Power Transmission Belt Rubber Composition for Fatigue and Efficiency

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Solution Overview

Problem

Power transmission belts face a trade-off between lateral pressure resistance, durability, and fuel saving performance, with increased rubber hardness improving the former but deteriorating bending fatigue and fuel efficiency, and existing solutions fail to simultaneously enhance bending fatigue and fuel saving performance without compromising lateral pressure resistance and durability.

Innovation Solution

Incorporating a compression rubber layer with a rubber composition containing a fatty acid amide and short fibers, which enhances dispersibility and adhesiveness of the short fibers, reducing friction coefficient and improving mechanical characteristics without increasing rubber hardness, thereby improving bending fatigue and fuel saving performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rubber hardness is increased to improve lateral pressure resistance and durability, then the lateral pressure resistance and durability are improved, but the bending fatigue and fuel saving performance are deteriorated

Engineering Contradiction:
Improvelateral pressure resistance and durabilityVSAvoidfuel saving performance
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical composition parameters of the rubber layer by introducing a specific rubber composition containing polybutadiene rubber (30-70 parts by mass), styrene-butadiene rubber (10-40 parts by mass), and sulfur (0.5-2.0 parts by mass). This compositional parameter change allows achieving the desired hardness (85-92°JIS-A) while maintaining flexibility and reducing power transmission loss, thereby resolving the contradiction between durability and fuel efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite rubber material system combining polybutadiene rubber and styrene-butadiene rubber in specific proportions. This composite material provides both the hardness needed for lateral pressure resistance and the elasticity required for good bending fatigue resistance and fuel saving performance, thus resolving the technical contradiction

Inventive Principle:
Principle #40Composite materials

2Strength

If the rubber hardness is increased to improve lateral pressure resistance, then the lateral pressure resistance is improved, but the belt life may expire early due to deteriorated bending fatigue

Engineering Contradiction:
Improvelateral pressure resistanceVSAvoidbelt life
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The patent optimizes the rubber composition parameters including the specific ratio of polybutadiene rubber to styrene-butadiene rubber, sulfur content (0.5-2.0 parts by mass), and the presence of extenders and activators. These parameter changes enable achieving high lateral pressure resistance while maintaining good bending fatigue resistance, preventing early belt failure

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces sulfur as a vulcanizing agent and includes extenders and activators in the rubber composition. These intermediary substances facilitate the cross-linking reaction that provides both lateral pressure resistance and flexibility, allowing the rubber layer to withstand both compression forces and bending fatigue, thus extending belt life

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively reduces power transmission loss, enhances transmission efficiency, and maintains lateral pressure resistance and durability, achieving a balance between conflicting characteristics of bending fatigue and fuel saving performance.

Implementation Method 1

the fatty acid amide blooms (precipitates) or bleeds-out to the surface (the friction transmission surface coming into contact with a pulley) of the compression rubber layer to reduce the friction coefficient on the rubber layer surface

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

the elastic modulus in the grain direction (short fiber orientation direction) is increased by the orientation of the aramid fiber to thereby maintain the lateral pressure resistance

Methodology Applied
Scientific EffectReinforcement:

Data Source

PatentEP2711587B1Power transmission belt
Publication Date: 2016.02.10 MITSUBOSHI BELTING LTD
  • EP2711587B1 patent drawingFigure 1~3
  • EP2711587B1 patent drawingFigure 4~6
  • EP2711587B1 patent drawingFigure 7

AI summary

The present invention relates to a power transmission belt containing an adhesive rubber layer having a core wire embedded therein in the longitudinal direction of the belt, a compression rubber layer formed on one surface of the adhesive rubber layer, and an extensible rubber layer formed on another surface of said adhesive rubber layer, in which at least the compression rubber layer contains a fatty acid amide and a short fiber.