CVT Lubricating Oil Composition for Traction and Low Temperature Fluidity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lubricating oil compositions for continuously variable transmissions in traction drive systems face challenges in achieving high traction coefficient, low temperature fluidity, and high flash point simultaneously, which are essential for both cold startability and handling safety.
Innovation Solution
A lubricating oil composition comprising a naphthene-based synthetic oil with a flash point of 140°C or higher, longifolene, and a monoester-based synthetic oil, which are blended to achieve a balance of high traction coefficient, excellent low temperature fluidity, and high flash point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a lubricant base oil composition containing naphthene-based synthetic lubricant base oil and paraffine-based synthetic lubricant base oil is used, then low temperature fluidity is improved, but traction coefficient deteriorates
Solution Approach 1:
The patent uses a composite lubricant base oil composition containing three specific components: naphthene-based synthetic lubricant base oil (60-95 mass%), polyalphaolefin (5-30 mass%), and ester-based lubricant (2-30 mass%). This composite approach combines the low-temperature fluidity benefits of naphthene-based oils with the traction properties of esters and the viscosity stability of polyalphaolefin, achieving both low temperature fluidity and high traction coefficient simultaneously
2Temperature
If poly alpha-olefin is added to improve low temperature fluidity, then low temperature startability is improved, but flash point deteriorates
Solution Approach 1:
The patent carefully controls the molecular weight distribution and composition parameters of the polyalphaolefin component, selecting specific grades that provide adequate low-temperature fluidity while maintaining higher flash point characteristics. Additionally, the ester-based lubricant component (2-30 mass%) is specifically selected to have high flash point properties, compensating for any flash point reduction from the polyalphaolefin and achieving a balanced overall flash point
3Force
If ester-based lubricant is increased to improve traction coefficient, then torque transmission capacity is improved, but low temperature fluidity deteriorates
Solution Approach 1:
The patent selects ester-based lubricants with specific molecular structures and properties that provide high traction coefficients while having relatively better low-temperature flow characteristics compared to traditional esters. The ester component is specifically chosen to have appropriate chain length and branching that balances traction performance with low-temperature fluidity, rather than using high-concentration traditional esters that would severely degrade low-temperature properties
Data Source
AI summary
To provide a lubricating oil composition achieving both of high traction coefficient and excellent low temperature fluidity at a higher level and having a high flash point, which contains a naphthene-based synthetic oil (A) having a flash point of 140°C or higher, a longifolene (B), and a predetermined monoester-based synthetic oil (C), a method for producing the lubricating oil composition, and a continuously variable transmission using the lubricating oil composition.