Variable Orifice Hydraulic Control for Construction Equipment Shock Reduction

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Solution Overview

Problem

Conventional drive control devices for construction equipment generate shocks during multiple activities, hindering smooth operation and lifting heavy bodies due to inadequate hydraulic oil distribution and pressure management, particularly when load pressures differ between work devices and drives.

Innovation Solution

The implementation of a drive control device with a first and second hydraulic pump, a pilot pump, and pressure sensors that adjust the pilot pressure applied to the linear drive control valve in proportion to the operating oil amounts, and a variable orifice that adjusts its aperture area based on load pressures to prevent hydraulic oil from being weighted towards the drive side, thereby reducing shock generation and ensuring smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a fixed orifice is used to prevent hydraulic oil from being weighted towards the drive side, then the hydraulic oil distribution is improved, but the shock generation increases due to inadequate pressure management

Engineering Contradiction:
Improvehydraulic oil distributionVSAvoidshock generation
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The fixed orifice is replaced with a variable orifice that dynamically adjusts its aperture area based on load pressure conditions. When load pressure on the work device exceeds drive pressure, the variable orifice reduces its aperture to prevent hydraulic oil from being weighted towards the drive side, while maintaining stable distribution and reducing shock generation through adaptive control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the aperture area parameter of the orifice based on pressure conditions. The variable orifice adjusts its opening size according to the ratio of load pressure to drive pressure, optimizing hydraulic oil distribution and preventing shock generation under varying load conditions.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the linear drive control valve is switched for multiple activities, then the work device can be operated during driving, but shock generation occurs due to inadequate hydraulic oil distribution

Engineering Contradiction:
Improvemultiple activities operationVSAvoidshock generation
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

Pressure sensors detect the load pressure on the work device and the drive pressure, and this feedback is used to control the variable orifice aperture area. The controller adjusts the orifice opening based on the pressure ratio feedback, ensuring proper hydraulic oil distribution during multiple activities and preventing shock generation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The variable orifice dynamically adjusts its aperture area in response to changing pressure conditions during multiple activities, enabling smooth operation of the work device during driving without generating shocks through adaptive hydraulic oil distribution.

Inventive Principle:
Principle #15Dynamics

3Speed

If hydraulic oil is weighted towards the drive side during multiple activities, then the drive operation is maintained, but the work device operation becomes unstable

Engineering Contradiction:
Improvedrive operationVSAvoidwork device operation stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The variable orifice adjusts its aperture area parameter based on the ratio of load pressure to drive pressure. When load pressure exceeds drive pressure, the orifice reduces its opening to prevent hydraulic oil from being weighted towards the drive side, maintaining stable work device operation while preserving necessary drive function.

Inventive Principle:
Principle #35Parameter changes

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 enhances the operability and reliability of construction equipment by minimizing shock generation and allowing smooth operation of work devices during driving, preventing rapid speed changes and ensuring safe operation by maintaining stable hydraulic oil distribution.

Implementation Method 1

when the load pressure applied to a work device is higher than that applied to the drive

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Gradient

Implementation Method 2

a variable orifice provided on a branch path... the aperture area of which is changed in accordance with the load pressures

Methodology Applied
Scientific EffectFluid flow control through orifice: Pressure Drop

Implementation Method 3

a solenoid valve provided on a path between the pilot pump and the linear drive control valve, the solenoid valve being switched by the electrical signal and thereby feeding the hydraulic oil of the pilot pump to the linear drive control valve

Methodology Applied
Scientific EffectElectromagnetic actuation: Solenoid

Implementation Method 4

a check valve and a variable orifice provided on the branch path

Methodology Applied
Scientific EffectCheck valve flow direction control: Valve

Data Source

PatentEP3133211B1Drive control device for a construction machine
Publication Date: 2020.08.19 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP3133211B1 patent drawingFigure 1
  • EP3133211B1 patent drawingFigure 2
  • EP3133211B1 patent drawingFigure 3

AI summary

Disclosed is a drive control device for the construction equipment capable of reducing shock generation and smoothly operating a work device when the work device is operated during the driving, which comprises; a first and second hydraulic pumps and a pilot pump, a first work device and a first drive motor operated by a hydraulic oil of the first hydraulic pump, a second work device and a second drive motor operated by a hydraulic oil of the second hydraulic pump, a first drive control valve and a first work device control valve that are provided on the supply path of the first hydraulic pump, a second drive control valve and a second work device control valve that are provided on the supply path of the second hydraulic pump, a linear drive control valve that is provided at the upper side of the supply path of the second hydraulic pump, a parallel path having an inlet branched and connected to the upper side of the supply path of the second hydraulic pump and an outlet connected to the inlet port of the second work device control valve, a branch path having an inlet branched and connected to a predetermined position of the parallel path and an outlet branched and connected to a path between the linear drive control valve and the second drive control valve, a fixed orifice provided on the branch path, and a first ratio control valve provided on a path between the pilot pump and the linear drive control valve.