Pilot Pressure Switching in Hydraulic Emergency Valve Failure
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Solution Overview
Problem
Operators face safety risks during emergency operations of hydraulic systems when an electromagnetic proportional valve fails due to adhesion or contamination, as they must manually open the valve outside the cab, exposing them to hazards.
Innovation Solution
A hydraulic system with a pilot pressure supply unit that includes an electromagnetic proportional valve with a detent-type emergency manual operation function and a pilot pressure switching unit, featuring a pilot pressure unloading solenoid valve and an emergency operation activation switch, which controls the pilot pressure to ensure safety by maintaining the pilot pressure in an unloading state until the valve is manually opened, then switching to an on-loading state to supply pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electromagnetic proportional valve is equipped with a detent-type emergency manual operation function to enable manual opening, then the system can operate during valve failure, but operators must perform manual operations outside the cab exposing them to safety hazards
Solution Approach 1:
A solenoid valve is introduced as an intermediary device between the operator and the electromagnetic proportional valve. The solenoid valve can be operated from inside the cab and automatically opens the electromagnetic proportional valve when activated, eliminating the need for operators to physically access the valve outside the cab while maintaining system operability during failures
Solution Approach 2:
The system prepares emergency operation capabilities in advance by equipping the electromagnetic proportional valve with a detent-type manual operation function and a solenoid valve activation mechanism. This preliminary preparation ensures that when failure occurs, the system can quickly transition to emergency operation mode without requiring complex on-site adjustments or exposing operators to hazards
2Speed
If a pilot pressure supply unit continuously supplies pilot pressure to ensure actuator readiness, then the system responds quickly to operations, but safety risks increase during emergency situations
Solution Approach 1:
The pilot pressure supply system transitions from a static continuous supply mode to a dynamic controlled supply mode. The solenoid valve dynamically adjusts the pilot pressure supply based on operational needs - maintaining pressure during normal operation for quick response, and enabling safe emergency operation by controlling pressure release and reapplication timing
Solution Approach 2:
The system applies preliminary anti-action by preparing the solenoid valve to counteract the continuous pilot pressure supply during emergency situations. When emergency operation is detected, the solenoid valve can release the pilot pressure before manual valve opening, preventing dangerous actuator movement, and then reapply pressure after safe conditions are established
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 operators to perform emergency operations safely by ensuring the pilot pressure is only applied after manual intervention, reducing the risk of accidents and enhancing overall safety during system failures.
Implementation Method 1
an electromagnetic proportional valve that has a detent-type emergency manual operation function
Implementation Method 2
a pilot pressure unloading solenoid valve for switching a pilot pressure between the on-loading and the unloading state by energization
Implementation Method 3
a hydraulic pump; a control valve for supplying an operating pressure from the hydraulic pump to an actuator
Data Source
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AI summary
Provided is a hydraulic system with which an operator can safely perform work during an emergency operation even in the event that an electromagnetic proportional valve itself has failed. This hydraulic system is provided with a hydraulic pump, a control valve, and a pilot pressure supply unit. The pilot pressure supply unit has: an electromagnetic proportional valve that has a detent-type emergency manual operation function with which a pilot oil passage can be opened manually and generates pilot pressure for a control valve; a controller that controls the degree of opening of the electromagnetic proportional valve in accordance with the operation of an operation lever; and a pilot pressure switching unit that switches the oil pressure state of the pilot pressure supply unit between an on-loading state and an unloading state. The pilot pressure switching unit performs control to implement the unloading state when the electromagnetic proportional valve is being opened manually and performs control to implement the on-loading state after the electromagnetic proportional valve has been opened manually.