Shock Absorber Lubricant Additive System for Stability
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Solution Overview
Problem
Conventional lubricating oils for automobile shock absorbers enhance friction between an oil seal and a piston rod, but this increases friction at other interfaces, impairing riding comfort and failing to suppress micro-vibration during high-speed driving, while also generating excessive foam and compromising low-temperature flowability.
Innovation Solution
A lubricating oil composition incorporating alkenylsuccinimide, acidic phosphite diester, and perbasic alkaline earth metal sulfonate or phenate in specific amounts within a mineral or synthetic base oil, which enhances friction at the oil seal-piston rod interface, reduces friction at the piston rod-guide bush interface, and suppresses foaming, maintaining driving stability and comfort even under lateral loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the frictional force between oil seal and piston rod is enhanced to suppress micro-vibration, then driving stability is improved, but the friction coefficient at other sliding interfaces (piston rod and guide bush) increases, impairing riding comfort
Solution Approach 1:
The patent applies local quality by using a multi-component additive system where each component selectively affects specific interfaces. The alkenylsuccinimide primarily enhances friction at the oil seal-piston rod interface, while the acidic phosphite diester and perbasic alkaline earth metal sulfonate/phenate/salicylate control friction at the piston rod-guide bush interface, allowing different friction characteristics at different locations
Solution Approach 2:
The patent changes the chemical composition parameters of the lubricating oil by incorporating specific additives in controlled amounts. The alkenylsuccinimide (0.1-2.0 mass%), acidic phosphite diester (0.1-2.0 mass%), and perbasic alkaline earth metal sulfonate/phenate/salicylate (0.001-0.3 mass%) work together to modify friction characteristics at different interfaces through chemical adsorption and film formation
2Stability of the object's composition
If conventional lubricating oil reduces friction at sliding interfaces to enhance vibration damping, then vibration damping effect is improved, but micro-vibration during high-speed driving cannot be suppressed
Solution Approach 1:
The patent changes the friction parameter at the oil seal-piston rod interface by adding alkenylsuccinimide, which increases the frictional force specifically at this interface. This localized friction enhancement provides the necessary damping force to suppress micro-vibrations during high-speed driving, while the other additives ensure this doesn't compromise overall vibration damping performance
3Object-affected harmful factors
If the friction coefficient at piston rod and guide bush interface is reduced to improve riding comfort, then riding comfort is improved, but vibration cannot be damped when lateral load is applied
Solution Approach 1:
The patent applies local quality by differentiating the friction control at different interfaces. The acidic phosphite diester and perbasic alkaline earth metal sulfonate/phenate/salicylate are formulated to reduce friction at the piston rod-guide bush interface for comfort, while the alkenylsuccinimide maintains adequate friction at the oil seal-piston rod interface for vibration damping under lateral loads
4Speed
If low-temperature flowability is improved to ensure operation in cold districts, then flowability is improved, but riding comfort may be impaired
Solution Approach 1:
The patent changes the viscosity parameter of the base oil to optimize low-temperature flowability while maintaining appropriate viscosity at operating temperature. The base oil is selected or formulated to have low viscosity at cold temperatures for good flowability, but the additive system ensures the overall lubrication performance and friction characteristics remain appropriate for comfort at normal operating temperatures
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 lubricating oil composition effectively enhances driving stability and riding comfort by optimizing frictional forces and foaming properties, while ensuring excellent low-temperature flowability, thus addressing the limitations of conventional shock absorber oils.
Implementation Method 1
lubricating oils for a shock absorber in automobiles have exhibited enhanced vibration damping effect through reducing the friction at a sliding interface between an oil seal and a piston rod
Implementation Method 2
the micro-vibration can be suppressed through enhancing the frictional force between an oil seal and a piston rod, resulting in enhanced-level driving stability during high-speed driving
Data Source
AI summary
To provide a lubricating oil composition including a base oil which is composed of a mineral oil and/or a synthetic oil and which has a viscosity index of 95 or higher, and (A) an alkenylsuccinimide in an amount of 0.1 to 2.0 mass %, (B) an acidic phosphite diester having a C6 to C10 hydrocarbon group in an amount of 0.1 to 2.0 mass %, and (C) at least one species selected from among a perbasic alkaline earth metal sulfonate, a perbasic alkaline earth metal phenate, and a perbasic alkaline earth metal salycilate, in an amount of 0.001 to 0.3 mass %, with respect to the total amount of the composition. When employed in an automobile shock absorber, the composition enhances the frictional force at an interface between an oil seal and a piston rod of an automobile shock absorber, reduces the friction coefficient at an interface between a piston rod and a guide bush, suppresses foaming to thereby enhance driving stability during travel of the automobile, and improves riding comfort even when the automobile travels while receiving a lateral load exerted by small steps present on the road surface.