Fiber Tensile Elements for Rail Bogie Force Transmission

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Solution Overview

Problem

Existing rail vehicle designs face challenges in efficiently transmitting longitudinal forces from a bogie to a support structure, particularly in terms of weight and installation space, especially in driven bogies where high forces are generated, leading to bulky and heavy components that occupy significant space.

Innovation Solution

The use of highly resilient fiber elements, such as Kevlar or carbon fibers, to transmit tensile forces from the bogie to the support structure, replacing traditional metal tie rods and allowing for a more distributed and adaptable connection that reduces weight and installation volume, with fiber elements connected to the support structure via multiple points and distribution elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If traditional metal tie rods or push/pull rods are used to transmit longitudinal forces, then the force transmission capability is sufficient, but the weight and installation volume increase significantly

Engineering Contradiction:
Improvelongitudinal force transmission capabilityVSAvoidweight of force transmission components
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The patent uses fiber-reinforced composite materials (such as carbon fiber or glass fiber reinforced plastics) to manufacture the tie rods. These composite materials provide high tensile strength and stiffness while significantly reducing weight compared to traditional metal rods, directly resolving the contradiction between force transmission capability and weight.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters from metal to fiber-reinforced composite materials, which have different mechanical properties including higher strength-to-weight ratio. This parameter change enables the tie rods to maintain sufficient force transmission capability while reducing weight and installation volume.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional metal tie rods with elastomer bearings are used, then the force transmission is reliable, but the installation space requirement increases

Engineering Contradiction:
Improveforce transmission reliabilityVSAvoidinstallation volume at connection points
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The integration of elastomer bearings directly into the fiber-reinforced plastic tie rod structure eliminates the need for separate metal bearing housings and mounting brackets. This reduces the installation volume at connection points while maintaining the reliability of force transmission through the elastomer bearing's shock absorption and friction compensation capabilities.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent merges the tie rod structure with the elastomer bearing into an integrated composite component. The elastomer bearing is embedded within or attached to the fiber-reinforced plastic tie rod, combining the force transmission function and the shock absorption function into a single compact unit, thereby reducing installation space.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If solid metal cross members are used to transmit longitudinal forces, then the structural strength is sufficient, but the bending load on the cross member increases and requires solid construction

Engineering Contradiction:
Improvestructural strength of supporting structureVSAvoidbending stress on cross member
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The use of fiber-reinforced plastic tie rods changes the force transmission characteristics from rigid metal-to-metal connection to a more compliant composite connection. The elastomer bearing within the composite tie rod provides flexibility that reduces impact loads and bending stresses on the supporting structure's cross members, while the high strength of the composite materials maintains overall structural integrity.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4117975B1Assembly for transmitting longitudinal forces in a rail vehicle
Publication Date: 2024.03.20 SIEMENS MOBILITY GMBH
  • EP4117975B1 patent drawingFigure 1
  • EP4117975B1 patent drawingFigure 2
  • EP4117975B1 patent drawingFigure 3

AI summary

The invention relates to an assembly for transmitting longitudinal forces from a bogie (DG) to a support structure (TS) of a rail vehicle. The bogie (DG) is connected to the support structure (TS) via two tensile elements (FE1) that transmit longitudinal forces, which are formed by two movement directions of the rail vehicle, from the bogie (DG) to the support structure (TS) in the form of tensile forces. When viewed in the travel direction of the rail vehicle, the two tensile elements (FE1) are arranged opposite each other. According to the invention, the tensile element (FE1) is designed as a fiber element (FE1), and the fiber element (FE1) is made of fibers with a high load-bearing capacity and is designed to solely transmit tensile forces.