| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a sealing material capable of reducing inserting force (joining force) required for inserting a spigot into a socket. <P>SOLUTION: The sealing material 45 includes a valve 47 held between the inner peripheral face of the socket and the outer peripheral face of the spigot, the valve 47 having a circular cross section and consisting of a first valve 48 and a second valve 49 joined to each other. On an outer peripheral portion of the first valve 48, a first seal portion 50 is formed to be pressed against the inner peripheral face of the socket. On an inner peripheral portion of the second valve 49, a second seal portion 51 is formed to be pressed against the outer peripheral face of the spigot. A constricted portion 53 is formed on a joint area between the first valve 48 and the second valve 49. The second valve 49 whose inner diameter is set to be smaller than the outer diameter of the spigot is expandable in a tube-radial direction with the deformation of the constricted portion 53. <P>COPYRIGHT: (C)2010,JPO&INPIT |
