Hydraulic Valve Clearance Detection via Return-Spring Neutral Reset
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Solution Overview
Problem
Existing methods for detecting mechanical play in hydraulic valves with motor-driven valve drives are inefficient, as they often rely on measuring play by moving against points or stops, which is not reliable for systems with significant elasticity and tolerances.
Innovation Solution
A method that involves moving the valve slide into a neutral position using a return spring, then calculating the clearance by determining the difference in distances from defined positions, allowing for accurate detection of play without relying on point measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If play detection is performed by moving the valve spool against points or stops, then the detection method is simple, but the measurement precision is poor due to system elasticity and tolerances
Solution Approach 1:
The method performs preliminary actions by moving the valve spool to extreme positions (first and second positions) before measuring play. The valve spool is first moved to a first position beyond the neutral position, then to a second position beyond the neutral position in the opposite direction. These preliminary movements establish the boundaries for accurate play calculation, allowing the system to account for elasticity and tolerances by measuring the total travel distance between defined positions rather than relying on simple point-to-point measurements.
2Measurement precision
If the valve spool is moved to defined positions beyond the neutral position, then the play detection accuracy is improved, but the detection time increases
Solution Approach 1:
The system uses the valve drive's own positioning capabilities and the return spring's natural action to perform the detection sequence. The valve spool is moved to defined positions using the valve drive, then the current is reduced to allow the return spring to move the valve spool back toward neutral. This self-service approach leverages existing system components and their natural behaviors, avoiding the need for additional measurement devices or complex external testing equipment, thereby reducing overall detection time while maintaining accuracy.
3Reliability
If the return spring is used to move the valve spool back to neutral position with reduced current, then the detection method becomes more reliable, but the device complexity increases
Solution Approach 1:
The method implements feedback by continuously monitoring the valve spool position during the detection sequence. The control unit tracks the valve spool's movement from the first position to the second position, and monitors when the return spring moves the valve spool back toward the neutral position. This feedback mechanism allows the system to accurately determine the play by calculating the difference between the first and second positions, ensuring reliable detection while using the existing control unit and position sensing capabilities without adding complex external monitoring systems.
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 method provides a reliable and repeatable way to detect mechanical play, enabling effective compensation for system tolerances and elasticity, improving the precision and efficiency of hydraulic valve operation.
Implementation Method 1
a valve spool of the hydraulic valve driven by the valve drive is clamped with at least one return spring which is designed to push the valve spool from any valve spool position back into a neutral position of the valve spool when the valve drive is de-energized
Data Source
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AI summary
Method for detecting a mechanical clearance (Ws) in a system (3) comprising a hydraulic valve (1) and a valve actuator (5) for actuating the hydraulic valve (1), wherein a valve spool (2) of the hydraulic valve (1) driven by the valve actuator (5) is clamped with at least one return spring (6) which is configured to push the valve spool (2) back to a neutral position (4) of the valve spool (2) from any valve spool position (7) when the valve actuator (5) is de-energized.