Connecting Rod Center Link Fracture Splitting Without V-Groove Machining
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Solution Overview
Problem
Fracture-splitting techniques in connecting rod fabrication often result in undesired fracture propagation due to material characteristics or design issues, necessitating costly remedial measures like machining V-grooves to control the fracture path.
Innovation Solution
A method involving forming a green workpiece from powdered metal with strategically designed V-notches and channels, followed by sintering, forging, and machining to create a separation plane for controlled fracture, allowing precise fracture propagation without the need for additional machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fracture-splitting is performed on workpieces with certain design or material characteristics, then the fracture propagates in an undesired manner, but adding remedial measures like machining V-grooves increases manufacturing cost and complexity
Solution Approach 1:
The patent applies preliminary action by forming V-notches and channels into the green workpiece before sintering and forging. These features are created in advance during the powder metallurgy forming stage, allowing the fracture to propagate along the desired separation plane without requiring subsequent machining operations. The V-notches are formed at strategic locations where the separation plane intersects the exterior surfaces, pre-defining the fracture path before the material is sintered and forged.
Solution Approach 2:
The patent utilizes parameter changes by transforming the physical state of the material through sintering and forging processes. The green workpiece with V-notches and channels is sintered to form a sintered workpiece, then forged to densify and close the channels while maintaining the V-notches. This parameter change in material density and structure allows the pre-formed V-notches to effectively guide fracture propagation in the final forged component without requiring additional machining.
2Manufacturing precision
If remedial measures like machining V-grooves are added to control fracture propagation, then fracture control improves, but production cost increases
Solution Approach 1:
The patent merges the formation of V-notches with the initial green workpiece forming process. Instead of adding a separate machining operation after manufacturing, the V-notches are created during the powder metallurgy forming stage using conventional forming techniques. This merging of operations eliminates the need for costly post-manufacturing machining while achieving the same fracture control effect.
Solution Approach 2:
The patent discards the need for expensive remedial machining operations by recovering the fracture control function through pre-formed V-notches in the green workpiece. The V-notches serve dual purposes: they are formed using standard forming processes (discarding the need for specialized machining) and simultaneously provide the fracture guidance function that would otherwise require costly post-processing.
3Ease of manufacture
If V-notches and channels are formed in the green workpiece before sintering and forging, then controlled fracture propagation is achieved without additional machining, but the forming process complexity increases
Solution Approach 1:
The patent applies local quality by forming V-notches and channels only at specific locations in the green workpiece where the separation plane intersects the exterior surfaces. Rather than modifying the entire workpiece, the V-notches are localized to the critical fracture propagation zones. This localized approach provides precise fracture control while minimizing the complexity of the forming process, as only specific regions require the additional forming steps.
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
Enables controlled fracture propagation along a predetermined plane, reducing the need for costly remedial measures and improving the precision and stability of the joint, thus lowering production costs and enhancing the quality of the finished article.
Implementation Method 1
sintering the green workpiece to form a sintered workpiece
Implementation Method 2
driving the fracturing tool apart while the fracturing tool is inserted into the second bore to fracture the forged workpiece along the separation plane into first and second forged components
Data Source
AI summary
A method includes powder forging and machining a workpiece that is fractured to divide the workpiece into separate components. In a green form in which the workpiece is formed of compacted powdered metal and has a body that is generally shaped as a parallelepiped with a pair of end faces. The body defines a bore, a pair of V-notches and a pair of channels. The V-notches are formed into the bore parallel to the central axis of the bore and cooperate to define a separation plane. Each of the channels is formed in an associated one of the end faces at a location where the separation plane intersects the end face. During forging, the channels are closed but create a stress riser that aids in directing the fracture when the components are separated from one another.