Hydraulic Steering Device with Segmented Flow Control Valves
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Solution Overview
Problem
Hydraulic steering devices lack high functional safety and reliability, particularly in steer-by-wire systems, which hinders their use in street-legal vehicles, as they are prone to errors and require manual correction by the driver.
Innovation Solution
A hydraulic steering device with a flow control valve arrangement featuring individually controllable groups of valves, allowing for error detection and correction, and a common release shut-off valve for secondary flow control, enabling automatic correction of steering movements and improved functional safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flow control valve arrangement with individually controllable groups of valves is used, then functional safety and reliability are improved, but device complexity increases
Solution Approach 1:
The flow control valve arrangement is divided into multiple individually controllable valve groups (first and second groups of controllable valves), each capable of independent operation. This segmentation allows selective activation of specific valve groups based on operational requirements, enabling error detection and correction mechanisms while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
The control unit receives feedback signals from sensors monitoring the hydraulic system's operational state and uses this information to automatically activate appropriate valve groups for error correction. The system continuously monitors steering movements and compares expected versus actual behavior, triggering corrective actions through specific valve group activation when deviations are detected, thereby maintaining high functional safety.
2Reliability
If a common release shut-off valve is added for secondary flow control, then safety is improved, but device complexity increases
Solution Approach 1:
The common release shut-off valve serves multiple functions: it controls the secondary flow path, works in conjunction with the controllable valve groups for error correction, and provides an additional layer of safety control. By designing this single valve to perform multiple safety-related functions, the patent reduces the need for separate dedicated components for each safety function, thereby improving safety without proportionally increasing device complexity.
3Measurement precision
If individually controllable valve groups are implemented, then error detection capability is improved, but manufacturing complexity increases
Solution Approach 1:
The valve system is segmented into standardized, independently controllable groups that can be manufactured as modular units. Each valve group contains similar internal structures and control mechanisms, allowing for standardized manufacturing processes, interchangeable components, and simplified assembly procedures. This modular segmentation enables precise error detection through individual valve control while maintaining ease of manufacture through repetition of proven design modules.
Solution Approach 2:
The patent utilizes controllable valves that can change their flow parameters (open/closed states, flow rates) based on electrical control signals. This parameter controllability allows the same physical valve structure to perform multiple detection and correction functions by simply changing its operational state, thereby improving error detection capability without requiring additional physical components or complex manufacturing variations.
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 fault-tolerant electro-hydraulic steering system that can be used on the road, automatically correcting steering errors and ensuring the vehicle's steerability, even without manual intervention, enhancing the system's reliability and safety.
Implementation Method 1
hydraulic steering device having a steering valve (12) having an inlet connection (20) and an outlet connection (26) which are connected to a supply system (28)... a steering cylinder (48) which is connected to steerable wheels of the vehicle... cylinder connections (40, 42) which are connected to the steering valve (12)
Implementation Method 2
The position of the control piston is centered in relation to the control sleeve by means of a spring element. Against the force of this spring element, the control piston and control sleeve can be rotated relative to one another to a limited extent.
Data Source
Figure 1
AI summary
The invention relates to a hydraulic steering device which hydraulically connects a steering cylinder (48) to a supply system (28). The supply system (28) can be hydraulically connected to the steering cylinder (48) in an operative manner via a steering valve (12) in order to form a main flow connection, and the supply system (28) can be hydraulically connected to the steering cylinder (48) in an operative manner via a flow regulating valve arrangement (50) in order to form an auxiliary flow connection which bypasses the main flow connection. The flow regulating valve arrangement (50) can be controlled by an electric control device (74). The flow regulating valve arrangement (50) comprises individually controllable valve groups (52, 54), each of which is connected into the feed line and the return line of the auxiliary flow connection.