Isolation Valve for Load-Reaction Steering Feedback
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Solution Overview
Problem
Existing parallel steering circuits in off-highway vehicles lack a load-reaction feature, which is preferred by manufacturers for providing feedback to operators through the steering wheel, but current systems cause unintended movement of the steering wheel when one steering circuit is actuated, leading to operational inefficiencies.
Innovation Solution
A steering system with a fluid actuator and two steering circuits in parallel, where one circuit includes a load-reaction feature and an isolation valve that can enable or disable this feature, allowing external loads to be transmitted to the operator only when intended, preventing unintended steering wheel movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a load-reaction feature is incorporated into a steering circuit, then operators receive feedback through the steering wheel, but unintended steering wheel movement occurs when parallel circuits are actuated
Solution Approach 1:
An isolation valve is introduced as an intermediary component between the first steering circuit and the fluid actuator. This valve selectively controls fluid communication, allowing the load-reaction feature to be enabled or disabled based on which steering circuit is active, thereby preventing unintended steering wheel movement while preserving feedback when needed
Solution Approach 2:
The system dynamically switches between different operational states by actuating the isolation valve based on which steering circuit is active. When the second steering circuit is actuated, the valve disables load-reaction; when the first steering circuit is active, the valve enables load-reaction feedback, allowing the system to adapt its behavior to current operational conditions
2Adaptability or versatility
If parallel steering circuits are used, then steering control flexibility is improved, but load-reaction feature cannot be implemented
Solution Approach 1:
The isolation valve serves as a mediator that reconciles the conflict between parallel circuit operation and load-reaction functionality. By selectively enabling or disabling fluid communication based on which circuit is active, it allows both parallel steering control flexibility and load-reaction feedback to coexist in the same system
Solution Approach 2:
The load-reaction feature is applied locally to specific operational conditions rather than being universally enabled or disabled. The isolation valve creates different functional states for different steering circuits, allowing load-reaction to be present when the first circuit is active and absent when the second circuit is active
Data Source
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AI summary
A steering system includes a fluid actuator (22), a first steering circuit (18) in selective fluid communication with the fluid actuator (22), and a second steering circuit (20) in selective fluid communication with the fluid actuator (22) and disposed in parallel to the first steering circuit. The second steering circuit includes a load-reaction feature (72) and an isolation valve (76) with the isolation valve (76) being adapted to enable and disable the load-reaction feature (72).