A rotary cutterbar disk hub assembly for diverting debris includes a cutterbarhousingdefining an internal cavity and a bearing housing defining an axis and coupledto the cutterbarhousing. A labyrinth is defined in the bearing housing circumferentially aboutthe axis, and abarrier is formed by the bearing housing at a location radially outward of thelabyrinth. A diskhub is positioned concentric with the axis and coupled to the bearing housingand cutterbarhousing. The disk hub forms at least one protrusion that extends towards thebearing housingand is radially adjacent to the labyrinth. The barrier restricts a portion ofthe debris fromentering the labyrinth, and the at least one protrusion severs debris that isdisposed near thelabyrinth as the disk hub rotates.
