Self-lubricating composite friction part
Disclosed is a self-lubricating composite friction part ( 1 ) that can be subjected, during operation, to temperatures that are at least equal to 250° C. The part includes, along the friction surface ( 2 ), a single layer of a material consisting of weft and warp yarns made of polytetrafluoroethylene, the material being impregnated with a thermostable resin having a glass transition temperature that is at least equal to 250° C. It is applied to a reinforcing layer ( 3 ).
1. A self-lubricating composite friction part configured for operation temperatures at least equal to 250° C., comprising:
along a friction surface, a friction layer consisting of a single layer of a woven layer fabric formed of a 2×2 twill having pairs of crossing weft and warp strands all consisting of polytetrafluoroethylene, said fabric being impregnated with a heat-stable resin having a glass transition temperature equal to or greater than 250° C.
2. The self-lubricating composite friction part according to claim 1 , wherein the weft strands or the warp strands are formed by short fibres linked to one another.
3. The self-lubricating composite friction part according to claim 1 , wherein the fabric has a thickness of at least 0.10 mm.
4. The self-lubricating composite friction part according to claim 3 , wherein the fabric has a thickness of at least 0.5 mm.
5. The self-lubricating composite friction part according to claim 1 , wherein the weft strands and the warp strands have a count of at least 100 dtex.
6. The self-lubricating composite friction part according to claim 1 , wherein the resin is a thermosetting polyimide.
7. The self-lubricating composite friction part according to claim 1 , further comprising:
a reinforcing layer bordering the fabric opposite the friction surface, said reinforcing layer being impregnated with a same resin as the fabric.
8. The self-lubricating composite friction part according to claim 1 , constituting a bearing.
9. The self-lubricating composite friction part according to claim 1 , constituting a guide rail.
10. A method Moth d for the manufacture of a self-lubricating composite friction part according to claim 1 , comprising:
forming a friction layer consisting of a single layer of fabric formed by the helical winding of a strip of fabric formed by weft strands and warp strands, all constituted by polytetrafluoroethylene, on a mandrel according to a winding angle such that the strip comes edge-to-edge with itself after each turn; and
impregnating the fabric with a heat-stable resin having a glass transition temperature of at least 250° C.
11. The method according to claim 10 , wherein the resin is a thermosetting polyimide.
12. The self-lubricating composite friction part according to claim 2 , the fabric has a thickness of at least 0.10 mm.
13. The self-lubricating composite friction part according to claim 2 , wherein the weft strands and the warp strands have a count of at least 100 dtex.
14. The self-lubricating composite friction part according to claim 3 , wherein the weft strands and the warp strands have a count of at least 100 dtex.
15. The self-lubricating composite friction part according to claim 4 , wherein the weft strands and the warp strands have a count of at least 100 dtex.
16. The part according to claim 1 , wherein the weft and warp strands are each formed by a single filament formed by polytetrafluoroethylene fibres linked to each other by twisting so that the weft and warp strands have irregular surfaces.
17. A self-lubricating composite friction part configured for operation temperatures at least equal to 250° C., comprising:
along a friction surface, a friction layer consisting of a single layer of a woven layer fabric formed of weft and warp strands all consisting of polytetrafluoroethylene, said fabric being impregnated with a heat-stable resin having a glass transition temperature equal to or greater than 250° C.,
wherein the fabric is a weave formed by crossings of pairs of weft strands and of pairs of warp strands, and
wherein the weft and warp strands are each formed by a single filament formed by polytetrafluoroethylene fibres linked to each other by twisting so that the weft and warp strands have irregular surfaces.