Camshaft Adjusting Arrangement Radial Stress Control
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Solution Overview
Problem
Existing camshaft adjusting devices face challenges in maintaining precise radial compressive stress between components due to production tolerances, leading to inconsistent press-fits and potential mechanical issues.
Innovation Solution
Incorporating groove-like recesses as compensating elements on the cylindrical receiving and seating faces of the components to reduce radial compressive stress, allowing for elastic or plastic deformation and controlling the axial joining force, thus maintaining the press-fit within a defined range without sacrificing cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a press-fit is provided between the cylindrical receiving face and cylindrical seating face to afford sufficient grip, then the radial compressive stress increases to ensure mechanical connection, but the production tolerances cause the stress to vary outside the predefined tolerance band
Solution Approach 1:
The patent introduces compensating elements (grooves or recesses) at specific locations on the cylindrical seating face or receiving face. These local modifications create zones that accommodate dimensional variations, allowing the press-fit to maintain consistent radial compressive stress despite production tolerances. The compensating elements are strategically positioned to distribute and equalize the stress distribution across the contact surface.
Solution Approach 2:
The patent modifies the geometric parameters of the contact surface by introducing compensating elements that change the local contact area and stress distribution. By altering the surface topology through grooves or recesses, the system compensates for variations in component dimensions, thereby maintaining the radial compressive stress within the predefined tolerance band across different production batches.
2Manufacturing precision
If production tolerances are tightened to maintain radial compressive stress within tolerance band, then the press-fit consistency improves, but the production cost increases
Solution Approach 1:
Rather than tightening all production tolerances across the entire component, the patent applies compensating elements only at critical locations on the cylindrical faces. This localized approach maintains stress consistency without requiring expensive precision manufacturing across the whole part, thereby controlling production costs while achieving the desired stress tolerance.
Solution Approach 2:
The compensating elements are designed to automatically compensate for dimensional variations within the component design itself, eliminating the need for post-manufacturing adjustments or inspections. The grooves or recesses self-adjust to accommodate tolerance variations, providing a cost-effective solution that does not require additional manufacturing processes or quality control steps.
3Strength
If axial joining force is increased to ensure adequate press-fit, then the mechanical connection strength improves, but the assembly forces exceed admissible limits and compromise fatigue strength
Solution Approach 1:
The compensating elements create localized zones that optimize the stress distribution during assembly. By concentrating the joining force in specific areas through the grooves or recesses, the system achieves adequate mechanical connection strength without requiring excessive overall axial force, thereby protecting the components from fatigue damage.
Solution Approach 2:
The compensating elements are pre-designed into the component geometry to cushion and distribute the axial joining force during assembly. These features act as built-in stress distributors that prevent force concentration, allowing the press-fit to be performed within admissible force limits while still achieving the required mechanical connection strength.
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 compensating elements effectively manage production tolerances, ensuring a controlled and limited radial compressive stress, reducing assembly forces and maintaining fatigue strength while maintaining economic production and precise alignment.
Implementation Method 1
allowing for elastic or plastic deformation
Implementation Method 2
allowing for elastic or plastic deformation
Data Source
AI summary
A camshaft adjusting arrangement for varying angular position of a camshaft relative to a crankshaft of an internal combustion engine which has a drive element that is driven by the crankshaft and is rotatable in relation to the camshaft, at least two hydraulic chambers, to which a hydraulic fluid can be admitted to set a defined relative rotational position between the drive element and camshaft, formed between the drive element and camshaft, a first component and a second component. The first component has a cylindrical receiving face which receives a cylindrical seating face of the second component. To keep the resulting radial compressive stress between the components within an admissible range, at least one compensating element is arranged in the cylindrical receiving face of the first component and/or in the cylindrical seating face of the second component.