Hydraulic Pilot Circuit Pressure Switching for Failure Detection
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Solution Overview
Problem
Hydraulic pilot circuits in industrial machines are susceptible to failures due to contamination, particularly when a solenoid valve's spool becomes stuck, making it difficult to detect failures automatically during normal operations.
Innovation Solution
A failure detection device that includes a controller, pressure sensor, and alarm device, which monitors and switches the hydraulic pilot circuit's pressure states to detect deviations from predetermined values, automatically identifying failures by measuring pilot oil path pressures during normal lever operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hydraulic pilot circuit is used for control, then control precision is improved, but susceptibility to contamination increases
Solution Approach 1:
The failure detection device performs preliminary detection of contamination or abnormalities in the hydraulic pilot circuit before they cause complete system failure. By continuously monitoring pilot oil pressure and comparing it against predetermined thresholds, the system can identify contamination buildup or component degradation early, allowing for preventive maintenance before the spool becomes stuck or the system fails completely.
2Reliability
If automatic failure detection is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The failure detection device uses pilot oil pressure as an intermediary parameter to indirectly detect spool sticking or contamination. Instead of directly monitoring the spool position or contamination levels, the system measures the pilot oil pressure downstream, which changes characteristically when a failure occurs. This intermediary approach simplifies the detection system while maintaining high reliability.
Solution Approach 2:
The invention replaces complex mechanical detection mechanisms with a simpler pressure-based detection system. Instead of using mechanical sensors to directly detect spool position or contamination, the system uses pressure sensors to monitor pilot oil pressure, which provides indirect but reliable failure detection with fewer moving parts and lower complexity.
3Measurement precision
If pressure monitoring is continuous, then detection accuracy is improved, but energy consumption increases
Solution Approach 1:
The failure detection device performs periodic monitoring of pilot oil pressure at key operational points rather than continuous monitoring. The system checks pressure when the operation lever is operated and when it returns to neutral, which are the critical moments when failures are most likely to manifest. This periodic approach maintains detection accuracy while significantly reducing energy consumption compared to continuous monitoring.
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 reliable and automatic detection of hydraulic pilot circuit failures, preventing erroneous detection and allowing for timely troubleshooting, thereby enhancing the reliability of industrial and construction machines.
Implementation Method 1
a pressure sensor that measures a pressure in the pilot oil path
Data Source
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AI summary
Provided is a failure detection device which is capable of automatically detecting a failure of a hydraulic pilot circuit following a normal lever operation. 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 that supplies operating pressure to an actuator; a pilot oil path that connects the pilot pressure source and a pilot pressure supply unit; and a pressure control unit that is disposed in the pilot oil path to control 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 in the pilot oil path; 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.