Hydraulic Pilot Circuit Failure Detection for Stuck Valve Spools
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulic pilot circuits in industrial machines are susceptible to contamination, leading to potential failures such as a stuck spool in switching valves, which can prevent the spool from returning to its non-excitation state, and existing technologies lack effective methods for automatic failure detection during normal operation.
Innovation Solution
A failure detection device is implemented in the hydraulic pilot circuit, comprising a pressure sensor and a controller that measures and controls the pressure in the pilot oil path, allowing for sequential pressure switching and diagnosis based on normal lever operation, including a pilot pressure source, pilot pressure supply unit, pilot oil path, and pressure control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a switching valve is provided in a hydraulic pilot circuit to control pilot pressure, then the pilot circuit can effectively control the main circuit, but the spool may become stuck due to contamination, leading to circuit failure
Solution Approach 1:
The system performs preliminary actions by sequentially actuating the solenoid valve to different positions (first position, second position, third position) before actual operation to detect potential spool sticking issues. The controller commands pressure changes in advance and monitors sensor feedback to identify failures before they affect main circuit operation.
Solution Approach 2:
A pressure sensor provides continuous feedback on the pilot oil path pressure to the controller. The controller compares the actual pressure with expected pressure values at each solenoid valve position to detect anomalies. This feedback mechanism enables real-time monitoring and automatic detection of spool sticking failures.
2Reliability
If failure detection is performed continuously, then detection reliability is improved, but false detection may occur during neutral states, reducing accuracy
Solution Approach 1:
The failure detection mechanism dynamically adapts its operation based on the state of the operation lever. When the lever is in a non-neutral position, the system performs failure detection by sequentially switching the solenoid valve. When the lever returns to neutral, the system suspends detection or performs it in a different manner, preventing false detections during neutral transitions.
Solution Approach 2:
The system changes the detection parameters based on the operation lever state. Detection is activated only when the lever is in a non-neutral position, and the solenoid valve switching sequence is adjusted according to the current operational state. This parameter change ensures detection occurs only when meaningful pressure changes are expected.
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
Enables automatic detection of hydraulic pilot circuit failures, preventing erroneous detection during neutral states and ensuring reliable failure identification, thereby enhancing the operational reliability of industrial machines and construction equipment.
Implementation Method 1
a pressure sensor that measures the pressure on a downstream side in a pilot pressure supply direction of the pressure control unit in the pilot oil path
Implementation Method 2
a pressure control unit that is disposed in the pilot oil path to control a pressure of the pilot oil path
Data Source
AI summary
The failure detection device is a failure detection device of a pilot circuit, the pilot circuit including: a pilot pressure source; a pilot pressure supply unit that supplies pilot pressure to a control valve; a pilot oil path that connects the pilot pressure source and a pilot pressure supply unit; and a pressure control unit that controls a pressure of the pilot oil path, the failure detection device including: a pressure sensor that measures the pressure on a downstream side in a pilot pressure supply direction of the pressure control unit; and a controller that controls the pressure control unit to sequentially switch the pressure of the pilot oil path and performs a failure diagnosis based on a measurement result of the pressure sensor at this time, as an operation lever which receives an operation for operating the actuator returns to a neutral state.