Rolling Tool Hollow-Crowned Flanks for Gear Edge Noise
Solution Overview
Problem
Existing methods for producing crowned toothing on gear wheels face challenges in precision and efficiency, particularly in achieving accurate width crowning without additional machining steps and in maintaining gear quality, as they often require complex tooling and can result in edge carriers leading to noise issues.
Innovation Solution
A rolling tool with multiple hollow-crowned areas on its tooth flanks allows for cross-rolling to produce crowned toothing during the compaction process, enabling the creation of various curve shapes, including progressive crowning, which reduces edge contact and enhances surface quality, and allows for simultaneous machining of multiple gears with improved accuracy and reduced cycle time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If width crowning is applied through hard fine machining (honing or grinding), then good running properties and contact patterns are achieved, but additional machining steps increase manufacturing complexity and time
Solution Approach 1:
The crown is formed on the rolling tool teeth before the rolling process, so that the crowning action is already built into the tool. This preliminary preparation of the tool geometry eliminates the need for subsequent hard fine machining operations, as the crowning is applied during the rolling process itself
Solution Approach 2:
The formation of the crown on the toothing and the compaction of the sintered material are merged into a single rolling process. The rolling tool simultaneously performs both functions: shaping the crown geometry and densifying the material, thereby eliminating separate machining steps
2Reliability
If a crowned toothing is produced by traditional rolling methods, then contact patterns improve, but edge carriers occur leading to locally excessive pressures and noise
Solution Approach 1:
The rolling tool features hollow-crowned tooth flanks with varying curvature radii in different axial regions. This local variation in crown geometry creates different contact zone distributions along the tooth width, preventing concentration of contact stresses at the edges and eliminating edge carriers that cause noise and excessive local pressures
3Manufacturing precision
If multiple hollow-crowned areas are used on the rolling tool, then net shape gearing with improved accuracy is achieved, but tool design complexity increases
Solution Approach 1:
The tooth flank of the rolling tool is divided into multiple hollow-crowned areas along the axial direction, with each area having a specific curvature radius. This segmentation allows different regions of the gear toothing to be formed with optimal crown geometry, improving overall accuracy while the modular design of the tool facilitates manufacturing
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 the production of crowned toothing with improved running properties, reduced noise behavior, and increased strength at the edge areas, while allowing for 'net shape' gearing without post-processing, and can be used for both sintered and helical gears, with the tool design accommodating different diameters and curvature variations for enhanced compression and surface density.
Implementation Method 1
at least regionally compacting the toothing of the gear wheel
Implementation Method 2
contact pressure that causes surface pressure between the tooth flanks of the tool and the workpiece
Data Source
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AI summary
The invention relates to a rolling tool (2) for producing crowned teeth on a gear (5) using a transverse rolling process, in particular for compressing the teeth of the gear (5) at least in some areas, comprising a tool body (6) which has tool teeth (7) projecting radially outward for meshing with the teeth of the gear (5) to be rolled, wherein at least some areas of the tool teeth (7) are concave in the axial direction in the area of the tooth flanks. The invention relates to another tool for producing crowned teeth as well as to an apparatus, a method, and a gear.