Wheel Loader Traction Force Control for Lifting Work

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Solution Overview

Problem

Wheel loaders face challenges in maintaining sufficient traction force during lifting work, as the existing traction force control systems require operators to manually adjust settings, leading to reduced operability and inefficient performance due to insufficient traction force.

Innovation Solution

A wheel loader system that includes a traction force control section, which automatically adjusts the maximum traction force based on work situation determination, acceleration operation amount, and boom angle, allowing for increased traction force during lifting work without operator intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traction force control is executed to reduce maximum traction force and suppress slipping or stalling, then reliability is improved, but productivity deteriorates due to insufficient traction force during lifting work

Engineering Contradiction:
Improvesuppression of slipping or stallingVSAvoidefficiency of lifting work
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the maximum traction force based on real-time detection of work situations. When lifting work is detected (boom angle ≥ threshold and digging situation), the system automatically increases the maximum traction force to sufficient levels. When lifting work is not being performed, the system maintains reduced maximum traction force to prevent slipping or stalling. This dynamic adjustment resolves the contradiction by making the traction force adaptive to current operational needs rather than fixed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms by continuously monitoring work situation parameters (boom angle, digging status) and using this information to automatically adjust the maximum traction force. The control system receives feedback about current operations and modifies traction force accordingly, enabling the system to maintain optimal performance across different work conditions without manual intervention.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If operator manually adjusts maximum traction force level according to work circumstances, then adaptability is improved, but ease of operation deteriorates due to troublesome operations

Engineering Contradiction:
Improveadaptation to different work circumstancesVSAvoidoperability of wheel loader
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system performs self-service by automatically detecting work situations and adjusting maximum traction force without requiring operator intervention. The work situation determination section autonomously monitors boom angle and digging status, and the traction force control section automatically modifies traction force parameters based on these detections. This eliminates the need for operators to manually adjust settings, resolving the contradiction by making the system self-adaptive while maintaining ease of operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system replaces manual mechanical adjustment operations with automated electronic control. Instead of requiring operators to physically adjust traction force settings based on their judgment of work conditions, the system uses sensors and control algorithms to automatically detect work situations and adjust parameters. This substitution of manual operation with automated control resolves the contradiction between adaptability and ease of operation.

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

3Productivity

If maximum traction force is increased to obtain sufficient traction force during lifting work, then productivity is improved, but reliability deteriorates due to generation of slipping or stalling

Engineering Contradiction:
Improvetraction force during lifting workVSAvoidsuppression of slipping or stalling
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system uses dynamic adjustment to provide high maximum traction force only when lifting work is detected (boom angle ≥ threshold and digging situation), and maintains reduced maximum traction force during other operations. This temporal and conditional differentiation allows the system to achieve sufficient traction force for productivity while preventing slipping or stalling during non-lifting operations, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2667060B1Wheel loader and method for controlling wheel loader
Publication Date: 2014.12.10 KOMATSU LTD
  • EP2667060B1 patent drawingFigure 1
  • EP2667060B1 patent drawingFigure 2
  • EP2667060B1 patent drawingFigure 3~4

AI summary

A traction force control section of a wheel loader reduces maximum traction force to below the maximum traction force with traction force control in an off state when the traction force control is in an on state. The traction force control section increases the maximum traction force when determination conditions are satisfied with the traction force control in the on state. The determination conditions include that the work situation is digging, that the operation amount of the acceleration operation member is the predetermined operation threshold or more, and that a boom angle is the predetermined angle threshold or more.