Cross-linked Elastomeric Synchronous Belt Cold Flow Resistance
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Solution Overview
Problem
Synchronous drive belts face challenges with mechanical stability and high-temperature resistance due to cold flow issues in thermoplastic polyethylene facing fabrics, especially in high-performance applications with increasing power levels and operating temperatures.
Innovation Solution
A synchronous drive belt with a cross-linked elastomeric body formed from a reaction product of polyisocyanate and hydroxyl functional polyol, which envelops or embeds a fabric reinforcement, providing enhanced mechanical stability and thermal resistance by forming the outer surface of the continuous tooth section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermoplastic polyethylene is used as facing fabric covering, then low friction wear resistance is provided, but cold flow occurs during service away from loaded areas
Solution Approach 1:
The patent changes the material parameter from thermoplastic polyethylene to cross-linked elastomeric material (specifically cross-linked polyurethane or similar elastomers). This parameter change eliminates cold flow by creating a cross-linked molecular structure that maintains dimensional stability while preserving low friction properties and wear resistance.
Solution Approach 2:
The invention uses composite construction where the cross-linked elastomeric body integrates with the fabric reinforcement (such as polyamide 6,6 stretch fabric) to create a unified facing structure. This composite approach combines the advantages of both materials: the elastomeric provides cold flow resistance and the fabric provides structural integrity and adhesion.
2Strength
If woven polyamide 6,6 stretch fabric is used for tooth covering, then good mechanical properties and adhesion are achieved, but mechanical stability decreases at high temperatures
Solution Approach 1:
The patent creates a composite structure where the fabric reinforcement is embedded within or covered by the cross-linked elastomeric material. This composite approach allows the fabric to provide adhesion and mechanical properties while the cross-linked elastomeric outer layer provides high temperature resistance and dimensional stability.
Solution Approach 2:
The invention changes the material parameter of the tooth covering from pure fabric to a fabric-elastomeric composite. The cross-linked elastomeric material has superior high temperature stability compared to the fabric alone, thereby raising the overall temperature resistance of the tooth covering system.
3Ease of operation
If thermoplastic polyethylene layer is applied through heat and cool molding, then low friction surface is formed, but cold flow increases near melting point
Solution Approach 1:
The patent changes the material parameter from thermoplastic polyethylene to cross-linked elastomeric material, which has a fundamentally different thermal behavior. The cross-linked structure prevents the material from softening and flowing near its service temperature, thereby eliminating cold flow while maintaining low friction properties.
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 significantly improves durability, cold flow resistance, and temperature resistance, ensuring long-term performance under high mechanical and thermal stresses.
Implementation Method 1
a cross-linked elastomeric body based upon a urethane material formed from the reaction product of a polyisocyanate and a hydroxyl functional polyol
Implementation Method 2
the fabric reinforcement is enveloped by the cross-linked elastomeric body
Data Source
AI summary
A synchronous drive belt includes an outer tension section and opposing continuous tooth section defining an outer surface. The synchronous drive belt further includes a cross-linked elastomeric body, and a tensile reinforcement section disposed between the outer tension section and the cross-linked elastomeric body. A fabric reinforcement is disposed inwardly adjacent the outer surface of the continuous tooth section, and the fabric reinforcement is enveloped by the cross-linked elastomeric body. Further, the cross-linked elastomeric body forms the outer surface of the continuous tooth section. In some aspects, the cross-linked elastomeric body contains a urethane material, which may be formed from the reaction product of a polyisocyanate and a hydroxyl functional polyol during a belt molding process. The polyisocyanate and the hydroxyl functional polyol may envelop the fabric reinforcement prior to reacting during the belt molding process, or even while reacting in the molding process.