Hydraulic Steering System Emergency Actuation
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Solution Overview
Problem
Hydraulic steering systems for industrial trucks face inefficiencies, high costs, and space constraints due to complex designs and the need for large steering columns and high-pressure lines, which also result in noise and limited emergency steering capabilities.
Innovation Solution
A compact and cost-effective hydraulic steering system with an integrated pump device that enables emergency steering by forcing hydraulic oil flow between the steering cylinder chambers, sharing a single hydraulic pump with other vehicle loads and incorporating a priority valve for adequate oil supply, along with a manually operable pump and shock valves for robustness, and a pressure control valve to reduce installation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a complex steering column is used for direct transmission steering, then steering control is achieved, but the space available in the footwell is limited and the system becomes bulky
Solution Approach 1:
The patent replaces the mechanical direct transmission steering column with a hydraulic steering system. The steering wheel is connected to a hydraulic pump that generates hydraulic pressure to actuate the steering cylinder, eliminating the need for a complex mechanical steering column and associated linkages in the footwell area.
Solution Approach 2:
The patent employs a hydraulic steering system where hydraulic fluid transmitted through hoses actuates a steering cylinder. This hydraulic mechanism replaces the mechanical steering column, achieving steering control while significantly reducing the space required in the footwell area.
2Ease of operation
If high-pressure steering unit lines are installed close to the vehicle driver region, then steering functionality is achieved, but disruptive flow-related noise occurs during steering movement
Solution Approach 1:
The patent introduces a hydraulic tank as an intermediary reservoir for the hydraulic fluid. The system includes a hydraulic pump that draws fluid from the tank and a steering cylinder that returns fluid to the tank. This intermediary tank allows for quieter operation by providing a buffer that reduces turbulent flow noise in the driver region.
3Reliability
If steering units with integrated emergency steering are used, then emergency steering capability is achieved, but the system becomes expensive and requires large installation space
Solution Approach 1:
The hydraulic pump serves multiple functions: it provides hydraulic pressure for normal steering operation and also acts as the emergency steering pump. The same hydraulic tank serves as both the operating fluid reservoir and the emergency steering fluid source. This multi-functionality eliminates the need for separate emergency steering components, reducing cost and installation space.
Solution Approach 2:
The patent merges the emergency steering system with the normal hydraulic steering system. The steering cylinder, hydraulic tank, and pump are shared between normal operation and emergency steering. This consolidation reduces the overall system complexity, cost, and installation space requirements compared to having separate systems.
4Device complexity
If a steering system shares a single hydraulic pump with other vehicle loads, then cost and space are reduced, but adequate oil supply to the steering block may be insufficient during normal operation
Solution Approach 1:
The system dynamically prioritizes hydraulic fluid supply to the steering system when steering demands are detected. The control system monitors steering requests and ensures adequate fluid flow to the steering cylinder takes precedence over other hydraulic loads, maintaining reliable steering operation while sharing the pump resource.
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 solution provides a space-saving, energy-efficient, and cost-effective steering system with enhanced emergency steering functionality, remaining operational even during system failures, and reduces noise and installation complexity.
Implementation Method 1
Activating said pump device allows an emergency steering function to be carried out by means of a forced flow of hydraulic oil between the two chambers of the steering cylinder
Implementation Method 2
at least two second hydraulic connections for supplying hydraulic oil from the hydraulic pump to the steering block and feeding the hydraulic oil back into the hydraulic tank
Implementation Method 3
a controllable valve assembly which receives control signals from a steering angle detection device and is designed to convey hydraulic oil to the steering cylinder on the basis of said control signals
Data Source
AI summary
The present invention relates to a hydraulic steering system for a vehicle, in particular an industrial truck, comprising: a steering cylinder having two chambers and a hydraulic connection at each of the two chambers for activating a steering movement of at least one wheel of the vehicle; at least one hydraulic pump; at least one hydraulic tank for receiving hydraulic oil; and a steering block which comprises: two first hydraulic connections for connecting to the two hydraulic connections of the steering cylinder; at least two second hydraulic connections for supplying hydraulic oil from the hydraulic pump to the steering block and feeding the hydraulic oil back into the hydraulic tank; and a controllable valve assembly which receives control signals from a steering angle detection device and is designed to convey hydraulic oil to the steering cylinder on the basis of said control signals; the controllable valve assembly being further designed to be shiftable into at least one neutral position in which it allows a flow of hydraulic oil between the two chambers of the steering cylinder. The hydraulic steering system further comprises a pump device which is designed to stimulate the flow of hydraulic oil between the two chambers of the steering cylinder when the valve assembly is in the neutral position.