Grease Composition for Low Temperature Stick Slip Suppression
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Solution Overview
Problem
Existing grease compositions used in automobiles lack low temperature performance and fail to effectively suppress stick slip in ball joints, especially at extreme temperatures ranging from -40°C to 80°C.
Innovation Solution
A grease composition comprising a base oil, a urea-based thickener, a sarcosine derivative, and a fatty acid zinc salt, where the particles containing the urea-based thickener have an arithmetic average particle diameter of 2.0 µm or less, and the base oil is a blended hydrocarbon-based synthetic oil with specific viscosity and viscosity index ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If solid lubricants such as amide compounds are used, then starting torque and rotating torque are improved at ordinary temperature, but low temperature performance deteriorates as they solidify at -40°C
Solution Approach 1:
The patent changes the physical state parameter of the lubricant from solid (amide compounds) to liquid (hydrocarbon-based synthetic oil) to enable operation at low temperatures while maintaining lubrication effectiveness through controlled viscosity characteristics
Solution Approach 2:
The patent uses a composite base oil formulation combining hydrocarbon-based synthetic oil with specific viscosity (200 mm²/s at 40°C) and viscosity index (≥140) to achieve both low-temperature fluidity and high-temperature lubrication performance
2Force
If solid lubricants such as amide compounds are used, then lubrication performance is improved at ordinary temperature, but high temperature performance deteriorates as they melt at 80°C or more
Solution Approach 1:
The patent changes the phase stability parameter by using liquid hydrocarbon-based synthetic oil instead of solid amide compounds, ensuring the lubricant remains in liquid state and maintains lubrication performance at high temperatures up to 80°C and beyond
Solution Approach 2:
The patent optimizes the viscosity characteristics of the base oil to provide appropriate lubrication film thickness and friction reduction performance across the entire operating temperature range, with specific attention to maintaining effective lubrication at high temperature contact zones
3Device complexity
If urea-based thickener particles with large particle diameter are used, then grease structure is simplified, but low temperature performance deteriorates
Solution Approach 1:
The patent changes the particle size parameter of the urea-based thickener from large to fine (arithmetic average particle diameter of 2.0 µm or less) to improve low-temperature performance while maintaining adequate grease structure and consistency
Solution Approach 2:
The patent divides the thickener into fine particles to enhance distribution uniformity and prevent agglomeration, which improves low-temperature fluidity and lubrication performance while maintaining structural integrity
4Stability of the object's composition
If grease composition is optimized for high temperature stability, then oil release at high temperature is reduced, but low temperature performance deteriorates
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: base oil viscosity (200 mm²/s at 40°C), viscosity index (≥140), and thickener particle size (≤2.0 µm) to achieve both high-temperature stability with controlled oil release and low-temperature performance
Solution Approach 2:
The patent creates a universal grease formulation that performs effectively across the entire operating temperature range from -40°C to 80°C and beyond, with the hydrocarbon-based synthetic oil providing both low-temperature fluidity and high-temperature 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 grease composition achieves excellent low temperature performance and effectively suppresses stick slip, ensuring improved ride quality and lubrication efficiency across a wide temperature range.
Implementation Method 1
an arithmetic average particle diameter on an area basis as measured by the laser diffraction/scattering method
Data Source
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AI summary
Provided is a grease composition having an excellent low temperature characteristic and further capable of suppressing stick slip, which contains a base oil (A), a urea-based thickener (B), a sarcosine derivative (C), and a fatty acid zinc salt (D), wherein particles containing the urea-based thickener (B) in the grease composition satisfies Requirement (I), the base oil (A) is a blended base oil containing a high viscosity hydrocarbon-based synthetic oil having a specific kinematic viscosity (A1), a low viscosity hydrocarbon-based synthetic oil having a specific kinematic viscosity (A2), and an ultra-high viscosity hydrocarbon-based synthetic oil having a number average molecular weight (Mn) of 2,500 to 4,500 and a specific kinematic viscosity (A3), a 40°C kinematic viscosity of the base oil (A) is 500 mm2/s to 1,500 mm2/s, a viscosity index of the base oil (A) is 140 or more, and a content of the fatty acid zinc salt (D) is 10 mass% to 20 mass% based on a total amount of the grease composition.