Combine Harvester Threshing Element Geometry for Humid Rice Harvesting
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Solution Overview
Problem
Conventional threshing elements in combine harvesters are ineffective in humid conditions, particularly when harvesting rice, as they tend to form plugs that disrupt the straw flow and increase power consumption, leading to inefficient grain detachment and operability issues.
Innovation Solution
A threshing element with a specific geometry, featuring an inclined front face and combing fins with a carefully controlled height ratio and angle, designed to maintain straw pressure effectively while preventing plug formation, optimized for use on a cylindrical rotor in axial combine harvesters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional threshing elements are used in humid conditions, then grain detachment is attempted, but plug formation occurs that disrupts straw flow and increases power consumption
Solution Approach 1:
The patent modifies the geometric parameters of the threshing element, specifically the front face angle (30-60 degrees) and combing fin dimensions, to change how straw is processed. This parameter optimization prevents plug formation while maintaining grain detachment efficiency in humid conditions
Solution Approach 2:
The threshing element is divided into distinct functional zones: a front face for initial compression and an array of combing fins for grain detachment. This segmentation allows each zone to perform its specific function optimally, preventing plug formation while ensuring effective grain removal
2Productivity
If threshing elements compress straw to detach grains, then grain detachment improves, but plug formation occurs that increases power consumption
Solution Approach 1:
The optimized front face angle (30-60 degrees) and combing fin geometry change the compression characteristics, allowing effective grain detachment with reduced power consumption by preventing plug formation that would otherwise require excessive power to overcome
3Productivity
If threshing elements have steep front faces to increase impact on grain, then grain detachment improves, but plug formation is facilitated
Solution Approach 1:
The patent specifies an optimized front face angle range of 30-60 degrees, which balances the impact force on grains for effective detachment while preventing the excessive steepness that would cause plug formation. This parameter optimization resolves the contradiction between detachment efficiency and plug prevention
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
The solution effectively detaches grains from stalks and prevents plug formation, maintaining efficient operation even in wet conditions, such as during rice harvesting, by optimizing the pressure and penetration of combing fins within the air gap between the rotor and stator.
Implementation Method 1
The threshing elements protrude from the rotor surface and are designed to locally compress the sheaf of straw circulating in the gap between the rotor and the stator
Implementation Method 2
strike or comb the grains, thus detaching them from the ears in which they are embedded
Implementation Method 3
a cylindrical rotor, driven in rotation inside a stator
Implementation Method 4
separate the straw from the grain by gravity at a sieve located at the bottom
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
A threshing element (3) intended to be mounted on a cylindrical rotor (2) equipping a combine harvester (1), of a given radius (R1) and axis (XX') oriented along the front/rear direction of the given combine harvester (1), associated with a cylindrical base surface (20), having the same axis (XX') and the same diameter (R1) as the surface of the rotor (2), containing the points of contact between the threshing element (3) and the surface of the rotor (2) and coinciding with said surface of the rotor (2) when said threshing element (3) is mounted on said rotor (2), comprising an upper face (30) formed by an inclined front face (31) rising from said base surface (20) to a compression face (32) disposed at a substantially constant height h1 of the base surface (20), the front face and the compression face each forming a part of the upper face, characterized in that said threshing element supports at least two flat combing wings (35, 36),having a front edge (350, 360) rising from the surface of the same part (31, 32) of the upper face (30) at an angle (β) less than 45° with said surface, up to a summit edge (351, 361) disposed at a substantially constant height h2 of the base surface (20), and in which the ratio (h2-h1)/h2 is between 0.30 and 0.50.