Pilot Pressure Switching in Hydraulic Emergency Actuation
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Solution Overview
Problem
In emergency operations of hydraulic systems, the sudden actuator movement caused by electromagnetic proportional valves being fully opened or closed leads to shock, and existing manual emergency operation methods also result in sudden actuator operation, posing safety risks.
Innovation Solution
A hydraulic system with a pilot pressure switching unit that allows the electromagnetic proportional valve supply pressure to be switched to a lower second pressure during emergencies, utilizing a bleed-off passage whose opening area adjusts with spool stroke to control operating oil pressure and actuator speed, enabling gradual actuator movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electromagnetic proportional valve is fully opened during emergency operation, then the actuator can be operated quickly, but the actuator is suddenly operated or suddenly stopped generating shock
Solution Approach 1:
The patent applies beforehand cushioning by introducing a shock-absorbing mechanism that pre-prepares to mitigate the sudden pressure changes caused by full opening of the electromagnetic proportional valve. This cushioning effect prevents the harmful shock from propagating through the hydraulic system when the actuator operates suddenly during emergency conditions.
Solution Approach 2:
The patent uses an intermediary element (such as a cushioning chamber or damping device) between the electromagnetic proportional valve and the actuator. This intermediary absorbs and moderates the sudden pressure surge when the valve opens fully, allowing the actuator to respond quickly while preventing shock transmission to other system components.
2Adaptability or versatility
If the electromagnetic proportional valve is manually fully opened during emergency operation, then the valve can be operated without electricity, but the actuator is suddenly operated generating shock
Solution Approach 1:
The shock-absorbing mechanism is built into the system architecture so that it automatically activates during manual emergency operation. When the electromagnetic proportional valve is manually opened, the cushioning mechanism pre-prepares to absorb the pressure surge, allowing the valve to be operated without electricity while preventing shock generation.
Solution Approach 2:
An intermediary cushioning device is positioned in the hydraulic circuit to mediate between the manually operated electromagnetic proportional valve and the actuator. This intermediary ensures that even when the valve is opened manually without electrical control, the actuator operates smoothly without generating shock.
3Reliability
If the controller cannot control the electromagnetic proportional valve, then emergency operation mode is activated, but the actuator cannot be precisely controlled
Solution Approach 1:
The system applies self-service by automatically switching to emergency operation mode when the controller can no longer control the electromagnetic proportional valve. The shock-absorbing mechanism and pressure control system automatically activate without requiring manual intervention, maintaining reliable operation while preserving actuator control precision through the inherent pressure regulation capabilities of the cushioning system.
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
The system ensures safe and gradual operation of actuators during emergencies by controlling the operating oil pressure and actuator speed, preventing sudden shocks and enhancing safety in hydraulic systems.
Implementation Method 1
an electromagnetic proportional valve which supplies a pilot pressure to the control valve
Implementation Method 2
a hydraulic pump; a pilot-type control valve which supplies an operating oil pressure from the hydraulic pump to an actuator
Implementation Method 3
the control valve has a bleed-off passage whose opening area increases and decreases according to a stroke of a spool based on a pilot pressure, and is capable of controlling the operating oil pressure to be supplied to the actuator according to the opening area
Data Source
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AI summary
Provided are: a hydraulic system and an emergency operation method which can slowly drive an actuator during an emergency operation and are excellent in safety. This hydraulic system is provided with: a hydraulic pump; a pilot-type control valve; an electromagnetic proportional valve which supplies a pilot pressure to the control valve; a controller which controls the electromagnetic proportional valve; and a pilot pressure switching unit which is capable of switching the electromagnetic proportional valve supply pressure supplied from a pilot pressure source to the electromagnetic proportional valve, to a first pressure during a normal operation, or to a second pressure lower than the first pressure. The control valve is provided with a bleed-off passage, and is capable of controlling the operating oil pressure supplied to the actuator, according to the opening area thereof. During an emergency operation, the electromagnetic proportional valve supply pressure is switched from the first pressure to the second pressure, the electromagnetic proportional valve is brought into a fully opened state, and the operating oil discharge amount from the hydraulic pump increases and decreases, and the operating oil pressure increases and decreases, and thus the operating speed of the actuator is controlled.