One-piece composite lip seal

• US 5,163,692 A
• Filed: 07/15/1991
• Issued: 11/17/1992
• Est. Priority Date: 07/24/1989
• Status: Expired due to Term

• Current Assignee: Saint-Gobain Performance Plastics Corporation (Compagnie De Saint-Gobain)
• Original Assignee: Furon Company (Compagnie De Saint-Gobain)
• Inventors: Schofield, Alan P., Krzemien, Mark A.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): CUMMINGS, SCOTT
• Application Number:
  US07/730,581
• Time in Patent Office: 491 Days
• Field of Search: 277/152, 277/153, 277/164, 277/188 R, 277/188 A, 277/205, 277/227
• US Class Current: 277/436
• CPC Class Codes: F05C 2225/04 PTFE [PolyTetraFluorEthylene]
• CPC Class Codes: F16J 15/3236 with at least one lip for each surface, e.g. U-cup packings

Abstract

A composite one-piece dynamic lip seal forms a dynamic ring seal between static and dynamic surfaces in a variety of applications requiring fluid sealing. The lip seal body is generally U-shaped in cross section and is principally made from a soft elastomeric material. The seal has ID and OD legs on opposite sides of a cavity in its high pressure end, forming ID and OD lips of the seal, either of which can be the dynamic leg of the seal depending upon the application. A U-shaped energizer spring is integrally bonded to the elastomer and is aligned with the U-shaped cross section of the seal so that ID and OD legs of the spring apply radial spring loading to the ID and OD legs of the seal. A reinforcing ring integrally bonded to the elastomeric body of the seal forms an exterior contact surface and an elastomeric reinforcement along a substantial length of the dynamic leg of the seal, from a low pressure end of the seal to an end spaced from the high pressure end of the seal. The reinforcing ring bonds to the elastomeric body, which then forms the contact surface on the dynamic leg of the seal continuously from the reinforcing ring to the high pressure end of the seal. The reinforcing ring is made from a fluorocarbon polymer such as PTFE with a low coefficient of friction and a high compressive modulus.

Claims

1. A composite one-piece lip seal for forming a dynamic ring seal between static and dynamic surfaces of relatively movable parts, the lip seal body being made of an elastomeric material, the seal having a relatively narrower radial low pressure end and a relatively wider radial high pressure end and a dynamic leg extending between the low pressure and high pressure ends to form the seal'"'"'s contact surface to said dynamic surface during use, the seal including spring means for energizing the dynamic leg of the seal in its sealing contact, the seal further including a reinforcing ring having an L-shaped cross-section integrally molded and bonded to the elastomeric body of the seal, the long leg of the L being relatively thin and of substantially uniform width and forming an exterior surface and an elastomer reinforcement means along at least one-half the length of the dynamic leg of the seal, the long leg of the L extending from the low pressure end of the seal to a location spaced less than about one-half the distance from the seal'"'"'s high-pressure end with the elastomeric body which extends beyond the end of the long leg of the L forming the contact surface on the dynamic leg of the seal continuously from the end of the reinforcing ring to the high pressure end of the seal, the reinforcing ring including a radial leg which extends inwardly a short distance along the low pressure end of the seal, the outer surface of the radial leg being flush with the surface of the low pressure end of the seal, said reinforcing ring being made from a fluorocarbon polymer having a lower coefficient of friction and a higher compressive modulus than the elastomer.

2. Apparatus according to claim 1 in which the spring means comprises a finger spring molded and bonded to the elastomer, the finger spring having circumferentially spaced apart gaps filled with the elastomer to support the finger spring during deformation.

3. Apparatus according to claim 1 in which the spring means is metal.

4. Apparatus according to claim 1 wherein the reinforcing ring has a relatively smooth shape comprising smooth curves and transition angles where it is bonded to the elastomeric body of the seal.

5. Apparatus according to claim 1 wherein the long leg of the L extends along the exterior portion of the dynamic leg of the seal continuously from its top at the seal'"'"'s low pressure end to its bottom at a location about 75% to about 95% of the distance from the seal'"'"'s low pressure end.

28. Apparatus according to claim 1 in which the ring-shaped spring is metal.

6. A composite one-piece dynamic lip seal for forming a dynamic ring seal between static and dynamic surfaces, the lip seal body being generally U-shaped in cross section and being principally made from an elastomeric material, the seal having ID and OD legs on opposite sides of a cavity in its high pressure end, forming ID and OD legs of the seal, either of which can be the dynamic leg of the seal during use, the seal including an energizer spring integrally molded and bonded to the elastomer so that the spring energizes the dynamic leg of the seal;

and a reinforcing ring having an L-shaped cross-section integrally molded and bonded to the elastomer body of the seal, the long leg of the L being relatively thin and of substantially uniform width, extending along an exterior portion of the dynamic leg of the seal from a low pressure end of the seal to its bottom at a location spaced less than about one-half the distance from the seal'"'"'s high pressure end, the long leg of the L thereby forming an exterior contact surface an a means of reinforcement of the elastomer along at least one-half the length of the dynamic leg of the seal, with the elastomer extending beyond the long leg of the L forming the contact surface on the dynamic leg of the seal continuously from the end of the reinforcing ring to the high pressure end of the seal, the reinforcing ring including a radial leg which extends inwardly a short distance along the low pressure end of the seal, the outer surface of the radial leg being flush with the surface of the low pressure end of the seal, said reinforcing ring being made from a fluorocarbon polymer having a substantially lower coefficient of friction and a substantially higher compressive modulus than the elastomeric body of the seal.

7. Apparatus according to claim 6 in which the reinforcing ring has a coefficient of friction less than about 0.1 and a compressive modulus greater than about 57,000 psi.

8. Apparatus according to claim 7 in which the reinforcing ring is made from a material selected from the group consisting of PTFE, PFA, or FEP, without fillers.

9. Apparatus according to claim 7 in which the reinforcing ring is made from a material selected from the group consisting of PTFE, PFA or FEP, with fillers.

10. Apparatus according to claim 6 in which the seal is carried by a piston and has its OD leg sealed against a cylinder bore.

11. Apparatus according to claim 6 in which the ID leg of the seal is sealed around a piston rod.

12. Apparatus according to claim 6 in which the elastomer is bonded to the reinforcing ring by an etching and adhesive bonding process.

13. Apparatus according to claim 6 in which the elastomer is molded and bonded to the spring and the reinforcing ring in a molding process under applied heat and pressure for flowing the elastomer into contact with the spring and reinforcing ring.

14. Apparatus according to claim 6 in which the energizer spring is metal.

15. Apparatus according to claim 6 wherein the reinforcing ring has a relatively smooth shape comprising smooth curves and transition angles where it is bonded to the elastomeric body of the seal.

16. Apparatus according to claim 6 wherein the long leg of the L extends along the exterior portion of the dynamic leg of the seal continuously from its top at the seal'"'"'s low pressure end to its bottom at a location about 75% to about 95% of the distance from the seal'"'"'s low pressure end.

17. A composite one-piece dynamic lip seal for use between adjacent dynamic and static surfaces of relatively movable parts, the composite seal being generally of a ring shape and having a seal wall which in cross section is defined by converging inside and outside legs, a relatively narrower low pressure end wall toward which the inside and outside legs of the seal converge, and a cavity in a relatively wider, high-pressure end of the seal forming a pair of seal lips on ID and OD sides of the seal wall, thereby forming a generally U-shaped cross section, the seal being adapted so that either the ID or OD leg of the seal acts as the dynamic leg of the seal during use, the body of the seal wall being comprised predominantly of an elastomeric material;

the seal wall further including a ring-shaped spring of generally U-shaped cross section having ID and OD legs, the spring being integrally molded and bonded to the elastomeric body of the seal with the legs of the spring aligned generally with the U-shaped cross section of the seal wall so that the ID and OD legs of the spring energize the ID and OD lips of the seal; and

a reinforcing ring having an L-shaped cross-section integrally molded and bonded to the elastomeric body of the seal, the long leg of the L being relatively thin and of substantially uniform width, and extending along an exterior portion of the dynamic leg of the seal continuously from the seal'"'"'s low pressure end to its bottom at a location spaced less than about one-half the distance from the seal'"'"'s high pressure end so that an exterior portion of said elastomeric body forms the dynamic leg of the seal continuously from its top at the bottom of the long leg of the L to the seal'"'"'s high-pressure end, the short leg of the L being a radial leg which extends inwardly a short distance along the low pressure end of the seal, the outer surface of the radial leg being flush with the surface of the low pressure end of the seal, said reinforcing ring being made of a fluorocarbon polymer having a substantially lower coefficient of friction and a substantially higher compressive modulus than the elastomeric body of the seal.

18. Apparatus according to claim 17 in which the reinforcing ring is on the ID leg of the seal.

19. Apparatus according to claim 17 in which the reinforcing ring is on the OD leg of the seal.

20. Apparatus according to claim 17 in which the spring comprises a finger spring.

21. Apparatus according to claim 17 in which the coefficient of friction of the reinforcing ring is less than about 0.1.

22. Apparatus according to claim 17 in which the compressive modulus of the reinforcing ring is greater than about 57,000 psi.

23. Apparatus according to claim 17 in which the reinforcing ring has a Shore D hardness of greater than about 50.

24. Apparatus according to claim 17 in which the reinforcing ring predominantly comprises PTFE.

25. Apparatus according to claim 17 in which the reinforcing ring extends along a substantial length of the dynamic leg of the seal.

26. Apparatus according to claim 17 in which the OD leg of the seal is on a piston sealed in a cylinder bore.

27. Apparatus according to claim 17 in which the ID leg of the seal is sealed around a piston rod.

29. Apparatus according to claim 17 wherein the reinforcing ring has a relatively smooth shape comprising smooth curves and transition angles where it is bonded to the elastomeric body of the seal.

30. Apparatus according to claim 17 wherein the long leg of the L extends along the exterior portion of the dynamic leg of the seal continuously from its top at the seal'"'"'s low pressure end to its bottom at a location about 75% to about 95% of the distance from the seal'"'"'s low pressure end.