Design Challenge - March 2016

Ajuria High-Performance Combine Harvester

Alberto Seco

The addition of an extra pair of wheels to a conventional combine harvester would allow for the development of a higher-performance machine, even bigger than the currently available 500-550hp 10-class models. But while the trend for bigger tractors on a conventional frame seems to be working well, the combine size required for operating a 50ft header would require a new chassis. So could a six-wheel system provide the basis for an 850hp combine with a 16,500-liter grain tank and enable compatibility with headers from 50-60ft?

The front area of the machine would have to support massive loads due to the huge header, grain tank and threshing system, so adding an extra axle there seems to be a logical decision. A front bogie axle drive system would allow the use of wider tires than the dual combinations on a typical single front axle. The oscillating bogie would provide an even distribution of weight with reduced ground pressure and tractive effort on all four tires, while offering a more convenient frame when moving on tricky routes from one field to another.

This bogie configuration would also leave more room for the threshing mechanisms and make possible a longer system, ideal for effectively managing all the straw supplied by the wider header. To complete the driveline, a rear drive/steering axle with bigger tires would add the rear traction required for this size of machine. Enabling such a big header would increase productivity while lowering soil compaction through a reduction in the number of machines needed for harvesting, and also reducing the pass percentage on a field. Transporting a high-performance harvester can be a problem. So to move the header easily when mounted (for travel between fields) or to transport the unmounted header, it would be foldable, ensuring it would be no wider/longer than 30ft. A greater width of the throat would be needed to control the torque of the header from side to side, so the vehicle is 4,300mm wide.

The threshing and separation system would be a hybrid system consisting of a set of transversal concave and threshing drums and two counter-rotating diameter rotors. The long (11,850mm) structure of the combine would therefore support twin rotors over 5m long to better manage the straw by offering a bigger separation area, especially where moisture could be a problem at the end of the working day. By running two rotors, the machine’s height can be restricted to 4,750mm, making better use of the width of the feeder throat by keeping the mat of material wider and thinner.

Instead of increasing the size of the grain tank upward, the body of the combine would open out toward both sides, resulting in a folding grain tank that grows wider instead of higher. A high-diameter unloading auger placed in the center of the machine, over the grain tank, would enable truly flexible grain unloading all around the combine. The wide header involves the use of a longer unloading tube, so this auger would be foldable in the rear section of the harvester, which would also shelter the straw chopper and the chaff spreader.

Convenient access to the cab is provided from both sides by means of dual ladders that wrap around the front wheels. Half of the ladder platform can be tilted for better access to the mechanisms during maintenance and cleaning operations.

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Alberto Seco

Alberto Seco has been involved in design projects from cell phones to heavy equipment. After a spell at an Italian design consultancy and as an industrial designer, he now works in the auto sector






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