Rail Vehicle Hollow-Shaft Motor Protective Material

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Solution Overview

Problem

Existing rail vehicle systems with hollow shaft motors face issues of damage and safety risks due to motor fastening failures, which can lead to accidents and harm to people.

Innovation Solution

A protective material is arranged in the radial air gap between the rotor and the wheelset shaft, softer than both, to prevent direct contact and damage in case of motor fastening failure, with options including protective rings or tubes that support the rotor and maintain separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor fastening is made robust to prevent rotor contact with the wheelset shaft, then the reliability improves, but the device complexity and weight increase

Engineering Contradiction:
Improvemotor mounting reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A protective material is introduced as an intermediary element between the rotor and the wheelset shaft. This material serves as a mediator that absorbs impact energy and prevents direct contact between the hard rotor and the shaft, thereby maintaining reliability without requiring complex fastening mechanisms or additional structural elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective material is designed as a sacrificial element that may deform or be consumed during impact events. By using a relatively simple, replaceable protective material rather than complex permanent structural modifications, the system achieves protection while minimizing overall device complexity and cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If a protective material is added between the rotor and wheelset shaft, then damage risk reduces, but the device complexity increases

Engineering Contradiction:
Improvedamage riskVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The protective material is pre-installed in the radial air gap between the rotor and the wheelset shaft to provide cushioning before any impact event occurs. This advance preparation ensures that when motor fastening failure occurs, the protective material is already in position to absorb impact energy and prevent damage to critical components.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The protective material functions as a flexible or deformable barrier that can absorb impact forces through elastic or plastic deformation. This thin protective layer or shell provides effective damage protection without adding significant structural complexity or occupying excessive space within the motor assembly.

Inventive Principle:
Principle #30Flexible shells and thin films

3Object-affected harmful factors

If the protective material is made softer to better absorb impact, then the protection effectiveness improves, but the material selection and manufacturing complexity increase

Engineering Contradiction:
Improveimpact absorptionVSAvoidmaterial selection
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The protective material is selected with specific physical parameters (softer hardness, appropriate yield strength) that optimize its impact absorption capability. By carefully controlling the material parameters to be softer than both the rotor and wheelset shaft, the system achieves effective shock absorption while maintaining compatibility with standard manufacturing processes and material availability.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively prevents the rotor from falling onto the wheelset shaft, reducing damage and safety risks by using materials like aluminum, copper, or rubber that absorb the impact, ensuring the rotor and wheelset remain separated even during motor fastening failures.

Implementation Method 1

the protective material is softer than the material of the wheelset shaft and softer than at least one material of the rotor... the protective material separates the rotor from the wheelset shaft in the event of a failure of the motor fastening

Methodology Applied
Scientific EffectImpact absorption: Deformation

Data Source

PatentEP4143070B1Arrangement for a rail vehicle
Publication Date: 2024.04.10 SIEMENS MOBILITY GMBH DE
  • EP4143070B1 patent drawingFigure 1
  • EP4143070B1 patent drawingFigure 2
  • EP4143070B1 patent drawingFigure 3

AI summary

The invention relates to an arrangement (5) for a rail vehicle, having at least one electric hollow-shaft motor with a hollow rotor, and having a wheelset shaft, wherein the wheelset shaft runs through the hollow rotor, and wherein the rotor (12) is separated from the wheelset shaft (20) at least in certain sections by a radial air gap (50) which ensures a mechanical clearance between the wheelset shaft (20) and the rotor (12). It is provided according to the invention that a protective material is arranged in the region of the radial air gap (50) between the rotor (12) and the wheelset shaft (20), which protective material, in the event of failure of a motor fastening (14) of the hollow-shaft motor (10) and subsequent support of the rotor (12) on the wheelset shaft (20), separates the rotor (12) from the wheelset shaft (20), wherein the protective material is softer than the material of the wheelset shaft (20) and softer than at least one material of the rotor (12).