Double-Cogged V-Belt Rubber Composition for Shear Durability

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Solution Overview

Problem

Power transmission belts with cellulose-based fine fibers face challenges in achieving optimal durability due to limitations in the elastic modulus and fiber distribution within the rubber composition, leading to inadequate resistance against shear loads and lateral pressure.

Innovation Solution

A double-cogged V-belt design incorporating a rubber composition with cellulose-based fine fibers and carbon black, where the adhesive rubber layer has a higher storage normal modulus in the grain direction and a lower modulus in the cross-grain direction, enhancing durability through a specific arrangement of the uncrosslinked rubber sheet before crosslinking and the use of cellulose-based fine fibers and carbon black.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If elastic modulus is increased to improve durability, then resistance to lateral pressure is improved, but flexibility and power transmission performance deteriorate

Engineering Contradiction:
Improveresistance to lateral pressureVSAvoidpower transmission performance
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent optimizes the specific parameters of reinforcement materials: cellulose fiber diameter (1-10 μm) and length (100-1000 μm), carbon black particle size, and their respective contents in the rubber composition. By carefully controlling these parameters, the patent achieves an elastic modulus that provides sufficient lateral pressure resistance while maintaining the flexibility needed for effective power transmission, thus resolving the contradiction between durability and operational performance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3971444B1Transmission belt
Publication Date: 2023.04.19 BANDO CHEM IND LTD
  • EP3971444B1 patent drawingFigure 1A
  • EP3971444B1 patent drawingFigure 1B~1C
  • EP3971444B1 patent drawingFigure 2

AI summary

A power transmission belt (B) includes a belt body (10) made of rubber and a cord (12) embedded in the belt body (10). The belt body (10) has a portion (11) having the cord (12) embedded therein, and the portion (11) is made of a rubber composition having a storage normal modulus at 25°C in a grain direction of 80 MPa or more and the ratio of the storage normal modulus at 25°C in the grain direction to a storage normal modulus at 25°C in a cross-grain direction of 1.20 or more to 2.50 or less. The rubber composition is arranged such that the grain direction corresponds to a belt length direction and the cross-grain direction corresponds to a belt width direction.