PURPOSE: To perform joining with high dimensional accuracy and to obtain an excellent scroll blank material by dividing end plate parts to upper and lower parts, providing bead holes for irradiation of an electron beam in the upper end plate part, joining the lap parts by the electron beam and prohibiting the molten and solidified parts thereof from projecting from the plane part of the end plate.
CONSTITUTION: A scroll member is divided to a spiral belt-like member 2A, an upper end plate member 3B1, a lower end plate member 3B2, and a boss member 4A. Plural recessed holes 5 are provided on the plane of the upper end plate part 3B1 in the part corresponding to the position on the line of the member 2A and an electron beam is irradiated through the holes 5 to join the member 3B1 and the member 2A. The projection of the melted and solidified part 8 welded by the electron beam from the holes 5 is prohibited and a weld beam 9 is made as short as possible to prevent generation of thermal strain.
SUZUKI MASAKI
MINAGAWA SADATOSHI
