| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem that an end face of a base formed by die casting has a size variation of a casting surface so that sufficient dimensional accuracy cannot be obtained for laser welding, while the relation between position of a cover and the base and position of illuminating a laser is very important to hermetically seal the cover and the base of the magnetic disk unit by laser welding. <P>SOLUTION: An outer circumference surface of a rib 14 of the base 12 is a machined face 17, and electropainting and casting surface are eliminated. An outer cover 20 having a completely same contour as the base 12 is set on the rib 14, and the laser 40 is illuminated from the upper surface so that variation of the position for illuminating laser to both of the cover and base can be regulated within a range of±0.05 mm. Herewith, bead 42 is stably formed by laser welding, to fully hermetically seal the housing, so that helium can be prevented from leaking into the housing. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
