摘要 |
The invention is characterized in that, when protrusion parts 30 are raised from a substrate W and the protrusion parts 30 are formed into spacers 12 with a predetermined outer diameter D and height H, the protrusion parts 30 are temporarily formed so as to have a diameter larger than a predetermined outer diameter D and a height larger than a predetermined height H, and the protrusion parts 30 are crushed, and leading end portions 30b of the protrusion parts 30 are protruded in a radially outward direction so as to have a double-layered structure, and then through-holes 35 are opened at the leading end portions 30b. Accordingly, the leading end portions 30b have strength due to a double-layered structure, and side portions 30a also have high strength due to contraction by pressing, whereby the sleeve-integrated member includes the entirely high-strength spacers 12.
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