Grease Composition for Four-Point Contact Bearing Torque Reduction

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Solution Overview

Problem

Conventional grease compositions fail to effectively reduce torque in four-point contact bearings, especially under conditions of high radial load or low rolling speed, where sliding motion increases torque and leads to stick-slip phenomena.

Innovation Solution

A grease composition is developed using lithium soap or lithium complex soap as a thickener, combined with a base oil and a friction modifier comprising fatty acids, phosphate esters, thiophosphate esters, and zinc dithiophosphates, optimized for reduced torque in rolling sliding motions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the size of mechanical parts is reduced to achieve energy consumption reduction, then weight and size are reduced, but torque of bearing increases due to increased rolling sliding motion

Engineering Contradiction:
Improveweight of bearingVSAvoidtorque of bearing
Core Design Contradiction:
Weight of moving objectVSForce

Solution Approach 1:

The invention changes the chemical composition parameters of the grease by specifying precise ratios of多元醇酯 (20-40 mass%), 二醇酯 (10-30 mass%), and 单醇酯 (10-30 mass%), along with specific additive packages, to optimize lubrication properties and reduce torque in compact bearings

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite grease formulation combining multiple ester types (多元醇酯, 二醇酯, 单醇酯) with specific additives (anti-wear agents, extreme pressure agents, antioxidants) to create a synergistic lubricating material that effectively reduces torque in miniaturized bearings

Inventive Principle:
Principle #40Composite materials

2Device complexity

If conventional grease compositions are used in four-point contact bearings under high radial load or low rolling speed, then the bearing structure is simple, but sliding motion increases torque and causes stick-slip phenomenon

Engineering Contradiction:
Improvebearing structureVSAvoidtorque
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The invention optimizes the viscosity index and lubricity parameters of the grease by selecting specific ester combinations and additives, enabling the grease to maintain effective lubrication film under high radial load and low speed conditions, preventing stick-slip phenomenon

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The grease acts as an intermediary substance that modifies the interaction between bearing surfaces, using its chemical composition (esters and additives) to reduce direct metal-to-metal contact and sliding friction under extreme operating conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

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 significantly reduces friction and torque in rolling sliding motions, particularly in four-point contact bearings, while maintaining excellent low-temperature flowability and heat resistance.

Implementation Method 1

a grease composition capable of effectively reducing torque... the grease composition significantly reduces friction and torque in rolling sliding motions

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

a friction modifier comprising fatty acids, phosphate esters, thiophosphate esters, and zinc dithiophosphates, optimized for reduced torque in rolling sliding motions

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP3492564B1Grease composition
Publication Date: 2024.02.28 KYODO YUSHI CO LTD

AI summary

A grease composition comprises a thickener, a base oil, and a friction modifier. The friction modifier comprises: at least one selected from the group consisting of fatty acids, fatty acid metal salts, phosphate esters, thiophosphate esters, and zinc dithiophosphates; and a polyhydric alcohol ester.