Railcar Bodyshell Corner Post Inversion for Collision Safety

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Solution Overview

Problem

Stainless steel railcars with a single skin structure are prone to the side outside plate being peeled off during an offset collision due to exposure and inadequate welding, whereas aluminum alloy railcars with overlapping side outside plates and corner posts also face peeling issues.

Innovation Solution

A bodyshell structure where the front end portion of the side outside plate is covered by the corner post from the outer side, preventing direct impact and enhancing safety by using a configuration that includes side and end outside plates, corner posts, and a specific joining method to prevent peeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the side outside plate and corner post are joined by spot welding in a single skin structure, then the manufacturing process is simplified, but the side outside plate may be peeled off during offset collision

Engineering Contradiction:

Improvemanufacturing processVSAvoidresistance to peeling during collision

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent inverts the conventional overlapping arrangement by having the corner post overlap the side outside plate instead of the side outside plate overlapping the corner post. This reversal positions the corner post's front end portion to cover the front end portion of the side outside plate, preventing it from being hooked during offset collision while maintaining spot welding simplicity

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the potential harm of the exposed front end portion of the side outside plate being hooked during collision into a beneficial configuration where the corner post's overlapping structure prevents such hooking. The corner post's front end portion acts as a protective cover that transforms the vulnerable exposed area into a protected area, thereby converting the harmful exposure into a beneficial protective feature

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of manufacture

If the front end portion of the side outside plate is exposed to the outside, then the manufacturing and assembly is easier, but the front end portion may be hooked at the time of offset collision

Engineering Contradiction:

Improveassembly processVSAvoidhooking during offset collision

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The corner post acts as an intermediary protective element between the external environment and the front end portion of the side outside plate. By positioning the corner post to overlap and cover the side outside plate's front end portion, it serves as a mediator that prevents direct contact and hooking during offset collision, thereby protecting the vulnerable area

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8707873B2Bodyshell structure of railcar

Publication Date: 2014.04.29 KAWASAKI RAILCAR MFG CO LTD

AI summary

A bodyshell of a railcar includes side outside plates and end bodyshells. The side outside plates are respectively provided at both end portions of an underframe in a vehicle width direction. The end bodyshell includes end outside plates and corner posts. The end outside plates are respectively provided at front and rear end portions of the underframe. The corner posts are respectively provided at four corners of the underframe and are joined to the end outside plates and the side outside plates. Moreover, the corner post includes a side plate joining portion. The side plate joining portion overlaps a front end portion of the side outside plates from an outer side in the vehicle width direction and is joined to the side outside plate.