Truck frame for a construction machine

摘要

A left fore leg ( 31 ) is formed to shape by a casting means, integrating an inner joint portion ( 31 A), an outer joint portion ( 31 B) and an intermediate tubular portion ( 31 C) into an unitary tubular structure. In this case, a joining end ( 31 A 1 ) of the inner joint portion ( 31 A) as well as an outer joining end ( 31 B 1 ) of the outer joint portion ( 31 B) is in the form of an open end of a rectangular shape. Accordingly, it becomes possible to cut the production cost of truck frame ( 11 ) and to form a longer welding bead around the outer periphery of the respective inner and outer joining ends ( 31 A 1 ) and ( 31 B 1 ) to enhance the joint strength between the inner joint portion ( 31 A) and a center frame ( 12 ) as well as the joint strength between the outer joint portion ( 31 B) and a side frame ( 22 ).