Hydraulic Control Valve Pressure Drop Adjustment
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Solution Overview
Problem
Existing hydraulic control systems for vehicles face challenges in maintaining balanced pressure distribution across motors in series and parallel circuits, leading to imbalances and operational issues such as wheel scuffing and unwanted wheel slip, especially during turns and varying terrain conditions.
Innovation Solution
A hydraulic control valve with a spool and relief valve configuration that allows for non-linear pressure drop adjustment across motors without complex control circuitry, using a body with defined ports and fluid communication passages to vary pressure based on system pressure, enabling adaptive pressure splitting and traction control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flow dividers are used in parallel motor circuits to ensure all wheels spin, then wheel slip is reduced, but pressure drop increases causing operation problems in creep mode
Solution Approach 1:
The patent changes the flow distribution parameters dynamically by using variable orifices that adjust their flow characteristics based on spool position. The spool position varies with system pressure, automatically adjusting the flow split ratio to optimize performance across different operating modes including creep mode where high pressure drop would be problematic.
Solution Approach 2:
The invention introduces dynamic flow control through a movable spool that responds to pressure changes. Unlike fixed flow dividers, this dynamic system automatically adjusts the flow distribution to motors based on real-time pressure conditions, reducing pressure drop in creep mode while maintaining wheel slip control when needed.
2Stress or pressure
If series motor circuits are used to share pressure, then pressure distribution is improved, but flow equality causes wheel scuffing during turns
Solution Approach 1:
The patent applies local quality by providing different flow control characteristics to different motors through individually controlled orifices. Each motor can receive customized flow based on its specific needs (determined by spool position), allowing the system to maintain good pressure distribution while accommodating different flow requirements during turning operations.
Solution Approach 2:
The invention segments the flow control function by providing separate variable orifices for each motor circuit. This segmentation allows independent adjustment of flow to each motor, decoupling the pressure sharing benefit of series circuits from the flow equality constraint that causes wheel scuffing during turns.
3Reliability
If complex control circuitry is used to adjust pressure drop across motors, then performance is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service control where the valve assembly automatically adjusts flow distribution based on inherent pressure-differential-driven spool movement. The system uses the system's own pressure differentials to control the spool position, which in turn controls the orifice openings, creating a self-regulating system that improves performance without requiring external complex control circuitry.
Solution Approach 2:
The movable spool acts as an intermediary element that translates pressure differential signals into flow control actions. This simple mechanical intermediary provides intelligent pressure control performance without requiring complex electronic or hydraulic control circuits, bridging the gap between pressure sensing and flow regulation.
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 reduces system complexity and cost while maintaining or improving performance by dynamically adjusting pressure distribution across motors, enhancing traction and reducing operational issues like wheel slip and motor cavitation.
Implementation Method 1
The spool includes a first fluid communication passage fluidly connected to the first port, a second fluid communication passage fluidly connected to the second port, and a third fluid communication passage fluidly connected to the third port
Implementation Method 2
The relief valve is movable between an open position and a closed position to control flow through the fourth port
Implementation Method 3
Hydraulic fluid is directed to the third port to move the spool from a biased position to a second operative position
Data Source
AI summary
A hydraulic control valve maintains the pressure at a control port at a desired percentage of the pressure at two other ports as the pressure at the two other ports varies. Upon the pressure at the control port reaching a predetermined pressure setting, a fourth port will open to maintain the control port at a second desired percentage of the two other ports.