Rotary Sieve Shell with Oscillatory Motion for Grain Cleaning
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Solution Overview
Problem
Existing combine harvesters have limitations in the cleaning performance of their cleaning devices, which struggle to effectively separate grains from non-grain components due to the inefficiencies in air-flowing systems and sieve designs, resulting in suboptimal separation rates.
Innovation Solution
A combine harvester with a cleaning device featuring a rotating sieve device with a sieve jacket that combines rotary and oscillatory movements, where the sieve surface has openings with bulges that enhance air permeability and separation performance, allowing for a more efficient separation of grains and non-grain components through centrifugal and oscillatory forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a flat, air-flowed cleaning device with oscillating sieves is used, then the separation area can be increased to improve cleaning performance, but the device complexity and air consumption increase
Solution Approach 1:
The invention replaces flat oscillating sieves with a rotary sieve shell having a curved, drum-like structure. The sieve shell rotates about a horizontal axis and features circumferentially distributed openings, transforming the separation mechanism from planar oscillation to three-dimensional rotary motion. This curvature enables continuous separation action throughout the rotation cycle, improving cleaning performance without requiring multiple large flat sieve surfaces
Solution Approach 2:
The invention introduces an oscillating mechanism that superimposes transverse oscillations on the rotary motion of the sieve shell. The oscillation is generated by an eccentric cam mechanism that converts rotational motion into reciprocating oscillatory motion of the sieve shell. This dynamic combination of rotation and oscillation enhances the separation effect by creating variable airflow patterns and preventing material stagnation, thereby improving productivity without proportionally increasing device complexity
2Productivity
If the sieve openings are made larger to increase throughput, then the grain throughput increases, but the separation precision decreases
Solution Approach 1:
The invention varies the opening dimensions and distribution pattern around the circumference of the sieve shell. Different sections of the sieve shell have differently sized and spaced openings optimized for specific separation tasks. The openings are arranged in multiple rows with varying pitch, creating zones of different separation selectivity along the rotation path. This local variation allows the system to maintain high separation precision for light chaff while permitting adequate throughput for heavier grain
Solution Approach 2:
The invention transitions from two-dimensional flat sieve openings to three-dimensional circumferential openings in a rotary shell. The openings are distributed around the entire circumference of the drum, creating a volumetric separation space rather than a planar one. This dimensional transformation allows material to be separated through multiple passes as it contacts different sections of the rotating sieve, effectively increasing separation precision without reducing overall throughput capacity
3Device complexity
If a rotary sieve assembly with circular perforations is used, then the device complexity is reduced, but the separation effect is insufficient
Solution Approach 1:
The invention superimposes oscillatory motion on the rotary motion of the sieve shell using an eccentric cam mechanism. The cam converts uniform rotational motion into non-uniform oscillatory motion, creating variable separation forces during rotation. This dynamic motion pattern prevents material from simply falling through static openings and instead creates repeated contact opportunities with the sieve surface, significantly enhancing the separation effect while maintaining a relatively simple mechanical structure
Solution Approach 2:
The oscillating motion of the sieve shell creates mechanical vibration that enhances the separation effect. The reciprocating transverse oscillations superimposed on the rotary motion generate vibratory forces that prevent material bridging over openings and promote consistent particle-sieve contact. This vibration mechanism improves separation effectiveness without requiring complex multi-component assemblies, maintaining device simplicity while boosting productivity
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 significantly improves the separation performance and throughput by utilizing the combined forces to lift heavier grains and lighter chaff, resulting in a higher cleaning efficiency and increased grain throughput.
Implementation Method 1
the heavier grain particles to be lifted until they can pass through the opening at the apex of the protrusion due to centrifugal force
Implementation Method 2
A blower located below the sieves supplies the two sieves with an airflow from below. The airflow and the oscillation motion move non-grain components over the sieves and discharge them from the combine harvester.
Implementation Method 3
the opening cross-section of each opening extends section by section in the direction of the oscillation movement of the screen shell. This increases the air permeability of the screen shell and consequently improves the separation efficiency.
Data Source
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AI summary
The present invention relates to a combine harvester (1) with a cleaning device (5) which separates components of a harvested crop stream into grain (K) and non-grain components (NKB) by segregation, wherein the cleaning device (5) comprises a sieve device (7) rotating about a rotary axis (6) with a sieve shell (8) that is at least partially sieve-shaped and extends circumferentially around the rotary axis (6), wherein segregation is effected by superimposing a rotary movement and an oscillatory movement of the sieve shell (8) oriented transversely to the rotary axis (6), wherein the sieve shell (8) has a surface (26, 26') perforated with openings (27), wherein each opening (27) has an opening cross-section extending perpendicular to the surface (26, 26') of the sieve shell (8), which is formed by at least one oriented perpendicular to the rotary axis (6) arranged in the sieve shell (8) in the region of the respective opening (27). bulge (28,28') of the surface (26) is limited and/or the surface (26, 26') has a substantially wave-like structure (35, 35').