Micro Shear Hub Dual Ring Isolator for Exhaust Vibration

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Solution Overview

Problem

Existing automotive exhaust system isolators face challenges in achieving a soft on-center rate while enduring spike durability loads, with common designs experiencing poor tensile fatigue properties and stress concentrations, leading to vulnerability under overloaded conditions.

Innovation Solution

The proposed isolator assembly features a mounting bracket with a pair of spaced apart rings and an elastomer shear hub component, including an outer diameter and inner diameter shear hub connected via a transition portion, which defines a central mounting bore to receive an external hanger component, allowing for shear loading that avoids tension stress and distributes load effectively, thereby enhancing durability and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If common isolator designs (puck, spoke, shear leg) are used, then manufacturing cost or structural simplicity is reduced, but tensile fatigue properties deteriorate and stress concentrations increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidtensile fatigue properties
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The isolator is segmented into multiple functional zones: an elastomeric body with embedded reinforcement structure, a mounting bracket with mounting bore, and a hanger component. The reinforcement structure is further segmented into multiple reinforcement elements distributed throughout the elastomeric body, creating distinct load-bearing pathways that prevent stress concentration in any single area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The isolator employs a composite structure combining elastomeric material with embedded reinforcement elements. The reinforcement structure includes reinforcement elements (such as fabric, wire mesh, or structural ribs) embedded within the elastomeric body, creating a composite material system that maintains flexibility while resisting tensile fatigue and distributing stresses uniformly throughout the structure.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If soft on-center rate is achieved through elastomeric material design, then vibration isolation performance is improved, but durability under spike loads deteriorates

Engineering Contradiction:
Improvevibration isolation performanceVSAvoiddurability under spike loads
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The reinforcement structure is embedded beforehand within the elastomeric body during manufacturing, creating a pre-prepared load-bearing framework. This reinforcement structure acts as a cushioning backbone that activates during spike load events, preventing material failure before it occurs while maintaining the soft elastomeric characteristics during normal vibration isolation operations.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The composite structure combines the compliance of elastomeric material with the strength of embedded reinforcement elements. During normal operation, the elastomeric material provides soft vibration isolation. During spike load events, the reinforcement structure engages to distribute and bear the extreme loads, preventing catastrophic failure while maintaining the desired soft on-center rate for vibration isolation.

Inventive Principle:
Principle #40Composite materials

3Device complexity

If elastomeric material is loaded in tension (puck design), then manufacturing simplicity is improved, but material abuse and failure risk increase

Engineering Contradiction:
Improvestructural simplicityVSAvoidmaterial failure risk
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Instead of loading the elastomeric material primarily in tension as in conventional puck designs, the reinforcement structure is designed to carry tensile loads while the elastomeric material primarily experiences compression and shear. This inversion of the primary load path protects the elastomeric material from abusive tensile stresses that lead to fatigue failure, while maintaining structural simplicity through the embedded reinforcement approach.

Inventive Principle:
Principle #13The other way round (Inversion)

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 achieves a lower and more stable rate of deflection, reducing stress on the elastomeric material and improving the isolator's performance and reliability by eliminating compression and tension stresses, thus enhancing the vehicle's Noise, Vibration, and Harshness (NVH) characteristics.

Implementation Method 1

an elastomer shear hub component which includes an outer diameter (OD) shear hub extending between the pair of spaced apart rings, and an inner diameter (ID) shear hub disposed within the OD shear hub

Methodology Applied
Scientific EffectShear deformation: Shear Stress

Implementation Method 2

The elastomer shear hub component may include an outer diameter (OD) shear hub extending between the pair of spaced apart rings

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentUS9845720B2Micro shear hub dual ring isolator
Publication Date: 2017.12.19 THE PULLMAN CO LLC
  • US9845720B2 patent drawing
  • US9845720B2 patent drawing
  • US9845720B2 patent drawing

AI summary

The present disclosure relates to an isolator assembly for supporting an exhaust component from a structural portion of a vehicle. The isolator assembly has a mounting bracket having a pair of spaced apart rings defining a mounting bore. An elastomer shear hub component is disposed within the mounting bracket and has an outer diameter (OD) shear hub extending between the pair of spaced apart rings, and an inner diameter (ID) shear hub disposed within the OD shear hub. The ID shear hub defines a central mounting bore adapted to receive an external hanger component.