Hydraulic Axle Link Bearing Assembly for Stable Wheelset Alignment

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Solution Overview

Problem

Existing arrangements for transmitting longitudinal forces in rail vehicles do not effectively convert unstable modes into stable modes, leading to suboptimal driving stability and speed.

Innovation Solution

The solution involves a hydraulic axle control arm bearing system with a damping element, where each axle control arm bearing has two chambers connected via external lines, allowing fluid exchange and incorporating a damping element that adjusts stiffness and damping based on the movement of a fluid-filled cylinder with a movable stamp, coupled with a spring and damper.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If hydraulic axle link bearings with external connections are used to transmit longitudinal forces, then the driving behavior is optimized with adjustable wheelset alignment, but the component density in the axle control arm area increases

Engineering Contradiction:
Improveadjustable wheelset alignmentVSAvoidcomponent density
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A damping element is introduced as an intermediary component connected between the first chambers of the axle link bearings. This damping element mediates the fluid exchange between chambers, providing the necessary damping effect without requiring direct modification of the axle control arm bearings themselves, thus avoiding increased component density in the critical axle area.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The damping function is relocated from the spatial dimension of the axle control arm area to a different dimensional space - the hydraulic fluid circuit dimension. By implementing damping through fluid flow control in the hydraulic system rather than through mechanical components in the axle assembly, the solution achieves damping functionality without increasing component density in the axle control arm area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If fluid exchange between chambers is implemented to provide damping, then driving stability is enhanced, but the system complexity increases

Engineering Contradiction:
Improvedriving stabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hydraulic system performs dual functions: it transmits longitudinal forces through the axle link bearings and simultaneously provides damping through controlled fluid exchange between chambers. The existing hydraulic fluid and chamber structure serve the additional damping function without requiring separate dedicated damping components, reducing overall system complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The hydraulic chambers and fluid circulation system are designed to perform multiple functions simultaneously - force transmission and damping. The same hydraulic infrastructure that enables adjustable wheelset alignment also provides the damping effect through controlled fluid exchange, eliminating the need for separate damping mechanisms and reducing system complexity.

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

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

This configuration enhances driving stability and safety by converting unstable modes into stable modes, allowing for increased driving speeds and maintaining a high level of safety without increasing component density in the axle control arm area.

Implementation Method 1

The overflow channel creates a fluid displacement between the two chambers, resulting in the required low longitudinal stiffness when cornering and the required high stiffness when traveling straight or on curves.

Methodology Applied
Scientific EffectFluid displacement: Hydraulic Press

Implementation Method 2

An elastic (rubber) element is arranged in the annular gap such that it at least partially delimits two diametrically opposed chambers, referred to as the first chamber and the second chamber, respectively.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

a damping element that adjusts stiffness and damping based on the movement of a fluid-filled cylinder with a movable stamp, coupled with a spring and damper

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP4237308B1Assembly for transmitting longitudinal forces in a rail vehicle
Publication Date: 2024.11.06 SIEMENS MOBILITY GMBH
  • EP4237308B1 patent drawingFigure 1
  • EP4237308B1 patent drawingFigure 2
  • EP4237308B1 patent drawingFigure 3~4

AI summary

The invention relates to an assembly for transmitting longitudinal forces in a rail vehicle, comprising a first and second hydraulic axle link bearing (ALL1, ALL2), a wheel set (RS1), and a rotary frame (DGST) of the rail vehicle. Each axle link bearing (ALL1, ALL2) has a respective housing element (GEHA, GEHI) and a respective first and second chamber (KAM11, KAM12, KAM21, KAM22) filled with a fluid (FLU). In the event of a change in the position of the housing elements (GEHI, GEHA) relative to each other, fluid is exchanged between connected chambers of the axle link bearings (ALL1, ALL2). The fluid exchange is produced by a change in the position of the housing elements (GEHI, GEHA) relative to each other, and the change in position causes the transmission of longitudinal forces which are transmitted between the wheel set (RS1) and the rotary frame (DGST) via the axle link bearings (ALL1, ALL2). A first chamber (KAM11) of the first axle link bearing (ALL1) is connected to a first chamber (KAM21) of the second axle link bearing (ALL2) via a damping element (FDE) in order to exchange fluid. Simultaneously, a second chamber (KAM12) of the first axle link bearing (ALL1) is directly connected to a second chamber (KAM22) of the second axle link bearing (ALL2) in order to exchange fluid.