Rail Vehicle Coupling Device Impact Energy Absorption
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Solution Overview
Problem
Existing coupling devices for rail vehicles do not provide uniform and effective passive safety over a long deformation path during impacts, and are difficult to install in vehicles without pre-existing safety elements.
Innovation Solution
A coupling device featuring a pipe section with a uniform inner diameter and a support made of nodular cast iron, where the pipe is enlarged at one end to accommodate the support, and connected via shear bolts that release at a defined impact force, allowing the support to deform the pipe and absorb energy without jamming or vibrations, enabling installation in vehicles without prior safety elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a coupling support with larger diameter than pipe inner diameter is used to absorb impact energy, then energy absorption capability is improved, but jamming and violent vibrations occur during impact
Solution Approach 1:
A sliding ring made of sliding material (preferably ductile iron) is introduced as an intermediary element between the coupling support and the pipe section. This sliding ring enables smooth relative movement during impact, preventing direct metal-to-metal contact and eliminating jamming and violent vibrations while maintaining effective energy absorption through controlled deformation.
2Ease of manufacture
If the pipe section is made with uniform inner diameter throughout deformation area, then manufacturing is simplified, but positioning and centering the pipe on the support becomes difficult
Solution Approach 1:
The pipe section features a localized internal diameter expansion at one end, creating a transition zone with different dimensional characteristics from the uniform deformation area. This local variation provides positioning and centering features for the coupling support while the majority of the pipe maintains uniform diameter for simplified manufacturing and consistent energy absorption characteristics.
3Stability of the object's composition
If the support is fixed to the coupling flange with shear bolts, then the support remains stable during normal operation, but the support cannot engage the pipe during impact
Solution Approach 1:
The connection between the coupling support and flange transitions from a static fixed state (during normal operation with shear bolts) to a dynamic engaged state (during impact when shear bolts release). This dynamic behavior allows the system to maintain stability when needed and enable energy absorption when required, with the support freely engaging the pipe section during collision events.
4Loss of energy
If the pipe section is made long to provide sufficient deformation path, then energy absorption is improved, but installation and removal becomes difficult
Solution Approach 1:
The coupling device is divided into separable components, with the pipe section being a distinct removable element from the coupling half assembly. This segmentation allows the long pipe section to be installed and removed as a separate component, facilitating maintenance and vehicle retrofitting while preserving the sufficient deformation path length needed for effective energy absorption.
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 ensures even energy absorption over a long deformation path without cracking or jerking, allowing for effective passive safety and easy installation in vehicles, with the support remaining intact during normal operation and only engaging during impacts.
Implementation Method 1
a coupling support that interacts with the pipe section and has a larger diameter than the inner diameter of the pipe section. This support expands and deforms the pipe section when pressed into it during an impact.
Implementation Method 2
the support is manufactured with a sliding ring made of sliding material, preferably ductile iron (gray cast iron)
Data Source
Figure 1
AI summary
A coupling device for a rail vehicle is equipped with at least one coupling (1) comprising a coupling flange (6) and a pipe section (8). A coupling part (3) with a support (5) is held within the pipe section, forming a passive safety device. The pipe section (8) is provided on its inner side with a diameter extension (12) that accommodates this support (5). In the event of an impact, this support (5) of the coupling part (3) is guided within the pipe section (8) in a way that absorbs the impact force and allows it to slide. The pipe end (9) of the pipe section (8) can be attached to the coupling flange (6) by a detachable connection (11).Furthermore, the materials of the pipe section (8) and the support (5) guided within it are matched in such a way that the support (5), which penetrates the pipe section upon impact, causes the pipe section to expand in the area of plastic deformation, with the support sliding along the inside of the pipe section with an almost uniform frictional force. This results in simple manufacturing as well as crack-free and jerk-free deformation of the pipe along its entire deformation path.