Railcar Bogie Plate Spring Using CFRP Fiber Orientation

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Solution Overview

Problem

Conventional axle arm type bogies are heavy due to steel structures, requiring complex and time-consuming welding and assembly, and steel springs are inadequate for vibration damping and durability.

Innovation Solution

A railcar bogie plate spring made of carbon fiber reinforced plastic (CFRP) with fibers oriented to optimize compressive, tensile, and shear loads, reducing weight and cost, and featuring a core member with inclined fibers to distribute loads effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If steel structures and steel springs are used for the bogie, then strength and durability are ensured, but the weight becomes heavy and manufacturing complexity increases

Engineering Contradiction:
Improvebogie strengthVSAvoidbogie weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by replacing traditional steel structures with fiber-reinforced plastic (FRP) composite materials. The bogie frame and springs are constructed using layered composite structures with fibers oriented in specific directions to achieve required strength while significantly reducing weight. This directly resolves the contradiction by providing both strength and weight reduction through material composition changes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by varying the fiber orientation and layering configuration in different regions of the bogie structure. The composite material structure has different fiber arrangements in areas experiencing different stress conditions, optimizing strength where needed while minimizing weight elsewhere. This allows the structure to achieve necessary strength characteristics without uniform weight distribution.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If steel structures with welding and assembly operations are used, then structural integrity is achieved, but manufacturing time and cost increase

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent merges multiple manufacturing operations into a single composite material forming process. Instead of separately manufacturing steel components and then welding/assembling them, the entire bogie structure is formed by laying and curing composite material layers in a integrated mold, significantly reducing manufacturing steps and time while maintaining structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies preliminary action by pre-orienting fibers and pre-positioning structural features during the composite material layup phase before curing. This preliminary arrangement of materials ensures structural integrity is built-in during manufacturing rather than requiring post-manufacturing assembly and welding operations, reducing both time and complexity.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If single steel springs are used, then结构简单性 is maintained, but vibration damping is insufficient and durability decreases

Engineering Contradiction:
Improvespring structure complexityVSAvoidspring durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces single steel springs with composite material spring structures that utilize layered fiber arrangements. The composite construction provides inherent vibration damping through the layered structure and fiber-matrix interface, while maintaining spring functionality. This resolves the contradiction by improving durability and vibration damping without significantly increasing structural complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality to the spring structure by varying fiber orientation and layer density in different regions of the spring. Areas requiring higher durability and damping have enhanced composite layering, while other areas maintain simpler structures. This localized optimization improves reliability without uniformly increasing complexity throughout the entire spring.

Inventive Principle:
Principle #3Local quality

4Reliability

If laminated plate springs are used instead of single springs, then vibration damping and strength are improved, but the number of parts increases and assembly becomes cumbersome

Engineering Contradiction:
Improvespring performanceVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple laminated plate layers into an integrated composite spring structure formed in a single manufacturing process. Instead of assembling separate laminated plates, the entire multi-layer spring is created by laying and curing composite material layers together, maintaining the performance benefits of lamination while eliminating the assembly complexity of multiple separate parts.

Inventive Principle:
Principle #5Merging (Combining)

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

The solution results in a lightweight, durable bogie plate spring with improved assembly efficiency, reduced costs, and enhanced durability by optimizing load distribution and using CFRP for strength and fatigue resistance.

Implementation Method 1

an upper surface member (12) constituted by fiber reinforced plastic in which reinforced fibers are stacked so as to extend in a longitudinal direction

Methodology Applied
Scientific EffectFiber reinforcement: Composite Materials

Implementation Method 2

in a side view of the core member (16), the reinforced fibers are inclined relative to a bending neutral axis so as to intersect with one another

Methodology Applied
Scientific EffectShear stress resistance through fiber orientation: Shear Stress

Implementation Method 3

enhanced durability by optimizing load distribution and using CFRP for strength and fatigue resistance

Methodology Applied
Scientific EffectFatigue resistance: Fatigue

Data Source

PatentEP2757016B1Railcar bogie plate spring
Publication Date: 2020.01.01 GH CRAFT
  • EP2757016B1 patent drawingFigure 1
  • EP2757016B1 patent drawingFigure 2
  • EP2757016B1 patent drawingFigure 3

AI summary

A railcar bogie plate spring (10) of the present invention includes: an upper surface member (12) constituted by fiber reinforced plastic in which reinforced fibers are stacked so as to extend in a longitudinal direction; a lower surface member (14) constituted by fiber reinforced plastic in which reinforced fibers are stacked so as to extend in the longitudinal direction; and a core member (16) arranged between the upper surface member (12) and the lower surface member (14). The core member (16) is constituted by fiber reinforced plastic in which: reinforced fibers are stacked in a width direction perpendicular to a stack direction of the upper surface member (12) and the lower surface member (14); and in a side view of the core member (16), the reinforced fibers are inclined relative to a bending neutral axis so as to intersect with one another.