Dimensionally Stable Polyester Power Transmission Belt

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Solution Overview

Problem

Existing power transmission belts, particularly those for variable speed and clutching applications, face challenges with dimensional stability due to elongation and heat shrinkage, which affect performance characteristics, and current high-performance materials are costly and not economically viable for high-volume applications.

Innovation Solution

A power transmission belt with a tensile cord made from dimensionally stable polyester fibers, such as A360 or A363, which exhibits extremely low heat shrinkage and high modulus, characterized by a Dimensional Stability Index (DSI) of less than 6%, ensuring stability and performance in variable speed drives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional polyester cord is used in power transmission belts, then the belt is economical and low-cost, but the belt exhibits high elongation and high heat shrinkage resulting in poor dimensional stability

Engineering Contradiction:
Improvedimensional stabilityVSAvoidcost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the polyester fiber structure through stretching during processing to achieve high modulus and low elongation. This transforms conventional polyester into dimensionally stable polyester (DSP) that maintains low cost while improving dimensional stability characteristics for power transmission belt applications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material solution by combining stretched polyester fibers with specific rubber compounds and belt construction methods. This composite approach achieves dimensional stability comparable to expensive materials like aramid, carbon, or glass while maintaining the cost advantages of polyester, resolving the contradiction between performance and manufacturability.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If higher-performance materials such as aramid, carbon, glass, or PEN are used to achieve low elongation and low heat shrinkage, then dimensional stability is improved, but the cost increases significantly

Engineering Contradiction:
Improvedimensional stabilityVSAvoidcost
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent employs a cost-effective polyester-based solution that provides sufficient dimensional stability for high-volume applications without requiring expensive long-lasting materials like aramid or carbon fiber. This approach prioritizes economical materials that meet performance requirements for mass production applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention transforms conventional polyester into a high-performance alternative through physical processing (stretching) that changes its mechanical parameters. This creates dimensionally stable polyester that rivals expensive materials in performance while maintaining cost effectiveness, eliminating the need to use costly alternatives.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2167840B1Power transmission belt
Publication Date: 2014.03.05 THE GATES CORP
  • EP2167840B1 patent drawingFigure 1~3
  • EP2167840B1 patent drawingFigure 4
  • EP2167840B1 patent drawing

AI summary

A power transmission belt comprising a polyester tensile cord having a heat shrinkage at 100°C of less than 1% and/or a heat shrinkage at 150°C of less than about 1.5% and/or a dimensional stability index of less than about 6%. The belt has a heat shrinkage after 24 hours at 100°C of less than 1%. The polyester may be that sold under the trade name A360 or A363 by Performance Fibers, Inc. or equivalent polyethylene terephthalate. The tensile cord is particularly suited for use in V-belts for variable speed drives.