Differential Pressure Controller for Hydraulic Flow Regulation
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Solution Overview
Problem
Hydraulic systems for work vehicles face challenges in adjusting pressure differentials across metering orifices of control valves, requiring precise control of hydraulic fluid flow to ensure identical operation of multiple devices, such as excavator tracks, while allowing for reduced fluid flow to certain components like hydraulic motors for slower speeds.
Innovation Solution
A differential pressure controller senses maximum regulated pressure downstream of pressure compensating valves and produces an output pressure that can be supplied to the pump or pressure compensating valves, allowing for adjustable pressure differentials by combining load sense pressure with a setting pressure, enabling varying flow output across control valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pressure compensation valves are used to maintain identical pressure differentials across all control valves, then identical operation of multiple devices is achieved, but the ability to provide reduced hydraulic fluid flow to selected components is lost
Solution Approach 1:
The system divides the pressure compensation function into two segments: a common pressure compensation valve that maintains identical pressure differentials across all control valves, and individual flow control valves that can be selectively adjusted to reduce flow to specific components. This segmentation allows simultaneous achievement of identical operation for most devices and reduced flow capability for selected components.
Solution Approach 2:
The patent applies local quality by allowing different pressure differential characteristics for different parts of the system. Most control valves receive identical pressure differentials through the common compensation valve, while selected control valves can have their pressure differentials locally adjusted through individual flow control valves to achieve reduced flow rates to specific components like hydraulic motors.
2Device complexity
If a single pressure differential is maintained across all control valves, then system simplicity is preserved, but the capability to independently control flow rates to different components is reduced
Solution Approach 1:
The pressure control mechanism is segmented into a common pressure compensation valve that serves all control valves and individual flow control valves for selected components. This segmentation maintains overall system simplicity while enabling independent flow control where needed.
Solution Approach 2:
Individual flow control valves act as intermediaries between the common pressure compensation system and selected control valves. These intermediary devices allow independent flow rate adjustment to specific components without disrupting the overall pressure compensation mechanism that maintains identical operation across most devices.
3Productivity
If pressure differentials are reduced across selected control valves, then hydraulic fluid flow to those valves is reduced, but maintaining identical pressure differentials across all valves prevents selective flow reduction
Solution Approach 1:
The system applies local quality by allowing most control valves to maintain identical pressure differentials through the common compensation valve, while selected control valves can have their pressure differentials locally modified through individual flow control valves. This enables selective flow reduction to specific components like hydraulic motors without affecting the identical operation of other devices.
Solution Approach 2:
The pressure differential control is segmented into a common pathway that maintains uniform pressure differentials and individual pathways with adjustable flow control valves. This segmentation allows selective modification of pressure differentials for specific components while preserving uniform pressure differential characteristics for the rest of the system.
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 precise control of hydraulic fluid flow across multiple devices, enabling identical operation of devices like excavator tracks and adjustable speed settings, while reducing fluid flow to components like hydraulic motors, enhancing operational flexibility and efficiency.
Implementation Method 1
A differential pressure controller senses maximum regulated pressure downstream of pressure compensating valves and produces an output pressure that can be supplied to the pump or pressure compensating valves
Implementation Method 2
The pressure compensation valves control the pressures existing on the downstream sides of the metering orifices to produce the desired pressure differentials across the metering orifices
Implementation Method 3
Hydraulic systems are employed in many circumstances to provide hydraulic power from a hydraulic power source to multiple loads
Implementation Method 4
The operation of the hydraulically actuated devices depends upon the hydraulic fluid flow to those devices, which in turn depends upon the cross-sectional areas of metering orifices of the control valves
Data Source
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AI summary
A hydraulic control valve assembly (10), method and system, characterized by control valves (26) each having a variable metering orifice; a compensator (28) that controls flow of fluid from the variable metering orifice to a work port (A,B) in response to a differential in pressures acting on opposite first and second sides of the compensator, wherein a first side receives a pressure at the downstream side of the variable metering orifice; a load sense passage (34) providing a load sense pressure; and a differential pressure controller (40) having a first inlet connected to a pump supply port and a second inlet connected to the load sense passage, the controller having a first operational mode in which load sense pressure at the second inlet is supplied to an outlet of the controller and a second operational mode in which flow from the first inlet is metered to the outlet of the controller to provide a differential control output pressure, and wherein an outlet of the differential pressure controller is connected to a pump control port and/or to the second side of the pressure compensating valve of at least one of the control valves..