Asymmetrical Comminuting Roll Teeth Hardening for Wear Resistance
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Solution Overview
Problem
Forage harvester crop processors experience premature wear of comminuting rolls due to uneven kernel cracking, leading to inconsistent performance and increased maintenance costs, with existing hardening methods like induction hardening and chrome plating causing localized deformation and indiscriminate hardening of teeth edges.
Innovation Solution
The crop processor design features comminuting rolls with asymmetrical tooth profiles and hard regions, where the leading edge of one roll and the trailing edge of the other have greater hardness, and a wear-resistant layer is applied via laser-cladding, allowing for differential wear and self-sharpening, reducing maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If induction hardening treatment is applied to comminuting rolls, then wear resistance of teeth is improved, but localized melting and deformation occur due to concentrated energy in tip region
Solution Approach 1:
The patent applies selective hardening only to specific regions of the teeth - the leading edges and trailing edges - rather than hardening the entire tooth structure. This localized approach provides wear resistance where needed while avoiding deformation in other areas. The hardening treatment is concentrated at the edges that contact the crop material, leaving the tooth body and tip regions unaffected.
Solution Approach 2:
The teeth are divided into distinct regions with different hardness properties. The leading edges and trailing edges are hardened to provide wear resistance, while the intermediate regions and tip regions remain softer and more ductile. This segmentation allows each region to perform its specific function optimally without the negative effects of uniform hardening.
2Reliability
If chrome electro-plating is applied to comminuting rolls, then wear resistance is improved, but indiscriminate hardening of both leading and trailing edges causes gradual blunting
Solution Approach 1:
Instead of uniformly hardening both edges of the teeth, the patent selectively hardens only the leading edges and trailing edges separately. This creates a differential hardness distribution that allows the leading edge to wear and self-sharpen while the trailing edge maintains its geometry, preventing the blunting effect caused by uniform hardening.
Solution Approach 2:
The patent introduces dynamic wear characteristics where the leading edge is designed to wear gradually and self-sharpen during operation, while the trailing edge remains more stable. This dynamic approach allows the teeth to maintain optimal geometry over time through controlled wear rather than requiring frequent replacement.
3Productivity
If comminuting rolls are replaced at regular intervals, then consistent kernel cracking performance is maintained, but maintenance costs increase
Solution Approach 1:
The leading edges of the teeth are designed to self-sharpen during operation through controlled wear. As the leading edge contacts the crop material, it gradually wears in a way that maintains or even sharpens the cutting geometry, eliminating the need for frequent replacements and maintaining consistent performance over extended periods.
Solution Approach 2:
The differential hardening treatment is applied in advance during manufacturing, creating a hardness distribution that predisposes the teeth to self-sharpening behavior during operation. This preliminary preparation ensures that the teeth will automatically maintain their geometry through wear patterns established during normal use.
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 configuration prolongs the life of the comminuting rolls by preferentially wearing the harder edges, maintaining effective kernel cracking performance and reducing maintenance costs by allowing the rolls to sharpen and maintain efficiency over time.
Implementation Method 1
The leading edge of the teeth of the second comminuting roll may comprise a hard region formed by heating and melting the leading edge with a laser, followed by rapid cooling of the heated leading edge
Implementation Method 2
followed by rapid cooling of the heated leading edge
Implementation Method 3
the comminuting rolls are subjected to an induction hardening treatment which involves inducing an alternating magnetic field in the surface of the comminuting rolls to cause localised heating
Implementation Method 4
to cause localised heating of the roll's peripheral surface to a temperature which is above the transformation range of the constituent alloy
Implementation Method 5
the surface of the teeth can also be coated with a thin hard chrome layer, following the induction hardening treatment
Data Source
AI summary
A crop processor for cracking kernels in a forage harvester, the crop processor including: a housing having an inlet and an outlet; and a first and a second comminuting roll mounted inside the housing, the comminuting rolls being arranged in parallel to define an opening between the rolls, the comminuting rolls being configured to rotate, during use, in opposing rotation directions to transport a flow of harvested crop, received from the inlet, through the opening towards the outlet, wherein the first comminuting roll is configured to rotate at a greater speed than the second comminuting roll; wherein the first and second comminuting rolls each include a plurality of teeth arranged on a circumferential surface of the comminuting roll, each of the plurality of teeth includes a leading edge which faces in the rotation direction of that comminuting roll.