Wheel Loader Hydraulic Control Block for Pulling-Load Throttling

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Solution Overview

Problem

Existing mobile work machines, such as wheel loaders, face inefficiencies due to high energy consumption and losses from varying load pressures, as pumps must generate the highest pressure to ensure function, leading to suboptimal energy use and control issues.

Innovation Solution

The design incorporates a control block with fewer fine control notches on the inflow edge and more on the outflow edge, allowing the control block to throttle flow and maintain minimum pressure, enabling efficient displacement control and reducing energy losses by using an electrically adjustable pressure regulator and a controller to manage movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump generates the highest pressure to ensure proper functioning of all consumers, then the reliability of the hydraulic system is improved, but the energy consumption increases significantly

Engineering Contradiction:
Improvehydraulic system reliabilityVSAvoidpump energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control block features asymmetric control edges that dynamically adjust flow resistance based on operating conditions. The inlet control edge has fewer or no fine control notches for quick opening, while the outlet control edge has more fine control notches for precise throttling, enabling the system to adapt pressure and flow dynamically rather than maintaining constant high pressure

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameters of the control block edges - the inlet control edge is designed with fewer fine control notches compared to the outlet control edge which has more fine control notches. This parameter differentiation enables selective throttling at the outlet while maintaining quick response at the inlet, optimizing energy usage while ensuring reliable operation

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the pump delivers total flow rate at the highest load pressure, then all consumers can be supplied, but energy losses occur due to pressure differences among consumers

Engineering Contradiction:
Improveconsumer supply capabilityVSAvoidhydraulic energy loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The control block is designed with different local qualities at its inlet and outlet edges. The inlet control edge has fewer fine control notches providing minimal resistance and quick opening, while the outlet control edge has more fine control notches providing precise local throttling. This local differentiation allows each edge to perform its specific function optimally, enabling selective flow control to reduce energy losses from pressure differences

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the inlet control edge has fine control notches for precise flow control, then flow allocation is improved, but the response time increases and control becomes less efficient

Engineering Contradiction:
Improveflow control precisionVSAvoidcontrol response speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The control block functionality is segmented between its inlet and outlet edges. The inlet control edge is simplified with fewer or no fine control notches for fast response and quick opening from center position. The outlet control edge is equipped with more fine control notches for precise flow throttling. This segmentation allows each edge to be optimized for its specific control task without compromise

Inventive Principle:
Principle #1Segmentation

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 energy efficiency by optimizing hydraulic medium flow, ensuring consistent movement and reducing energy waste, particularly during pulling loads, without the need for additional components, while maintaining full energetic advantage during primary function use.

Implementation Method 1

the outlet control edge throttles the discharge quantity through the discharge of the cylinder

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Implementation Method 2

A pressure regulator is provided which interacts with the pump in such a way that the minimum pressure is maintained on the cylinder side on which an increase in volume occurs due to the pulling load

Methodology Applied
Scientific EffectPressure regulation: Pressure Increase

Data Source

PatentEP3987119B1Mobile working machine
Publication Date: 2024.10.09 LIEBHERR WERK BISCHOFSHOFEN GMBH
  • EP3987119B1 patent drawingFigure 1
  • EP3987119B1 patent drawingFigure 2
  • EP3987119B1 patent drawingFigure 3

AI summary

The present invention relates to a mobile work machine, in particular a wheeled loader, having a hydraulic circuit and having a pump (P) for conveying a hydraulic medium through the hydraulic circuit and having at least one control block (CB) having an inflow control edge (ZK) and an outflow control edge (AK) for controlling the flow of the hydraulic fluid, wherein the work machine has a working tool and a cylinder for actuating the working tool and wherein the cylinder has an outflow (A) and an inflow (B) for the hydraulic fluid, the outflow being fluidically connected to the outflow control edge and the inflow being fluidically connected to the inflow control edge, the inflow control edge having no fine control notches or fewer fine control notches than the outflow control edge, which has one or more fine control notches, such that, in the event of a load pulling on the working tool, the outflow control edge throttles the outflow volume through the outflow of the cylinder.