Railway Bogie Coil Spring Noise Insulation Disc
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Solution Overview
Problem
Existing rail chassis, particularly freight car bogies, generate high levels of noise due to structure-borne noise transmission, which is challenging to reduce without costly and complex conversions, especially in the Y25 bogie design, where noise pollution is increasingly regulated and economically unsustainable.
Innovation Solution
A layered annular disc made of elastomeric material with different elastic and damping properties is placed between the coil spring and its connection components, preventing metallic contact and utilizing an impedance jump effect to reflect structure-borne sound waves, combined with a structured surface to equalize pressure and enhance deformability, allowing for effective noise insulation without altering the bogie's usability or increasing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If steel coil springs are used in the suspension system, then the bogie structure remains simple and cost-effective, but structure-borne noise transmission increases significantly
Solution Approach 1:
An annular elastomeric disc is introduced as an intermediary element between the steel coil spring and the axle bearing housing. This disc serves as a mediator that blocks the transmission path of structure-borne noise while maintaining the mechanical connection and load-bearing function of the suspension system.
Solution Approach 2:
The solution combines steel coil springs with elastomeric material in a composite suspension system. The steel spring provides mechanical strength and suspension function, while the elastomeric disc provides noise insulation, creating a composite structure that leverages the advantages of different materials.
2Object-generated harmful factors
If elastomer springs are used instead of steel springs, then structure-borne noise insulation improves, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The elastomeric noise insulation component is segmented into a separate annular disc that is placed between the steel spring and the housing, rather than requiring a complete replacement of the spring assembly with complex elastomeric springs. This segmentation simplifies manufacturing and installation.
Solution Approach 2:
The annular elastomeric disc is designed as a relatively simple, inexpensive component that can be easily manufactured and installed as a retrofit solution, making it economically viable compared to complete elastomeric spring replacements.
3Ease of manufacture
If the elastomeric disc has a smooth surface, then manufacturing is simpler, but pressure distribution between spring and connection component becomes uneven
Solution Approach 1:
The elastomeric disc features localized structural variations: a smooth outer surface for simple manufacturing and a structured inner surface with protrusions for even pressure distribution. This local quality differentiation optimizes both manufacturing ease and functional performance in different areas of the same component.
4Ease of manufacture
If the elastomeric disc is made as a single homogeneous layer, then manufacturing is simpler, but noise insulation effectiveness across different frequencies is reduced
Solution Approach 1:
The elastomeric disc is constructed as a composite structure with multiple layers of elastomeric material having different properties. This layered composite design enhances noise insulation effectiveness across different frequency ranges while maintaining relative manufacturing simplicity.
Solution Approach 2:
Different layers of the elastomeric disc have different local properties (varying elasticity and damping characteristics) to optimize noise insulation for different frequency ranges, with each layer tailored to address specific noise transmission issues.
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 significantly reduces environmental noise pollution by effectively insulating against structure-borne noise, maintaining the bogie's operational properties and simplicity, while being economically viable for retrofitting existing rail undercarriages.
Implementation Method 1
utilizing an impedance jump effect to reflect structure-borne sound waves
Implementation Method 2
A layered annular disc made of elastomeric material with different elastic and damping properties
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Rail chassis, in particular bogie for a freight wagon, with axles mounted in axle bearing housings or wheel bearing housings, wherein a suspension with coil springs made of steel is provided between axle bearing housings and wagon body or wagon shell, wherein an annular, sound-insulating disc having an elastomeric material is arranged between the coil spring and at least one of its contact surfaces on the respective connecting component, which in cross-section is made up of several layers with different elastic and/or damping properties, wherein at least the outer layers of the disc consist of elastomeric material.