Rolling Bearing Grease Composition for Rust and Flaking Resistance
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Solution Overview
Problem
Existing grease compositions for bearings used in wet environments, such as electromagnetic clutches and idler pulleys, face challenges in simultaneously preventing rust and white layer flaking, with increased rust inhibitor amounts or types often compromising white layer flaking resistance.
Innovation Solution
A grease composition for rolling bearings that includes a base oil, a thickener, a rust inhibitor comprising calcium sulfonate, zinc sulfonate, and zinc carboxylate, and an extreme pressure agent such as zinc dialkyldithiophosphate, carefully balanced to prevent white layer flaking and impart excellent rust-preventing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blending amount of rust inhibitor is increased or multiple kinds of rust inhibitors are blended, then the rust-preventing property is improved, but the white layer flaking resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the content ratios of three different rust inhibitors (calcium sulfonate: 0.10-10.00 mass%, zinc sulfonate: 0.20-10.00 mass%, zinc carboxylate: 0.10-10.00 mass%) to achieve optimal rust prevention while maintaining white layer flaking resistance. This quantitative parameter optimization resolves the contradiction by finding the precise compositional balance point.
Solution Approach 2:
The patent uses a composite approach by combining three different types of rust inhibitors (calcium sulfonate, zinc sulfonate, and zinc carboxylate) with an extreme pressure agent (zinc dialkyldithiophosphate: 2.00-14.00 mass%). This composite material strategy allows the system to achieve both rust prevention and white layer flaking resistance through synergistic effects, where each component contributes different protective mechanisms.
2Reliability
If a grease composition provides excellent rust-preventing property in wet environment, then the bearing reliability is improved, but the white layer flaking resistance may be compromised
Solution Approach 1:
The extreme pressure agent (zinc dialkyldithiophosphate) acts as an intermediary that forms a protective reaction film on the bearing surfaces. This intermediary layer provides dual functionality: it prevents white layer flaking through extreme pressure protection while also contributing to rust prevention, thereby mediating between the two competing requirements.
Solution Approach 2:
The grease composition employs a composite material system combining multiple rust inhibitors with an extreme pressure agent, where each component serves a specific function. The synergistic interaction between these composite materials enables simultaneous achievement of rust prevention in wet environments and white layer flaking resistance, which cannot be achieved by single additives alone.
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 prevents white layer flaking and provides excellent rust-preventing properties for rolling bearings, even in wet environments, by forming a reaction film with the extreme pressure agent and a dense adsorption film with the rust inhibitors.
Implementation Method 1
a reaction film including the zinc dialkyldithiophosphate is formed, and the occurrence of white layer flaking in the rolling bearing can be prevented
Implementation Method 2
since the grease composition includes predetermined amounts of a calcium sulfonate, a zinc sulfonate, and a zinc carboxylate as the rust inhibitors, the occurrence of rust can be prevented
Data Source
AI summary
The present invention relates to a grease composition including: a base oil; a thickener; a rust inhibitor; and an extreme pressure agent, in which the rust inhibitor includes, with respect to a total mass of the grease composition: 0.10 mass % to 10.00 mass % of a calcium sulfonate; 0.20 mass % to 10.00 mass % of a zinc sulfonate; and 0.10 mass % to 10.00 mass % of a zinc carboxylate, and the extreme pressure agent includes, with respect to the total mass of the grease composition, 2.00 mass % to 14.00 mass % of a zinc dialkyldithiophosphate.