Shaft Elevation Welding for Notch-Resistant Functional Element Joining

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Solution Overview

Problem

Existing methods for connecting functional elements to a shaft, such as welding, often result in the formation of metallurgical notches and shaped notches, which can lead to microcracks and potential fracture, especially when the functional elements are placed in grooves on the shaft.

Innovation Solution

A process involving the formation of elevations on the shaft by material removal, allowing functional elements to be welded directly to these elevations, thereby avoiding the formation of metallurgical notches on the shaft surface and ensuring full accessibility for the welded seam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If functional elements are placed in grooves on the shaft and welded, then firm integral bonds are achieved, but metallurgical notches and shaped notches form leading to potential fracture

Engineering Contradiction:

Improvebond strengthVSAvoidfracture risk

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Instead of placing functional elements in grooves (concave features), the invention uses elevations (convex features) on the shaft surface. This inversion eliminates the shaped notch that would form in a groove, while still providing a geometric constraint for welding. The elevation creates a positive geometric fit that maintains bond strength without the harmful stress concentration of a groove-shaped notch.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention extracts the harmful shaped notch from the design by eliminating the groove entirely. By using elevations instead of grooves, the design removes the geometric feature that creates stress concentration and potential fracture sites, while retaining the essential function of providing a welded connection between the functional element and shaft.

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If grooves are cut into the shaft for receiving functional elements, then positioning is improved, but material is weakened at the groove site

Engineering Contradiction:

Improvepositioning accuracyVSAvoidmaterial strength

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The invention inverts the conventional approach by using elevations instead of grooves. The elevation provides a positive geometric feature that improves positioning accuracy through a positive fit, while simultaneously preserving material strength by removing material only where necessary to create the elevation, rather than creating a stress-concentrating groove.

Inventive Principle:

Principle #13The other way round (Inversion)

3Strength

If welding is performed on shaft surfaces, then firm bonds are achieved, but metallurgical notches form which can lead to microcracks

Engineering Contradiction:

Improvebond strengthVSAvoidmetallurgical notch formation

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention applies local quality by creating elevations with specific geometric characteristics at the welding location. The elevation provides a localized geometric constraint that improves weld quality and reduces metallurgical notch formation. The elevated surface creates a positive fit that distributes stress more evenly during welding, reducing the severity of metallurgical notches compared to welding in a groove.

Inventive Principle:

Principle #3Local quality

4Ease of manufacture

If grooves are used to receive functional elements, then assembly is simplified, but the faces placed in the groove cannot be reached for welding

Engineering Contradiction:

Improveassembly easeVSAvoidweld accessibility

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The invention inverts the conventional groove design by using elevations. This inversion exposes the welding faces by positioning them on the outer surface of the elevation, making them accessible to welding equipment. The elevation geometry naturally presents the welding surfaces in a more accessible configuration compared to hidden faces within a groove, while still providing the geometric constraint needed for proper alignment during assembly.

Inventive Principle:

Principle #13The other way round (Inversion)

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 reduces the risk of fracture by eliminating the co-occurrence of metallurgical and shaped notches, enhances the accessibility and quality of the welded joint, and ensures an uninterrupted integral bond, leading to improved durability and reliability of the shaft and functional elements.

Implementation Method 1

the functional elements are welded to the elevations on the shaft

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentUS12331788B2Process for connecting functional elements to a shaft

Publication Date: 2025.06.17 LIST AG

AI summary

A method for connecting functional elements (14) to a shaft (10, having the following steps: (a) forming elevations (12) for receiving the functional elements (14), said elevations (12) being machined out of the shaft (10) by removing material, and (b) welding the functional elements (14) to the elevations (12) on the shaft (10).