Two-Stage Stiffness Elastomer for Railway Axle Suspension
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Solution Overview
Problem
Existing elastic devices in railway vehicles face a contradiction in designing longitudinal stiffness for high-speed operation on straight lines and curve passing performance, as they typically have combined stiffness that is soft at first and then becomes hard, failing to adequately address both requirements and increasing the risk of derailment.
Innovation Solution
A two-stage stiffness type elastomer combined device is designed with a small-stiffness elastic element and a large-stiffness elastic element, where the small-stiffness element is pre-compressed and serially arranged with the large-stiffness element, allowing the device to transition from hard to soft stiffness as the load increases, optimizing both snaking critical operation speed and curve passing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the longitudinal positioning stiffness of the longitudinal elastic device is increased to improve snaking critical operation speed on straight lines, then the snaking critical operation speed is improved, but the lateral force on curves becomes excessively large causing derailment risk
Solution Approach 1:
The patent applies the dynamics principle by designing an elastomer combined device with variable stiffness characteristics. The device transitions from a static stiffness system to a dynamic one where the combined stiffness changes with deformation displacement. At small displacements (straight line operation), the device exhibits large combined stiffness to suppress snaking motion. At large displacements (curve passage), the device exhibits small combined stiffness to reduce lateral force. This dynamic stiffness adaptation resolves the contradiction between improving snaking critical speed and reducing curve lateral force.
Solution Approach 2:
The patent implements parameter changes by modifying the stiffness parameter of the elastomer combined device based on operating conditions. Through the series-parallel connection configuration of elastomers, the device achieves different combined stiffness values at different deformation stages. The stiffness parameter is not fixed but varies with the deformation displacement, allowing the device to provide high stiffness for snaking suppression at low displacements and low stiffness for lateral force reduction at high displacements, thereby resolving the technical contradiction.
2Device complexity
If existing elastomer devices with soft-then-hard stiffness characteristic are used, then the structure is simple, but the device cannot simultaneously satisfy both straight line stability and curve passing performance requirements
Solution Approach 1:
The patent applies segmentation by dividing the elastomer system into multiple independent elastomer elements connected in series-parallel configuration. Instead of using a single elastomer with fixed stiffness characteristics, the device segments the elastic function across multiple elements (first elastomer in series, second and third elastomers in parallel). This segmentation enables the combined device to exhibit complex stiffness characteristics (large at small displacements, small at large displacements) that cannot be achieved by simple individual elastomers, thereby improving performance adaptability while maintaining reasonable structural complexity.
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 device achieves a higher snaking critical operation speed on straight lines and ensures safe curve passage by adjusting stiffness properties, effectively addressing the contradiction and improving the overall dynamic performance and safety of railway vehicles.
Implementation Method 1
a small-stiffness elastic element 1 and a large-stiffness elastic element 2, wherein the small-stiffness elastic element 1 is arranged in an elastomer pre-compression device 3 and is serially arranged with the large-stiffness elastic element 2 under the action of a pre-compression load F1
Data Source
AI summary
The present invention provides a two-stage stiffness type elastomer combined device, including at least one small-stiffness elastic element and a large-stiffness elastic element, wherein the small-stiffness elastic element is arranged in an elastomer pre-compression device and is serially arranged with the large-stiffness elastic element under the action of a pre-compression load F1. The device has combined stiffness being hard at first and then becoming soft and is used as an elastic axle box suspension device of a railway vehicle, effectively solving the contradiction that a linear snaking critical operation speed of the vehicle and curve passing performance of the vehicle cannot be compromised. The device can also be applied to a variety of occasions requiring combined stiffness being soft at first and then becoming hard of an elastomer damping device between related members of the railway vehicle, so as to buffer the wheel rail impact of the vehicle, improve the dynamic performance of the vehicle and guarantee the operation safety of the vehicle to perfect the operation quality of the railway vehicle.