CV Joint Grease Composition for High-Temperature Durability
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Solution Overview
Problem
Existing grease compositions for constant-velocity joints (CVJs) do not adequately address durability and initial conformability at high temperatures, leading to vibrations and noise due to sliding resistance and friction, which is exacerbated by high-temperature environments.
Innovation Solution
A grease composition using a base oil with specific kinematic viscosity and viscosity index, combined with a diurea-based thickener and specific additives like zinc dialkyldithiophosphate, molybdenum dialkyl dithiocarbamate, and benzothiazole-thione, to enhance durability and initial conformability even in high-temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional grease compositions are used, then ordinary temperature durability is improved, but high temperature durability and initial conformability deteriorate
Solution Approach 1:
The invention changes the chemical composition parameters of the grease by incorporating specific additives (zinc dialkyldithiophosphate, molybdenum dialkyl dithiocarbamate, benzothiazole-thione derivatives) in controlled amounts to achieve optimal high-temperature performance while maintaining ordinary temperature durability
Solution Approach 2:
The invention creates a composite grease formulation by combining multiple additives with specific base oil and thickener components, where each component contributes specific properties that collectively resolve the temperature-dependent performance contradiction
2Object-generated harmful factors
If sliding resistance is reduced, then vibrations and noise are reduced, but durability at high temperature deteriorates
Solution Approach 1:
The invention optimizes the friction characteristics by adjusting the concentration and type of extreme pressure additives, achieving a balance between low sliding resistance (reduced vibrations and noise) and high-temperature durability through precise parameter control of the lubricant composition
3Manufacturing precision
If initial conformability is improved, then surface waviness is smoothed promptly, but high temperature stability deteriorates
Solution Approach 1:
The invention modifies the chemical parameters of the grease formulation, specifically the ratio and type of additives, to achieve rapid surface conformability while maintaining compositional stability at elevated temperatures through optimized chemical interactions
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 exhibits excellent durability, initial conformability, shear stability, and vibration resistance, maintaining lubricity and reducing sliding resistance across various temperature ranges.
Implementation Method 1
a base oil having a kinematic viscosity of 16.0 mm2/s or more at 100° C. and a viscosity index of 90 or more
Implementation Method 2
a zinc dialkyldithiophosphate, a non-oil-soluble molybdenum dialkyl dithiocarbamate, an oil-soluble molybdenum dialkyl dithiocarbamate
Implementation Method 3
a sliding resistance in the axial direction is generated by friction between the members inside the joint
Data Source
AI summary
A grease composition for a constant-velocity joint includes:(a) a base oil having a kinematic viscosity of 16.0 mm2/s or more at 100° C. and a viscosity index of 90 or more;(b) a diurea-based thickener, for example, an aliphatic diurea;(c) 0.2 to 2.0% by mass of zinc dialkyldithiophosphate;(d) 0.5 to 2.0% by mass of non-oil-soluble molybdenum dialkyl dithiocarbamate;(e) 0.5 to 3.0% by mass of oil-soluble molybdenum dialkyl dithiocarbamate;(f) 1.0 to 4.0% by mass of zinc dialkyldithiocarbamate; and(g) 0.1 to 1.5% by mass of a benzothiazole-thione or a derivative thereof, wherein (f):(g)=8:1 to 3:1 (mass ratio).