Forage Harvester Inductive Wear Detection With Disturbance Compensation

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Solution Overview

Problem

Existing forage harvesters face issues with unnecessary and delayed sharpening of chopping blades due to external factors influencing the induced voltage, leading to increased operating costs and reduced blade service life.

Innovation Solution

An inductive detection arrangement with disturbance compensation determines the condition of chopping knives, activating sharpening only when necessary, using a knife grinding device with a movable grindstone and an adjustment device to manage the sharpening process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If inductive detection is used to monitor blade condition, then blade wear can be detected, but external factors cause false readings leading to unnecessary sharpening

Engineering Contradiction:
Improveblade wear detection accuracyVSAvoidsharpening activation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A disturbance compensation unit is introduced as an intermediary between the inductive detection arrangement and the sharpening activation system. This unit processes the detected values by compensating for disturbances caused by external factors such as metal contamination, thereby filtering out false wear indications before triggering sharpening operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements a feedback mechanism where detected values from the inductive detection arrangement are continuously monitored and processed through disturbance compensation. The compensated information feeds back to the sharpening activation system, enabling continuous adjustment and refinement of sharpening decisions based on actual blade condition rather than raw sensor data.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If frequent sharpening is performed to ensure blade quality, then chopping quality is maintained, but operating costs increase and blade service life decreases

Engineering Contradiction:
Improvechopping qualityVSAvoidblade service life
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system enables self-service operation by automatically monitoring blade condition through inductive detection and autonomously determining when sharpening is actually needed. The disturbance compensation unit allows the system to serve itself by making accurate, independent decisions about maintenance timing without unnecessary human intervention or premature sharpening.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system changes the operational parameter from fixed-schedule sharpening to condition-based sharpening. By monitoring actual blade wear parameters through inductive detection and applying disturbance compensation, the system adjusts sharpening timing based on real blade condition rather than predetermined intervals, extending blade service life while maintaining chopping quality.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of stationary object

If sharpening is delayed to extend blade life, then service life increases, but chopping quality deteriorates

Engineering Contradiction:
Improveblade service lifeVSAvoidchopping quality
Core Design Contradiction:
Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The system replaces mechanical inspection methods with inductive detection technology. The inductive detection arrangement uses electromagnetic fields to sense blade wear and condition, substituting physical contact-based measurement with non-contact sensing. This allows for continuous monitoring without affecting blade operation, enabling timely sharpening decisions that maintain chopping quality while maximizing service life.

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

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 approach reduces unnecessary sharpening cycles, extends blade life, and lowers operating costs by ensuring timely and efficient blade maintenance.

Implementation Method 1

an inductive detection arrangement for detecting a parameter related to the chopping device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4595739A1Self-propelled forage harvester with an inductive detection assembly
Publication Date: 2025.08.06 CLAAS SELBSTFAHRENDE ERNTEMASCHINEN GMBH
  • EP4595739A1 patent drawingFigure 1
  • EP4595739A1 patent drawingFigure 2
  • EP4595739A1 patent drawingFigure 3

AI summary

The present invention relates to an agricultural work machine (1) designed as a self-propelled forage harvester (2) for picking up, processing, and forwarding harvested crops. This forage harvester (2) has a chopping device (6) for shredding the picked-up harvested crops, wherein the chopping device (6) comprises a drum housing (31) in which a chopping drum (7) and several chopping knives (8) are arranged, wherein these chopping knives (8) are arranged detachably, in particular replaceably, on the chopping drum (7). Furthermore, the forage harvester (2) comprises an inductive detection arrangement (25) for detecting the status of the chopping device (6).The present invention is based on the general idea that a blade condition of the chopping blades (8) is determined from the measured values of the inductive detection arrangement (25) taking into account a disturbance variable compensation, which forms the basis for determining the required grinding cycles of the chopping blades (8).