Toothed Belt
Toothed belt for use in contact with oil and comprising a body and a number of teeth extending from at least one surface of the body; the teeth are coated by a fabric; a resistant layer comprising a plastomer based on fluorine with the addition of elastomeric material, in which the plastomer is present in a larger quantity than the elastomeric material, is applied by adhesion onto the coating fabric. The elastomeric material forming the body of the belt is a copolymer obtained from a dienic monomer and a monomer containing nitrile groups, in which the nitrile groups are between 33% and 49%, preferably 39%, in weight with respect to the copolymer.
1. A method of providing a toothed belt for use in an oil-wet environment, the method comprising:
providing a toothed belt and adapting said toothed belt for use in direct contact with oil or at least partially immersed in oil, said belt comprising a body, a number of teeth extending from at least one first surface of said body,
said teeth being coated by a first fabric, said fabric being externally coated with a resistant layer, said resistant layer comprising
a fluorinated plastomer,
a first elastomeric material, and
a vulcanisation agent,
said fluorinated plastomer present in said resistant layer in a larger quantity than said first elastomeric material,
said body comprising a compound based on a second elastomeric material formed of a copolymer obtained from a dienic monomer and a monomer containing nitrile groups, and
said nitrile groups are in percentage between 33% and 49% in weight with respect to the weight of said copolymer.
2. The method of claim 1 , wherein said nitrile groups are in percentage 39% in weight.
3. The method of claim 1 , wherein said second elastomeric material further comprises hydrogenated butadiene acrylonitrile.
4. The method of claim 3 , wherein said hydrogenated butadiene acrylonitrile is modified with a zinc salt of polymethacrylic acid.
5. The method of claim 1 , wherein said resistant layer comprises said fluorinated plastomer in a quantity in weight of between 101 and 150 parts in weight with respect to said elastomeric material.
6. The method of claim 1 , wherein said fluorinated plastomer is polytetrafluoroethylene.
7. The method of claim 1 , wherein the back of said belt is coated by a second fabric.
8. The method of claim 1 , wherein said second fabric is coated on the outside by a second resistant layer.
9. The method of claim 1 , wherein said second resistant layer is equal to said first resistant layer.
10. The method of claim 1 , wherein said elastomeric material comprises fibres.
11. The method of claim 10 , wherein said fibres are present in a quantity in weight of between 0.5 and 15% with respect to said elastomeric material.
12. The method of claim 1 , wherein the belt comprises resistant inserts chosen from the group consisting of aramidic fibres, PBO and carbon fibres.
13. The method of claim 12 , wherein said resistant inserts have been treated with an RFL comprising an oil-resistant latex.
14. The method of claim 13 , wherein said latex comprises an elastomeric material formed of a copolymer obtained from a dienic monomer and a monomer containing nitrile groups.
15. The method of claim 1 , wherein said toothed belt comprises, between the teeth and said back, sides treated with a polymer resistant to expansion.
16. A method of using a toothed belt, the method comprising:
providing a toothed belt comprising:
a body;
a number of teeth extending from at least one first surface of said body;
said teeth being coated by a first fabric, said fabric being externally coated with a resistant layer, said resistant layer comprising:
a fluorinated plastomer;
said body comprising a compound based on an elastomeric material formed of a copolymer obtained from a dienic monomer and a monomer containing nitrile groups, and
said nitrile groups are in percentage between 33% and 49% in weight with respect to the weight of said copolymer; and
using said toothed belt in direct contact with oil or at least partially immersed in oil.
17. A timing control system for a motor vehicle engine comprising at least one drive pulley, one driven pulley, a toothed belt and means for maintaining said toothed belt in oil-wet condition; said toothed belt comprising a body and a number of teeth extending from at least one surface of said body; said teeth being coated by a fabric, said fabric being externally coated by a resistant layer, in which:
said resistant layer comprises a fluorinated plastomer, a first elastomeric material and a vulcanisation agent;
said fluorinated plastomer is present in said resistant layer in a larger quantity than said first elastomeric material;
said body comprises a compound based on a second elastomeric material formed of a copolymer obtained from a dienic monomer and a monomer containing nitrile groups; and
said nitrile groups are in percentage between 33% and 49% in weight with respect to the weight of said copolymer.
18. The timing control system of claim 17 , wherein said nitrile groups are in percentage 39% in weight.
19. The timing control system of claim 17 , wherein said second elastomeric material comprises hydrogenated butadiene acrylonitrile.
20. The timing control system of claim 19 , wherein said hydrogenated butadiene acrylonitrile is modified with a zinc salt of polymethacrylic acid.
21. The timing control system of claim 17 , wherein said resistant layer comprises said fluorinated plastomer in a quantity in weight of between 101 and 150 parts in weight with respect to said elastomeric material.
22. The timing control system of claim 17 , wherein said fluorinated plastomer is polytetrafluoroethylene.
23. The timing control system of claim 17 , wherein the back of said belt is coated by a second fabric.
24. The timing control system of claim 23 , wherein said second fabric is externally coated by a second resistant layer.
25. The timing control system of claim 24 , wherein said second resistant layer is equal to said first resistant layer.
26. The timing control system of claim 17 , wherein said elastomeric material comprises fibres.
27. The timing control system of claim 26 , wherein said fibres are present in a quantity in weight of between 0.5 and 15% with respect to said elastomeric material.
28. The timing control system of claim 17 , wherein the belt further comprises resistant inserts chosen from the group consisting of aramidic fibres, PBO and carbon fibres.
29. The timing control system of claim 28 , wherein said resistant inserts have been treated with an RFL comprising an oil-resistant latex.
30. The timing control system of claim 29 , wherein said latex comprises an elastomeric material formed of a copolymer obtained from a dienic monomer and a monomer containing nitrile groups.
31. The timing control system of claim 17 , wherein the belt further comprises, between the teeth and said back, sides treated with a polymer resistant to expansion.
32. The timing control system of claim 17 , wherein the system further comprises a sliding block tightener or a sliding block.
33. An oil-resistant toothed belt comprising a body and a number of teeth extending from at least one first surface of said body; said teeth being coated by a first fabric, said fabric being externally coated with a resistant layer, said belt comprising:
said resistant layer comprising a fluorinated plastomer, a first elastomeric material and a vulcanisation agent;
said fluorinated plastomer present in said resistant layer in a larger quantity than said first elastomeric material;
said body comprising a compound based on a second elastomeric material formed of a copolymer obtained from a dienic monomer and a monomer containing nitrile groups; and
said nitrile groups in a percentage between 33% and 49% in weight with respect to the weight of said copolymer.
34. The oil-resistant toothed belt of claim 33 , wherein said belt is suitable to resist for its lifetime when used in direct contact or partially immersed in oil.
35. The oil-resistant toothed belt of claim 33 , wherein said toothed belt is suitable to pass the duration tests which they undergo for use in motor vehicles.
36. The oil-resistant toothed belt of claim 33 , wherein said belt resists at least 80,000,000 cycles in the duration tests which they undergo for use in motor vehicles.
37. The oil-resistant toothed belt of claim 33 , wherein said nitrile groups are in percentage 39% in weight.
38. The oil-resistant toothed belt of claim 33 , wherein said second elastomeric material comprises hydrogenated butadiene acrylonitrile.
39. The oil-resistant toothed belt of claim 38 , wherein said hydrogenated butadiene acrylonitrile is modified with a zinc salt of polymethacrylic acid.
40. The oil-resistant toothed belt of claim 33 , wherein said resistant layer comprises said fluorinated plastomer in a quantity in weight of between 101 and 150 parts in weight with respect to said elastomeric material.
41. The oil-resistant toothed belt of claim 33 , wherein said fluorinated plastomer is polytetrafluoroethylene.
42. The oil-resistant toothed belt of claim 33 , wherein the back of said belt is coated by a second fabric.
43. The oil-resistant toothed belt of claim 33 , wherein said second fabric is coated on the outside by a second resistant layer.
44. The oil-resistant toothed belt of claim 33 , wherein said second resistant layer is equal to said first resistant layer.
45. The oil-resistant toothed belt of claim 33 , wherein said elastomeric material comprises fibres.
46. The oil-resistant toothed belt of claim 45 , wherein said fibres are present in a quantity in weight of between 0.5 and 15% with respect to said elastomeric material.
47. The oil-resistant toothed belt of claim 33 , wherein the belt further comprises resistant inserts chosen from the group consisting of aramidic fibres, PBO and carbon fibres.
48. The oil-resistant toothed belt of claim 47 , wherein said resistant inserts have been treated with an RFL comprising an oil-resistant latex.
49. The oil-resistant toothed belt of claim 48 , wherein said latex comprises an elastomeric material formed of a copolymer obtained from a dienic monomer and a monomer containing nitrile groups.
50. The oil-resistant toothed belt of claim 33 , wherein the belt further comprises between the teeth and said back sides treated with a polymer resistant to expansion.