Toothed Power Transmission Belt Thick Jacket Thin Cord Design
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Solution Overview
Problem
Conventional synchronous belts face limitations in load capacity and flexibility due to geometrical restrictions, particularly in pulley systems with non-standard pitch line differentials, and fail to fully utilize the potential of high-performance materials like carbon fiber.
Innovation Solution
A thick jacket, thin cord toothed belt design featuring a 6K carbon fiber tensile member and a stiff jacket, which increases flexibility and load carrying capacity while maintaining proper operation across a range of pulley pitch line differentials, reducing belt running temperature and extending service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the dimensions of the tensile member or jacket are changed to allow more flexibility and load capacity, then the load carrying capability is improved, but the pitch line differential changes adversely affecting pitch fit
Solution Approach 1:
The patent applies parameter changes by transitioning from conventional glass fiber cords (0.9-1.1mm diameter) to high-modulus carbon fiber cords (0.63-0.85mm diameter), fundamentally changing the material properties and dimensional parameters of the tensile member to achieve both improved load capacity and maintained pitch fit
Solution Approach 2:
The patent uses composite materials by combining carbon fiber cords with elastomeric compounds and jacket materials, creating a multi-material construction that leverages the high strength-to-weight ratio of carbon fiber while maintaining the flexibility and damping properties of elastomers
2Strength
If conventional materials are used in the belt, then the belt can be manufactured with standard dimensions, but the load capacity and flexibility are insufficient
Solution Approach 1:
The patent changes the material parameter from glass fiber to carbon fiber, which has superior tensile strength and modulus properties, enabling the belt to achieve higher load capacity while using thinner cord dimensions that improve flexibility
Solution Approach 2:
The patent applies local quality by using carbon fiber specifically in the tensile member cords where high strength is most critical, while other parts of the belt body and jacket can use conventional materials optimized for their specific functions
3Ease of operation
If the cord diameter is reduced to improve flexibility, then the belt flexibility increases, but the load carrying capacity decreases
Solution Approach 1:
The patent changes the material composition parameter from glass fiber to carbon fiber, which has approximately twice the tensile strength of glass fiber, allowing the cord diameter to be reduced by nearly 40% while maintaining or improving load carrying capacity
Solution Approach 2:
The patent optimizes the cord-to-jacket thickness ratio parameter to a specific range (0.8 to 1.6) that balances flexibility and load capacity, representing a departure from conventional design ratios
Data Source
Figure 1~4
Figure 2~3
Figure 5
AI summary
A toothed belt includes a body (12), at least one tooth (14) formed of the body, a jacket (16) disposed along a peripheral surface of the at least one tooth and having a compressed thickness in the range from 0.5 mm to about 0.8 mm, and at least one cord (18) embedded in the body and having a diameter. The at least one cord and said jacket have a ratio of said cord diameter to said jacket thickness of less than 1.8, and said cord diameter and said jacket thickness describe an optical belt PLD of about 2.1 mm or less.