Crankshaft Impact Correction for Concentricity and Length Tolerances
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Solution Overview
Problem
Modern internal combustion engines face challenges in achieving precise dimensional and positional tolerances, particularly concentricity and length specifications, in crankshafts due to variations during tempering and hardening processes, leading to difficulties in ensuring optimal performance without damaging the component.
Innovation Solution
A method involving the use of impact forces applied through impact tools to correct concentricity errors and length deviations by targeting specific transition radii between bearing journals and crank webs, allowing for precise adjustments while enhancing fatigue strength and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional post-processing methods (hot pressing or expansion) are used to correct concentricity errors and length deviations, then dimensional tolerances can be adjusted, but the crankshaft may suffer from adverse component damage and high financial/technical outlay
Solution Approach 1:
The patent applies localized plastic deformation through controlled impact forces to modify the dimensional parameters of the crankshaft. By applying precise impact forces at specific locations (transition radii between crank webs and journals), the method corrects concentricity errors and length deviations without requiring high-temperature hot pressing or expansive forces that could damage the component. This changes the physical state of the material locally through controlled yielding.
Solution Approach 2:
The correction process is segmented into targeted impact applications at specific transition radii rather than applying uniform forces throughout the entire crankshaft. The method identifies and treats only the specific sectors causing concentricity errors, dividing the correction task into localized interventions that minimize overall stress and damage risk.
2Manufacturing precision
If conventional post-processing methods are used to correct dimensional tolerances, then accuracy can be improved, but the financial and technical outlay increases significantly
Solution Approach 1:
The method utilizes the crankshaft's own structural features (transition radii between crank webs and journals) as the target for correction, rather than requiring external fixtures or complex positioning systems. The impact forces are applied directly to the crankshaft's existing geometry to induce self-correction of concentricity and length deviations, reducing the need for additional specialized equipment.
Solution Approach 2:
The patent employs controlled impact forces that temporarily change the dimensional parameters during correction, then allow the material to stabilize at new, corrected dimensions. This approach uses simple impact equipment rather than complex hot pressing or expansion systems, reducing technical outlay while achieving the required precision.
3Manufacturing precision
If impact forces are applied to correct concentricity errors, then manufacturing precision improves, but the structural integrity may be compromised
Solution Approach 1:
The patent applies impact forces only at specific transition radii where concentricity errors exist, rather than uniformly across the entire crankshaft. This localized approach corrects dimensional issues while minimizing disruption to the overall structural integrity. The impact zones are carefully selected to affect only the necessary regions for correction.
Solution Approach 2:
The method applies just enough impact force to achieve the required concentricity correction without excessive force that would compromise structural integrity. The impact energy is controlled to be sufficient for dimensional correction but limited to avoid causing damage, representing a precise balance between correction effectiveness and structural preservation.
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 approach enables precise correction of concentricity and length deviations with minimal financial and technical outlay, improving the fatigue strength and dimensional accuracy of crankshafts, allowing for significant improvements in concentricity and length corrections without causing adverse damage.
Implementation Method 1
an impact force for correcting the concentricity errors and/or the length deviation is introduced into at least one defined transition radius
Implementation Method 2
an impact force for correcting the concentricity errors and/or the length deviation is introduced into at least one defined transition radius between connecting-rod bearing journals and crank webs and/or between main bearing journals and the crank webs
Data Source
AI summary
The invention relates to a method for post-processing a crankshaft (4), in particular in order to correct concentricity errors and/or for a length correction. Sectors (S1,S2,S3,S4,S5,S6) of the crankshaft (4) which produce and/or characterize concentricity errors are detected and/or a length deviation (ΔL1ΔL2, ΔL3) from a target length (L1,L2, L3) is determined for at least one section of the crankshaft (4). An impact force (Fs) is then introduced into at least one defined transition radius (8) between connecting rod bearing journals (5) and crank webs (7) and/or between main bearing journals (6) and the crank webs (7) of the crankshaft (4) by means of at least one impact tool (16) in order to correct the concentricity errors and/or the length deviation (ΔL1ΔL2, ΔL3).