Integrated Pressure Compensation Valve for Low-Cracking Reverse Flow
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Solution Overview
Problem
Existing hydraulic systems require separate valves for reverse flow, load-sense signal generation, and pressure compensation, increasing complexity and cost, while conventional valves have high cracking pressure due to seal friction, limiting reverse flow efficiency.
Innovation Solution
A pressure compensation valve with integrated load-sense fluid signal generation and reverse free flow configuration, featuring a valve piston with biasing forces from reverse flow and pressure compensation springs, allowing fluid flow in both directions with reduced cracking pressure through full surface area pressure differential action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate valves are used for reverse flow, load-sense signal generation, and pressure compensation, then each function can be performed reliably, but system complexity and cost increase
Solution Approach 1:
The patent combines reverse flow valve, load-sense signal generation valve, and pressure compensation valve into a single integrated valve assembly. The valve body contains multiple internal passages and chambers that enable all three functions to be performed simultaneously by a single spool mechanism, eliminating the need for separate valves and reducing system complexity while maintaining functional reliability
Solution Approach 2:
The integrated valve is designed to perform multiple functions universally: it provides reverse flow capability through internal passages, generates load-sense signals through pressure differential detection across chambers, and performs pressure compensation through spring-biased spool positioning. This multi-functional design reduces the total number of components needed in the hydraulic system
2Reliability
If conventional valves with seals are used, then fluid sealing is maintained, but cracking pressure increases due to seal friction
Solution Approach 1:
The patent removes traditional seals from the spool assembly and replaces them with a clearance-based sealing mechanism. The spool fits within the valve body with precise clearances that provide adequate sealing through fluid pressure and viscosity, eliminating seal friction while maintaining acceptable sealing performance. This extraction of seals resolves the contradiction between sealing reliability and cracking pressure
Solution Approach 2:
The patent uses hydraulic principles to achieve sealing without mechanical seals. Fluid pressure differential across the spool and viscosity of the hydraulic fluid create sufficient sealing force through the clearance gaps, replacing mechanical seal contact with fluid-based sealing. This reduces cracking pressure while maintaining sealing effectiveness through proper clearance design and fluid properties
3Reliability
If additional shuttle valves or check valves are added for load-sense signal generation, then load-sense signal can be provided, but device complexity increases
Solution Approach 1:
The load-sense signal generation function is merged into the main valve body by creating internal passages that connect the high-pressure chamber to the load-sense port. The spool position naturally controls fluid communication between these chambers, providing load-sense signal generation without requiring separate shuttle valves or check valves. This integration eliminates additional components while ensuring reliable load-sense signal provision
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 integrated valve reduces system complexity and cost by enabling both forward and reverse flow with lower cracking pressure, maintaining a constant pressure drop across directional control valves and providing a load-sense signal without additional shuttle or check valves.
Implementation Method 1
when pressure level of fluid at the second port is higher than pressure level of fluid at the load-sense port, fluid flows from the second port to the spring chamber and the load-sense port
Implementation Method 2
a reverse flow spring applying a first biasing force on the valve piston in a proximal direction
Implementation Method 3
a pressure compensation spring disposed in a spring chamber and applying a second biasing force on the valve piston in a distal direction
Implementation Method 4
maintaining a constant pressure drop across directional control valves
Implementation Method 5
fluid from the first port applies a first fluid force on the valve piston in the proximal direction
Implementation Method 6
the first fluid force of fluid from the first port overcomes the second biasing force of the pressure compensation spring and the second fluid force of fluid in the spring chamber
Data Source
AI summary
An example valve includes: a first port, a second port, and a load-sense port; a valve piston configured to block fluid flow from the first port to the second port when the valve piston is in a neutral position; a reverse flow spring applying a first biasing force on the valve piston in a proximal direction; and a pressure compensation spring disposed in a spring chamber and applying a second biasing force on the valve piston in a distal direction, wherein when pressure level of fluid at the second port is higher than pressure level of fluid at the load-sense port, fluid flows from the second port to the spring chamber and the load-sense port, and wherein when pressure level of fluid at the load-sense port is higher than pressure level of fluid at the second port, fluid of the load-sense port is provided to the spring chamber.