Urea-Thickened Grease Composition for Torque and Leakage Balance

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Solution Overview

Problem

Conventional greases with high worked penetration for improved torque transmitting efficiency often compromise leakage prevention, leading to wear and seizure issues in mechanical components, especially in high-load applications like speed reducers and speed increasers.

Innovation Solution

A grease composition using a urea-based thickener with specific particle diameter and surface area, combined with an extreme pressure agent, to enhance both torque transmitting efficiency and leakage prevention performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the worked penetration of the grease is increased to improve torque transmitting efficiency, then the torque transmitting efficiency is improved, but the leakage prevention performance is lowered

Engineering Contradiction:
Improvetorque transmitting efficiencyVSAvoidleakage prevention performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the particle size distribution of the urea-based thickener (arithmetic average particle diameter of 2.0 μm or less, with 90% or more of particles being 3.0 μm or less) and optimizing the worked penetration within a specific range (300 to 450 at 25°C). This controlled parameter adjustment enables the grease to achieve both high torque transmitting efficiency and excellent leakage prevention performance simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material approach by combining a urea-based thickener with specific particle size characteristics, extreme pressure agents (sulfur-based, phosphorus-based, or sulfur-phosphorus-based), and base oil in optimized proportions. This composite formulation creates a grease that balances softness for torque transmission with structural integrity for leakage prevention

Inventive Principle:
Principle #40Composite materials

2Productivity

If the worked penetration of the grease is increased to improve torque transmitting efficiency, then the torque transmitting efficiency is improved, but the wear resistance and load resistance cannot be thoroughly secured

Engineering Contradiction:
Improvetorque transmitting efficiencyVSAvoidwear resistance and load resistance
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent controls the particle size parameters of the urea-based thickener (arithmetic average ≤2.0 μm, 90% ≤3.0 μm) and worked penetration (300-450 at 25°C) to create an optimal balance between softness for torque transmission and structural integrity for wear and load resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent formulates a composite grease system combining urea-based thickener with controlled particle distribution, extreme pressure agents (sulfur-based, phosphorus-based, or sulfur-phosphorus-based), and base oil, where the synergistic interaction of components provides both torque transmitting efficiency and protective films for wear and load resistance

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If a urea-based thickener is used in the grease, then the heat resistance and oxidation stability are improved, but the wear resistance and load resistance cannot be thoroughly improved even when an extreme pressure agent is blended

Engineering Contradiction:
Improveheat resistance and oxidation stabilityVSAvoidwear resistance and load resistance
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent optimizes the particle size parameters of the urea-based thickener (arithmetic average particle diameter of 2.0 μm or less, with 90% or more of particles being 3.0 μm or less) to enhance both the heat resistance/oxidation stability provided by the urea structure and the wear resistance/load resistance through improved extreme pressure agent distribution and reaction

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite formulation where the urea-based thickener with controlled particle size works synergistically with extreme pressure agents (sulfur-based, phosphorus-based, or sulfur-phosphorus-based), forming a multi-functional system that simultaneously provides thermal stability, oxidative stability, and superior wear and load protection

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3936591B1Grease composition
Publication Date: 2024.11.13 IDEMITSU KOSAN CO LTD
  • EP3936591B1 patent drawingFigure 1
  • EP3936591B1 patent drawingFigure 2
  • EP3936591B1 patent drawingFigure 3

AI summary

The present invention relates to provision of an extreme pressure agent-containing grease composition using, as a thickener, a urea-based thickener, the grease composition being excellent in both torque transmitting efficiency and leakage prevention performance and also excellent in wear resistance and load resistance. The grease composition contains a base oil (A), a urea-based thickener (B), and an extreme pressure agent (C), wherein particles containing the urea-based thickener (B) in the grease composition satisfies the following requirement (I): Requirement (I): an arithmetic average particle diameter of the particles on an area basis as measured by the laser diffraction/scattering method is 2.0 pm or less, and the extreme pressure agent (C) is at least one selected from an organic metal-based extreme pressure agent, a sulfur-based extreme pressure agent, a phosphorus-based extreme pressure agent, and a sulfur-phosphorus-based extreme pressure agent.