Confluence Valve Control in Hydraulic Machines Under Backpressure

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Solution Overview

Problem

Hydraulic machines face issues with backpressure in tank return lines causing malfunction of sensors and unintended movement of confluence control valves, especially when multiple actuators are operated simultaneously.

Innovation Solution

The hydraulic machine design includes a confluence control valve system with signal and pilot lines that manage pressure to direct fluid flow effectively, using drain lines to prevent backpressure interference and ensure accurate valve positioning, thereby maintaining operational stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple actuators are operated simultaneously, then the hydraulic machine can supply sufficient pressurized fluid to multiple actuators, but backpressure in tank return lines causes sensor malfunction and unintended valve movement

Engineering Contradiction:

Improveability to supply pressurized fluid to multiple actuatorsVSAvoidsensor malfunction and unintended valve movement

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the hydraulic circuit into separate return lines for different actuators, with each return line having its own tank connection path. This segmentation prevents backpressure from one actuator from affecting sensors and valves controlling other actuators, thereby maintaining reliability while enabling simultaneous operation of multiple actuators.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate pressure relief valves and check valves as mediators in the hydraulic circuit. These components act as buffers that prevent backpressure propagation from tank return lines to sensor lines and valve control lines, allowing multiple actuators to operate simultaneously without causing sensor malfunction or unintended valve movement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If a confluence control valve is used to direct fluid from one hydraulic source to another, then sufficient fluid supply is achieved, but the valve becomes susceptible to unintended movement due to backpressure

Engineering Contradiction:

Improvefluid supply capabilityVSAvoidunintended valve movement

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent introduces pilot lines with pressure relief valves as intermediary control paths for the confluence control valve. These pilot lines provide isolated pressure control that prevents backpressure from the main hydraulic circuit from affecting the valve's positioning, thereby preventing unintended movement while maintaining the valve's ability to direct fluid flow effectively.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical pressure control of the confluence control valve with a pilot pressure control system. Instead of relying on main circuit pressure that is subject to backpressure, the valve position is controlled by pilot pressure applied through separate pilot lines, substituting a more stable pressure control mechanism that eliminates unintended valve movement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical 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 configuration prevents sensor malfunctions and unintended valve movements, ensuring reliable operation even when multiple actuators are active, by managing pressure through signal and pilot lines and using drain lines to mitigate backpressure effects.

Implementation Method 1

a confluence control valve in fluid communication with the first hydraulic source and, in a confluence position, directing fluid from the first hydraulic source to the first attachment control valve

Methodology Applied

Scientific EffectHydraulic pressure differential: Pressure Gradient

Implementation Method 2

When the first travel control valve is in a non-neutral position and the first attachment control valve is in a first non-neutral position, first signal pressure may be generated in the first signal line to move the confluence control valve to the confluence position

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

When first pilot pressure is generated in the first pilot line, the first pilot pressure may move the confluence control valve to the confluence position

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS11371537B2Hydraulic machine

Publication Date: 2022.06.28 VOLVO CONSTRUCTION EQUIPMENT AB

AI summary

In a hydraulic machine, first travel control valve and a first attachment control valve are in fluid communication with a second hydraulic source. A confluence control valve is in fluid communication with a first hydraulic source and, in a confluence position, directs fluid from the first hydraulic source to the first attachment control valve. A first signal line and a first pilot line are connected to the confluence control valve. When the first travel control valve is in a non-neutral position and the first attachment control valve is in a first non-neutral position, first signal pressure is generated in the first signal line to move the confluence control valve to the confluence position. First pilot pressure, when generated in the first pilot line, moves the confluence control valve to the confluence position.