Rail Vehicle Side Wall Structure for Lightweight Laser Welding

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Solution Overview

Problem

Existing rail vehicle side wall constructions face challenges in combining low mass, high strength, good accessibility for corrosion protection, and suitability for automated welding, particularly at the transition from side walls to roofs, due to complex manufacturing processes and limited accessibility for welding.

Innovation Solution

A side wall design integrating a roof longitudinal beam into the structure, using a grid-like assembly of bows and frames with a planking system, manufactured in one piece and welded using laser processes, allowing for simple, flat sheet metal parts and eliminating the need for overlapping sheets and complex bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If spot welding is used to join overlapping sheet metal parts, then the joining strength is achieved, but the mass of the component increases and corrosion protection becomes problematic

Engineering Contradiction:
Improvejoining strengthVSAvoidcomponent mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent merges the roof longitudinal beam function into the side wall structure itself by extending the planking in one piece from the vertical to the inclined section, eliminating the need for separate overlapping sheet metal parts and spot welding joints at the roof transition area.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical spot welding process with laser welding technology, which enables butt joints and T-joints without requiring sheet overlap, thereby reducing mass and eliminating corrosion protection issues at overlap points.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If complex bending is performed on very large sheet metal parts to create roof longitudinal beams, then the structural strength is achieved, but the manufacturing complexity and accessibility for welding increases

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent segments the side wall into a grid-like assembly of bows and frames with planking, where the planking itself forms the roof longitudinal beam function through its continuous one-piece construction from vertical to inclined sections, avoiding complex bending of large sheets.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces complex mechanical bending processes with laser welding technology, which can directly join flat sheet metal parts into the required structural configuration without intricate forming operations, significantly simplifying manufacturing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If traditional differential construction with separate roof longitudinal beams is used, then the structural integrity at door openings is achieved, but the manufacturing process becomes complex and time-consuming

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent combines the roof longitudinal beam function directly into the side wall planking structure, where the one-piece planking extending from vertical to inclined sections provides the necessary structural reinforcement at door openings while simplifying the manufacturing process.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the traditional multi-step manufacturing process with laser welding technology, which enables direct joining of flat sheet metal parts with minimal heat input, reducing manufacturing time and complexity while maintaining structural integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 design achieves a strong, lightweight side wall with easy corrosion protection and automated welding capabilities, reducing manufacturing complexity and minimizing heat-affected zones, thus enhancing the structural integrity and appearance.

Implementation Method 1

Laser welding offers significant advantages, as it allows for butt joints and T-joints while minimizing heat input

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 2

A commonly used welding process is spot welding, in which an electric current is passed through two overlapping sheets, melting them locally

Methodology Applied
Scientific EffectSpot welding: Welding

Data Source

PatentEP4341146B1Side wall for a rail vehicle
Publication Date: 2025.12.10 SIEMENS MOBILITY GMBH
  • EP4341146B1 patent drawingFigure 1
  • EP4341146B1 patent drawingFigure 2
  • EP4341146B1 patent drawingFigure 3

AI summary

A side wall (1) for a rail vehicle of differential design, configured for fastening the lower end (2) to a base frame and the upper end (3) to a roof, comprising a grid structure of bows (4) and frames (5), and panelling (6) of said grid structure, wherein the panelling (6) is produced in one piece and comprises a vertical first section (7) and a second section (8) which is arranged at the upper end (3) of the side wall (1) and is angled or bent with respect to the first section (7), and wherein a cover plate (9) which is oriented substantially perpendicularly in the installed position of the side wall (1) is connected to the panelling (6) at the upper end of the second section (8), and wherein a plurality of ribs (10) which are distributed along the longitudinal extent of the side wall (1) are welded in in the intermediate space between the upper section of the panelling (6) and the cover plate (9).