Fiber-Reinforced Resin Plate Spring Unit for Bogie Maintenance

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Solution Overview

Problem

The existing plate spring units for railcar bogies require labor-intensive bonding and integration of members, leading to increased maintenance costs and inefficiencies, as well as the need to replace the entire unit when damaged, which affects production efficiency and reliability.

Innovation Solution

A plate spring unit configuration where a lower and upper fiber-reinforced resin plate spring are separately provided, with spacers allowing relative displacement, eliminating the need for bonding and enabling individual replacement of damaged components, while maintaining elastic support through the use of end spacers and axle boxes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the upper surface member, core material member, and lower surface member are bonded and integrated to form a plate spring, then the plate spring can achieve the function of a side sill and primary suspension, but the entire plate spring must be replaced when any part is damaged, increasing maintenance cost

Engineering Contradiction:
Improvefunctional integrityVSAvoidmaintenance cost
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The plate spring is divided into separate members (upper surface member, core material member, lower surface member) that are not bonded together, allowing individual replacement of damaged components while maintaining overall functionality. Each member can be independently inspected, removed, and replaced without affecting the other members.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the upper surface member, core material member, and lower surface member are bonded and integrated, then the plate spring achieves structural unity, but soundness check of bonded portions requires labor after production, reducing production efficiency

Engineering Contradiction:
Improvestructural unityVSAvoidproduction efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The plate spring members are kept as separate, unbonded components that can be independently manufactured and inspected. This eliminates the need for complex soundness checks of bonded joints, as each member can be quality-checked independently during production, significantly improving manufacturing efficiency.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If the plate spring members are bonded and integrated, then the structure is compact, but a step of bonding and integrating stacked members is required, increasing manufacturing complexity

Engineering Contradiction:
Improvestructural compactnessVSAvoidmanufacturing process
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The plate spring members are manufactured separately as independent components without bonding processes. Each member can be produced using standard manufacturing techniques, and assembly simply involves stacking the members in the correct sequence, greatly simplifying the manufacturing process while maintaining structural functionality.

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 improves production efficiency, reduces maintenance costs, enhances reliability, and extends the life of the plate springs by allowing relative displacement and maintaining elastic support even when one of the springs is damaged.

Implementation Method 1

both longitudinal direction end portions of the plate spring unit are supported in use by respective axle boxes from below, a longitudinal direction middle portion of the plate spring unit supporting in use a cross beam from below

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3306129B1Plate spring unit and railroad vehicle bogie
Publication Date: 2020.11.11 KAWASAKI JUKOGYO KK
  • EP3306129B1 patent drawingFigure 1
  • EP3306129B1 patent drawingFigure 2
  • EP3306129B1 patent drawingFigure 3

AI summary

A plate spring unit applied to a railcar bogie includes: a lower plate spring including both longitudinal direction end portions supported by the respective axle boxes from below, the lower plate spring being made of fiber-reinforced resin; an upper plate spring arranged above the lower plate spring with a gap and including a middle portion pressed from above by a pressing member provided at the cross beam, the upper plate spring being made of fiber-reinforced resin; a middle spacer sandwiched between a middle portion of the lower plate spring and the middle portion of the upper plate spring; and an end spacer sandwiched between the end portion of the lower plate spring and an end portion of the upper plate spring and allowing relative displacement between the end portion of the lower plate spring and the end portion of the upper plate spring in a longitudinal direction.