Patent ID: 7070017

Claim:
A swing mechanism of a construction machine, comprising: an inner ring on the side of a vehicular base carrier relatively rotatably coupled with an outer ring on a swing frame on the side of an upper swing structure of the construction machine, a ring gear provided on the inner periphery of said inner ring and meshed with a swinging pinion on the side of said upper swing structure, a center joint located within an opening provided in said swing frame at a rotational center thereof, and a grease bath located beneath said swing frame and around said center joint and defining an annular grease bath portion around a top plateau wall connected to said center joint, thereby to lubricate meshed portions of said ring gear and said swing pinion, wherein said grease bath seal comprises: an annular seal member having a height larger than a width of a spacing between said swing frame of said upper swing structure and said top plateau wall of said grease bath in a free state and interposed in a compressed state between said top plateau wall and said swing frame at a position radially outward of said center joint; and said seal member being detachably fixed either on the side of said swing frame or on the side of said top plateau wall of said grease bath, and having an annular sliding portion extended out in a radially inward direction from the other side for pressed sliding contact with said top plateau wall or said swing frame.