Chopper Drum Clamp Bearing With Spherical Contact for Low-Wear Cutting

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Solution Overview

Problem

Forage harvesters face challenges in maintaining low-wear and precise control of the chopping drum's movement over time due to fluctuating cutting forces and bearing wear, which affects cutting quality and increases maintenance needs.

Innovation Solution

The chopping drum assembly is rotatably suspended between frame parts using clamp bearings with spherical surfaces, allowing for frictionless and tension-free mounting, and a hydraulic actuator for height adjustment, enabling low-wear and precise operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional bearings are used to support the chopper drum, then the drum can rotate, but the bearings experience high wear and bearing play increases over time due to fluctuating cutting forces

Engineering Contradiction:
Improvebearing durabilityVSAvoidbearing wear
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies spherical surfaces to the clamping bearing elements. The frame part-side element and assembly-side element both feature spherical surfaces that complement each other, creating a spherical contact interface. This spherical geometry allows the chopper drum assembly to self-align and accommodate fluctuating cutting forces without generating bearing play, while distributing loads evenly to minimize wear on the contact surfaces.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Manufacturing precision

If the chopper drum assembly is rigidly mounted to maintain precise cutting, then cutting quality is maintained, but the mounting experiences internal stress and increased wear

Engineering Contradiction:
Improvecutting precisionVSAvoidinternal stress
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The spherical contact surfaces enable the chopper drum assembly to maintain precise cutting position while accommodating movements through spherical rotation rather than rigid constraints. This allows the assembly to self-align with the frame parts, eliminating internal stresses that would arise from rigid mounting while preserving cutting precision through the constrained spherical motion.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent transitions from a static rigid mounting to a dynamic spherical joint that allows controlled movement. The clamping bearings with spherical surfaces enable the chopper drum assembly to dynamically adjust its position in response to varying cutting conditions, maintaining precision while reducing stress through adaptive motion rather than fixed constraints.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the chopper drum assembly is securely clamped to prevent movement, then positioning stability is achieved, but the assembly becomes difficult to remove and maintain

Engineering Contradiction:
Improvepositioning stabilityVSAvoidassembly removability
Core Design Contradiction:
Stability of the object's compositionVSEase of repair

Solution Approach 1:

The clamping bearing is divided into two separate elements: a frame part-side element and an assembly-side element. These segmented components can be independently positioned and clamped, allowing the assembly to be securely held during operation while enabling easy removal by releasing the clamping mechanism. The segmentation facilitates maintenance without compromising positioning stability during use.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clamping mechanism transitions between two states: during operation, the elements are clamped together to provide stable positioning; during maintenance, the clamping is released to allow easy removal. This dynamic switching between secured and removable states resolves the contradiction between stability and ease of repair.

Inventive Principle:
Principle #15Dynamics

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 solution reduces wear and tear on bearings, maintains precise cutting quality, and allows for easy maintenance and adjustment of the chopping drum, enhancing the operational longevity of the forage harvester.

Implementation Method 1

the contact points between a frame part-side element and an assembly-side element of the clamping bearing lie on a spherical surface centered on the rotation axis

Methodology Applied
Scientific EffectSpherical contact surface: Friction

Implementation Method 2

To drive the rotation of the shaft (and thus the height adjustment of the adapter), a hydraulic actuator can be provided between the frame parts and the chopper drum assembly.

Methodology Applied
Scientific EffectHydraulic actuator: Hydraulic Press

Data Source

PatentEP3925429B1Forage harvester
Publication Date: 2024.12.25 CLAAS SELBSTFAHRENDE ERNTEMASCHINEN GMBH
  • EP3925429B1 patent drawingFigure 1
  • EP3925429B1 patent drawingFigure 2
  • EP3925429B1 patent drawingFigure 3~5

AI summary

A forage harvester comprises a chopping drum assembly (12) and two frame parts (13), between which the chopping drum assembly (12) is rotatably suspended. The chopping drum assembly (12) is held on both frame parts (13) by a clamping bearing (16) that defines a rotation axis (3). Contact points between a frame-side element (18) and an assembly-side element (17) of the clamping bearing (16) lie on a spherical surface (20, 24) centered on the rotation axis (3).