Rail Vehicle Central Buffer Coupling Collision Safety

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Solution Overview

Problem

Current central buffer couplings in rail vehicles do not adequately absorb increased impact energy as required by the new collision safety standards, necessitating a design enhancement for improved collision safety.

Innovation Solution

Incorporation of a collision element with a deformation area that irreversibly deforms during collisions, transferring kinetic energy to the car body and absorbing forces through a spring mechanism, along with a support system that allows horizontal movement of the coupling shaft, enabling efficient energy absorption and conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the spring mechanism and energy absorption elements are used to absorb impact forces, then the collision safety is improved, but the device complexity increases

Engineering Contradiction:
Improvecollision safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The coupling shaft is divided into a first portion and a second portion, with the second portion being displaceable relative to the first. This segmentation allows the energy absorption function to be separated from the primary coupling function, enabling the spring mechanism and deformation elements to absorb impact energy independently while maintaining the overall structural integrity of the coupling system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A stop element is introduced as an intermediary component between the coupling shaft and the car body. This stop element limits the displacement of the coupling shaft during collisions and works in conjunction with the spring mechanism to control the energy absorption process, preventing excessive deformation while maintaining collision safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the coupling shaft is made rigid for stable power transmission, then the power transmission reliability is improved, but the collision energy absorption capability deteriorates

Engineering Contradiction:
Improvepower transmission reliabilityVSAvoidcollision energy absorption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The coupling shaft is segmented into a first portion for stable power transmission and a second portion that can displace relative to the first portion. This allows the first portion to maintain rigidity for reliable power transmission during normal operation, while the second portion provides the necessary compliance for collision energy absorption through its relative displacement capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling shaft transitions from a static rigid structure to a dynamic system where the second portion can displace relative to the first portion during collisions. This dynamic behavior enables the system to absorb collision energy through controlled deformation while maintaining structural integrity and power transmission capability during normal operation.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the center buffer coupling is designed to absorb increased impact energy according to new standards, then the collision safety is improved, but the manufacturing cost increases

Engineering Contradiction:
Improvecollision safetyVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The coupling shaft is segmented into replaceable portions, with the second portion being designed as a separate, replaceable component. This segmentation allows the energy-absorbing elements to be replaced independently after collision damage, reducing manufacturing costs by avoiding the need to replace the entire coupling shaft assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The energy absorption elements and second portion of the coupling shaft are designed as sacrificial components that can be replaced after collision damage. This approach allows the main coupling structure to be preserved and reused, reducing overall manufacturing costs by recovering and reusing the primary coupling components while discarding only the damaged energy-absorbing elements.

Inventive Principle:
Principle #34Discarding and recovering

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

Enhances collision safety by effectively converting kinetic energy into deformation energy, allowing for cost-effective retrofitting and simple component replacement, while maintaining geometric dependencies with side buffers in mixed train couplings.

Implementation Method 1

The spring mechanism FDW is connected at one end END to a car body (not shown here) of the rail vehicle and includes a spring-loaded or elastic fastening of the second end of the coupling shaft KPS inside the spring mechanism FDW

Methodology Applied
Scientific EffectSpring mechanism: Spring

Implementation Method 2

tensile forces or compressive forces acting between the coupled rail vehicles via the KPK coupling head and KPS coupling shaft are absorbed and, if necessary, transmitted to the car body in a damped manner

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

In addition, the FDW spring mechanism features energy absorption elements, for example, which absorb or convert kinetic energy acting on the FDW spring mechanism via the KPS coupling shaft in the event of a collision. In the process, the energy absorption elements undergo permanent plastic deformation.

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 4

The PAS pendulum support ensures that the MPK center buffer coupling assumes a desired horizontal position during operational and uncoupled operation of the rail vehicle

Methodology Applied
Scientific EffectPendulum support: Pendulum

Implementation Method 5

The central buffer coupling, or more precisely its coupling shaft, is supported vertically and springily downwards by a PAS pendulum support

Methodology Applied
Scientific EffectSpring support: Spring

Data Source

PatentEP4294695B1Rail vehicle having central buffer coupling
Publication Date: 2024.11.27 SIEMENS MOBILITY GMBH
  • EP4294695B1 patent drawingFigure 1
  • EP4294695B1 patent drawingFigure 2
  • EP4294695B1 patent drawingFigure 3

AI summary

The invention relates to a rail vehicle having a central buffer coupling. The central buffer coupling (MPK) has a coupling head (KPK), a rod-shaped coupling shaft (KPS) and a spring mechanism (FDW) as elements. The coupling head (KPK) is designed for connection to a coupling head of another rail vehicle and is connected to the coupling shaft (KPS). Said shaft is inserted into the spring mechanism (FDW) and is mounted and fastened therein in such a way that, during operation of the rail vehicle, impact forces or tensile forces acting on the coupling head (KPK) are resiliently absorbed by the spring mechanism (FDW) and transferred to a wagon body (WK). A support (PAS) is coupled to the coupling shaft (KPS) and is connected to the wagon body (WK). A collision element (CB), which is rigidly but detachably connected to both the support (ABS) and the wagon body (WK), is arranged between the support (ABS) and the wagon body (WK). The collision element (CB) has a deformation region (DB) which is designed such that kinetic energy, which is transferred to the collision element (CB) via the coupling shaft (KPS) and via the coupled support (PAS) in the event of a collision, irreversibly deforms the deformation region (DB) in a predetermined manner.