PEEK BEARING WITH TRAPPED PTFE BEARING LINER

摘要

A sleeve bearing (10) for use on rotary valve shafts (14) subjected tosubstantial operating pressures sufficent to extrude PTFE includes acylindrical nonmetallic bearing jacket (11), preferably composed from PEEK.The bearing jacket has a cylindrical inner cavity (20) defined betweenopposite annular cavity end lips (22, 24) within which cavity is disposed acylindrical PTFE liner (12). The annular cavity end lips on the inner surfaceof the cylindrical nonmetallic bearing jacket extend inwardly to an end lipsurface wherein the diameter of said end lip surface is slightly longer thanthe diameter of the rotary shaft (14) of the control valve. A suitableadhesive is used to bond the liner (12) to the bearing jacket (11). The cavityend lips maintain the liner in position if the adhesive fails. The end lipconstruction and the close clearances between the end lips and the rotaryshaft enable the PTFE liner to carry greater load than in other PTFE bearingconstructions before beginning to extrude PTFE. After the PTFE liner begins toextrude PTFE, the close clearances ensure that any overloaded PTFE ismaintained within the cavity (20) of the nonmetallic bearing jacket.