PROBLEM TO BE SOLVED: To prevent the case in which a circulation that a large amount of grains overflows a grain sieve, the overflowing grain is sent through a second screw to a treatment rotor, the grain sent to the treatment rotor is leaked to the grain sieve again is repeated in the machine of combine harvester.SOLUTION: The grain threshing machine has a constitution that a detection sensor 34 for a grain amount is arranged below the rear end of the grain sieve 20, the actions of a dust-sending valve 10a and an adjustment net 94 are controlled on the basis of the detection result detected by the detection sensor 34 for a grain amount, the action of a sieve plate is controlled, an amount of grains leaked from the grain sieve 20 is increased and a large amount of grains is prevented from overflowing from the rear end of the grain sieve 20.COPYRIGHT: (C)2010,JPO&INPIT【課題】グレンシーブから多量の穀粒が横溢し、横溢した穀粒が二番スクリューを介して処理ロータに送出され、処理ロータに送出された穀粒が再びグレンシーブに漏下するという循環をコンバインの機内で繰り返すことを防ぐ。【解決手段】グレンシーブ20の後端下方に穀粒量検出センサ34を設け、該穀粒量検出センサ34にて検出された検出結果に基づいて、送塵弁10a及び調整網94の動作を制御し、またシーブ板の動作を制御して、グレンシーブ20から漏下する穀粒量を増加させ、グレンシーブ20の後端から多量の穀粒が横溢することを防ぐ構成とした。【選択図】図2
