| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that a prior technique which applies discontinuity between a shoulder part and a seal part complicates a shape and sacrifices processing efficiency. <P>SOLUTION: In a screw joint, a nose part outer circumferential surface 31 of a pin 3 has a single tapered shape, a seal surface 21 of a box 1 has an outwardly convex curved shape, and a sealing point x<SB POS="POST">p</SB>defined by a formula is 0.2 inch or more, wherein p: a contact surface pressure, x: a tube axis direction distance from a pin tip end, x1, x2: a lower limit and upper limit in an x variance range corresponding to a seal part. <P>COPYRIGHT: (C)2013,JPO&INPIT |
