Conical Rubber-Metal Spring Structure for Rail Bogie Stability

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Solution Overview

Problem

Existing rubber-metal spring elements for rail vehicles require significant installation space, are heavy, costly, and prone to tilting due to their design, which affects their usability and stability, especially under lateral deformation, and suffer from load softening with increasing vertical loads.

Innovation Solution

A conical layered spring design with alternating layers of elastomeric material and metal, featuring different cone angles and diameters, and structured surfaces to enhance stability and reduce tilting, along with varying layer thicknesses to minimize stress softening and corrosion, using non-standard connecting elements for improved geometry and cement reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a combination of layered and conical springs is used to meet rigidity and stability requirements, then vertical mobility and lateral mobility are enabled, but the installation space (especially height) increases significantly

Engineering Contradiction:
Improverigidity and stabilityVSAvoidinstallation space (height)
Core Design Contradiction:
Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

The patent merges the layered spring and conical spring into a single integrated rubber-metal spring element. The rubber layers provide lateral mobility while the metal conical layers provide vertical mobility with set rigidities, combining both functions in one component rather than requiring separate layered and conical spring assemblies.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a composite structure with alternating layers of elastomeric material (rubber) and metal. This composite design allows the rubber layers to provide flexibility and lateral mobility while the metal layers provide structural rigidity and vertical spring properties, achieving both mobility requirements in a compact single-component design.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If two separate spring components (layered and conical) are used, then functional division is achieved, but the weight and manufacturing cost increase due to additional machining and assembly

Engineering Contradiction:
Improvefunctional divisionVSAvoidcomponent weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent combines multiple spring functions into a single rubber-metal spring element, eliminating the need for separate layered and conical spring components. This integration reduces the total weight by removing redundant structural elements and connection components while maintaining all necessary spring functions through the alternating rubber-metal layer design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single rubber-metal spring element performs multiple functions simultaneously: the rubber layers provide lateral mobility and shock absorption, while the metal conical layers provide vertical spring support with controlled rigidity. This multi-functional design eliminates the need for multiple specialized components, reducing overall weight and simplifying the assembly.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Strength

If standard metal connecting elements are used between spring layers, then structural integrity is maintained, but corrosion resistance decreases and manufacturing complexity increases

Engineering Contradiction:
Improvestructural integrityVSAvoidcorrosion resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent uses a composite of rubber and metal in alternating layers, where the rubber layers act as both structural elements and protective barriers. The rubber material inherently provides corrosion resistance while maintaining structural integrity through its elastic properties, eliminating the need for separate metal connecting elements that would be susceptible to corrosion.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different materials with specific local properties: rubber layers are used where flexibility and corrosion resistance are needed, while metal layers are used where high strength and rigidity are required. This local optimization of material properties ensures structural integrity where needed while providing corrosion resistance in appropriate locations.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If uniform layer thickness is used in spring layers, then manufacturing is simplified, but lateral stiffness decreases with increasing vertical load due to stress softening

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidlateral stiffness stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent varies the thickness of rubber and metal layers at different positions within the spring element. Thicker layers are placed in regions requiring higher stiffness and load-bearing capacity, while thinner layers are used where less support is needed. This non-uniform thickness distribution maintains lateral stiffness under vertical loads while still allowing for relatively simple manufacturing processes.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameters (layer thickness, cone angles, diameters) of the spring layers to optimize performance. By adjusting these parameters, the spring maintains stable lateral stiffness characteristics under varying vertical loads, preventing stress softening while managing manufacturing complexity through systematic parameter variation.

Inventive Principle:
Principle #35Parameter changes

5Stability of the object's composition

If conical layers with different cone angles are used, then lateral stiffness and stability are improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvelateral stiffness and stabilityVSAvoidcone angle precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent employs conical layers with different cone angles and diameters at different locations within the spring element. This local variation in geometric properties optimizes lateral stiffness and stability in specific regions where needed, while the overall design maintains manufacturability by using standard conical forming processes with controlled precision requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent systematically varies geometric parameters including cone angles, layer diameters, and thicknesses to achieve optimal lateral stiffness and stability. These parameter changes are designed to work together in a coordinated manner, allowing the spring to achieve enhanced stability while maintaining reasonable manufacturing precision requirements through balanced design trade-offs.

Inventive Principle:
Principle #35Parameter changes

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 design achieves a compact, lightweight, and corrosion-resistant spring element with increased lateral stiffness and stability, allowing for higher loads and deflections without tilting, enhancing driving comfort and safety against derailment while extending service life by reducing wear and stress.

Implementation Method 1

a conical layered spring is constructed from several alternating and concentrically arranged layers of elastomeric material or rubber on the one hand and metal on the other hand

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The cone spring mainly enables vertical mobility with set rigidities, which are particularly responsible for the train's safety against derailment

Methodology Applied
Scientific EffectRigidity:

Data Source

PatentEP3387287B1Rubber/metal spring element
Publication Date: 2023.01.11 CONTITECH LUFTEDERSYSTEME GMBH
  • EP3387287B1 patent drawingFigure 1
  • EP3387287B1 patent drawingFigure 2

AI summary

A rubber/metal spring element, in particular for use in bogies of rail vehicles, wherein the rubber/metal spring element is arranged between an upper connection element, which is connected to the sprung mass, and a lower connection element, which is connected to the unsprung mass, and is constructed in the form of a conical layer spring made up of a plurality of alternately and concentrically arranged layers made of elastomeric material or rubber, on one hand, and metal, on the other hand, wherein the individual layers are designed in the form of conical annular bodies, wherein the two conical surfaces of at least one of the conical annular bodies have different cone angles in relation to the common vertical axis of the concentric rubber and metal layers forming the conical layer spring.