Electro-Hydraulic Tilting Actuator With Fail-Safe Gravity Centering

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Solution Overview

Problem

Existing tilting systems for rail vehicles face challenges with hydraulic systems requiring significant space and effort due to large relative movements, and electromechanical systems suffer from jamming issues and power electronics space constraints.

Innovation Solution

An electro-hydraulic actuator (EHA) with a hydraulic cylinder, electrically operable pump, and hydraulic valves is designed to be compact and fail-safe, allowing for efficient tilting and centering without continuous energy use, using hydraulic check and control valves to leverage gravity for positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hydraulic system with central hydraulic unit is used, then the tilting function is achieved, but the space requirement and system complexity increase due to large relative movements and hydraulic piping

Engineering Contradiction:
Improvetilting functionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the hydraulic system into modular components: a compact hydraulic unit integrated with the actuator, individual hydraulic cylinders at each tilting point, and distributed hydraulic supplies. This segmentation eliminates the need for a single large central hydraulic unit and extensive piping, reducing system complexity while maintaining the tilting function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a centralized hydraulic architecture to a distributed modular architecture, effectively changing the spatial dimension of system organization. By placing hydraulic supplies locally near actuators and integrating them with cylinder assemblies, the system reduces the dimensional footprint and complexity of hydraulic routing.

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

2Volume of moving object

If an electromechanical actuator (EMA) is used, then the footprint is reduced, but power electronics space requirements and jamming risks increase

Engineering Contradiction:
Improveactuator footprintVSAvoidjamming risk
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent employs a hydraulic cylinder instead of an electromechanical spindle drive. The hydraulic cylinder uses fluid pressure to generate linear motion, eliminating the spindle mechanism that is prone to jamming. This hydraulic approach maintains compact dimensions while significantly improving reliability by removing the inherent jamming vulnerability of mechanical spindles.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Volume of moving object

If an electromechanical actuator (EMA) is used, then the actuator size is reduced, but the power electronics housing space and relative movement tolerance requirements increase

Engineering Contradiction:
Improveactuator sizeVSAvoidpower electronics housing
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent merges the hydraulic supply unit with the actuator assembly into an integrated compact package. The hydraulic pump, tank, and control valves are combined with the hydraulic cylinder in a single modular unit, eliminating the need for separate power electronics housing and reducing the overall space requirements while maintaining actuator compactness.

Inventive Principle:
Principle #5Merging (Combining)

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 EHA provides a compact, energy-efficient, and fail-safe solution that minimizes energy consumption and eliminates jamming risks, ensuring safe operation and reduced installation space requirements compared to electromechanical actuators.

Implementation Method 1

the hydraulic supply comprises a hydraulic pump, preferably electrically operated

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

hydraulic valves comprise at least one directional control valve, at least one preferably unlockable check valve

Methodology Applied
Scientific EffectHydraulic valve control: Valve

Implementation Method 3

in the event of a failure of the power supply to the hydraulic pump, the hydraulic cylinder can be depressurized, allowing the car body to center itself solely under the influence of gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4385850A1Actuator for a tilting system of a rail vehicle
Publication Date: 2024.06.19 LIEBHERR TRANSPORTATION SYST
  • EP4385850A1 patent drawingFigure 1
  • EP4385850A1 patent drawingFigure 2
  • EP4385850A1 patent drawingFigure 3

AI summary

The present invention relates to an actuator for a tilting technology system of a rail vehicle, wherein the actuator is an electro-hydraulic actuator and comprises a hydraulic cylinder and a hydraulic supply for the hydraulic cylinder, wherein the hydraulic supply comprises a hydraulic pump, preferably electrically operated, a hydraulic tank and hydraulic valves.