Flexible Connecting Rod Small End for Abrasion and Lubrication
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Solution Overview
Problem
Conventional connecting rods in internal combustion engines face issues with abrasion and dysfunction due to the use of sliding bushings, which are prone to oil blockage and interlocking under high explosion pressures, leading to increased production costs and reduced operational reliability.
Innovation Solution
A connecting rod with a flexible structure made of hard material, featuring a center hole with tile-shaped supporting structures that allow elastic deformation to match the bending deformation of the piston pin, eliminating the need for a sliding bushing and ensuring proper lubrication through adjustable oil grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a sliding bushing is pressed in the small end of the connecting rod, then the abrasion between the small end and piston pin is reduced, but the bushing is prone to oil blockage and interlocking under high explosion pressures
Solution Approach 1:
The patent removes the sliding bushing component entirely from the connecting rod small end structure. Instead of using a separate bushing element that requires oil grooves and is susceptible to blockage, the invention integrates the bearing function directly into the small end structure itself, eliminating the source of reliability problems while maintaining abrasion protection
Solution Approach 2:
The patent introduces a special coating layer as an intermediary between the metal small end and the piston pin. This coating layer serves as the actual bearing surface that reduces abrasion, while the underlying metal structure provides mechanical strength. The coating material is specifically selected to prevent interlocking and maintain lubrication under high pressure conditions
2Object-affected harmful factors
If a wear reducing bimetal bushing is used, then the abrasion is weakened, but it is much difficult to select the material for the bearing under high explosion pressures, thereby increasing the production cost
Solution Approach 1:
The patent employs a composite structure consisting of a metal base material (providing strength) and a specialized coating layer (providing bearing properties). This composite approach allows the use of cost-effective base materials while achieving the required wear resistance and pressure tolerance through the coating, avoiding the need for expensive bimetal bushings
Solution Approach 2:
The patent changes the surface properties of the small end through coating application rather than changing the bulk material properties. This allows the base material to remain simple and cost-effective while the surface parameters (friction coefficient, hardness, lubricity) are optimized for high-pressure bearing applications, simplifying material selection and reducing costs
3Stability of the object's composition
If an intensified rigid structure is adopted for mounting the sliding bearing, then a reliable interference fit is provided, but the operational reliability is restricted by the allowable specific pressure of the alloy material
Solution Approach 1:
The patent applies different properties to different parts of the small end structure. The base metal provides rigid structural support and interference fit capability, while the localized coating layer provides the bearing surface with high pressure tolerance. This local differentiation allows the rigid structure to maintain its stability while the coating protects against pressure-induced failures
4Object-affected harmful factors
If a sliding bushing is used, then the friction surface is provided, but the oil path is easy to block and ablation or interlocking occurs on the friction surface due to oil shortage
Solution Approach 1:
The patent eliminates the oil groove system that is inherent to sliding bushings. By removing the bushing component and its associated lubrication channels, the invention eliminates the problem of oil path blockage entirely. The coating-based bearing surface does not require grooves, ensuring continuous oil film formation without blockage risks
Solution Approach 2:
The coating layer acts as a sacrificial element that protects the underlying metal structure. While the coating may wear or degrade over time, it prevents catastrophic failure of the entire small end assembly. The coating can be reapplied or the part replaced more easily than replacing a failed bushing system, improving overall reliability
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
This design enhances friction performance, prevents interlocking, and maintains engine reliability while reducing manufacturing costs by eliminating the need for bushings and ensuring consistent lubrication, thus improving the overall performance and longevity of the engine.
Implementation Method 1
The flexible structure of the small end operates to allow an elastic deformation of the center hole along an axial direction thereof produced by cylinder pressure exerted on the piston pin to adapt to a bending deformation of the piston pin along the axial direction
Data Source
AI summary
A connecting rod of an internal combustion engine, including a small end and a shank. The small end employs a flexible structure made of hard material. The hard material is a steel or alloy material having a tensile strength greater than or equal to 700 megapascal. The small end of the flexible structure includes a circular body, a center hole, and a flexible support. The circular body encircles the center hole, and the center hole is a complete circular hole having a constant diameter. The small end matches with a piston pin. The flexible structure of the small end operates to allow an elastic deformation of the center hole along an axial direction thereof produced by cylinder pressure exerted on the piston pin to adapt to a bending deformation of the piston pin along the axial direction.