HELICALLY TOOTHED DRIVE BELT

Abstract

A helically toothed drive belt made of elastomeric material having internal tensile cords made of aramid fibers, which tensile cords are arranged in the longitudinal direction of the drive belt, wherein the tensile cords each have two strands made of aramid fibers, wherein each of the strands has a twist and the strands are also twisted around one another to form the tensile cord, and the outside diameter of the tensile cord is less than 0.5 mm.

Claims

1-11. (canceled)

12. A helically toothed drive belt comprising elastomeric material having internal tensile cords made of aramid fibers, wherein the tensile cords are arranged in the longitudinal direction of the drive belt, wherein the tensile cords each have two strands made of aramid fibers, wherein each of the two strands has a first twist and the two strands are also twisted around one another with a second twist to form each the tensile cords, and wherein the outside diameter of each of the tensile cords is less than 0.5 mm.

13. The helically toothed drive belt as claimed in claim 12, wherein the outside diameter of each of the tensile cords is between 0.3 mm and 0.4 mm.

14. The helically toothed drive belt as claimed in claim 12, wherein adjacent spacing between the tensile cords, averaged over 10 of the tensile cords adjacently spaced, is in the region of 1.2 times to 1.7 times the outside diameter of each of the tensile cords.

15. The helically toothed drive belt as claimed in claim 12, wherein at least one of the two strands has the first twist which is greater than 300 (in each case based on a meter, in accordance with DIN 60900 Part 4).

16. The helically toothed drive belt as claimed in claim 15, wherein at least one of the two strands has the first twist which is greater than 400 (in each case based on a meter, in accordance with DIN 60900 Part 4).

17. The helically toothed drive belt as claimed in claim 12, wherein both of the strands have the first twist which is greater than 300.

18. The helically toothed drive belt as claimed in claim 17, wherein both of the strands have the first twist which is greater than 400.

19. The helically toothed drive belt as claimed in claim 12, wherein the second twist of the strands around one another is greater than 300.

20. The helically toothed drive belt as claimed in claim 19, wherein the second twist of the strands around one another is greater than 400.

21. The helically toothed drive belt as claimed in claim 12, wherein the two strands are situated adjacent to one another in the drive belt and are twisted around one another alternately with an S twist and a Z twist.

22. The helically toothed drive belt as claimed in claim 12, wherein the two strands are situated adjacent to one another in the drive belt and are twisted around one another alternately in groups with an S twist and a Z twist.

23. The helically toothed drive belt as claimed in claim 12, wherein the elastomeric material comprises polyalphaolefin rubber in a proportion of more than 60 phr (parts per hundred rubber).

24. The helically toothed drive belt as claimed in claim 12, wherein the elastomeric material comprises ethylene-propylene copolymer (EPM) rubber in a proportion of more than 60 phr (parts per hundred rubber).

25. The helically toothed drive belt as claimed in claim 12, wherein the elastomeric material comprises ethylene-propylene-diene (EPDM) rubber in a proportion of more than 60 phr (parts per hundred rubber).

26. The helically toothed drive belt as claimed in claim 12, wherein the elastomeric material comprises partially hydrogenated nitrile rubber (HNBR) in a proportion of more than 60 phr (parts per hundred rubber).

27. The helically toothed drive belt as claimed in claim 12, wherein the elastomeric material comprises fully hydrogenated nitrile rubber (HNBR) in a proportion of more than 60 phr (parts per hundred rubber).

28. The helically toothed drive belt as claimed in claim 12, wherein the elastomeric material is cross-linked using peroxides.

29. The helically toothed drive belt as claimed in claim 12, wherein the elastomeric material comprises ethylene-propylene-diene (EPDM) rubber in a proportion of 75 phr (parts per hundred rubber), wherein the first twist is 450/m, wherein the second twist is 450/m, and wherein the outside diameter of each of the tensile cords is 0.35 mm.

30. A method for producing the tensile cords of the helically toothed drive belt as claimed in claim 12, wherein the tensile cords are each produced in a direct cabling process.

31. A steering gear in an electromechanical steering system of a motor vehicle comprising the helically toothed drive belt as claimed in claim 12.

Description

[0033] The invention will be explained in more detail on the basis of an exemplary embodiment. In the figures:

[0034] FIG. 1 shows a drive belt according to the invention for a steering gear

[0035] FIG. 2 shows a tensile cord of the drive belt shown in FIG. 1 in an enlarged perspective view

[0036] FIG. 1 shows a helically toothed drive belt 1 according to the invention for a steering gear, said belt being composed of elastomeric material, namely 75 phr EPDM. The drive belt is provided with internal tensile cords 2 consisting of aramid fibers arranged in the longitudinal direction of the drive belt. The teeth of the drive belt slope at an angle α to the longitudinal direction 3 of the belt.

[0037] FIG. 2 shows a tensile cord in an enlarged perspective view only as a schematic diagram. It can be seen here that the tensile cords 2 each have two strands 4, 5.

[0038] The strands consist of aramid fibers. Each of the strands has a first twist, which is indicated here only symbolically by the arrows 4a and 5a for the sake of clarity. Arrows at both ends indicate that the direction of twist is not restricted in either case. The strands 4 and 5 as such are also twisted around one another, i.e. entwined, to form the tensile cord 2. The twisting of the strands—the twine—is symbolized by the arrow 6. This twisting 6 of the strands takes place alternately in the form of an S or Z twist with the strands side-by-side. Here, the outside diameter 7 of the tensile cord is 0.35 mm.

[0039] Here, based on the meter, in accordance with DIN 60900 Part 4, the first twist of strand 4 in the direction of twist 4a is 450/m, and the first twist of strand 5 in the direction of twist 5a is likewise 450/m. Moreover, the second twist 6 of the strands around one another is likewise 450/m here.

LIST OF REFERENCE DESIGNATIONS

[0040] 1 Helically toothed drive belt [0041] 2 Tensile cord [0042] 3 Longitudinal direction of the drive belt [0043] 4 Strand [0044] 4a Twist of strand 4 [0045] 5 Strand [0046] 5a Twist of the strand 5 [0047] 6 Twisting of the strands around one another (twine) [0048] 7 Outside diameter of the tensile cord