Peek bearing with trapped PTFE bearing liner

• US 5,568,983 A
• Filed: 06/21/1994
• Issued: 10/29/1996
• Est. Priority Date: 06/21/1994
• Status: Expired due to Term

• Current Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Original Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Inventors: Wilson, Robert T.
• Primary Examiner(s): Footland, Lenard A.
• Application Number:
  US08/262,940
• Time in Patent Office: 861 Days
• Field of Search: 384/296, 384/300, 384/297, 384/295, 384/909
• US Class Current: 384/295
• CPC Class Codes: F16C 2208/32 Polytetrafluorethylene [PTFE] F16C2208/58 takes precedence
• CPC Class Codes: F16C 2208/36 Polyarylene ether ketones [PAEK], e.g. PEK, PEEK F16C2208/58 takes precedence
• CPC Class Codes: F16C 2240/40 Linear dimensions, e.g. length, radius, thickness, gap
• CPC Class Codes: F16C 2240/60 Thickness, e.g. thickness of coatings
• CPC Class Codes: F16C 2240/70 Diameters; Radii
• CPC Class Codes: F16C 33/20 Sliding surface consisting mainly of plastics F16C33/22 - F16C33/28 take precedence

Abstract

A sleeve bearing for use on rotary valve shafts subjected to substantial operating pressures sufficient to extrude PTFE includes a cylindrical nonmetallic bearing jacket, preferably composed from PEEK. The bearing jacket has a cylindrical inner cavity defined between opposite annular cavity end lips within which cavity is disposed a cylindrical PTFE liner. 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 larger than the diameter of the rotary shaft of the control valve. A suitable adhesive is used to bond the liner to the bearing jacket. 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 of the nonmetallic bearing jacket.

Claims

1. A bearing for use on a fluid control valve having a rotary shaft subject to operating load pressures sufficient to overload and extrude PTFE, said bearing comprising:

a cylindrical PTFE liner adapted to surround the rotary shaft to enable the shaft to rotate with respect to the liner during use of the fluid control valve with the cylindrical PTFE liner bearing the operating load pressures which may be sufficient to extrude PTFE;

a cylindrical non-metallic bearing jacket having an interior surface and including a cylindrical inner cavity defined between opposite annular cavity end lips for retaining said liner, said cavity end lips extending inwardly from the interior surface to an end lip surface wherein the diameter of said end lip surface is slightly larger than the diameter of said rotary shaft and wherein the clearance between said end lip surface and the rotary shaft is zero on the load side of the bearing; and

said cylindrical PTFE liner having a thickness sufficient to nest said liner in said cavity between said cavity end lips and with the inner diameter of said liner conforming to the diameter of said end lips surface so that with said rotary control valve under substantial operating pressure sufficient to extrude PTFE, any overloaded PTFE is maintained within said cavity and between said cavity end lips of said bearing jacket.

2. The bearing set forth in claim 1, wherein the cylindrical bearing jacket is formed from a fluorocarbon.

3. The bearing set forth in claim 1, wherein the cylindrical bearing jacket is formed from PEEK.

4. A bearing for use on a fluid control valve having a rotary shaft subject to operating load pressures sufficient to overload and extrude PTFE, said bearing comprising:

a cylindrical PTFE liner adapted to surround the rotary shaft to enable the shaft to rotate with respect to the liner during use of the fluid control valve with the cylindrical PTFE liner bearing the operating load pressures which may be sufficient to extrude PTFE;

a cylindrical non-metallic bearing jacket having an interior surface and including a cylindrical inner cavity defined between opposite annular cavity end lips for retaining said liner, said cavity end lips extending inwardly from the interior surface to an end lip surface wherein the diameter of said end lip surface is slightly larger than the diameter of said rotary shaft and wherein the clearance between said end lip surface and the rotary shaft is less than or equal to 0.0075 inches; and

said cylindrical PTFE liner having a thickness sufficient to nest said liner in said cavity between said cavity end lips and with the inner diameter of said liner conforming to the diameter of said end lips surface so that with said rotary control valve under substantial operating pressure sufficient to extrude PTFE, any overloaded PTFE is maintained within said cavity and between said cavity end lips of said bearing jacket.

5. A bearing for use on a movable operating member subject to operating load pressures sufficient to overload and extrude PTFE, said bearing comprising:

a cylindrical PTFE liner adapted to surround the movable operating member to enable the movable operating member to move with respect to the liner with the cylindrical PTFE liner bearing the operating load pressures which may be sufficient to extrude PTFE;

a cylindrical non-metallic bearing jacket having an interior surface and including a cylindrical inner cavity defined between opposite annular cavity end lips for retaining said liner, said cavity end lips extending inwardly from the interior surface to an end lip surface wherein the diameter of said end lip surface is slightly larger than the diameter of said movable operating member and wherein the clearance between said end lip surface and the operating member is zero on the load side of the bearing; and

said cylindrical PTFE liner having a thickness sufficient to nest said liner in said cavity between said cavity end lips and with the inner diameter of said liner conforming to the diameter of said end lips surface so that with said movable operating member under substantial operating pressure sufficient to extrude PTFE, any overloaded PTFE is maintained within said cavity and between said cavity end lips of said bearing jacket.

6. A bearing for use on a fluid control valve having an operating member subject to operating load pressures sufficient to overload and extrude PTFE, said bearing comprising:

a cylindrical PTFE liner adapted to surround the operating member to enable the operating member to move with respect to the liner during use of the fluid control valve with the cylindrical PTFE liner bearing the operating load pressures which may be sufficient to extrude PTFE;

a cylindrical non-metallic bearing jacket having an interior surface and including a cylindrical inner cavity defined between opposite annular cavity end lips for retaining said liner, said cavity end lips extending inwardly from the interior surface to an end lip surface wherein the diameter of said end lip surface is slightly larger than the diameter of said operating member and wherein the clearance between said end lip surface and the operating member is zero on the load side of the bearing; and

said cylindrical PTFE liner having a thickness sufficient to nest said liner in said cavity between said cavity end lips and with the inner diameter of said liner conforming to the diameter of said end lips surface so that with said fluid control valve under substantial operating pressure sufficient to extrude PTFE, any overloaded PTFE is maintained within said cavity and between said cavity end lips of said bearing jacket.