Pilot Pressure Switching for Shock-Free Hydraulic Emergency Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Emergency operation systems in hydraulic working machines experience sudden actuator movement and shock due to electromagnetic proportional valves being fully opened or closed, leading to safety concerns during failures like electric circuit breakdowns or valve contamination.
Innovation Solution
A hydraulic system with a pilot pressure switching unit that transitions the electromagnetic proportional valve supply pressure from a first pressure to a second, lower pressure during emergencies, allowing controlled operation speed through the bleed-off passage's adjustable opening area, ensuring the actuator operates slowly and safely.
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 sudden movement and shock are generated
Solution Approach 1:
The patent applies beforehand cushioning by introducing a decompression valve that reduces pilot pressure before it reaches the electromagnetic proportional valve during emergency operation. This pre-reduction of pressure cushions the system against sudden movements and shock when the valve opens, while still allowing the actuator to operate. The decompression valve creates a controlled pressure reduction path that prevents harmful shock effects while maintaining operational capability.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the pilot pressure level based on operation mode. During normal operation, full pilot pressure is supplied to the electromagnetic proportional valve for precise control. During emergency operation, the decompression valve reduces the pilot pressure to a lower level, changing the pressure parameter to prevent shock while maintaining actuator operation. This parameter change resolves the contradiction between speed and shock prevention.
2Reliability
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 and shock is generated
Solution Approach 1:
The decompression valve provides beforehand cushioning for manual emergency operation as well. When the electromagnetic proportional valve is manually opened during emergency operation, the decompression valve has already reduced the pilot pressure to a safe level, preventing shock and sudden movement. This ensures reliable emergency operation capability while eliminating the harmful shock effect.
3Speed
If a pilot pressure source supplies constant pressure to the electromagnetic proportional valve, then the valve responds quickly, but the actuator cannot be controlled to operate slowly during emergencies
Solution Approach 1:
The patent applies parameter changes by introducing a decompression valve that modifies the pilot pressure parameter based on operation mode. During normal operation, the full pilot pressure from the pilot pressure source is supplied to the electromagnetic proportional valve for quick response. During emergency operation, the decompression valve reduces the pilot pressure, which slows down the actuator operation while maintaining valve responsiveness. This parameter change enables both quick response and controlled slow operation.
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 effectively prevents sudden actuator movement and shock during emergencies, ensuring safe operation by gradually activating or deactivating the actuator, thus enhancing safety in hydraulic working machines.
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
Implementation Method 4
a pilot pressure switching unit in which an electromagnetic proportional valve supply pressure supplied from a pilot pressure source to the electromagnetic proportional valve is capable of being switched to a first pressure during a normal operation or a second pressure lower than the first pressure
Data Source
AI summary
This hydraulic system is provided with: a hydraulic pump; a pilot-type control valve; an electromagnetic proportional valve; a controller; and a pilot pressure switching unit which is capable of switching the electromagnetic proportional valve supply pressure 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.