Railcar Bogie Leafspring Electrodes With Laser-Exposed Carbon Fibers

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Solution Overview

Problem

The challenge is to maintain stable electrical contact between electrodes and carbon fibers on fiber-reinforced resin plate springs used in railcar bogies, as excessive resin removal can damage the fibers and incomplete removal leads to poor conduction, causing variations in measured values.

Innovation Solution

A method involving partial laser irradiation to remove resin and expose conductive fibers, followed by precise attachment of electrodes to these exposed regions, ensuring stable and accurate electrical contact and reducing individual variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If resin is scraped by polishing to expose carbon fibers, then electrical contact between electrode and carbon fibers is achieved, but individual variations occur due to inadequate or excessive scraping

Engineering Contradiction:
Improveelectrical contact stabilityVSAvoidexposed region consistency
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical polishing system with a laser beam system to remove resin and expose carbon fibers. The laser beam precisely ablates the resin surface without mechanical contact, eliminating variations caused by manual or automated polishing pressure and scratch depth differences. This substitution of mechanical action with optical/thermal action achieves consistent fiber exposure and stable electrical contact.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and properties of the resin through controlled laser irradiation parameters (power, speed, pulse duration). By adjusting these parameters, the resin is selectively removed to expose carbon fibers at controlled depths, ensuring consistent exposed region characteristics across different samples. This parameter control prevents both inadequate removal and excessive fiber damage.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If resin is removed to expose carbon fibers for electrode attachment, then electrical conduction is enabled, but carbon fibers are cut and contact state changes causing measured value variations

Engineering Contradiction:
Improveelectrical conductionVSAvoidcarbon fiber integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent replaces mechanical scraping with laser ablation to remove resin. The laser beam selectively vaporizes and removes resin material through controlled heating, avoiding mechanical forces that would cut or damage carbon fibers. This non-contact removal process preserves fiber integrity while exposing sufficient surface area for electrode attachment and electrical conduction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes phase transition of resin from solid to gas/vapor through laser-induced heating. The resin undergoes thermal decomposition and vaporization, transitioning phases to be removed as gas products. This phase change mechanism allows selective resin removal without mechanical contact, preventing fiber cutting while achieving adequate exposure for electrical contact.

Inventive Principle:
Principle #36Phase transitions

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

This approach stabilizes the quality of fiber-reinforced resin plate springs by ensuring consistent electrical contact, reducing variations in measured values and enhancing maintenance efficiency by allowing reliable monitoring of the plate spring's state.

Implementation Method 1

a resin removing step of partially irradiating a surface of fiber-reinforced resin, prepared by including electrically conductive fibers in resin, of a plate spring with a laser beam to partially remove the resin and partially expose the electrically conductive fibers

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3348448B1Method for manufacturing leafspring with electrodes for railcar truck
Publication Date: 2021.04.14 KAWASAKI JUKOGYO KK
  • EP3348448B1 patent drawingFigure 1
  • EP3348448B1 patent drawingFigure 2~3
  • EP3348448B1 patent drawingFigure 4

AI summary

A method of producing an electrode-equipped plate spring of a railcar bogie includes: a resin removing step of partially irradiating a surface of fiber-reinforced resin, prepared by including electrically conductive fibers in resin, of a plate spring with a laser beam to partially remove the resin and partially expose the electrically conductive fibers; and an electrode forming step of attaching an electrode to an exposed region formed by partially exposing the electrically conductive fibers of the fiber-reinforced resin.