Rail Car Underframe Assembly Modular Force Transmission

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Solution Overview

Problem

Existing rail vehicle car body structures are not adequately adapted for modular designs with tubular main sections and end modules, particularly in terms of force transmission and deformation resistance during collisions, leading to complex and heavy structures.

Innovation Solution

A steel underframe assembly with a bolster subassembly and steel sub-frame that attaches to the tubular module and end module, respectively, allowing direct transfer of longitudinal forces and minimizing deformation, while enabling modular assembly and easy refurbishment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a large interface area is used between the end module frame and the tubular main section to transfer longitudinal forces, then force transmission capability is improved, but the structure becomes complex and heavy

Engineering Contradiction:

Improvelongitudinal force transmissionVSAvoidstructure complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The underframe is divided into a steel sub-frame and a steel bolster subassembly that are mechanically detachably connected. This segmentation allows the complex force transmission function to be distributed across separate modular components, reducing overall structural complexity while maintaining force transmission capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The steel bolster subassembly acts as an intermediary component between the end module and the tubular main section. It provides a dedicated interface for longitudinal force transmission through coupling engagement, eliminating the need for a large complex interface area between the end module frame and tubular section

Inventive Principle:

Principle #24Intermediary (Mediator)

2Force

Engineering Contradiction:

Improvelongitudinal force transmissionVSAvoidunderframe weight

Core Design Contradiction:

ForceVSWeight of stationary object

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If fixed energy absorbers are used in the front frame, then collision energy absorption is improved, but the structure loses adaptability for different collision scenarios

Engineering Contradiction:

Improvecollision impact resistanceVSAvoidenergy absorption adaptability

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The energy absorbers are designed to be interchangeable rather than fixed, allowing the system to dynamically adapt to different collision scenarios. Different energy absorber configurations can be installed depending on the specific operational requirements and collision risk profiles

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system allows changing the energy absorption parameters by swapping different energy absorber components. This enables optimization of the energy absorption characteristics based on specific operational conditions, vehicle configurations, and safety requirements

Inventive Principle:

Principle #35Parameter changes

4Strength

If the end module is permanently attached to the tubular main section, then structural integrity is improved, but refurbishment and repair become difficult

Engineering Contradiction:

Improvestructural integrityVSAvoidend module refurbishment

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mechanical detachable connection is designed in advance to facilitate future refurbishment activities. This preliminary design decision enables quick release and replacement of end modules without requiring complex disassembly procedures, significantly improving ease of repair

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2130739B1Rail car underframe assembly and modular car body for a rail vehicle

Publication Date: 2013.09.25 BOMBARDIER TRANSPORTATION GMBH

Figure 1~8
Figure 3~4
Figure 5~6

AI summary

A rail vehicle car body includes two end modules (14), at least one of which is provided with a lateral access door, and a tubular module (18) extending from one of the two end modules to the other and mechanically fastened to the two end modules. The tubular module comprises a doorless shell made of longitudinal aluminium alloy extruded profiles extending from one of the two end modules to the other and longitudinally welded together. With such a structure, the interior outfit of the rail car can be installed through one of the open ends of the tubular module, after the longitudinal profiles of the shell have been welded together and painted. Similarly, refurbishment is simplified, since one of the end modules can be removed to give access to the interior of the tubular module.