ROTATION DEVICE FOR CONSTRUCTION MACHINE

摘要

A floating seal (23) is provided between a mounting bracket (12) which is affixed to a side frame (6) and a roller (15) which can rotate relative to the mounting bracket (12), and lubricating oil (L) retained within the roller (15) is sealed by the floating seal (23). An air permeable plug (31) provided with an air permeable member (34) consisting of a porous material having interconnected foams is provided to the lid body (17) of the roller (15). The air permeable member (34) of the air permeable plug (31) allows air and/or water vapor to flow between the inside and outside of the roller (15) and prevents the lubricating oil (L) and/or substances such as rainwater and dust from flowing therebetween. The configuration can always equalize the pressure inside the roller (15) and the pressure outside thereof.