PROBLEM TO BE SOLVED: To provide a drive shaft for a bush cutter which reduces vibration.SOLUTION: A drive shaft of a bush cutter comprises a first shaft on an engine side, a second shaft on a cutting blade side, and a coupling part for transmitting the rotation of the first shaft to the second shaft. The coupling part comprises a first cylindrical component having a first shaft insertion hollow part, and a second cylindrical component having a second shaft insertion hollow part. The first cylindrical component and the second cylindrical component have a thick distal end part and a thin rear end part, respectively. The thin rear end part of the first cylindrical component and the thin rear end part of the second cylindrical component are disposed to face each other. A cylindrical cover member for covering the first cylindrical component and the second cylindrical component is provided. A spring is disposed in a gap between the cylindrical cover member and the thin rear end parts of the cylindrical components. A viscous fluid or viscous rubber are applied to the spring and/or filled in a spiral gap of the spring.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT【課題】振動を減衰させる刈払機用駆動軸の提供。【解決手段】原動機側の第1軸、刈刃側の第2軸、第1軸の回転を第2軸に伝えるカップリング部とから構成され、カップリング部は、第1軸挿入中空部を有する第1筒状部品と、第2軸挿入中空部を有する第2筒状部品とを有し、第1筒状部品と第2筒状部品は、それぞれ、肉厚先端部と肉薄後端部を有し、第1筒状部品の肉薄後端部と第2筒状部品の肉薄後端部は対向配置され、第1筒状部材と第2筒状部材の肉薄後端部をカバーする筒状カバー部材が設けられ、筒状カバー部材と筒状部品の肉薄後端部との間の空隙には、バネが配置されるとともに、粘性流体または粘性ゴムが前記バネに塗布および/または前記バネのらせん状空隙に充填されている刈払機の駆動軸。【選択図】図1
