Load Sense Relief Valve with Pilot Vent Pressure Adjustment
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Solution Overview
Problem
Hydraulic systems face challenges in achieving electronically adjustable pressure limits while withstanding high pressures, which increases design costs and complexity due to the need for robust electrohydraulic load sense relief valves.
Innovation Solution
The system incorporates an electrohydraulic load sense relief valve with a control valve that adjusts pressure in the pilot vent, allowing for electronic control of pressure limits, using a solenoid to balance high pressures and a relief valve with a mechanical setting that can be increased by the controlled pressure, enabling adjustable pressure limits within a predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a robust electrohydraulic load sense relief valve is used to achieve electronically adjustable pressure limits, then pressure control capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The relief valve is divided into two functional parts: a mechanical relief valve providing a fixed baseline pressure setting, and a separate low-pressure electrohydraulic control valve that adjusts the pilot vent pressure. This segmentation allows each component to be optimized independently, reducing overall complexity while achieving electronic adjustability.
Solution Approach 2:
A low-pressure electrohydraulic control valve is introduced as an intermediary device to control the pilot vent pressure. This mediator translates electronic control signals into pressure adjustments that modify the mechanical relief valve's operation, enabling electronic pressure limit adjustment without requiring the main relief valve to withstand high pressures directly.
2Reliability
If high-pressure withstanding components are used, then pressure limit reliability is improved, but manufacturing cost increases
Solution Approach 1:
The low-pressure electrohydraulic control valve acts as a mediator that handles the electronic control function at low pressure, allowing the mechanical relief valve to operate at high pressure without requiring expensive high-pressure electronic components. This separates the reliability requirements for pressure containment from electronic control.
Solution Approach 2:
The patent replaces the need for expensive high-pressure electrohydraulic components with a mechanical relief valve augmented by a low-pressure electrohydraulic control system. The mechanical valve provides reliable high-pressure containment, while the low-pressure electronic system provides adjustable control, reducing manufacturing costs.
3Device complexity
If a mechanical relief setting is used, then device simplicity is improved, but adaptability to different pressure limits deteriorates
Solution Approach 1:
The system combines a static mechanical relief setting with a dynamic electrohydraulic control system. The pilot vent pressure control valve dynamically adjusts the effective pressure limit by modifying the pressure in the relief chamber, allowing the mechanical valve to maintain its simple design while the system achieves electronic adjustability.
Solution Approach 2:
The patent changes the pressure parameter in the relief chamber through the electrohydraulic control valve. By adjusting the pilot vent pressure, the effective pressure limit of the mechanical relief valve is modified, enabling adaptability to different pressure limits while maintaining the simplicity of the mechanical valve design.
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
This solution allows for electronically adjustable pressure limits in hydraulic systems, reducing the need for high-strength components and lowering costs by using a low-pressure electrohydraulic pressure regulating valve to control higher load sense pressures, while maintaining system stability and efficiency.
Implementation Method 1
using a solenoid to balance high pressures
Implementation Method 2
a main poppet moveable between a first position and a second position, where a poppet spring biases the main poppet toward the first position
Implementation Method 3
a relief spring acts on the second side of the relief poppet. The relief spring defines a mechanical relief setting
Data Source
AI summary
A load sense pressure regulating system is provided. The load sense pressure regulating system can be operable between a flow regulation mode and a pressure limiting mode. When the load sense pressure control system is in the flow regulation mode, flow between a load sense inlet and a pilot vent are metered by a main poppet. The load sense pressure regulating system can also include a control valve downstream from the pilot vent that is configured to control a relief setting of a relief valve to regulate the load sense pressure within a desired operating range.