Torsional Damper Rubber Composition for Damping and Durability
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Solution Overview
Problem
Existing rubber compositions for torsional dampers face challenges in achieving high damping performance while maintaining product durability and compound processability, as increasing the amount of carbon black or liquid polyolefin oligomer can lead to deteriorated durability and processability issues.
Innovation Solution
A rubber composition for torsional dampers is developed, comprising at least one polymer (EPM, EPDM, or EBDM), a liquid polyolefin oligomer, graphite, and a peroxide-based crosslinking agent, with specific weight ratios and molecular weight ranges to achieve optimal damping performance, durability, and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the amount of carbon black is increased to achieve high damping performance, then tan δ increases, but product durability deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of EPDM rubber, carbon black, and liquid polyolefin oligomer. This composite approach allows the carbon black to provide damping performance while the liquid polyolefin oligomer protects against durability deterioration, resolving the contradiction between high tan δ and product durability
Solution Approach 2:
The liquid polyolefin oligomer acts as an intermediary substance that mediates between carbon black and the rubber matrix. It prevents the harmful effects of carbon black on durability while preserving the damping performance benefits, thus resolving the contradiction
2Object-generated harmful factors
If the amount of liquid polyolefin oligomer is increased to achieve high damping performance, then tan δ increases, but compound processability deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter of the liquid polyolefin oligomer to be 3,000 to 4,000. This parameter change allows sufficient damping performance while maintaining acceptable compound processability, resolving the contradiction between high tan δ and ease of manufacture
3Object-generated harmful factors
If tan δ is made large to reduce crankshaft vibration, then temperature dependence of E′ worsens, but vibration reduction performance improves
Solution Approach 1:
The composite material system with optimized carbon black and liquid polyolefin oligomer content creates a balanced rubber composition that achieves high tan δ while maintaining acceptable temperature dependence of E′, resolving the contradiction between vibration reduction and natural frequency stability
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 composition achieves high damping performance with excellent balance among physical properties, improved durability, and enhanced compound processability, ensuring effective vibration reduction and temperature stability of the crankshaft.
Implementation Method 1
the rubber material is required to have large tan δ (damping characteristic) in a wide temperature region
Implementation Method 2
the rubber material is required to have satisfactory temperature dependence of a spring constant (temperature dependence of E′ (vibration characteristic))
Implementation Method 3
a peroxide-based crosslinking agent
Data Source
AI summary
A rubber composition for a torsional damper has (A) a minimum value of tan δ at −30° C. to 120° C. of 0.140 or more, (B) a ratio of tan δ at −30° C. to tan δ at 60° C. of 3.5 or less, and (C) a ratio of E′ at −30° C. to E′ at 60° C. of 21 or less.