Railway Vehicle Rubber Stopper Segmentation for Uniform Vulcanization

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Solution Overview

Problem

Conventional stoppers for railway vehicles made of vulcanized rubber face issues with non-uniform properties due to heat transfer differences, leading to unstable resilient characteristics and prolonged molding times, especially as thickness increases, and require complex jacket molds.

Innovation Solution

The stopper is designed as separate inner and outer rubber elastic bodies that are molded separately and assembled in contact, allowing for efficient heat transfer and reduced molding time without the need for jacket molds, while maintaining resilient characteristics similar to a single block.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stopper is molded as a single thick block, then the resilient characteristics and durability are improved, but the heat transfer uniformity deteriorates leading to non-uniform properties

Engineering Contradiction:
Improveresilient characteristicsVSAvoiduniformity of properties
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The stopper is divided into an outer body and an inner body that are molded separately and then assembled together. This segmentation allows each part to be molded with uniform thickness, ensuring consistent heat transfer and uniform vulcanization properties, while the assembled structure provides the necessary overall thickness for resilient characteristics.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If a stopper is molded at low temperature for long time to reduce heat transfer variation, then the uniformity of properties is improved, but the production rate decreases

Engineering Contradiction:
Improveuniformity of propertiesVSAvoidproduction rate
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

By segmenting the thick stopper into two thinner parts (outer body and inner body), each part can be molded quickly at normal temperature with uniform heat transfer. The separate molding of these thinner parts significantly reduces the total production time compared to molding a single thick block at low temperature for an extended period.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If a jacket mold is used to control heat transfer, then the uniformity of properties is improved, but the device complexity increases

Engineering Contradiction:
Improveuniformity of propertiesVSAvoidmold structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of using a complex jacket mold structure to control heat transfer, the invention segments the stopper into outer and inner bodies that are molded separately using simple molds. This eliminates the need for complex heat control mechanisms while achieving uniform properties through the thinner, more evenly heated individual components.

Inventive Principle:
Principle #1Segmentation

4Reliability

If the thickness of the stopper is increased, then the resilient characteristics are improved, but the heat transfer uniformity deteriorates

Engineering Contradiction:
Improveresilient characteristicsVSAvoidheat transfer uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The thick stopper structure required for resilient characteristics is achieved by assembling two separately molded bodies (outer and inner) rather than molding one thick block. This segmentation allows each component to have uniform thickness and heat transfer properties, while the combined assembly provides the necessary overall thickness for mechanical performance.

Inventive Principle:
Principle #1Segmentation

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 configuration stabilizes product characteristics and significantly reduces molding time while maintaining the resilient performance of a single block stopper, allowing for efficient manufacturing and assembly.

Implementation Method 1

A stopper 'b' made of a vulcanized rubber is molded by heating a mold charged with an unvulcanized rubber between upper and lower hot plates

Methodology Applied
Scientific EffectVulcanization:

Implementation Method 2

as the thickness of the stopper increases, the difference in heat transfer between the surface of the stopper and the interior of the stopper becomes significant

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP2957477B1A stopper, a railway vehicle and a method of manufacturing a stopper
Publication Date: 2019.09.25 TOYO TIRE CORP
  • EP2957477B1 patent drawingFigure 1~2
  • EP2957477B1 patent drawingFigure 3~5
  • EP2957477B1 patent drawingFigure 6

AI summary

A stopper (1) is provided for a railway vehicle, the stopper being interposed between an air spring (21) and a truck, and the stopper (1) includes an outer body (5) made of a rubber elastic body and an inner body (6) made of a rubber elastic body disposed in the outer body (5) so as to be in contact with the outer body (5). In a method of manufacturing the stopper (1), the inner body (6) and the outer body (5) are separately vulcanized and molded before the inner body (6) is assembled into the outer body (5).