Radial Face-Gear Coupling Teeth for Higher Load Capacity

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Solution Overview

Problem

Conventional cross-tooth gearing in rail vehicle drive trains experiences high local loads leading to cracks, necessitating a solution with higher load-bearing capacity at similar cost-effectiveness compared to known systems like Klingelnberg cyclopalloid face gears and Hirth gears.

Innovation Solution

A radial-axially movable coupling with trapezoidal cross-section coupling teeth and flat tooth flanks aligned radially, where tooth tips extend along a radial center line, distributing torque more favorably and avoiding intersecting pairs, allowing for varying or constant tooth and gap widths across the radius, and symmetrical tooth distribution for balanced resilience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cross-toothing with four groups of teeth arranged diametrically is used, then cost-effectiveness is improved compared to Klingelnberg cyclopalloid face gears and Hirth gears, but high local loads occur in the flange leading to cracks

Engineering Contradiction:
Improvecost-effectivenessVSAvoidload-bearing capacity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent transitions from the conventional symmetrical cross-toothing arrangement (with intersecting tooth tip center lines) to an asymmetrical radial arrangement where all tooth tip center lines are aligned parallel to the radial direction and converge at the pivot point. This asymmetrical configuration redistributes the load paths to avoid concentration at intersecting points, thereby increasing load-bearing capacity while maintaining the cost-effective manufacturing approach of cross-toothing

Inventive Principle:
Principle #4Asymmetry

2Device complexity

If tooth tips are arranged with intersecting center lines in pairs, then conventional cross-tooth gearing structure is maintained, but areas with high local loads occur leading to cracks

Engineering Contradiction:
Improvegearing structureVSAvoidcrack resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent inverts the conventional design approach by reversing the tooth tip arrangement: instead of having tooth tip center lines intersect in pairs at different locations, all tooth tip center lines are now aligned radially and converge at the single pivot point. This inversion of the geometric arrangement eliminates the harmful intersecting stress concentrations while preserving the fundamental cross-tooth gearing structure and its manufacturing advantages

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3052365B1Coupling for rotationally fixed connecting of a shaft
Publication Date: 2021.03.10 VOITH PATENT GMBH
  • EP3052365B1 patent drawingFigure 1
  • EP3052365B1 patent drawingFigure 2
  • EP3052365B1 patent drawingFigure 3

AI summary

The invention relates to a coupling half for rotationally fixed connecting of a shaft having a flange (1), which bears coupling teeth (3) on an axial face, wherein the coupling teeth (3) are designed as a face gear having a plurality of teeth (5) positioned adjacent to each other, each separated by a tooth gap and having a trapezoidal cross-section and flat tooth flanks (5.1), and a flat tooth crest (5.2) positioned on the axial face of the coupling half is arranged between every two tooth flanks (5.1). The invention is characterized in that the tooth crests (5.2) each extend between the tooth flanks (5.1) along a tooth crest center line (5.3) which is aligned in the radial direction to a rotation axis (4) of the coupling half.