Hydraulic Steering Flow Boosting with Safety Isolation
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Solution Overview
Problem
Hydraulic steering devices with power amplification face safety risks due to lack of adaptability across different applications and potential malfunctions in the control circuit, leading to unsafe steering behavior when the supply pump fails.
Innovation Solution
The steering device incorporates electrically controllable hydraulic control lines and relief valves to prevent counterproductive secondary oil flows, along with switchable check valves to ensure safe operation, allowing only the active control line to receive signals and using a flow-limiting valve to regulate oil flow, thereby enhancing safety and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bypass line with flow control valve is added to enable current amplification, then steering safety is improved during normal operation, but the risk of unsafe steering behavior increases when the control circuit malfunctions
Solution Approach 1:
The patent applies preliminary anti-action by introducing check valves in the bypass line that automatically prevent counterproductive secondary oil flows before they can cause unsafe steering behavior. The check valves are pre-configured to block reverse flow paths, thereby anticipating and preventing potential control circuit malfunctions rather than reacting to them after occurrence.
Solution Approach 2:
The patent converts the potential harm of control circuit malfunctions into a benefit by designing the bypass line with check valves that automatically activate when malfunctions occur. The malformed control signals that would normally cause unsafe steering behavior are instead intercepted and converted into safe operating conditions through the check valve mechanism, which redirects oil flow through safe paths.
2Measurement precision
If the steering device is designed for a specific application with fixed linear dependency, then steering precision is improved for that application, but adaptability to different applications is reduced
Solution Approach 1:
The patent applies dynamics by making the linear dependency between steering wheel speed and steering oil flow rate adjustable rather than fixed. The system can dynamically adapt its characteristics through the bypass line configuration, allowing the same steering device to be optimized for different applications by adjusting the flow control valve settings or bypass line parameters, thereby achieving both precision and adaptability.
3Force
If the secondary flow volume is increased to improve power steering performance, then steering effort is reduced, but the risk of overwhelming the vehicle driver increases when malfunctions occur
Solution Approach 1:
The patent applies beforehand cushioning by incorporating check valves and flow control mechanisms in the bypass line that limit the maximum secondary flow volume. These safety mechanisms are built into the system design to cushion against potential malfunctions, ensuring that even when control circuits fail, the secondary flow cannot exceed safe limits that would overwhelm the driver, while still providing sufficient power assistance during normal operation.
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 design significantly increases safety by preventing unsafe steering behaviors and allowing the device to function effectively across various applications with reduced manual effort, even in emergency steering mode, by isolating non-active control lines and regulating oil flow, thus ensuring vehicle control during malfunctions.
Implementation Method 1
a flow control valve (20), which is controlled by the pressure difference, which is tapped off via a constant throttle (25)
Implementation Method 2
which can be actuated by the return pressure of the secondary oil flow and opens at a predetermined return pressure
Data Source
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AI summary
The invention is therefore based on the object of avoiding malfunctions in the steering device of the generic type. To this end, it is proposed that, in a steering device of the generic type, the control line (39, 38) which leads to the flow regulating valve (20) of the secondary flow line and lies opposite the active control line (38, 39) can be switched into a non-functional state.