PROBLEM TO BE SOLVED: To provide a cutting blade of a stalk shredding machine with a structure wherein stalk gathering performance with a concave cutting part is easily kept while stalks are easily prevented from being twined around a cutting-blade driving shaft.SOLUTION: The cutting blade is formed as described below. An included angle &theta1 between the front-side blade edge fe2 and the rear-side blade edge re2 of the concave cutting part 53 is an acute angle, and an included angle &theta3 between the rear-side blade edge re2 and a straight line s tangent to a rotating circle of a circular disc 5A is larger than an included angle &theta2 between the front-side blade edge fe2 and the straight line s tangent to the rotating circle of the circular disc 5A. The shape of a serrated blade edge e1 of a saw blade-shaped cutting part 52 is formed so as to have a forward tilting wave profile. The front-side blade edge fe2 of the concave cutting part 53 is formed along an extended line of the serrated blade edge e1 of the saw blade-shaped cutting part 52 on the front side of its rotation direction, and the rear-side blade edge re2 is formed along an extended line of the serrated blade edge e1 of the saw blade-shaped cutting part 52 on the rear side of its rotation direction.COPYRIGHT: (C)2010,JPO&INPIT【課題】刈刃駆動軸に対する茎稈の巻き付きを防止し易い構造のものでありながら、凹入刃部による茎稈の掻き込み性能を良好に保ち易い構造の茎稈細断装置の切断刃を提供する。【解決手段】凹入刃部53の前側刃縁fe2と後側刃縁re2との夾角θ1が鋭角で、かつ、前側刃縁fe2と円盤状ディスク5Aの回転円に対する接線sとの夾角θ2よりも後側刃縁re2と円盤状ディスク5Aの回転円に対する接線sとの夾角θ3が大きな角度であるように形成され、鋸刃状刃部52の波形刃縁e1の形状が前傾した波形に形成され、凹入刃部53の前側刃縁fe2はその回転方向前方側の鋸刃状刃部52の波形刃縁e1の延長線に沿って形成され、後側刃縁re2はその回転方向後方側の鋸刃状刃部52の波形刃縁e1の延長線に沿って形成されている。【選択図】図23
