Coated Tolerance Ring Assembly for Heat Transfer and Retention

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Solution Overview

Problem

Existing tolerance rings in assemblies with moving parts face challenges in providing effective thermal transfer and retention forces between components, particularly in high-temperature environments where differential thermal expansion and wear occur, leading to potential loosening of assembled components.

Innovation Solution

A tolerance ring design featuring a substrate with a thermal enhancement layer and a retention layer, where the thermal enhancement layer has a Vickers hardness of 100 W/m·K and the retention layer provides a significant retention force, integrated with a plurality of projections that deform elastically or plastically to maintain positional relationships between inner and outer members, enhancing thermal conductivity and retention force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional tolerance ring is used between inner and outer components, then the assembly can be manufactured with standard tolerances, but thermal transfer between components is insufficient and retention force decreases under thermal expansion conditions

Engineering Contradiction:
Improveretention forceVSAvoidthermal transfer
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The tolerance ring employs a composite structure with a substrate made of one material and a coating layer made of a different material. The substrate provides mechanical strength and retention force, while the coating layer enhances thermal conductivity. This composite material approach allows the single component to simultaneously achieve both high retention force and effective thermal transfer, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The tolerance ring applies different material properties to different regions: the substrate provides structural integrity and retention characteristics, while the coating layer applied to specific surfaces provides enhanced thermal conductivity where needed. This local differentiation of material properties allows the component to optimize both retention force and thermal transfer performance in their respective functional zones.

Inventive Principle:
Principle #3Local quality

2Temperature

If the tolerance ring is designed with high thermal conductivity material, then thermal transfer improves, but retention force and mechanical strength may be compromised

Engineering Contradiction:
Improvethermal transferVSAvoidretention force
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

Instead of using a single material that must compromise between thermal conductivity and strength, the invention uses a composite structure where the substrate provides mechanical strength and the coating layer provides thermal conductivity. This allows both properties to be optimized independently in different layers, eliminating the need to sacrifice retention force for thermal performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The tolerance ring is segmented into two functional layers: a substrate layer that handles mechanical loading and retention, and a coating layer that handles thermal transfer. This segmentation allows each layer to be optimized for its specific function without compromising the other, enabling the component to achieve both high strength and high thermal conductivity simultaneously.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If the tolerance ring uses a solid rigid structure, then manufacturing precision is maintained, but adaptability to thermal expansion and elastic deformation is reduced

Engineering Contradiction:
Improvepositional relationshipVSAvoidthermal expansion accommodation
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The tolerance ring is designed with elastic properties that allow it to dynamically adapt to changing conditions. The ring can elastically deform to accommodate thermal expansion of adjacent components while maintaining precise positional relationships. This dynamic behavior enables the component to transition from a static rigid structure to an adaptive elastic structure that responds to thermal and mechanical loads.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention utilizes changes in physical parameters of the tolerance ring material, specifically its elastic modulus and thermal expansion coefficient, to enable adaptation. By selecting materials with appropriate parameter ranges, the ring can maintain manufacturing precision under normal conditions while adapting to thermal expansion through controlled elastic deformation when temperature changes occur.

Inventive Principle:
Principle #35Parameter changes

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 tolerance ring effectively transfers heat and maintains a strong retention force between components, minimizing clearance and ensuring stable assembly performance even under conditions of thermal expansion and wear, thereby improving the reliability and longevity of assemblies.

Implementation Method 1

the thermal enhancement layer defines a portion of the an exterior surface of the tolerance ring... the tolerance ring being adapted to provide at least one of a) a thermal transfer between the inner member and the outer member

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the tolerance ring comprises a plurality of projections protruding radially inward or radially outward... integrated with a plurality of projections that deform elastically or plastically to maintain positional relationships

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

the tolerance ring comprises a plurality of projections protruding radially inward or radially outward... integrated with a plurality of projections that deform elastically or plastically to maintain positional relationships

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 4

the tolerance ring provides a coefficient of friction between the retention layer and the outer member, μ1, and a coefficient of friction between the substrate and the outer member, μ2

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentUS11873865B2Tolerance ring and assembly
Publication Date: 2024.01.16 SAINT GOBAIN PERFORMANCE PLASTICS RENCOL LIMITED
  • US11873865B2 patent drawing
  • US11873865B2 patent drawing
  • US11873865B2 patent drawing

AI summary

A tolerance ring including a substrate, and an overlying layer including at least one of a thermal enhancement layer and a retention layer, the thermal enhancement layer including at least one of i) Vickers hardness <400 VPM or ii) a thermal conductivity >100 W/m·K, the tolerance ring being adapted to provide at least one of a) a thermal transfer between the inner member and the outer member, b) a coefficient of friction between the retention layer and the outer member, μ1, and a coefficient of friction between the substrate and the outer member, μ2, and where μ1>μ2, or c) a retention force, Rf, between the inner member and the outer member, and the assembly has an assembly force, Af, and where Rf>0.1 Af, wherein the tolerance ring includes a plurality of projections protruding radially inward or radially outward.