Pre-Loaded Cutter Gear Train for Windrower Chatter Control

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Solution Overview

Problem

Agricultural windrowers experience gear chatter due to uneven loading of the cutter assembly, leading to premature wear of gears, as the gear train is alternately loaded in different rotational directions during operation.

Innovation Solution

A cutter control system that pre-loads the gear train by driving the first gear at a higher speed and the second gear at a lower speed, using a dual motor configuration with a controller to maintain torque wind-up in one rotational direction, thereby reducing gear chatter and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the gear train is driven by a single motor, then the device complexity is reduced, but gear chatter and premature wear occur due to uneven loading in different rotational directions

Engineering Contradiction:
Improvemotor configurationVSAvoidgear wear
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The single motor drive is segmented into two separate motors, each driving one end of the gear train. This segmentation allows independent control of each motor to maintain unidirectional loading on the gears, preventing gear chatter and premature wear while distributing the mechanical load more evenly across the gear train.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system preliminarily adjusts the speed of each motor to compensate for the natural speed differential that occurs along the gear train. By proactively controlling the motors to maintain proper speed relationships, the system prevents gear backlash and chatter before they occur, ensuring reliable operation.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If dual motors are used to drive the gear train, then gear chatter is reduced, but the control system complexity increases

Engineering Contradiction:
Improvegear engagementVSAvoidcontrol system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system continuously monitors the operational status of both motors and adjusts their speeds in real-time based on feedback signals. This feedback mechanism ensures that the speed differential between motors is optimized to maintain unidirectional gear loading, reducing gear chatter while providing automated control that manages the increased system complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system dynamically changes the operational parameters (speeds) of the two motors to optimize gear train performance. By adjusting motor speeds as operational conditions change, the system maintains proper gear engagement and prevents chatter, managing the complexity through adaptive parameter control rather than fixed settings.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If gears are allowed to rotate in different directions due to uneven loading, then the cutter assembly can adapt to varying crop conditions, but gear wear increases prematurely

Engineering Contradiction:
Improvecrop handlingVSAvoidgear lifespan
Core Design Contradiction:
Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

The control system intentionally creates an asymmetric speed relationship between the two motors, with one motor running slightly faster than the other. This asymmetric control maintains consistent unidirectional loading on the gears, preventing backlash and chatter that would cause premature wear, while still allowing the cutter assembly to adapt to varying crop conditions through the overall variable speed capability of the system.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4032386B1Work vehicle having a cutter assembly with a pre-loaded gear train and method of controlling same
Publication Date: 2024.11.27 DEERE & CO
  • EP4032386B1 patent drawingFigure 1
  • EP4032386B1 patent drawingFigure 2
  • EP4032386B1 patent drawingFigure 3

AI summary

The present invention relates to a work vehicle (20) for cutting crops including a header (32). The header includes a cutter assembly (34) comprising a series of rotary cutters (52) arranged in a lengthwise direction. A gear train (58), having a first gear (60A) and a second gear (60B), is coupled to the series of rotary cutters to transfer power. A first motor (78) is coupled to the first gear and a second motor (80) coupled to the second gear. A controller is operably connected to the first motor and the second motor to control operation thereof. The control system drives the first gear at a first speed via the first motor and drives the second gear at a second speed via the second motor. The second speed is different than the first speed to pre-load the gear train into enmeshing engagement with each other in one rotational direction.