Development of a Roller Concave for Combine Harvester of Soybean

Abstract

A combine harvester concave was developed to reduce staining during soybean harvest. Preliminary tests showed that one of the causes of soybean staining is that high-moisture stems become entangled in the concave, remain in the thresher, and come into contact with the soybean grains. Newly designed concaves with freely revolving rollers were placed around threshing cylinder, and their performance was studied. The roller concave with a roller of diameter 21 mm arranged at a gap of 18 mm or 24 mm showed less staining compared to standard concaves. Its grain distribution under the concave, threshing losses, and torque for driving the threshing cylinder were equal to that of standard concaves.