Work Vehicle Lock Valve Control via Pilot Pressure and Elapsed Time
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Solution Overview
Problem
Existing work vehicles face challenges in accurately determining whether the operation member is in an activation position when the lock member is switched to the release position, leading to potential unexpected activation of the hydraulic actuator.
Innovation Solution
The implementation of a system comprising a hydraulic actuator, operation member, pilot valve, actuator control valve, lock member, lock valve, elapsed time detection, and pilot pressure determination sections, which switches the lock valve based on elapsed time and pilot pressure to accurately determine the activation position and prevent unintended actuator activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure switches are used to determine activation position, then the system can detect operation member position, but the determination accuracy is insufficient
Solution Approach 1:
The patent replaces the mechanical pressure switch system with an electronic detection system comprising a pilot pressure detection section and a controller. The pilot pressure detection section detects pilot pressure generated by the pilot valve, and the controller processes this signal to determine operation member position. This substitution provides more accurate and reliable position detection while maintaining system simplicity.
Solution Approach 2:
The patent introduces pilot pressure as an intermediary parameter to detect operation member position. Instead of directly detecting mechanical position, the system detects the pilot pressure that is generated in response to operation member position, providing indirect but more accurate measurement. The pilot pressure serves as a mediator between the mechanical operation and the electronic detection system.
2Speed
If the lock member is switched to release position quickly, then operation response is fast, but unexpected actuator activation may occur
Solution Approach 1:
The patent implements preliminary detection of operation member position before allowing actuator activation. The controller detects whether the operation member is in the activation position using the pilot pressure detection section before the lock member switching takes effect. This preliminary check prevents unexpected activation by ensuring the operation member is properly positioned before releasing the lock.
Solution Approach 2:
The patent employs feedback control where the controller continuously monitors the pilot pressure signal to determine operation member position and uses this information to control the lock member switching. The system feedback loop ensures that activation only occurs when both the lock is released and the operation member is in the correct position, preventing unintended activation while maintaining fast response.
Data Source
AI summary
A lock valve switching section switches a lock valve from a locked state to a released state when a lock member is switched from a locked position to a release position. An erroneous operation monitoring section maintains the lock valve in the released state when the pilot pressure is equal to or more than a predetermined pressure when elapsed time, which is from a point in time where the lock member is switched from the locked position to the release position, is equal to or more than the predetermined time. The erroneous operation monitoring section switches the lock valve to the locked state when the pilot pressure is equal to or more than the predetermined pressure when the elapsed time is less than the predetermined time.