| 摘要 |
<p>PURPOSE:To form a union with a hole having high strength by a forging means without needing a correcting process for the surface and the hole. CONSTITUTION:On a blank 1 providing a spherical head part 3 on the tip part of a cylindrical boss part 2, a bottomed hole 4 arriving at the head part 3 by penetrating into the boss part 2 is provided. While inserting a guide punch 7 into this bottomed hole 4 in the condition of allowing a little shifting to the outer part, two flanks opposed to the head part 3 are worked into the flat surfaces with a trim punch 5 and a trim die 6. Thereafter, to the head part executing the flattening work, a through-hole 4 communicated with the bottomed hole between mutually both worked flat surfaces F, F is bored.</p> |
