Dual-Path Hydraulic Pressure Limiting for Steering Response

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Solution Overview

Problem

Dual path machines face issues with heat generation, reduced efficiency, and steering delays due to the absence of pressure limiter or pressure compensated override hardware, leading to uncontrollability and reduced component life, necessitating a solution to enhance controllability, efficiency, and cooling package reduction.

Innovation Solution

A system and method incorporating an electronic control system with pressure sensors and electro-hydraulic valves, paired with a hydraulic system featuring pumps and motors, which electronically limits pressure and provides pressure-sensitive overrides to improve steering and efficiency by scaling propel commands based on pressure feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If pressure limiter or pressure compensated override hardware is installed in dual path machines, then heat generation is reduced and efficiency is improved, but the steering performance deteriorates due to interference with the steering mechanism

Engineering Contradiction:
Improveheat generationVSAvoidsteering performance
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The patent replaces mechanical pressure limiter hardware with an electronic control system that uses sensors, processors, and actuators to regulate hydraulic pressure. This substitution eliminates the physical interference with steering mechanisms while maintaining pressure control functionality through electronic modulation of pump displacement based on real-time pressure feedback

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electronic control system as an intermediary between the hydraulic pumps and the dual path machine operations. This intermediary processes pressure sensor data and modulates pump displacement accordingly, enabling pressure control without direct mechanical intervention in the steering path

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If dual path machines operate at high speeds with low motor displacement, then productivity is improved, but steering control deteriorates due to insufficient torque output

Engineering Contradiction:
Improvetraveling speedVSAvoidsteering controllability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent implements dynamic adjustment of pump displacement based on real-time operating conditions including speed and pressure feedback. The electronic control system continuously modulates pump displacement to optimize torque output at different operating points, enabling sufficient steering torque even at high speeds where motor displacement is low

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs a feedback control mechanism where pressure sensors monitor hydraulic system pressure and feed this information to the electronic control system. The controller uses this feedback to adjust pump displacement dynamically, ensuring optimal torque delivery for steering control while maintaining high-speed operation capability

Inventive Principle:
Principle #23Feedback

3Ease of operation

If no pressure limiter hardware is used in dual path machines, then steering mechanism is not interfered with, but component life is reduced due to excessive heat and high pressure

Engineering Contradiction:
Improvesteering mechanism operationVSAvoidcomponent life
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical pressure limiter hardware with an electronic control system that uses sensors, processors, and actuators to regulate hydraulic pressure. This substitution eliminates the physical interference with steering mechanisms while maintaining pressure control functionality through electronic modulation of pump displacement based on real-time pressure feedback

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements preliminary pressure control by continuously monitoring hydraulic pressure through sensors and proactively adjusting pump displacement before excessive pressure or heat can damage components. The electronic control system anticipates pressure build-up and modulates pump output accordingly, preventing thermal and pressure-related component failure

Inventive Principle:
Principle #10Preliminary action

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

The solution reduces steering delay, enhances machine controllability at high speeds, increases efficiency, and decreases the need for a large cooling package, thereby improving component life and power management in high-pressure and speed situations.

Implementation Method 1

A plurality of pressure sensors connect within the hydraulic system to sense pressure

Methodology Applied
Scientific EffectPressure sensing:

Implementation Method 2

the hydraulic system has a plurality of electro hydraulic valves which are in fluid communication with actuators attached to the pumps

Methodology Applied
Scientific EffectElectro-hydraulic actuation:

Implementation Method 3

The computer scales the steering and speed information to determine a modified propel command. The modified propel command is transmitted by the control system to control the speed and direction of the machine

Methodology Applied
Scientific EffectElectronic feedback control: Feedback

Implementation Method 4

The hydraulic control system includes a pair of pumps in fluid communication with a pair of motors via a fluid conduit

Methodology Applied
Scientific EffectHydraulic power transmission: Hydraulic Press

Implementation Method 5

The motors are operatively connected to and drive the dual path machine

Methodology Applied
Scientific EffectHydraulic motor conversion:

Data Source

PatentEP3643585B1Electronic pressure limiting for dual path systems
Publication Date: 2022.03.09 DANFOSS POWER SOLUTIONS INC
  • EP3643585B1 patent drawingFigure 1
  • EP3643585B1 patent drawingFigure 2

AI summary

A pressure limiting system for a dual path machine wherein an input propel command from a propel device is scaled based upon the largest detected pressure in a hydraulic system to determine a modified propel command. Also, response time is adjusted within an electrical control system based upon the type of input propel command signal received.