body having a bore therethrough, a hub, and a one-way clutch mechanism. The pulley body is rotatable in a predominate direction. The hub defines an axis of rotation. The hub is disposed within the pulley body. The one-way clutch mechanism radially surrounds the hub. The one way clutch mechanism includes an engaged position and a disengaged position. The hub and the pulley body rotate together in the predominate direction if the one-way clutch mechanism is in the engaged position. The hub freely rotates with respect to the pulley body if the one-way clutch mechanism is in the disengaged position.