Two-Stage Proportional Hydraulic Valve With Low Pilot Fluid Demand
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Solution Overview
Problem
Hydraulic systems face inefficiencies due to the continuous demand for hydraulic fluid in pilot-operated proportional valves, even when deactivated, and direct drive proportional valves are susceptible to contamination-induced failures due to low driving force.
Innovation Solution
A proportional hydraulic two-stage valve integrating a pilot-operated stage with a solenoid and a main stage featuring a proportional spool, which uses both electromagnetic force and hydraulic pressure to drive the spool, reducing fluid demand in the deactivated state and enhancing force potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a pilot-operated proportional valve is used, then high force potential is achieved, but continuous hydraulic fluid demand occurs even when deactivated
Solution Approach 1:
The valve is divided into two distinct stages: a pilot stage with a pilot spool and a main stage with a main spool. The pilot stage uses minimal hydraulic fluid to generate control pressure, while the main stage uses this pilot pressure combined with electromagnetic force to actuate the main spool. This segmentation allows the system to achieve high force potential through the main stage while the pilot stage consumes minimal fluid even in the deactivated state.
2Quantity of substance
If a direct drive proportional valve is used, then hydraulic fluid usage is reduced, but the valve becomes susceptible to contamination-induced failures due to low driving force
Solution Approach 1:
The pilot stage acts as an intermediary between the electromagnetic solenoid and the main spool. It generates pilot pressure that, when combined with electromagnetic force, provides sufficient driving force to actuate the main spool reliably. This intermediary mechanism protects the main stage from contamination-induced failures by reducing the direct electromagnetic force requirement while maintaining high reliability through combined force actuation.
3Force
If a two-stage valve design is implemented, then force potential and fluid efficiency are improved, but device complexity increases
Solution Approach 1:
The patent merges the pilot stage and main stage into a single integrated valve assembly with shared housing and coordinated spool mechanisms. The pilot spool and main spool are positioned within the same valve body with integrated fluid passages that connect the two stages. This merging approach achieves the benefits of two-stage operation (high force potential and fluid efficiency) while minimizing the complexity increase through unified design and compact arrangement.
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 two-stage valve achieves high force potential akin to pilot-operated valves while minimizing hydraulic fluid usage, overcoming the inefficiencies and reliability issues of existing designs.
Implementation Method 1
a pilot-operated stage including a solenoid, the solenoid includes a solenoid chamber housing a solenoid pin. When the solenoid is energized, the solenoid actuates the solenoid pin
Implementation Method 2
hydraulic fluid from the supply source applies a force to the spool body in a direction of actuation by the solenoid pin
Data Source
AI summary
A valve includes a solenoid with a chamber housing a pin that actuates when the solenoid is energized. The valve also includes a spool housed within a sleeve. The sleeve includes a supply section with a supply port in communication with a supply source and a tank section with a tank port in communication with a reservoir. The spool includes a body including a first passage receiving fluid from the supply source when an opening for the first passage aligns with the supply port. When the solenoid is energized and the opening for the first passage aligns with the supply port, fluid from the supply source (i) applies a force to the spool body in a direction of actuation by the pin and (ii) flows to a second passage within the valve.