Trailer Wheel Steering Hydraulics for Stable Pressure Control

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Solution Overview

Problem

Hydraulic steering systems in trailers experience pressure fluctuations due to temperature changes, leading to unstable steering behavior and potential safety hazards, with existing systems requiring complex and costly warning systems to address these fluctuations.

Innovation Solution

A simplified hydraulic control circuit with a single pressure switch and integrated pressure-relief and non-return valves, along with a biasing system to maintain consistent pressure, and pressure-bleeding mechanisms to manage pressure changes, enhancing stability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the trailer is parked at low temperatures for extended periods, then the hydraulic pressure decreases due to temperature drop, but the steering behavior becomes unstable and less precise due to air compressibility in the hydraulic liquid

Engineering Contradiction:
Improvehydraulic liquid temperatureVSAvoidsteering behavior stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

A pressure sensor is integrated into the hydraulic circuit to continuously monitor pressure levels. When pressure drops below a threshold (indicating potential air presence or temperature effects), the sensor triggers a warning signal to the driver, enabling timely corrective action to maintain steering reliability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

A heating element is introduced as an intermediary component between the hydraulic liquid and the environment. The heating element actively compensates for low-temperature effects by warming the hydraulic liquid, preventing pressure drops and maintaining consistent steering behavior without requiring system redesign

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a warning system is added to detect pressure loss, then safety is improved, but the system complexity increases due to additional sensors and warning mechanisms

Engineering Contradiction:
ImprovesafetyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressure sensor serves dual functions: it monitors hydraulic pressure for safety warnings and simultaneously detects conditions indicating air presence in the system. By combining these monitoring functions into a single sensor unit, the system achieves enhanced safety without proportionally increasing complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated pressure sensor acts as a multi-functional component that provides both safety monitoring (pressure loss detection) and system diagnostics (air presence detection). This universal component replaces what would otherwise require separate sensing mechanisms, maintaining simplicity while improving reliability

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

The system maintains consistent hydraulic pressure, reducing the risk of unstable steering and simplifies manufacturing and maintenance, while providing reliable and predictable steering performance.

Implementation Method 1

at least one hydraulic element for absorbing a movement of a vehicle pulling the trailer

Methodology Applied
Scientific EffectHydraulic pressure transmission: Pascal's Law

Implementation Method 2

active control means comprise a pump

Methodology Applied
Scientific EffectHydraulic actuation: Hydraulic Press

Data Source

PatentEP4056455B1System for steering steerable wheels of a trailer
Publication Date: 2026.05.20 KONINK NOOTEBOOM GRP BV
  • EP4056455B1 patent drawingFigure 1
  • EP4056455B1 patent drawingFigure 2
  • EP4056455B1 patent drawingFigure 3

AI summary

The invention relates to a system (1) for steering steerable wheels (2) of a trailer (3), comprising a hydraulic control circuit (11), a hydraulic element (4) for absorbing a movement of a vehicle pulling the trailer (3), which hydraulic absorbing element (4) is connected for signal generation to the hydraulic control circuit (11), a hydraulic operating element (12) connected to the hydraulic control circuit (11) and acting on a steerable wheel (2), and means (20) connected to the hydraulic control circuit (11) for actively steering the steerable wheels (2), which active control means (20) comprise a pump (21). The hydraulic control circuit (11) may comprise a pressure-relief valve (28) arranged between the absorbing element (4) and the operating element (12) and a non-return valve (30) arranged between the pump (21) of the active control means (20) and the operating element (12), while the pressure-relief valve (28) and the non-return valve (30) may be integrated in a single valve unit (27). The system (1) may be provided with two absorbing elements (4) and two operating elements (12), wherein the hydraulic control circuit (11) comprises a single pressure sensor (39) which is connected for signal generation to the pump (21) of the active control means (20).