VIBRATION DAMPING MECHANISM FOR MOWER, CUTTING BLADE-SIDE POWER TRANSMITTING SHAFT, POWER TRANSMITTING SHAFT, AND CENTRIFUGAL CLUTCH DRUM ASSEMBLY

摘要

A vibration damping mechanism for a mower, a cutting blade-side power transmitting shaft, a power transmitting shaft, and a centrifugal clutch drum assembly, wherein the vibration damping mechanism reduces both twist vibration and flexural of the power transmitting shaft, uses a reduced number of parts, has a simple structure, is easily assembled, and is of low cost. A vibration damping mechanism (121) for a mower comprises an engine-side power transmitting shaft (136) portion connected to an engine and having formed in the outer periphery thereof a helical groove (136f), a cutting blade-side power transmitting shaft portion (6a) connected to a cutting blade and having in the outer periphery thereof a helical groove (146f) formed separated from the helical groove (136f) in the engine-side power transmitting shaft (136) portion, and a coiled spring  (144) having one end side engaged in the helical groove (136f) and the other end side engaged in the helical groove (146f) and having a predetermined spacing (Sa) between ring portions of that portion of the coiled spring which is not engaged with the helical grooves (136f, 146f).  The rotation of the engine-side power transmitting shaft (136) portion is transmitted to the cutting blade-side power transmitting shaft (6a) portion through the coiled spring (144).