CV Joint Boot Polymer Composition for Durable Squeak Reduction
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Solution Overview
Problem
Constant velocity joint boots made from thermoplastic polyester elastomer tend to produce noise, particularly squeaking, due to flange rubbing, which becomes more noticeable in quieter modern cars, and existing noise reduction methods using waxes either provide temporary relief or result in a slippery surface making boot installation difficult.
Innovation Solution
A polymer composition comprising a thermoplastic polyester elastomer with a combination of a fast diffusing unsaturated wax and a slow diffusing saturated wax, specifically formulated to provide a significant and sustained noise reduction, where the first wax has a weight loss of more than 0.60% and the second wax less than 0.40% over 2500 hours, ensuring effective noise reduction without compromising boot installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a single type of wax is added to the polymer composition, then initial noise reduction is achieved, but the noise returns after 10000-20000 km driving
Solution Approach 1:
The single wax additive is segmented into two distinct wax components: a fast-diffusing wax (0.01-0.5 wt%) that provides immediate noise reduction, and a slow-diffusing wax (0.01-0.5 wt%) that ensures long-term durability. This segmentation allows each wax to perform its specific function optimally, resolving the contradiction between initial effectiveness and long-term duration.
Solution Approach 2:
The invention changes the parameters of the wax additives by selecting waxes with specifically different diffusion rates. The fast-diffusing wax has high initial migration capability while the slow-diffusing wax has low migration rate, creating a synergistic effect that maintains noise reduction over extended periods without the noise returning after 10000-20000 km.
2Duration of action of moving object
If the amount of wax is increased to extend noise reduction duration, then the noise reduction duration increases, but the boot surface becomes too slippery for mounting
Solution Approach 1:
The invention optimizes the parameters of wax diffusion rates rather than simply increasing total wax amount. The fast-diffusing wax provides sufficient initial surface coverage for noise reduction, while the slow-diffusing wax replenishes the surface gradually, maintaining optimal friction characteristics for mounting without excessive slipperiness.
Solution Approach 2:
The polymer composition is formulated as a composite material containing two waxes with complementary properties. This composite approach allows the boot to achieve both long-term noise reduction durability and adequate surface friction for mounting, as the two waxes work synergistically to maintain balanced surface characteristics over time.
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 polymer composition significantly extends the time before noise reoccurs, providing a durable and effective noise reduction solution that maintains boot functionality and ease of installation.
Implementation Method 1
a first, fast diffusing wax having a weight loss of more than 0.60 weight % (wt.%) and a second, slow diffusing wax having a weight loss less than 0.40 wt.% after 2500 hours
Implementation Method 2
a first, fast diffusing wax having a weight loss of more than 0.60 weight % (wt.%) and a second, slow diffusing wax having a weight loss less than 0.40 wt.% after 2500 hours
Data Source
Figure 1
AI summary
Boot for a constant velocity joint of a polymer composition comprising a thermoplastic polyester elastomer, a first, fast diffusing wax having a weight loss of more than 0.6 wt.%, and a second slow diffusing wax having a weight loss of less than 0.4 wt.% after 2500 hours. Also a polymer composition is claimed.