REACTION FORCE OF WHEAT STALKS DURING THE REEL OPERATION OF A COMBINE HARVESTER

The purpose of this study is to clarify gathering operations appropriate to crop conditions, such as a crop’s physical properties and the extent of lodging, from viewpoint of the mechanical interactions between crops and a combine harvester reel. Because the gathering process by the reel involve the mechanical operation of forced displacement, the reaction force of a bunch of wheat stalks undergoing forced displacement was analyzed in our previous study, and the result has been verified by the experiment under a quasi-static loading rate. In the present study, in order to investigate the effect of loading rate and to discuss the application of the analytical method, which is valid under a quasi-static loading condition, to the actual reel operation, the reaction force of a bunch of wheat stalks was measured under several different loading rates by the experiment involving gathering operation of the reel. As the results, the horizontal reaction force increased its values in the negative x direction together with an increase in loading rates, and the analytical results had a large amount of error under high loading rates. The above result was examined in terms of the acceleration of forced displacement during the gathering operation. The acceleration increased its values in the positive x direction together with the increase in loading rates, and the peak of acceleration coincided with that of reaction force. From these results, the main reason for the increase in the reaction force was considered to be an effect of the inertia force of a wheat stalk caused by forced displacement involving the acceleration, and a subject of the current analytical method for applying to the actual reel operation was clarified.