Connecting Rod Eccentric Adjusting Device Lubrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing connecting rods for internal combustion engines with adjustable compression ratios face challenges in effectively lubricating the contact regions between the small end bearing eye and the eccentric, leading to potential material weakening and increased stress due to the introduction of lubricating oil bores, which also affect the weight and clearance of the rod.
Innovation Solution
Introducing lubricating oil bores into the small end bearing eye with varying radial wall thickness to create a lubricating oil film between the small end bearing eye and the eccentric, ensuring sufficient clearance and reduced weight by optimizing the wall thickness in regions with and without bores, and maintaining continuous transitions to avoid stress increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lubricating oil bores are introduced into the small end bearing eye, then lubrication is improved, but structural strength is weakened
Solution Approach 1:
The small end bearing eye is designed with non-uniform wall thickness: thicker in regions where lubricating oil bores are introduced to maintain structural strength, and thinner in other regions to reduce weight. This local variation in quality allows the bearing eye to simultaneously achieve adequate strength for load-bearing and effective lubrication through the bores.
2Strength
If wall thickness is increased to maintain strength, then structural integrity is improved, but weight increases
Solution Approach 1:
The bearing eye features spatially varying wall thickness with localized thickening only in critical regions where lubricating oil bores are present. This allows weight reduction in non-critical areas while maintaining sufficient strength and structural integrity in load-bearing regions, achieving an optimized balance between weight and strength.
3Ease of manufacture
If uniform wall thickness is used, then manufacturing is simplified, but stress concentration occurs at bore locations
Solution Approach 1:
The wall thickness is locally increased in regions surrounding the lubricating oil bores to compensate for the stress concentration that would otherwise occur at the bore locations. This local reinforcement prevents stress peaks while the overall simplified bore design maintains ease of manufacturing through standard drilling operations.
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 solution provides enhanced lubrication and reduced weight of the connecting rod while maintaining structural integrity and clearance for the eccentric rods, ensuring efficient operation and durability of the internal combustion engine.
Implementation Method 1
lubricating oil bores are introduced into the small end bearing eye and enable a lubricating oil film to be built up between the small end bearing eye and the eccentric
Data Source
AI summary
A connecting rod (10) has a big end bearing eye (11) for attachment to a crankshaft, a small end bearing eye (12) for attachment to a piston, and an eccentric adjusting device (13) for adjusting an effective connecting rod length. The eccentric adjusting device (13) has eccentric rods (15, 16) that engage on an eccentric lever (14), an eccentric (36) that is guided in an aperture in the eccentric lever (14) and in the small end bearing eye (12) and an aperture for accommodating a piston pin (37). Lubricating oil bores (38, 39) are introduced into the small end bearing eye (12) via which a lubricating oil film can be built up between the small end bearing eye (12) and the eccentric (36). The small end bearing eye (12) has a larger radial wall thickness in those regions in which the lubricating oil bores (38, 39).