Bolted Bogie Side Beam Structure for Repairable Rail Frames

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Solution Overview

Problem

Existing railway vehicle bogie frames face challenges in structural weight reduction, strength, reliability, and maintainability, particularly in welded joints, and there is a need for improved space utilization for additional components.

Innovation Solution

A side beam for a railway vehicle bogie frame using discrete structural members joined by bolt connections, featuring cantilevered suspension mounts and reinforcing components, which allows for additional space for components and enhances reliability and repairability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If welded joints are used in aluminium alloy bogie frames, then structural strength and reliability are improved, but residual stresses and heat affected zones are generated that reduce maintainability and increase complexity

Engineering Contradiction:
Improvereliability of bogie frameVSAvoidmaintainability of welded joints
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces welded joints with bolted mechanical connections in the aluminium alloy bogie frame. This substitution eliminates the harmful effects of welding (residual stresses, heat affected zones) while maintaining structural integrity. The bolted connections allow for easy disassembly, inspection, and replacement, significantly improving maintainability and reliability of the bogie frame structure.

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

2Volume of stationary object

If equipment is mounted on the outside of the bogie frame, then space for components is increased, but the width of the bogie frame increases

Engineering Contradiction:
Improvespace for componentsVSAvoidwidth of bogie frame
Core Design Contradiction:
Volume of stationary objectVSLength of stationary object

Solution Approach 1:

The patent utilizes the transverse direction dimension by extending suspension mounts outward from the centre plate. This creates additional volumetric space within the existing bogie width envelope, allowing equipment to be housed in the space between the extended suspension mounts without increasing the overall bogie width. This dimensional utilization resolves the contradiction between component space and bogie width.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Weight of moving object

If lightweight aluminium alloy is used for bogie frames, then weight is reduced, but strength and reliability of welded joints are compromised

Engineering Contradiction:
Improveweight of bogie frameVSAvoidstrength of joints
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent replaces welded joints with bolted connections in lightweight aluminium alloy bogie frames. This substitution resolves the strength-reliability issue by providing joints that are easier to control and inspect, while eliminating the harmful thermal effects of welding on the aluminium alloy. The bolted connections maintain structural integrity while preserving the weight advantages of using aluminium alloy.

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

Data Source

PatentEP4686637A1Side beam of a bogie frame for a railway vehicle
Publication Date: 2026.02.04 HITACHI LTD
  • EP4686637A1 patent drawingFigure 1
  • EP4686637A1 patent drawingFigure 2
  • EP4686637A1 patent drawingFigure 3

AI summary

A side beam (20) of a railway vehicle bogie frame (10) in which two such side beams define respective lateral sides of the bogie frame in relation to a longitudinal direction (L) of the railway vehicle (1) and a crossbeam (11) extends over a transverse direction (T) of the railway vehicle to join the side beams, the bogie frame being configured to carry, in use, front and rear wheelsets (3). The side beam is formed of discrete structural members comprising an elongate centre plate (21) which extends between first and second end portions (21a) thereof in the longitudinal direction between positions occupied, in use, by the wheelsets, a thickness direction of the centre plate being parallel to the transverse direction, and first and second suspension mounts (22) configured for mounting wheelset suspension elements thereto. The first and second suspension mounts are cantilevered from respectively the first and second end portions of the centre plate such that each suspension mount extends upwardly and longitudinally away from a respective junction with its end portion of the centre plate to define a space below the suspension mount for joining the suspension elements to the respective wheelset. At the respective junction each suspension mount has a greater width in the transverse direction than the thickness of the centre plate such that the suspension mounts protrude outwardly in the transverse direction from the centre plate. The discrete structural members are joined together by respective bolt connections (30).