Railcar Door Elastic Member Gap Design for Water Ingress Prevention

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Solution Overview

Problem

Existing railcar door designs face challenges in preventing water ingress while maintaining easy removal of caught objects and minimizing rubber deterioration, with contactless and contact-type door leading edge rubbers each having disadvantages such as water entry and reduced durability.

Innovation Solution

A contactless railcar door apparatus with a gap between first and second elastic members, featuring grooves and projections on their overlapping surfaces when closed, directs water downward and prevents it from entering the railcar, while maintaining easy object removal and reducing sensor misdetctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If contactless type door leading edge rubbers are used, then clothes of passengers caught in the door are easily removed, but water easily enters from outside into inside of railcar through gap between rubbers

Engineering Contradiction:
Improveease of object removalVSAvoidwater ingress
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The door leading edge rubber is divided into multiple segments: a first elastic member and a second elastic member, with a gap between them. This segmentation allows the door to maintain contactless operation (easy object removal) while the multiple segments work together to prevent water ingress through their combined overlapping structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a vertical dimension to water prevention by forming grooves on the outer surfaces of the elastic members that extend in the vertical direction. These grooves redirect water flow downward, preventing water from entering through the gap between the first and second elastic members, thus addressing the water ingress issue without compromising the contactless design.

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

2Object-affected harmful factors

If contact type door leading edge rubbers are used, then waterproof performance is high, but reaction force is applied to door and sensor misdetection occurs

Engineering Contradiction:
Improvewaterproof performanceVSAvoidsensor detection accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

By segmenting the door leading edge rubber into a first elastic member and a second elastic member with a gap between them, the invention eliminates the continuous contact that causes reaction forces. The segmented structure allows water to be redirected by the grooves while preventing the push-back force that triggers false sensor readings.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The grooves formed on the outer surfaces of the elastic members act as intermediary structures that intercept and redirect water flow. These grooves serve as a mediator between the gap between elastic members and the water, preventing direct water entry while allowing the gap to remain open for easy object removal.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If contact type door leading edge rubbers are used, then waterproof performance is high, but rubbers deteriorate due to abrasion and life decreases

Engineering Contradiction:
Improvewaterproof performanceVSAvoidrubber life
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The segmentation of the door leading edge rubber into separate first and second elastic members with a gap between them eliminates continuous rubbing contact. This reduces abrasion and deterioration of the rubber material, extending the service life while the grooves maintain waterproof performance by redirecting water flow.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If lip contact type door leading edge rubbers are used, then waterproof performance is higher than contactless type, but thin rubber lip deteriorates due to abrasion and life decreases

Engineering Contradiction:
Improvewaterproof performanceVSAvoidrubber life
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The invention uses a segmented structure with a gap between the first and second elastic members, eliminating the need for a thin rubber lip that contacts the opposing door. This segmentation prevents the abrasion issues that plague lip contact types while maintaining effective water prevention through the groove structure.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2927087B1Door device for railway vehicle, and railway vehicle
Publication Date: 2019.10.16 KAWASAKI JUKOGYO KK
  • EP2927087B1 patent drawingFigure 1
  • EP2927087B1 patent drawingFigure 2
  • EP2927087B1 patent drawingFigure 3

AI summary

A railcar door apparatus includes: a side sliding door configured to open and close a door opening portion of a side bodyshell of a railcar; a first elastic member attached to a door end of the side sliding door in a vertical direction; and a second elastic member opposed to the first elastic member so as not to contact the first elastic member when the side sliding door is completely closed, wherein: the first elastic member includes a first base portion and a first projecting wall portion projecting from the first base portion toward the second elastic member; the second elastic member includes a second base portion and a second projecting wall portion projecting from the second base portion toward the first elastic member; when the side sliding door is completely closed, a gap space is formed between the first elastic member and the second elastic member, and the first projecting wall portion and the second projecting wall portion are located so as to overlap each other when viewed from a normal direction of the side sliding door; and a plurality of grooves or projections extending in the vertical direction are formed on an outer surface of at least one of the first projecting wall portion and the second projecting wall portion, the outer surface facing the gap space.