Combine Harvester Grain Cleaning Drive: Phase Control for Peak Forces
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Solution Overview
Problem
The grain cleaning system in combine harvesters experiences high peak forces during sieve reciprocation, which can be destructive and require significant power, posing challenges to structural integrity and efficiency.
Innovation Solution
A drive system for the grain cleaning system that includes a chassis, chaffer, sieve, and drive shaft, with phase-controlled reciprocation of the chaffer and sieve links to minimize destructive forces and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the size and thickness of grain cleaning system components are increased to handle higher peak forces, then the strength and durability of components is improved, but the space for accommodating components is exceeded and the structural and functional geometry of the cleaning system is negatively impacted
Solution Approach 1:
The patent applies preliminary action by synchronizing the reciprocation of the chaffer and sieve to specific positions in their cycles. The chaffer is positioned at predetermined locations (such as at or near its rearwardmost position) when the sieve is at its forwardmost or rearwardmost positions, thereby proactively minimizing peak forces before they occur and reducing the need for oversized components
2Reliability
If larger and thicker components are used to handle higher peak forces, then the reliability of the cleaning system is improved, but the device complexity and geometric constraints are worsened
Solution Approach 1:
The drive system is configured to proactively position the chaffer and sieve at specific locations during their reciprocation cycles, minimizing peak forces before they occur. This preliminary positioning action enhances system reliability by reducing destructive forces while preserving the simple geometric design of existing components
3Productivity
If more power is provided to reciprocate the sieves to handle higher forces, then the productivity of the cleaning system is improved, but the energy consumption and power requirements are increased
Solution Approach 1:
The patent applies preliminary action by pre-positioning the chaffer and sieve at optimal locations during their reciprocation cycles, thereby minimizing peak forces before they occur. This reduces the power required to drive the cleaning system while maintaining productivity, as the synchronized positioning prevents force buildup that would require additional power to overcome
Solution Approach 2:
The drive system utilizes periodic action by synchronizing the reciprocation of the chaffer and sieve in a coordinated cyclic pattern. The chaffer and sieve reciprocate in a synchronized manner with specific phase relationships, creating periodic minimal-force positions that reduce overall power requirements while maintaining continuous cleaning productivity
Data Source
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AI summary
A grain cleaning system for a combine harvester includes a chaffer and a sieve positioned below the chaffer. A first link includes a first end and a second end coupled to the chaffer. A second link includes a first end and a second end coupled to the sieve. A drive shaft is driven by a drive system to rotate about a shaft axis, wherein rotation of the drive shaft drives the first link to reciprocate the chaffer and drives the second link to reciprocate the sieve. The drive system is configured to control reciprocating motion of the chaffer and sieve with the goals of (i) minimizing vibrations of the cleaning system, (ii) minimizing destructive forces on the bearings (and other components) of cleaning system, and (iii) minimizing the power required to reciprocate the chaffer and sieve back and forth.