Grease Composition Noise Reduction Low-Temperature Fluidity
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Solution Overview
Problem
Existing grease compositions fail to simultaneously achieve excellent noise reduction and operability at low temperatures due to limitations in fluidity and viscosity, with added polymers leading to hardening issues and restricted temperature ranges.
Innovation Solution
A grease composition combining a first base oil with poly-α-olefins or ethylene-α-olefin oligomers and a second base oil like polybutene, with silica as the thickener, where the first base oil exceeds 65% and the second base oil is between 1-35% of the total, maintaining kinematic viscosity and pressure-viscosity coefficients for improved noise reduction and low-temperature operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polymer is added to reduce noise, then noise reduction performance is improved, but the grease hardens upon heating and service life is reduced
Solution Approach 1:
The patent changes the chemical composition parameters by replacing conventional polymers with specific base oil combinations (poly-α-olefin/ethylene-α-olefin oligomer in 95:5 to 70:30 mass ratio) and controlling viscosity characteristics (kinematic viscosity at 40°C of 100-1000 mm²/s, pressure-viscosity coefficient of 10-20 GPa⁻¹) to achieve noise reduction without the hardening problem that limits service life
Solution Approach 2:
The patent creates a composite grease system by combining specific base oils (poly-α-olefin and ethylene-α-olefin oligomer) with complementary properties - the poly-α-olefin provides noise reduction through its pressure-viscosity coefficient while the ethylene-α-olefin oligomer maintains low-temperature fluidity, creating a synergistic composite that avoids the drawbacks of individual components
2Object-affected harmful factors
If base oils with high viscosity are used to reduce noise, then noise reduction is improved, but fluidity at low temperatures deteriorates due to high pour points
Solution Approach 1:
The patent optimizes the viscosity parameters by selecting base oils with specific kinematic viscosity ranges (100-1000 mm²/s at 40°C) and pressure-viscosity coefficients (10-20 GPa⁻¹), creating a balance where sufficient viscosity provides noise reduction while the optimized range maintains acceptable low-temperature fluidity
Solution Approach 2:
The patent combines poly-α-olefin (providing noise reduction through pressure-viscosity coefficient) with ethylene-α-olefin oligomer (providing low-temperature fluidity) in a specific mass ratio of 95:5 to 70:30, creating a composite base oil system where the complementary properties of each component synergistically address both noise reduction and low-temperature operability requirements
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 grease composition effectively reduces noise and maintains operability at low temperatures, as demonstrated by improved sound pressure levels and torque performance in vehicle air conditioning units, while avoiding the drawbacks of polymer-based greases.
Implementation Method 1
the base oil has a kinematic viscosity of 350 to 1400 mm2/s and a pressure-viscosity coefficient of 10 to 20 GPa-1, thereby excellent noise reducing effect is obtained
Implementation Method 2
the thickener comprises silica
Data Source
AI summary
The invention provides a grease composition capable of smoothly operating the lubricated parts even under wide-ranging temperature conditions, and at the same time, exhibiting excellent noise reducing effect on the lubricated parts. The grease composition containing a base oil and a thickener is provided, wherein the base oil includes at least one first base oil selected from the group consisting of poly-α-olefins and ethylene-α-olefin oligomers and at least one second base oil selected from the group consisting of polybutene, polyisobutylene, polymethacrylate, and styrene based copolymers, with the first base oil being contained in an amount of 65 mass% or more and the second base oil being contained in an amount of 1 mass% or more and less than 35 mass% based on the total mass of the base oil, the base oil having a kinematic viscosity of 350 to 1400 mm2/s at 40°C, the first base oil having a kinematic viscosity of 300 to 1200 mm2/s at 40°C, and the second base oil having a kinematic viscosity of 1500 to 200,000 mm2/s at 40°C.