SWING REDUCTION GEAR

摘要

A swing reduction gear (23) for a swing device which prevents admission of grease into the same and is reduced in pressing force of grease squeezed out from between mutually meshing teeth of a pinion (7) and an internal gear wheel (11) thereof. The swing reduction gear comprises a lower bearing for supporting an output shaft for rotation on a casing, a sealing collar (15) fitted on an outer periphery of the output shaft and located above a pinion integrated with the output shaft, a retainer (17) mounted on the casing below the lower bearing (14), and an oil seal fitted around the retainer and normally held in engagement with an outer periphery of the sealing collar. The oil seal has a lower face side lip portion formed thereon, and a disk-shaped plate is mounted on an outer periphery of the sealing collar such that the lower face side lip portion of the oil seal is normally held in contact with an upper face of the disk-shaped plate to prevent grease from entering the swing reduction gear.