Rail Vehicle Current Return Cable Inside Shaft

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Solution Overview

Problem

Existing short-circuit and current return devices in rail vehicles face issues with uncontrolled short-circuiting, current isolation from the vehicle structure, resistance instability, and increased malfunctions due to friction members, which pose safety and reliability concerns.

Innovation Solution

A short-circuit and current return device that uses a cable assembly to electrically connect the tires of two wheels, eliminating the need for friction members by routing the current through a cable that passes inside the shaft and is isolated by insulating materials within the hubs and shaft, ensuring controlled short-circuiting and stable resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If friction members are used to ensure short-circuit between rails, then the short-circuit function is achieved, but the resistance becomes unstable and malfunctions increase due to wear and contamination

Engineering Contradiction:

Improveshort-circuit stabilityVSAvoidnumber of friction members

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes friction members entirely from the short-circuit device, replacing them with a cable assembly that runs through the transmission shaft. This extraction eliminates wear, contamination, and resistance instability issues associated with friction members while maintaining the short-circuit function between rails.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical friction-based short-circuit system with an electrical cable system. The cable assembly with conductive elements provides the short-circuit path without mechanical contact, eliminating friction-related degradation and improving reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If current return path passes through axle or hub structure, then the current return function is achieved, but the current is not isolated from the vehicle structure causing safety concerns

Engineering Contradiction:

Improvecurrent isolationVSAvoidcurrent return path structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the current return path into isolated components: the cable assembly with conductive elements is separated from the vehicle structure by insulating materials. This segmentation ensures current isolation while maintaining a defined return path, preventing unintended current flow through sensitive components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces insulating materials as intermediaries between the cable assembly and the vehicle structure (hub, transmission shaft). These insulating materials act as mediators that allow the current return function while preventing electrical contact with the vehicle structure, ensuring safety and isolation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If two independent short-circuit devices are provided for each wheel, then the short-circuit coverage is improved, but the number of components increases and malfunction risks increase

Engineering Contradiction:

Improveshort-circuit coverageVSAvoidnumber of devices

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the short-circuit functions of both wheels into a single integrated device. The cable assembly runs through the transmission shaft connecting both wheels, providing short-circuit coverage for both rails through one device rather than two independent devices, reducing component count and malfunction risks.

Inventive Principle:

Principle #5Merging (Combining)

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 provides stable and controlled short-circuiting with reduced risk of malfunction, maintaining resistance below 10 mΩ, and isolates the short-circuit device from the rail vehicle structure, enhancing reliability and safety by eliminating friction-related issues.

Implementation Method 1

a cable assembly which electrically connects the tires of the two wheels, the cable assembly comprising a cable portion which extends inside the shaft between the two wheels

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

an insulating material which is arranged against the wall of the hub and which surrounds the friction assembly and the conductor element

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS8102075B2Track short-circuit and current return device for a rail vehicle

Publication Date: 2012.01.24 ALSTOM HOLDINGS SA

AI summary

A rail vehicle of the type comprising including at least one equipped axle which is provided with a transmission shaft which is movable in terms of rotation and which is fixedly joined in terms of rotation to two wheels, each of which is provided with a tire, the device including an electric current supply source, the source supplying a friction assembly with electric current. The friction assembly is alone and is electrically connected to a cable assembly which electrically connects the tires of the two wheels, the cable assembly including a cable portion which extends inside the transmission shaft between the two wheels.