Railway Wheel Web Inclination to Limit Rim Shift Under Braking Heat

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Solution Overview

Problem

Conventional railway vehicle wheels experience heat deformation and thermal stress during braking, leading to rim displacement and potential derailing, as well as fatigue fractures, making it difficult to simultaneously reduce both rim displacement and thermal stress in the web.

Innovation Solution

A railway vehicle wheel design featuring a web with a linear plate-thickness center line that inclines towards the flange, resisting rim displacement and minimizing stress concentration, combined with a decreasing plate thickness and specific angle and position configurations to reduce thermal stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional bent web designs are used, then manufacturing flexibility is improved, but rim displacement and thermal stress cannot be simultaneously reduced

Engineering Contradiction:
Improveweb shape flexibilityVSAvoidrim stability and stress resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the geometric parameters of the web by defining a specific plate-thickness center line configuration with linear sections at different angles. The first linear section has a first angle with the radial direction, and the second linear section has a second angle, creating optimized stress distribution paths that simultaneously reduce rim displacement and thermal stress during braking operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The web design employs asymmetric geometry where the plate-thickness center line consists of linear sections with different angles relative to the radial direction. This asymmetric configuration optimizes the stress distribution pattern to simultaneously address both rim displacement and thermal stress reduction, rather than using symmetric bent designs.

Inventive Principle:
Principle #4Asymmetry

2Stress or pressure

If the web plate thickness is decreased, then thermal stress is reduced, but structural strength may be compromised

Engineering Contradiction:
Improvethermal stress in webVSAvoidweb structural strength
Core Design Contradiction:
Stress or pressureVSStrength

Solution Approach 1:

The web is designed with varying plate thickness distributed along its length, with each section optimized for its specific functional requirements. The plate-thickness center line configuration creates local thickness variations that reduce thermal stress in high-heat areas while maintaining adequate structural strength in load-bearing regions.

Inventive Principle:
Principle #3Local quality

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 design effectively reduces rim displacement and thermal stress in the web during braking, enhancing the stability and longevity of the wheel by inhibiting rim swinging and stress concentration.

Implementation Method 1

a temperature of the wheel, particularly a temperature of a rim that forms an outer circumferential portion of the wheel rises, causing heat deformation of the rim

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the heat deformation of the rim and the occurrence of the thermal stress in the web during braking of the railway vehicle may cause a fatigue fracture of the wheel

Methodology Applied
Scientific EffectThermal stress: Thermal Expansion

Data Source

PatentEP3978265B1Wheel for railway vehicle
Publication Date: 2023.12.13 NIPPON STEEL CORPORATION
  • EP3978265B1 patent drawingFigure 1
  • EP3978265B1 patent drawingFigure 2
  • EP3978265B1 patent drawingFigure 3

AI summary

A wheel (100) includes a boss (10), a rim (20), and a web (30). The rim (20) includes a tread (21) and a flange (22). The web (30) connects the boss (10) and the rim (20). When the wheel (100) is viewed in its longitudinal section, the web (30) has a linear plate-thickness center line (A) that is inclined such that the plate-thickness center line (A) approaches the flange (22) side as it extends outward in a radial direction. When the wheel (100) is viewed in its longitudinal section, an outer end (Aa) of the plate-thickness center line (A) is positioned between the flange (22) and a center (211) of the tread (21) in an axial direction of the wheel (100).