Multi-Section Conical Spring Profile to Prevent Folding and Cracking

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Solution Overview

Problem

Conventional conical springs for locomotives face issues with inverse S curve stiffness, inadequate vertical stiffness under maximum load, and susceptibility to folding and cracking, which can lead to derailment and poor shock absorption.

Innovation Solution

A conical spring design with a multi-section rubber profile structure, featuring both multi-section downslope and upslope configurations, combined with a protruding lug boss, allows for adjustable stiffness changes and prevents folding and cracking by using smooth transitions and dual restrictions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional conical spring structure with single-profile rubber is used, then the structure is simple and easy to manufacture, but the vertical stiffness is insufficient under maximum load and the stiffness curve presents inverse S shape

Engineering Contradiction:
Improvevertical stiffnessVSAvoidrubber profile structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The rubber body is divided into multiple sections along its profile, creating a multi-section structure with different geometric characteristics in various regions. This segmentation allows each section to contribute differently to the overall stiffness characteristics, enabling the spring to achieve adequate vertical stiffness under maximum load while avoiding the inverse S curve phenomenon.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the rubber body are designed with different profile characteristics to provide locally optimized mechanical properties. The multi-section profile creates varying stiffness characteristics at different locations and loading stages, allowing the rubber to provide sufficient vertical stiffness where needed while maintaining appropriate compliance elsewhere.

Inventive Principle:
Principle #3Local quality

2Reliability

If the rubber body uses simple profiles, then the manufacturing is easy, but fold deformation occurs easily under vertical load causing stress concentration and rubber cracking

Engineering Contradiction:
Improveresistance to folding and crackingVSAvoidrubber profile structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rubber body profile is segmented into multiple sections with smooth transitions between them. This segmentation prevents sharp corners and abrupt geometric changes that would concentrate stress and initiate folding or cracking, while still maintaining manufacturing feasibility through standardized multi-section design patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multi-section profile incorporates smooth curved transitions between different sections rather than sharp angles or abrupt changes. This curvature design eliminates stress concentration points that would lead to fold deformation and cracking, significantly improving the reliability and fatigue life of the rubber body under repeated vertical loading.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Force

If the conical spring has large stiffness under no load, then the support function is strong, but the risk of locomotive derailment increases

Engineering Contradiction:
Improvevertical stiffnessVSAvoidderailment risk
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The multi-section rubber profile creates a dynamic stiffness characteristic where the vertical stiffness changes progressively with loading conditions. Under no load or light load, the rubber sections deform in a sequence that maintains lower effective stiffness, reducing derailment risk. As load increases, the progressive engagement of different sections provides increasing stiffness support.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The stiffness parameter of the conical spring is made variable through the multi-section profile design. The effective stiffness changes as a function of the compression level, with the rubber body transitioning through different deformation stages. This parameter change ensures appropriate stiffness at all loading conditions, preventing both derailment under light load and insufficiency under maximum load.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If the conical spring cannot provide large changeable stiffness under maximum vertical load, then the rubber structure remains simple, but ideal changeable stiffness cannot be achieved causing inverse S curve

Engineering Contradiction:
Improvechangeable stiffnessVSAvoidrubber profile structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rubber body is designed with a multi-section profile that enables progressive deformation through distinct stages. Each section is designed to engage at different compression levels, creating multiple stiffness change points that provide large changeable stiffness characteristics. This segmentation allows the simple rubber material to exhibit complex, adaptable stiffness behavior without requiring additional components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multi-section profile design causes the stiffness parameter to change significantly and non-linearly with compression. As the spring compresses, different sections engage in sequence, creating multiple inflection points in the force-deflection curve. This parameter change achieves large changeable stiffness that eliminates the inverse S curve while maintaining a simple monolithic rubber structure.

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 ensures stable vertical, transverse, and longitudinal stiffness adjustments, preventing derailment and maintaining effective shock absorption and noise reduction across varying loads, extending the spring's lifespan and reducing maintenance needs.

Implementation Method 1

the rubber body, the inner conical body and the outer conical body form a conical rubber metal spring together

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

an upper rubber profile of the rubber body and a lower rubber profile of the rubber body of the conical spring adopt a multi-segment structural form

Methodology Applied
Scientific EffectStress distribution:

Data Source

PatentEP3273091B1Method and product for conical spring having variable stiffness and capable of preventing folding and cracking
Publication Date: 2025.06.25 ZHUZHOU TIMES NEW MATERIAL TECHNOLOGY CO LTD
  • EP3273091B1 patent drawingFigure 1~3
  • EP3273091B1 patent drawingFigure 4~6
  • EP3273091B1 patent drawingFigure 7~9

AI summary

Disclosed is a method of a conical spring having a variable stiffness and capable of preventing folding and cracking. A rubber metal spring in a conical arrangement is formed altogether by a rubber body, an inner conical body and an outer conical body of the conical spring. An upper rubber profile of the rubber body is a multiple-section ramp-down structure, and a lower rubber profile of the rubber body is a multiple-section ramp-up structure. By changing the shape, slope, length and the number of sections of each of the multiple sections of the ramp-up and ramp-down structures, the variable stiffness of the conical spring can be adjusted several times, and the folding and cracking of the conical spring can be prevented. Further provided is a conical spring implementing this method.