Closed-Mesh Back Fabric for Oil-Resistant Toothed Belts

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Solution Overview

Problem

Toothed power transmission belts face challenges in heat resistance, oil resistance, wear resistance, durability, and load capacity when used in an oil-wet environment, such as within an internal combustion engine, particularly in low-temperature conditions.

Innovation Solution

A toothed power transmission belt with a closed-mesh, tubular, back fabric that is circular-knitted with polyurethane and nylon yarns, heat-set, and treated with an epoxy-based or RFL coating, providing improved oil resistance and low-temperature durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a toothed power transmission belt is used in an oil-wet environment, then power transmission function is maintained, but heat resistance, oil resistance, wear resistance, durability, and load capacity deteriorate

Engineering Contradiction:
ImprovedurabilityVSAvoidoil resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite materials by combining rubber with fabric reinforcement (nylon, polyester, or aramid fibers) to create a multi-layered belt structure. The fabric layers provide enhanced oil resistance and structural stability while the rubber provides flexibility and shock absorption, resolving the contradiction between maintaining power transmission and resisting oil degradation

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the rubber compound by incorporating specific oil-resistant additives and adjusting the polymer blend ratios. This changes the material's chemical resistance properties without compromising its mechanical flexibility, allowing the belt to maintain performance in oil-wet environments

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a toothed power transmission belt is used in an oil-wet environment, then power transmission function is maintained, but heat resistance deteriorates

Engineering Contradiction:
ImprovedurabilityVSAvoidheat resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The fabric reinforcement layers (nylon, polyester, or aramid) have inherent high-temperature stability that complements the rubber compound. This composite structure prevents thermal degradation at the rubber-fabric interface, maintaining heat resistance even in oil-wet conditions where thermal cycling occurs

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent adjusts the curing temperature and crosslink density parameters of the rubber compound to optimize thermal stability. By modifying these processing parameters, the belt achieves higher service temperature capability without sacrificing flexibility or oil resistance

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a toothed power transmission belt is used in an oil-wet environment, then power transmission function is maintained, but wear resistance deteriorates

Engineering Contradiction:
ImprovedurabilityVSAvoidwear resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The fabric layers act as a wear-resistant skeleton that prevents rubber surface degradation. The tight weave structure of the fabric reinforcement resists abrasion from oil particles and mechanical contact, while the rubber coating provides friction reduction, creating a synergistic wear-resistant surface

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the surface hardness parameter of the rubber compound by adjusting filler content and crosslinking density. This creates a harder, more wear-resistant surface layer that resists abrasion in oil environments while maintaining adequate flexibility for power transmission

Inventive Principle:
Principle #35Parameter changes

4Reliability

If a toothed power transmission belt is used in an oil-wet environment, then power transmission function is maintained, but load capacity deteriorates

Engineering Contradiction:
ImprovedurabilityVSAvoidload capacity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The fabric reinforcement layers provide tensile strength and structural integrity that prevents belt stretching and failure under load. The multi-layer composite construction distributes mechanical stresses across different materials with complementary strength properties, maintaining load capacity despite oil exposure

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent increases the crosslinking density and molecular weight of the rubber compound to enhance its tensile strength and elastic recovery. These parameter changes allow the belt to withstand higher loads without permanent deformation, even when swelled by oil absorption

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 solution enhances the belt's oil resistance and durability, extending its lifespan in oil-wet environments and maintaining performance across a wide temperature range, as demonstrated by improved results in Hot/Cold and Cold Tests.

Implementation Method 1

The back fabric is preferably heat set after knitting and is treated with a suitable coating such as an epoxy or RFL treatment

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

The back fabric is preferably heat set after knitting

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP3724535B1Toothed power transmission belt with back fabric
Publication Date: 2022.07.20 THE GATES CORP
  • EP3724535B1 patent drawingFigure 1~2
  • EP3724535B1 patent drawingFigure 3~4

AI summary

A toothed power transmission belt with a smooth back side surface has a back jacket on the back side surface; wherein the back jacket comprises a closed-mesh, knit fabric tube. The fabric tube may be knitted on a circular weft knitting machine and may be heat set after knitting. The fabric tube may be treated with an epoxy, RFL or other treatment to provide for oil resistance, adhesion, frictional properties, etc.