Hydraulic Flow Confluence Control for Boom and Option Actuators

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Solution Overview

Problem

The existing flow rate control systems for construction equipment suffer from performance interference and manipulability degradation due to surplus or insufficient hydraulic fluid flow rates during combined operations of boom down and option actuator operations.

Innovation Solution

A flow rate control apparatus and method that includes a confluence line and a controller to selectively block or open the flow of hydraulic fluid between the boom cylinder and option actuator, using pressure sensors and manipulation levers to determine when combined work is performed, ensuring optimal fluid distribution and preventing surplus flow interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the confluence line is opened to supply surplus flow rate from the first hydraulic pump to the option actuator during boom down operation, then the productivity is improved by utilizing surplus flow rate, but the performance of the option actuator is interfered and the manipulability is degraded due to insufficient or excessive flow rate

Engineering Contradiction:
ImproveproductivityVSAvoidperformance interference
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The confluence switching valve dynamically switches between open and closed states based on real-time detection of combined work conditions. When combined work is detected (boom down operation + option actuator operation), the valve closes the confluence line to prevent flow interference. When combined work is not detected, the valve opens the confluence line to utilize surplus flow rate, thereby dynamically optimizing both productivity and performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses manipulation levers and pressure sensors to detect whether combined work is being performed, and this detection feedback controls the opening/closing state of the confluence switching valve. This feedback mechanism ensures that the confluence line is closed during combined work to prevent performance interference, and opened during non-combined work to maximize productivity.

Inventive Principle:
Principle #23Feedback

2Reliability

If the confluence line is closed to prevent surplus flow rate from interfering with option actuator, then the reliability is improved by preventing performance interference, but the productivity is reduced by not utilizing surplus flow rate

Engineering Contradiction:
Improveperformance interferenceVSAvoidproductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The confluence switching valve dynamically adjusts its state based on operational conditions. During combined work, it closes to ensure reliable actuator performance. During non-combined work, it opens to maintain high productivity by utilizing surplus flow rate. This dynamic adaptation resolves the contradiction between reliability and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system continuously monitors manipulation lever positions and pressure sensor readings to detect combined work conditions. Based on this feedback, the confluence switching valve automatically switches between open and closed states, ensuring that productivity is maximized when possible while reliability is maintained when needed.

Inventive Principle:
Principle #23Feedback

3Reliability

If the flow rate is increased to meet the demand of option actuator, then the performance of option actuator is improved, but the flow rate becomes insufficient for boom cylinder operation

Engineering Contradiction:
Improveperformance of option actuatorVSAvoidflow rate supply
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system extracts the surplus flow rate from the first hydraulic pump's output and selectively directs it to the option actuator through the confluence line when needed. The confluence switching valve enables this extraction and selective distribution, ensuring that the option actuator receives sufficient flow without compromising the boom cylinder's operational flow requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The confluence line acts as an intermediary pathway that connects the first hydraulic pump's surplus flow to the option actuator. The confluence switching valve controls this intermediary pathway, enabling flow transfer when appropriate while maintaining independent flow control for both the boom cylinder and option actuator, thus resolving the flow rate allocation conflict.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Prevents performance interference and enhances manipulability by ensuring the correct flow rate is supplied to the boom cylinder during operations, maintaining efficient operation of both the boom and option actuators.

Implementation Method 1

first and second variable displacement hydraulic pumps 1 and 2... a boom cylinder 5 driven by hydraulic fluid of the first hydraulic pump 1... an option actuator 6 driven by hydraulic fluid of the second hydraulic pump 2

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

a first control valve 7 controlling a flow of the hydraulic fluid supplied from the first hydraulic pump 1 to the boom cylinder 5... a second control valve 8 controlling a flow of the hydraulic fluid supplied from the second hydraulic pump 2 to the option actuator 6

Methodology Applied
Scientific EffectFluid flow control:

Data Source

PatentEP3290595B1Flow rate control apparatus of construction equipment and control method therefor
Publication Date: 2021.02.17 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP3290595B1 patent drawingFigure 1~2
  • EP3290595B1 patent drawingFigure 3
  • EP3290595B1 patent drawingFigure 4

AI summary

Disclosed is a flow rate control apparatus for construction equipment, the apparatus including: a boom cylinder driven by hydraulic fluid; a first control valve for controlling a hydraulic fluid flow supplied to the boom cylinder; an option actuator driven by hydraulic fluid; a second control valve for controlling a hydraulic fluid flow supplied to the option actuator; a boom cylinder manipulation lever and an option actuator manipulation lever; a confluence line selectively confluence the hydraulic fluid supplied to the boom cylinder with the hydraulic fluid of the option actuator; a center bypass switching valve provided at the furthest downstream side of a fluid supply path of the first hydraulic pump; a confluence switching valve selectively opening and closing the confluence line; a confluence selection valve applying a pilot pressure to the confluence switching valve; and a controller for controlling the confluence selection valve.