Copolyetherester CVJ Boot Composition for Squeak Reduction
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Solution Overview
Problem
Constant-velocity joint (CVJ) boots in vehicles experience high-frequency squeak noise, particularly at high angles and low rotation speeds, which becomes more noticeable due to advancements in noise reduction in car interiors and the quiet operation of electric and hybrid vehicles, and is exacerbated by thinner boot designs and increased rotational demands.
Innovation Solution
A copolyetherester composition for CVJ boots incorporating stearates such as stearic acid, aluminium tristearate, aluminium distearate, and polytetrafluoroethylene (PTFE) is used, which significantly reduces squeak noise when formulated into the boot material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional copolyetherester formulations are used in CVJ boots, then the boots provide adequate mechanical protection and flexibility, but they generate high-frequency squeak noise under high angle and low rotation speed conditions
Solution Approach 1:
The patent modifies the chemical composition parameters of the copolyetherester by incorporating specific amounts of PTFE (0.01-5 wt%) and stearate (0.1-5 wt%) additives. This changes the surface properties and friction characteristics of the material, thereby reducing squeak noise generation while maintaining the boot's mechanical functionality
Solution Approach 2:
The patent creates a composite material system by combining copolyetherester base resin with PTFE and stearate additives. This composite formulation leverages the low-friction properties of PTFE and the lubricating characteristics of stearate to reduce squeak noise, while the copolyetherester provides the structural framework and elastomeric properties needed for CVJ boot functionality
2Weight of moving object
If the CVJ boot is made thinner to reduce weight and improve flexibility, then the boot allows better maneuvering and reduced material usage, but noise absorption capability is reduced making squeak more noticeable
Solution Approach 1:
The patent changes the friction and noise-generation parameters of the boot material itself by adding PTFE and stearate. This allows thin-walled boots to inherently suppress squeak at the source through modified surface properties, rather than relying on thickness for noise absorption
3Adaptability or versatility
If larger angles of rotation are implemented to meet consumer maneuvering requirements, then the boot provides improved steering capability, but squeak noise generation is exacerbated
Solution Approach 1:
The patent modifies the friction characteristics parameter of the boot material through PTFE and stearate incorporation. This enables the boot to accommodate larger rotation angles with reduced squeak generation, as the modified surface properties maintain smoother operation even at extreme angles where conventional materials would squeak
Data Source
AI summary
Provided herein is a copolyetherester resin composition that is suitable for the manufacture of CVJ boots showing reduced squeak. Further provided are CVJ boots comprising the copolyetherester resin composition.