Welded structure and welding method for boss and bracket

摘要

To provide such a boss welding structure for the arm of a working implement as is light in weight and easy in manufacture. In a cylindrical body formed of one sheet metal, there are formed a first hole and a second hole of predetermined shapes. A boss is equipped with a boss seat for covering the first hole, and a bracket is equipped with a bracket seat for covering the second hole. The boss and the bracket are inserted into the cylindrical body and are individually welded on the cylindrical body from the outer side of the cylindrical body such that the first hole is covered from the inner side with the boss seat whereas the second hole is covered with the bracket seat.