Urea-Thickened Grease Composition for Torque and Leak Control
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Solution Overview
Problem
Existing greases used in speed reducers and speed increasers face challenges in balancing torque transmission efficiency with leak prevention performance, often leading to abrasion and seizure due to reduced grease supply and high load conditions.
Innovation Solution
A grease composition with controlled urea-based thickener particles, having an area-based arithmetic average particle size of 2.0 µm or less and a specific surface area of 0.5 × 10^5 cm^2/cm^3, enhances both torque transmission efficiency and leak prevention performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the worked penetration of grease is increased to improve torque transmission efficiency, then the torque transmission efficiency is improved, but the leak prevention performance of the grease lowers
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size of the urea-based thickener (area-based arithmetic average particle size of 2.0 µm or less) and its specific surface area (0.5 × 10^5 cm^2/cm^3 or more). This parameter optimization allows the grease to achieve both high torque transmission efficiency and excellent leak prevention performance simultaneously, resolving the technical contradiction between these two properties.
Solution Approach 2:
The patent uses a composite material approach by combining base oil with urea-based thickener particles of specifically controlled size and surface area characteristics. This composite structure enables the grease to exhibit both soft consistency for torque transmission and sufficient structural integrity for leak prevention, overcoming the trade-off between these opposing requirements.
2Strength
If the proportion of thickener and additives is increased to improve wear resistance, then the wear resistance is improved, but the grease leak may occur frequently
Solution Approach 1:
The patent resolves this contradiction by changing the particle size parameter of the thickener to 2.0 µm or less with a specific surface area of 0.5 × 10^5 cm^2/cm^3 or more. This parameter optimization allows adequate thickener content to be used for wear resistance while maintaining proper grease consistency to prevent leakage, eliminating the need to increase thickener proportion at the expense of leak prevention.
3Productivity
If the worked penetration is increased to improve torque transmission, then the torque transmission efficiency is improved, but the grease supply amount gradually reduces causing abrasion and seizure
Solution Approach 1:
The patent applies parameter changes to the thickener particle size (2.0 µm or less) and specific surface area (0.5 × 10^5 cm^2/cm^3 or more) to achieve an optimal balance. This allows the grease to maintain both high torque transmission efficiency and adequate supply characteristics, preventing the gradual reduction in grease supply that leads to abrasion and seizure while still achieving excellent torque transmission.
Data Source
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AI summary
The present invention addresses a problem of providing a grease composition for speed reducers and speed increasers, excellent in both torque transmission efficiency and leak prevention performance. The grease composition contains a base oil (A) and a urea-based thickener (B), which is used for speed reducers and speed increasers, wherein the particles containing the urea-based thickener (B) in the grease composition satisfy the following requirement (I). Requirement (I): the area-based arithmetic average particle diameter of the particles is 2.0 pm or less, as measured by a laser diffraction/scattering method.