Rail Vehicle Air Suspension Pressure Equalization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing air spring systems for rail vehicles cannot reliably prevent car body tilting due to pressure differences between air springs, as the compensating devices in prior art designs often result in unpredictable and safety-critical pressure conditions in pneumatic connecting lines.

Innovation Solution

The compensating device includes an outlet connected to the environment as a pressure sink, which vents the control connection with higher pressure when a pressure difference threshold is exceeded, preventing excessive pressure differences by directing excess air to a pressure sink rather than establishing a connection between air springs, thus maintaining stable pressure conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If compensating devices use check valves to connect air springs together for pressure equalization, then pressure differences can be reduced, but the car body may still tilt due to unpredictable pressure conditions in pneumatic connecting lines

Engineering Contradiction:
Improvepressure equalization reliabilityVSAvoidcar body tilting
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the harmful pneumatic connecting lines from the pressure equalization process by introducing a separate venting path to the environment. Instead of relying on check valves to connect air springs together (which creates unpredictable pressure conditions in connecting lines), the system vents the higher-pressure air spring directly to the environment through a controlled outlet, eliminating the harmful pressure transmission through connecting lines that causes car body tilting.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary outlet connected to the environment as a pressure sink. This intermediary element serves as a safe discharge path for excess pressure, mediating between the high-pressure air spring and the environment without creating harmful pressure conditions in the pneumatic connecting lines. The outlet acts as a controlled interface that prevents direct pressure transmission through the connecting lines.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stress or pressure

If compensating devices establish connections between control connections to equalize pressure, then pressure differences are reduced, but safety-critical tilting cannot be reliably prevented

Engineering Contradiction:
Improvepressure difference between air springsVSAvoidsafety-critical tilting prevention
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The invention converts the harmful effect of pressure differences (which cause tilting) into a beneficial controlled venting process. Instead of trying to equalize pressure between air springs through connecting lines (which creates harmful pressure conditions), the system uses the pressure difference to drive a controlled venting action through a dedicated outlet. The pressure difference is harnessed to open the switching means and vent excess pressure safely to the environment, transforming the harmful pressure differential into a useful control mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If switching means connect control connections for pressure equalization, then pressure balance is achieved, but unnecessary interruptions in venting occur

Engineering Contradiction:
Improvepressure balanceVSAvoidventing process continuity
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The invention segments the pressure control function into separate pathways: a venting path to the environment for pressure relief, and a connection path between control connections for pressure equalization. By separating these functions and using a dedicated outlet for venting, the system avoids unnecessary interruptions in the venting process that would occur if the same pathway had to serve both equalization and venting functions. The switching means can independently control each pathway.

Inventive Principle:
Principle #1Segmentation

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 solution reliably prevents pressure differences from exceeding safety thresholds, ensuring the car body remains level and stable, reducing the risk of safety-critical tilting or damage from uneven pressure distribution.

Implementation Method 1

switching means which can be switched by means of the pressure difference present at the two control connections

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

bring about a pressure equalization between the first and the second control connection in at least one switching position

Methodology Applied
Scientific EffectPressure equalization:

Implementation Method 3

at least one outlet connected to the environment of the rail vehicle as a pressure sink

Methodology Applied
Scientific EffectPressure sink:

Data Source

PatentEP2307254B1Air suspension system for a rail vehicle
Publication Date: 2018.02.21 SIEMENS AG
  • EP2307254B1 patent drawingFigure 1
  • EP2307254B1 patent drawingFigure 2
  • EP2307254B1 patent drawingFigure 3~4

AI summary

The invention relates to an air suspension system for a rail vehicle having at least two air springs, a compressed air supply system for supplying air springs with compressed air, and at least one equalization device for reducing a pressure difference between air springs, wherein the equalization device has at least a first control port which is connected to at least one of the air springs, and a second control port which is connected to at least one other air spring, and switching means which can be switched by means of the pressure difference which is applied to the control ports, and in at least one switched position they bring about pressure equalization between the first and second control ports. The air suspension system makes it possible to prevent, in a particularly reliable way, a pressure-difference threshold value between air springs connected to the equalization device from being exceeded. For this purpose, the equalization device has at least one outlet which is connected to a pressure source, and in the case of pressure equalization by means of the equalization device the switching means connect through to the at least one outlet that control port to which a relatively high pressure is applied.