| 摘要 |
<p>A sleeve bearing (10) for use on rotary valve shafts (14) subjected to substantial operating pressures sufficent to extrude PTFE includes a cylindrical nonmetallic bearing jacket (11), preferably composed from PEEK. The bearing jacket has a cylindrical inner cavity (20) defined between opposite annular cavity end lips (22, 24) within which cavity is disposed a cylindrical PTFE liner (12). The annular cavity end lips on the inner surface of the cylindrical nonmetallic bearing jacket extend inwardly to an end lip surface wherein the diameter of said end lip surface is slightly longer than the diameter of the rotary shaft (14) of the control valve. A suitable adhesive is used to bond the liner (12) to the bearing jacket (11). The cavity end lips maintain the liner in position if the adhesive fails. The end lip construction and the close clearances between the end lips and the rotary shaft enable the PTFE liner to carry greater load than in other PTFE bearing constructions before beginning to extrude PTFE. After the PTFE liner begins to extrude PTFE, the close clearances ensure that any overloaded PTFE is maintained within the cavity (20) of the nonmetallic bearing jacket.</p> |
