Crop Processor Roll Assembly Double Press Fit
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Solution Overview
Problem
The existing exchangeable crop processor roll assemblies in forage harvesters face issues with a reliable connection to the drive shaft, as conical ring clamping methods can loosen due to shocks from foreign objects like stones or wood parts, leading to a need for a firmer yet removable connection to prevent wear and maintain processing efficiency.
Innovation Solution
A crop processor roll assembly with a double press fit system, featuring a sleeve with an inner interference fit to the shaft and an outer interference fit to the roll, allowing for elastic deformation and secure mounting without impeding roll replacement, utilizing lighter fits like H/n or h/N according to ISO 286-1 standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conical rings are used to clamp the roll surface to the shaft, then the connection is capable of withstanding normal processing forces, but the connection will loosen due to shocks from foreign objects like stones or wood parts
Solution Approach 1:
The invention changes the connection parameters by using an interference fit with specific tolerance classes (H7/p6 or H7/s6) instead of conical clamping. This parameter change provides a more stable connection that can withstand both normal processing forces and shocks from foreign objects without loosening.
Solution Approach 2:
The invention uses a cylindrical interference fit between the shaft and the roll hub instead of a conical shape. This cylindrical geometry provides uniform stress distribution and prevents the connection from loosening under shock loads, while still allowing for reliable mounting and dismounting.
2Stability of the object's composition
If a firmer connection is used to prevent loosening from shocks, then the connection stability improves, but the ease of removing and replacing the roll decreases
Solution Approach 1:
The invention uses specific interference fit tolerance classes (H7/p6 or H7/s6) that provide a balance between connection stability and ease of assembly/disassembly. The H7/p6 fit provides sufficient firmness to prevent loosening while still allowing for practical mounting and removal operations.
Solution Approach 2:
The invention introduces a hub as an intermediary component between the shaft and the roll. This hub with a cylindrical bore receives the shaft through interference fit, providing a stable connection while maintaining the ability to remove and replace the roll when needed.
3Reliability
If the roll connection is made more secure to withstand shocks, then the reliability under shock loads improves, but the device complexity increases
Solution Approach 1:
The invention achieves shock resistance by changing the fit parameters to interference fit with specific tolerance classes (H7/p6 or H7/s6) rather than using complex conical clamping mechanisms. This parameter change provides reliable shock resistance while maintaining a simple structural design.
Solution Approach 2:
The invention extracts the complex conical clamping mechanism and replaces it with a simpler cylindrical interference fit. This extraction of the unnecessary conical element simplifies the overall connection structure while maintaining or improving shock resistance capabilities.
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 provides a sturdy and reliable connection between the roll and shaft, resistant to shocks from foreign objects, while enabling easy replacement of worn rolls, maintaining processing efficiency and reducing maintenance costs.
Implementation Method 1
the interior of which is joined to said shaft by an inner interference fit
Implementation Method 2
the exterior of said sleeve is joined to said roll by an outer interference fit
Data Source
AI summary
A forage harvester is provided with a crop processor roll assembly that comprises a shaft and a removable crop processor roll having a fluted surface for cracking maize kernels. The roll has end plates, to which the shaft is connected by sleeves. The interior of the sleeve is joined to the shaft by two interference or press fits, and to the roll by a third press fit.